Ace844 Posted July 8, 2006 Posted July 8, 2006 Acanthosis nigricans Causes, incidence, and risk factors Acanthosis nigricans can affect otherwise healthy people, or it can be associated with medical problems. Some cases are genetically inherited. It is most common among people of African descent. Obesity can lead to acanthosis nigricans, as can many endocrine disorders. It is frequently found in people with diabetes. Some drugs, particularly hormones such as human growth hormone or oral contraceptives ("the pill"), can also cause acanthosis nigricans. People with cancers of the gastrointestinal or genitourinary tracts or with lymphoma can also develop severe cases of acanthosis nigricans. Acanthosis nigricans: Acanthosis nigricans is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Acanthosis nigricans, or a subtype of Acanthosis nigricans, affects less than 200,000 people in the US population. Ophanet, who are a consortium of European partners, currently defines a condition rare when if affetcs 1 person per 2,000. They list Acanthosis nigricans as a "rare disease". More information about Acanthosis nigricans is available from Orphanet Background: Although Addison may have seen a case of acanthosis nigricans (AN) before 1885 and misdiagnosed it as Addison disease, the first documented case of AN was in 1889. By 1909, this dermatosis had been described in approximately 50 patients and was suspected to be associated with internal malignancy. In 1976, Kahn et al published their landmark study in which the association between AN and insulin resistance was first described. Pathophysiology: AN most likely is caused by factors that stimulate epidermal keratinocyte and dermal fibroblast proliferation. In the benign form of AN, the factor is probably insulin or an insulinlike growth factor that incites the epidermal cell propagation. In malignant AN, the stimulating factor is hypothesized to be a substance secreted either by the tumor or in response to the tumor. Transforming growth factor-alpha is structurally similar to epidermal growth factor and is a likely candidate. Exogenous medications also have been implicated as etiologic factors. Frequency: In the US: The exact incidence of AN is unknown. In an unselected population of 1412 children, the changes of AN were present in 7.1%. Obesity is closely associated with AN, and more than one half of the adults who weigh greater than 200% of their ideal body weight have lesions consistent with AN. The malignant form of AN is far less common, and, in one study, only 2 of 12,000 patients with cancer had signs of AN. Mortality/Morbidity: AN is divided into 2 broad categories, benign and malignant. Patients with the benign form of AN experience very few, if any, complications of their skin lesions. However, many of these patients have an underlying insulin-resistant state that is the cause of their AN. The severity of the insulin resistance is highly variable and ranges from an incidental finding on routine blood studies to overt diabetes mellitus. The severity of skin findings may parallel the degree of insulin resistance, and a partial resolution may occur with treatment of the insulin-resistant state. Insulin resistance is the most common association of AN in the younger age population. Malignant AN is associated with significant complications because the underlying malignancy is often an aggressive tumor. Average survival time of patients with signs of malignant AN is 2 years, although cases in which patients have survived for up to 12 years have been reported. In older patients with new onset AN, most have an associated internal malignancy. Race: AN is much more common in people with darker skin pigmentation. The prevalence in whites is less than 1%. In Hispanics, the prevalence is 5.5%, and, in African Americans, the prevalence is the highest at 13.3%. The incidence is also increased in the Native American population. In contrast to the benign form, there is no racial propensity with malignant AN. Sex: The incidence of AN is equal for men and women. Age: Lesions of benign AN may be present at any age, including at birth, although it is found more commonly in the adult population. Malignant AN occurs more frequently in elderly persons; however, cases have been reported in children with Wilms tumor. CLINICAL Section 3 of 11 Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography History: Patients usually present with an asymptomatic area of darkening and thickening of the skin. Pruritus occasionally may be present. Lesions begin as hyperpigmented macules and patches and progress to palpable plaques. In approximately one third of cases of malignant AN, patients present with skin changes before any signs of cancer. In another one third of cases, the lesions of AN arise simultaneously with the neoplasm. In the remaining one third of cases, the skin findings manifest sometime after the diagnosis of cancer. Physical: AN is characterized by symmetrical, hyperpigmented, velvety plaques that may occur in almost any location but most commonly appear on the intertriginous areas of the axilla (see Image 1), groin, and posterior neck. The posterior neck is the most commonly affected site in children. The vulva is the most commonly affected site in females who are hyperandrogenic and obese. Acrochordons (skin tags) often are found in and around the affected areas. Occasionally, lesions of AN may be present on the mucous membranes of the oral cavity, nasal and laryngeal mucosa, and esophagus. The areola of the nipple also may be affected. Eye involvement, including papillomatous lesions on the eyelids and conjunctiva, may occur. Nail changes, such as leukonychia and hyperkeratosis, have been reported. The lesions of malignant AN are clinically indistinguishable from the benign forms. Causes: The definitive cause for AN has not yet been ascertained, although several possibilities have been suggested. Eight types of AN have been described. Obesity-associated AN, once labeled pseudo-AN, is the most common type of AN. Lesions may appear at any age but are more common in adulthood. The dermatosis is weight dependent, and lesions may completely regress with weight reduction. Insulin resistance is often present in these patients; however, it is not universal. Syndromic AN is the name given to AN that is associated with a syndrome. In addition to the widely recognized association of AN with insulin resistance, AN has been associated with numerous syndromes (see Image 2). The type A syndrome and type B syndrome are special examples. The type A syndrome also is termed the hyperandrogenemia, insulin resistance, and AN syndrome (HAIR-AN syndrome). This syndrome is often familial, affecting primarily young women (especially black women). It is associated with polycystic ovaries or signs of virilization (eg, hirsutism, clitoral hypertrophy). High plasma testosterone levels are common. The lesions of AN may arise during infancy and progress rapidly during puberty. The type B syndrome generally occurs in women who have uncontrolled diabetes mellitus, ovarian hyperandrogenism, or an autoimmune disease such as systemic lupus erythematosus, scleroderma, Sjögren syndrome, or Hashimoto thyroiditis. Circulating antibodies to the insulin receptor may be present. In these patients, the lesions of AN are of varying severity. Acral AN (acral acanthotic anomaly) occurs in patients who are in otherwise good health. Acral AN is most common in dark-skinned individuals, especially those of African American descent. The hyperkeratotic velvety lesions are most prominent over the dorsal aspects of the hands and feet. Unilateral AN, sometimes referred to as nevoid AN, is believed to be inherited as an autosomal dominant trait. Lesions are unilateral in distribution and may become evident during infancy, childhood, or adulthood. Lesions tend to enlarge gradually before stabilizing or regressing. Familial AN is a rare genodermatosis that seems to be transmitted in an autosomal dominant fashion with variable phenotypic penetrance. The lesions typically begin during early childhood but may manifest at any age. The condition often progresses until puberty, at which time it stabilizes or regresses. Drug-induced AN, although uncommon, may be induced by several medications, including nicotinic acid, insulin, pituitary extract, systemic corticosteroids, and diethylstilbestrol. Rarely, triazinate, oral contraceptives, fusidic acid, and methyltestosterone also have been associated with AN. The lesions of AN may regress following the discontinuation of the offending medication. Malignant AN, which is associated with internal malignancy, is the most worrisome of the variants of AN because the underlying neoplasm is often an aggressive cancer. AN has been reported with many kinds of cancer (see Image 3), but, by far, the most common underlying malignancy is an adenocarcinoma of gastrointestinal origin, usually a gastric adenocarcinoma. In an early study of 191 patients with malignant AN, 92% had an underlying abdominal cancer, of which 69% were gastric. Another study reported 94 cases of malignant AN, of which 61% were secondary to a gastric neoplasm. In 25-50% of cases of malignant AN, the oral cavity is involved. The tongue and the lips most commonly are affected with elongation of the filiform papillae on the dorsal and lateral surfaces of the tongue and multiple papillary lesions appearing on the commissures of the lips. Oral lesions of AN seldom are pigmented. Malignant AN is clinically indistinguishable from the benign forms; however, one must be more suspicious if the lesions arise rapidly, are more extensive, are symptomatic, or are in atypical locations. Regression of AN has been seen with treatment of the underlying malignancy, and reappearance may suggest recurrence or metastasis of the primary tumor. Mixed-type AN refers to those situations in which a patient with one of the above types of AN develops new lesions of a different etiology. An example of this would be an overweight patient with obesity-associated AN who subsequently develops malignant AN. DIFFERENTIALS Section 4 of 11 Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Addison Disease Hemochromatosis Pellagra Other Problems to be Considered: Becker nevus Confluent and reticulated papillomatosis of Gougerot and Carteaud syndrome Dowling-Degos disease Hypertrophic seborrheic keratosis Ichthyosis hystrix Linear epidermal nevus Parapsoriasis en plaque Pemphigus vegetans Quick Find Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Click for related images. Related Articles Addison Disease Hemochromatosis Pellagra Continuing Education CME available for this topic. Click here to take this CME. Patient Education Click here for patient education. WORKUP Section 5 of 11 Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Lab Studies: For patients with adult onset of AN, perform a basic workup for underlying malignancy. Screen for diabetes with a glycosylated hemoglobin level or glucose tolerance test. Screen for insulin resistance; a good screening test for insulin resistance is a plasma insulin level, which will be high in those with insulin resistance. This is the most sensitive test to detect a metabolic abnormality of this kind because many younger patients do not yet have overt diabetes mellitus and an abnormal glycosylated hemoglobin level, but they do have a high plasma insulin level. Histologic Findings: Histologic examination reveals hyperkeratosis, papillomatosis, and slight irregular acanthosis with minimal or no hyperpigmentation. The dermal papillae project upward as fingerlike projections, with occasional thinning of the adjacent epidermis. Pseudohorn cysts may be present. Clinical dyschromia is secondary to the hyperkeratosis and not to increased melanocytes or increased melanin deposition. TREATMENT Section 6 of 11 Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Medical Care: The goal of therapy is to correct the underlying disease process. Treatment of the lesions of AN is for cosmetic reasons only. Correction of hyperinsulinemia often reduces the burden of hyperkeratotic lesions. Likewise, weight reduction in obesity-associated AN may result in resolution of the dermatosis. No treatment of choice exists for AN. Topical medications that have been effective in some cases include keratolytics (eg, topical tretinoin). Oral agents that have shown some benefit include etretinate, isotretinoin, metformin, and dietary fish oils. Cyproheptadine has been used in cases of malignant AN because it may inhibit the release of tumor products. Dermabrasion and long-pulsed alexandrite laser therapy may also be used to reduce the bulk of the lesion. The goal of pharmacotherapy is to improve cosmetic appearance. Drug Category: Topical retinoids -- These agents promote shedding of hyperkeratotic skin. They are modifiers of keratinocyte adhesion, differentiation, and proliferation.Drug Name Tretinoin (Avita, Retin-A) -- Promotes detachment of cornified cells and enhances shedding of corneocytes. Inhibits microcomedo formation and eliminates lesions that are present. Makes keratinocytes in sebaceous follicles less adherent and easier to remove. Available as 0.025%, 0.05%, and 0.1% creams. Available also as 0.01% and 0.025% gels. Adult Dose Begin with lowest tretinoin formulation and increase as tolerated; apply hs or qod; lower frequency of application if irritation develops Pediatric Dose <12 years: Not established >12 years: Administer as in adults Contraindications Documented hypersensitivity Interactions Toxicity increases with coadministration of benzoyl peroxide, salicylic acid, and resorcinol; avoid topical sulfur, resorcinol, salicylic acid, other keratolytics, abrasives, astringents, spices, and lime Pregnancy C - Safety for use during pregnancy has not been established. Precautions Photosensitivity may occur with excessive sunlight exposure; caution in eczema; avoid mucous membranes, mouth, and angles of nose FOLLOW-UP Section 8 of 11 Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Complications: Complications vary depending on the etiology of AN. Appearance of AN during childhood usually is associated with a benign condition, and there are no important sequelae. Adult onset AN is more worrisome, and an underlying malignancy must be ruled out. However, most cases of adult onset AN are benign and often are associated with insulin resistance. Prognosis: The prognosis for patients with malignant AN is often poor. The associated malignancy frequently is advanced, and the average survival of these patients is approximately 2 years. Patient Education: Patients should be instructed that AN is not a skin disease per se, but rather a sign of an underlying problem. If a patient does have AN on the basis of insulin resistance, which is the most common reason, the treatment of the metabolic abnormality may lead to improvement of the appearance of the skin. Dietary changes and weight loss may cause the AN to regress almost completely. MISCELLANEOUS Section 9 of 11 Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Pictures Bibliography Medical/Legal Pitfalls: The only significant medical/legal pitfall in the management of AN is the failure to promptly diagnose an internal malignancy associated with AN. One should be aware of this possibility in middle-aged or older patients with a recent onset of AN that was extensive, symptomatic, or located in unusual sites. Arslanian SA: Type 2 diabetes mellitus in children: pathophysiology and risk factors. J Pediatr Endocrinol Metab 2000; 13 Suppl 6: 1385-94[Medline]. Burke JP, Duggirala R, Hale DE, et al: Genetic basis of acanthosis nigricans in Mexican Americans and its association with phenotypes related to type 2 diabetes. Hum Genet 2000 May; 106(5): 467-72[Medline]. Darmstadt GL, Yokel BK, Horn TD: Treatment of acanthosis nigricans with tretinoin. Arch Dermatol 1991 Aug; 127(8): 1139-40[Medline]. Fagot-Campagna A, Pettitt DJ, Engelgau MM, et al: Type 2 diabetes among North American children and adolescents: an epidemiologic review and a public health perspective. J Pediatr 2000 May; 136(5): 664-72[Medline]. Greenwood R, Tring FC: Treatment of malignant acanthosis nigricans with cyproheptadine. Br J Dermatol 1982 Jun; 106(6): 697-8[Medline]. Hud JA Jr, Cohen JB, Wagner JM, Cruz PD Jr: Prevalence and significance of acanthosis nigricans in an adult obese population. Arch Dermatol 1992 Jul; 128(7): 941-4[Medline]. Kihiczak NI, Leevy CB, Krysicki MM, et al: Cutaneous signs of selected systemic diseases. J Med 1999; 30(1-2): 3-12[Medline]. Mork NJ, Rajka G, Halse J: Treatment of acanthosis nigricans with etretinate (Tigason) in a patient with Lawrence-Seip syndrome (generalized lipodystrophy). Acta Derm Venereol 1986; 66(2): 173-4[Medline]. Mukhtar Q, Cleverley G, Voorhees RE, McGrath JW: Prevalence of acanthosis nigricans and its association with hyperinsulinemia in New Mexico adolescents. J Adolesc Health 2001 May; 28(5): 372-6[Medline]. Musso C, Cochran E, Moran SA, et al: Clinical course of genetic diseases of the insulin receptor (type A and Rabson-Mendenhall syndromes): a 30-year prospective. Medicine 2004; 83: 209-222[Medline]. Nguyen TT, Keil MF, Russell DL, et al: Relation of acanthosis nigricans to hyperinsulinemia and insulin sensitivity in overweight African American and white children. J Pediatr 2001 Apr; 138(4): 474-80[Medline]. Rosenbach A, Ram R: Treatment of acanthosis nigricans of the axillae using a long-pulsed (5-msec) alexandrite laser. Dermatologic Surgery 2004; 30: 1158-1160[Medline]. Sabir S, James WD, Schuchter LM: Cutaneous manifestations of cancer. Curr Opin Oncol 1999 Mar; 11(2): 139-44[Medline]. Sherertz EF: Improved acanthosis nigricans with lipodystrophic diabetes during dietary fish oil supplementation. Arch Dermatol 1988 Jul; 124(7): 1094-6[Medline]. Stuart CA, Smith MM, Gilkison CR, et al: Acanthosis Nigricans among Native Americans: an indicator of high diabetes risk. Am J Public Health 1994 Nov; 84(11): 1839-42[Medline]. Torley D, Bellus GA, Munro CS: Genes, growth factors and acanthosis nigricans. British Journal of Dermatology 2002; 147: 1096-1101[Medline]. Walling HW, Messingham M, Myers LM, et al: Improvement of acanthosis nigricans on isotretinoin and metformin. Journal of Drugs in Dermatology 2003; 2: 677-681[Medline]. Yeh JS, Munn SE, Plunkett TA, et al: Coexistence of acanthosis nigricans and the sign of Leser-Trelat in a patient with gastric adenocarcinoma: a case report and literature review. J Am Acad Dermatol 2000 Feb; 42(2 Pt 2): 357-62[Medline]. HyperviscositySyndrome?[/font:1d696383fd]
medic001918 Posted July 8, 2006 Posted July 8, 2006 For the extra credit...anyone notice similarities? Nice work PRPG, the similarities of the two are what I was going for by putting them together in the same thread. Strong work my friend. Shane NRMET-P
AZCEP Posted July 8, 2006 Posted July 8, 2006 Background: Hyperviscosity syndrome (HVS) refers to the clinical sequelae of increased blood viscosity. Increased serum viscosity usually results from increased circulating serum immunoglobulins and can be seen in Waldenström macroglobulinemia and multiple myeloma. It can also result from increased cellular blood components (typically white or red blood cells) in hyperproliferative states such as the leukemias, polycythemia, and the myeloproliferative disorders. The complications most commonly associated with this syndrome include mucous membrane bleeding, neurologic and pulmonary symptoms, and the associated retinopathy. Pathophysiology: Viscosity is a property of liquid and is described as the resistance that a liquid exhibits to the flow of one layer over another. As serum proteins or cellular components increase, the blood becomes more viscous, leading to the clinical symptoms of hyperviscosity syndrome secondary to the vascular stasis and resultant hypoperfusion. The normal relative serum viscosity ranges from 1.4-1.8 units (reported as Centipoises). Symptoms usually are not seen at viscosities of less than 4 units, and the hyperviscosity syndrome typically requires a viscosity greater than 5 units. Hyperviscosity syndrome is associated most commonly with plasma cell dyscrasias (the paraproteinemias) and is due to the large size of the excess immunoglobulin M (IgM) paraproteins in these disorders. Waldenström macroglobulinemia is the most common cause and accounts for about 85% of cases of HVS. Less frequently, the disease can occur in multiple myeloma (especially with myeloma proteins of the IgA and IgG3 types) and connective tissue diseases. Hyperviscosity syndrome can also be caused by the bone marrow hyperproliferative states: the leukemias, polycythemia, essential thrombocytosis, and the myelodysplastic disorders, which also increase serum viscosity. Confusion and mental status changes result from the increased viscosity of the blood and decreased cerebral blood flow. This sludging leads to segmental dilatation of retinal veins and retinal hemorrhages. Mucosal bleeding may occur from prolonged bleeding time caused by myeloma proteins interfering with platelet function. Cardiopulmonary symptoms such as shortness of breath, hypoxemia, acute respiratory failure, and hypotension also result from this sludging of blood and decreased microvascular circulation. History: Clinical symptoms generally are related to the triad of mucosal bleeding, visual changes, and neurologic symptoms. Constitutional symptoms and cardiorespiratory symptoms also contribute to the clinical presentation. Tendency to bleed is the most common symptom of hyperviscosity syndrome. Spontaneous gum bleeding Epistaxis Rectal bleeding Menorrhagia Persistent bleeding after minor procedures Visual changes range from blurred vision to vision loss. Neurologic manifestations are frequent and varied. The neurologic symptoms of hyperviscosity have been referred to as the Bing-Neal syndrome. Vertigo Hearing loss Paresthesias Ataxia Headaches Seizures Somnolence progressing to stupor and coma Other manifestations may include heart failure, shortness of breath, hypoxia, fatigue, and anorexia. In fact, one should have a high index of suspicion for HVS in patients with unexplained coma/altered mental status or unexplained shortness of breath especially in those with an underlying hematologic disorder. Physical: Physical findings are related to the major organ systems involved. Bruises, epistaxis, or gum bleeding may be noted. Ophthalmic examination may reveal decreased visual acuity, dilated retinal veins, “sausage-linked” or “boxcar segmentation” of the retinal veins, or retinal hemorrhages. Neurologic examination may reveal various findings, including diminished mental status, confusion, ataxia, or nystagmus. Cardiopulmonary examination may reveal signs of congestive heart failure with volume overload (rales, lower extremity edema, elevated JVP, and hypoxia). Causes: Increased serum viscosity usually results from increased circulating serum immunoglobulins and can be seen in Waldenström macroglobulinemia and multiple myeloma. Less commonly, the hyperproliferative blood cell disorders such as the leukemias, myeloproliferative diseases, polycythemia, and thrombocytosis may be implicated for the increased viscosity caused by proliferation of their respective cellular components. Prehospital Care: Be attentive to the ABCs and symptomatic support. Emergency Department Care: Plasmapheresis is the treatment of choice for initial treatment and stabilization of the hyperviscosity syndrome caused by the paraproteinemias (the majority of cases), while leukapheresis, plateletpheresis, and phlebotomy are indicated for leukostasis, and symptomatic thrombocytosis, and polycythemia, respectively. As plasmapheresis removes the circulating paraproteins, the serum viscosity decreases and symptoms improve. In similar fashion leukapheresis, plateletpheresis, and phlebotomy also decrease the serum viscosity by decreasing the existing cellular component in excess. Although symptoms of CHF from hyperviscosity may not respond to standard therapies, and, in fact, can be exacerbated due to the resultant dehydration from diuresis causing increased viscosity; plasmapheresis and/or cellular pheresis reverses these symptoms. While arranging for plasmapheresis, treat hemorrhage, CHF, and metabolic imbalances with standard therapies. Caveat: Use caution with the decision to proceed with packed red blood cell transfusion (pRBCs) for minor bleeding because a single unit of pRBCs may increase the viscosity enough to cause worsening symptoms and clinical decompensation. If plasma/cellular pheresis is not readily available and the patient is decompensating, one may try vigorous intravenous hydration coupled with a 2-3 unit phlebotomy in the interim as a temporizing measure. Upon commencing pheresis (especially leukapheresis) one should prepare for the possibility of tumor lysis syndrome and treat accordingly. Thank God for eMedicine, eh? Let's see, what next? How about Ashman's aberrancy?
AZCEP Posted July 9, 2006 Posted July 9, 2006 Wow. Sorry for slamming on the brakes so hard. I really expected someone to be able to answer this one. Here you go. Ashman's aberrancy is a type of rate related bundle branch block. Here is the description from Advanced ECG: Boards and Beyond 2nd edition 1. The refractory period of the cardiac tissues depends on the rate. The slower the rate, the longer the refractory period. The faster the rate, the shorter the refractory period. If this didn't happen the heart rate couldn't increase by very much. 2. The refractory period is set one beat at a time. The refractory period of a given beat depends on the distance between two beats. Therefore, if the R-R interval is constantly changing, as in atrial fibrillation, the refractory period will be constantly changing also. 3. The phenomena is reliant on having a long R-R interval followed by a short R-R. The short interval will cause the stimuli to land in a portion of the refractory period as set by the previous interval. Here is a link to a strip:http://www.tveatch.org/ekgs/ekg9.html You will notice that the upper strip has a long R-R with normally conducted complexes, followed by a widened premature beat. How about something a little more common now? AORTIC STENOSIS
medic429 Posted July 9, 2006 Posted July 9, 2006 Background: Aortic stenosis (AS) is the obstruction of blood flow across the aortic valve. AS has several etiologies: congenital unicuspid or bicuspid valve, rheumatic fever, and degenerative calcific changes of the valve. Pathophysiology: When the aortic valve becomes stenotic, resistance to systolic ejection occurs and a systolic pressure gradient develops between the left ventricle and the aorta. Stenotic aortic valves have a decreased aperture that leads to a progressive increase in left ventricular systolic pressure. This leads to pressure overload in the left ventricle, which, over time, causes an increase in ventricular wall thickness (ie, concentric hypertrophy). At this stage, the chamber is not dilated and ventricular function is preserved, although diastolic compliance may be affected. Eventually, however, the left ventricle dilates. This, coupled with a decrease in compliance, is associated with an increase in left ventricular end-diastolic pressure, which is increased further by a rise in atrial systolic pressure. A sustained pressure overload eventually leads to myocardial decompensation. The contractility of the myocardium diminishes, which leads to a decrease in cardiac output. The elevated left ventricular end-diastolic pressure causes a corresponding increase in pulmonary capillary arterial pressures and a decrease in ejection fraction and cardiac output. Ultimately, congestive heart failure (CHF) develops. Frequency: In the US: This is a relatively common congenital cardiac defect. Incidence is 4 in 1000 live births. Mortality/Morbidity: Sudden cardiac death occurs in 3-5% of patients with AS. Adults with AS have a 9% mortality rate per year. Once symptoms develop, the incidence of sudden death increases to 15-20%, with average survival duration of less than 5 years. Patients with exertional angina or syncope survive an average of 3 years. After the development of left ventricular failure, life expectancy is slightly greater than 1 year. Sex: Among children, 75% of cases of AS are in males. Age: AS usually is not detected until individuals are school aged. AS exists in up to 2% of those who are younger than 70 years. The etiology of AS in those aged 30-70 years can be rheumatic disease or calcification of a congenital bicuspid valve. In those older than 70 years, degenerative calcification is the primary cause of AS. Among people older than 75 years, 3% have critical AS. History: AS usually has an asymptomatic latent period of 10-20 years. Symptoms develop gradually. Ultimately, patients experience the classic triad of chest pain, heart failure, and syncope. Typical symptoms include the following: Palpitations Fatigue (may be an early symptom among children) Visual disturbances Gradual decrease in physical activity with insidious progression of fatigue and dyspnea on exertion Angina pectoris (30-40%) Patients may have a higher incidence of nitroglycerin-induced syncope than the general population. Always consider AS as a possible etiology for a patient in the ED with particular hemodynamic sensitivity to nitrates. Syncope during exertion: Proposed mechanisms include arrhythmias and left ventricular failure with an abrupt decline in cardiac output. Symptoms of left ventricular failure (eg, dyspnea on exertion, nocturnal cough, orthopnea, paroxysmal nocturnal dyspnea, hemoptysis) may occur. This is due to an elevation of the pulmonary capillary pressure from left ventricular dilation and reduced compliance. Physical: Palpation reveals a laterally displaced apex reflecting the presence of left ventricular hypertrophy. A systolic thrill may be palpable at the base of the heart, in the jugular notch, and along the carotid arteries. Crescendo-decrescendo systolic ejection murmur begins shortly after the first heart sound. The intensity increases toward midsystole, then decreases, and the murmur ends just before the second heart sound. It is generally a rough, low-pitched sound that is loudest at the base of the heart and most commonly is appreciated in the second right intercostal space. An ejection click may be auscultated. This is associated with bicuspid valves. An audible fourth heart sound indicates the presence of left ventricular hypertrophy in severe AS. Once the left ventricle dilates and fails, a third heart sound may be audible. Pulsus parvus et tardus: This is an arterial pulse with a delayed and plateaued peak, decreased amplitude, and gradual downslope. A high-pitched, diastolic blowing murmur may be present if the patient has associated aortic regurgitation. Causes: The ventricular pressure required to deliver a certain cardiac output at the required perfusion pressure is the pressure gradient across the valve in systole. This pressure gradient defines the degree of aortic valve obstruction. Newborns with significant AS develop CHF within the first week of life. The left ventricle is often too small to be compatible with life. The newborn heart develops left-to-right shunting through the patent foramen ovale, which leads to worsening CHF. Congenital AS caused by a congenital unicuspid or bicuspid aortic valve is usually asymptomatic in the otherwise healthy developing child. It often is diagnosed on routine physical examination, although a child may present with angina pectoris with exercise. As rheumatic fever decreases in frequency, so does rheumatic fever–induced AS. These patients have a fibrous contracture with shortening of the cusps due to recurrent inflammation from rheumatic carditis. Adjacent cusps tend to fuse at the commissures. This causes a form of acquired unicuspid or bicuspid aortic valve. Calcifications may develop, but the primary cause of stenosis is the adhesions that fuse the cusps. In patients older than 70 years, the most common cause of AS is degenerative calcification of the valve. Mönckeberg senile calcific AS occurs in elderly patients in whom all 3 cusps are highly calcified. Calcific AS also occurs in older patients with congenital or acquired bicuspid valves. Congenital bicuspid valves cause calcific AS 4 times more frequently than acquired forms do. Emergency Department Care: Prehospital and ED management is focused on acute exacerbations of the symptoms of AS. As always, assess and address airway, breathing, and circulation. If the patient is in cardiopulmonary arrest, perform resuscitation according to the recommendations of the American Heart Association in their Advanced Cardiac Life Support guidelines. A patient presenting with uncontrolled CHF should be treated supportively with oxygen, cardiac and oximetry monitoring, intravenous access, loop diuretics, nitrates (remembering the potential nitrate sensitivity of patients with AS), morphine (as needed and tolerated), and noninvasive or invasive ventilatory support (as indicated). Diagnostic studies in the ED should include ECG, chest radiograph, serum electrolytes, cardiac enzymes, CBC, and arterial blood gases (if hypoxemia or a mixed respiratory disease state is suspected). Emergency formal ultrasound may be useful in centers that have this capability. Vasodilators should be used judiciously in patients with AS, as they may cause a significant drop in blood pressure. Patients with heart failure due to AS that is resistant to medical management should be considered for emergent surgery. A patient presenting with angina pectoris requires monitoring and studies as listed above. Measures should be taken to relieve the chest discomfort. This may include administration of nitrates, oxygen, and morphine. Nitroglycerin-induced syncope occurs more often in patients with AS than in those without AS. This information should be obtained through the history at presentation. Syncope in the face of AS should be assessed and treated as in any patient presenting with a syncopal episode. A patient with AS may present initially with one or more of the above complaints. A thorough history and physical should be obtained in addition to baseline laboratory studies, a chest radiograph, and an ECG. Hospital admission, telemetry/intensive care unit admission, and cardiology consultation all should be considered. If available, an echocardiogram may be indicated in the ED. Atrial fibrillation in the setting of AS is considered a medical emergency and should be converted urgently in patients who are hemodynamically unstable. Associated symptoms also should be treated urgently. FROM eMedicine-http://www.emedicine.com/EMERG/topic40.htm How about Marfan Syndrome?
Rezq304 Posted July 10, 2006 Posted July 10, 2006 In a nut shell, Marfan Syndrome is: Marfan syndrome is a connective tissue disorder characterized by unusually long limbs. The disease also affects other bodily structures — including the lungs, eyes, heart and blood vessels — in less obvious ways. It is named for Antoine Marfan, the French pediatrician who first described it in 1896. Marfan syndrome received great public attention when the musical RENT premiered in 1996. The day before the musical premiered off-Broadway, its writer, Jonathan Larson, died of an aortic dissection, which was determined to have been caused by Marfan syndrome. Cause Marfan syndrome is an autosomal dominant disorder that has been linked to the FBN1 gene on chromosome 15. FBN1 codes for a protein called fibrillin-1, which is essential for the formation of elastic fibers found in connective tissue. Marfan syndrome is also an example of a dominant negative mutation. Marfan syndrome is associated with incomplete penetrance, therefore not all persons carrying the mutation develop the disease. Without the structural support provided by fibrillin, many connective tissues are weakened, which can have severe consequences on support and stability. A related disease has been found in mice, and the study of mouse fibrillin synthesis and secretion, and connective tissue formation, has begun to further our understanding of Marfan syndrome in humans. For instance it has been found that simply reducing the level of normal fibrillin-1 causes the Marfan related disease in mice [1]. More recently, transforming growth factor β (TGFβ) has been shown to play an important role in Marfan syndrome. Fibrillin-1 binds TGFβ, inactivating it. In Marfan syndrome, reduced levels of fibrillin-1 allow TGFβ to damage the lungs and heart. New treatments for Marfan, using antagonists of TGFβ, are being investigated (Habashi et al., 2006 Science 312(5770):117-21). [edit] Diagnosis Although genetic testing is available, a diagnosis is usually made solely on clinical findings. [edit] Epidemiology Estimates indicate that perhaps 1 in 10,000 people (0.01 percent of the population) has Marfan syndrome. It affects all races and both sexes equally. Most individuals with Marfan syndrome have another affected family member, but about 30 percent of cases are due to de novo genetic mutations. Genetic counseling is available for families who may be at risk for Marfan syndrome. [edit] Symptoms The most serious conditions associated with Marfan syndrome primarily involve the cardiovascular system. Marfan syndrome may cause leakage of the mitral or aortic valves that control the flow of blood through the heart. This may produce shortness of breath, an irregular pulse, and undue tiredness. Another complication is aortic aneurysm. Marfan syndrome sufferers may grow to larger than normal height, and typically have long, slender limbs and fingers. Sometimes the fingers have a long, thin, spidery appearance known as arachnodactyly. In addition to affecting height and limb proportions, Marfan syndrome may produce other skeletal symptoms. Curvature of the spine (scoliosis) is a common problem, as is abnormal indentation (pectus excavatum) or protrusion (pectus carinatum) of the sternum. These symptoms may in turn cause unusual pressure on the heart and lungs. Other symptoms include; abnormal joint flexibility, high palates, flat feet, stooped shoulders, and dislocation of the optic lens. Nearsightedness or myopia is a common condition associated with Marfan syndrome. In addition, the weakening of connective tissue often causes detachment of the retina and/or displacement of the lens in one or both eyes.[2] [edit] Treatment There is no cure for Marfan syndrome, but effective treatment allows many people with the disorder to live normally. The heart conditions related to Marfan syndrome may not necessarily produce obvious symptoms. As a result, regular checkups by a cardiologist are needed to monitor cardiovascular health. Potential problems may be detected through echocardiography, which involves the use of ultrasound to study the heart valves and the aorta. Beta blockers have been used to control some of the complications such as aortic aneurysms. If the dilation of the aorta threatens to lead to rupture a composite aortic valve and graft may be implanted. Although aortic graft surgery is a serious undertaking it usually results in a good outcome and a satisfactory quality of life. Elective aortic valve/graft surgery is usually considered when aortic dilatation reaches 50 millimeters, but each case needs to be specifically evaluated by a qualified cardiologist. New valve-sparing surgical techniques are becoming more common. Rupture of the aorta, or aortic dissection, is the most common cause of sudden death among Marfan syndrome sufferers. The skeletal and ocular manifestations of Marfan syndrome can also be serious, although not life-threatening. These symptoms are usually treated in the typical manner for the appropriate condition. This can also affect height, arm length, and life span. The blood pressure drug losartan prevents aortic aneurysms and lung problems in a model organism mouse model of the disease. Ok folks, let's go basic yet again and talk about posturing: Decorticate & Decerebrate
Rezq304 Posted July 11, 2006 Posted July 11, 2006 Wow folks, was I the official "thread killer" here????
Just Plain Ruff Posted July 11, 2006 Posted July 11, 2006 Ashman's Aberrancy UCLA School of Medicine, Department of Emergency Medicine, Torrance. The refractory period of the right bundle branch is increased when the R-R interval between the prior two conducted impulses is long. Thus, an impulse that arrives soon after the second of two impulses separated by a long R-R interval may be aberrantly conducted with a right bundle branch block morphology on electrocardiogram. This aberrant conduction is termed "Ashman's phenomenon" and is often responsible for isolated wide QRS complexes in the presence of underlying atrial fibrillation. This process may also produce runs of wide QRS complexes that must be distinguished from nonsustained ventricular tachycardia. A case of such multibeat Ashman's phenomena is presented, and the characteristics used to identify this phenomenon are discussed. A brief review of several recent studies on the differentiation of sustained ventricular tachycardia from supraventricular tachycardia with aberrancy in the setting of a regular underlying rhythm is given as well
Ace844 Posted July 11, 2006 Posted July 11, 2006 I think some of us just wanted to give others the opportunity to reply and learn..... :shock: :shock: Abnormal posturing Abnormal posturing, which indicates severe brain injury, refers to an involuntary flexion or extension of the extremities. It occurs when one set of muscles becomes incapacitated and the other set is not, and an external stimulus such as pain causes the working set of muscles to contract (AllRefer.com, 2003). Since posturing is an important indicator of the amount of damage that has occurred to the brain, it is used by medical professionals to measure the severity of a coma with the Glasgow Coma Scale (for adults) and the Pediatric Glasgow Coma Scale (for infants). Two types of abnormal posturing are decorticate and decerebrate posturing, also called decorticate and decerebrate responses, respectively. Opisthotonos, in which the head and back are arched backward, is another form of abnormal posturing. The presence of posturing indicates a severe medical emergency requiring immediate medical attention. Causes Posturing can be caused by conditions that lead to an increase in intracranial pressure and brain herniation. Such conditions include traumatic brain injury, stroke, intracranial hemorrhage, brain tumors, and encephalopathy (ADAM, 2005). Decorticate Posturing Patients with decorticate, or flexor, posturing present with the arms flexed, or bent inward on the chest, the hands are clenched into fists, and the legs extended. Decorticate posturing indicates damage to the mesencephalic region, or the corticospinal tract, along which impulses travel from the brain to the spinal cord (AllRefer.com, 2003). While an ominous sign of severe brain damage, decorticate posturing is not as serious as decerebrate posturing. Decerebrate Posturing In decerebrate, or extensor, posturing, the arms are extended by the sides, the head is arched back, and the legs are extended (ADAM, 2005). Decerebrate posturing indicates brain stem damage. A patient with decorticate posturing may begin to show decerebrate posturing, or may go from one form of posturing to the other (AllRefer.com). Posturing may occur on one or the other side of the body, or it may occur on both sides (AllRefer.com). [edit] References 1. ADAM. 2005. "Decerebrate Posture". 2. AllRefer.com. 2003 “Decorticate Posture”. Available via the World Wide Web. 3. World Health Organization. 2005. Management of Severe Malaria: A Practical Handbook. 4. Yamamoto, Loren G. 1996. “Intracranial Hypertension and Brain Herniation Syndromes: Radiology Cases in Pediatric Emergency Medicine". Volume 5, Case 6. Kapiolani Medical Center for Women and Children; University of Hawaii; John A. Burns School of Medicine. For a great reference check here::: http://medlib.med.utah.edu/neurologicexam/...or_anatomy.html Decorticate vs. Decerebrate · A UMN lesion above the level of the red nucleus will result in decorticate posture (thumb tucked under flexed fingers in fisted position, pronation of forearm, flexion at elbow with the lower extremity in extension with foot inversion) while a lesion below the level of the red nucleus but above the level of the vestibulospinal and reticulospinal nuclei will result in decerebrate posture (upper extremity in pronation and extension and the lower extremity in extension). The reason for this is that the red nucleus output reinforces antigravity flexion of the upper extremity. When its output is eliminated then the unregulated reticulospinal and vestibulospinal tracts reinforce extension tone of both upper and lower extremities. If there is a lesion in the medulla then all the brainstem motor nuclei as well as the direct corticospinal tract would be out and the patient would be flaccid acutely. If the patient were to survive, tone would return because of interneuronal activity at the spinal cord level. The Examination of a Comatose or Stuporous Patient Because the comatose patient cannot understand and follow commands, the examination of the comatose patient is a modified version of the neurological examination of an alert patient. If a patient is comatose, it is safe to assume that the nervous system is being affected at the brainstem level or above. The goal of a neurological examination in a comatose patient is to determine if the coma is induced by a structural lesion or from a metabolic derangement, or possibly from both. Two findings on exam strongly point to a structural lesion: 1. consistent asymmetry between right and left sided responses, and 2. abnormal reflexes that point to specific areas within the brain stem. Mental status is evaluated by observing the patient's response to visual, auditory and noxious (i.e., painful) stimuli. The three main maneuvers to produce a noxious stimulus in a comatose patient are: 1. press very hard with your thumb under the bony superior roof of the orbital cavity, 2. squeeze the patient's nipple very hard, and 3. press a pen hard on one of the patient's fingernails. Comatose patients may demonstrate motor responses indicative of more generalized reflexes. Decorticate posturing consists of adduction of the upper arms, flexion of the lower arms, wrists and fingers. The lower extremities extend in decorticate posturing. Decerebrate posturing consists of adduction of the upper arms, extension and pronation of the lower arms, along with extension of the lower extremities. In general, patients with decorticate posturing have a better prognosis than patients who exhibit decerebrate posturing. Posturing does not have any localizing utility in humans. Visual acuity cannot be tested in a comatose patient, but pupillary responses may be tested as usual. Visual fields may be partially evaluated by noting the patient's response to sudden objects introduced into the patient's visual field. Extra-ocular muscles may be evaluated by inducing eye movements via reflexes. The doll's eyes reflex, or oculocephalic reflex, is produced by moving the patient's head left to right or up and down. When the reflex is present, the eyes of the patient remain stationary while the head is moved, thus moving in relation to the head. Thus moving the head of a comatose patient allows extra-ocular muscle movements to be evaluated. An alert patient does not have the doll's eyes reflex because it is suppressed. If a comatose patient does not have a doll's eyes reflex, then a lesion must be present in the afferent or efferent loop of this reflex arc. The afferent arc consists of the labyrinth, vestibular nerve, and neck proprioceptors. The efferent limb consists of cranial nerves III, IV and VI and the muscles they innervate. Furthermore, the pathways that connect the afferent and efferent limbs in the pons and medulla may also be disrupted and cause a lack of the doll's eyes reflex in a comatose patient. If the patient is being examined in the emergency department or if there is a history of potential cervical spine injury, the doll's eyes reflex should not be elicited until after a cervical spine injury is ruled out. The oculovestibular reflex, or cold calorics, is produced by placing the patient's upper body and head at 30 degrees off horizontal, and injecting 50-100cc of cold water into an ear. The water has the same effect on the semicircular canal as if the patient's head was turned to the opposite side of the injection. Therefore, the patient's eyes will look towards the ear of injection. This eye deviation lasts for a sustained period of time. This is an excellent manuever to assess extra-ocular muscles in the comatose patient with possible cervical spine injury. If the oculovestibular reflex is absent, a lesion of the pons, medulla, or less commonly the III, IV, IV or VIII nerves is present. Unlike the oculocephalic reflex, the oculovestibular reflex is present in awake patients. In alert patients, this reflex not only induces eye deviation, it also produces nystagmus in the direction of the non-injected ear. The slow phase is towards the injected ear and the fast phase is away. Cranial nerve V may be tested in the comatose patient with the corneal reflex test. Cranial nerve VII may be examined by observing facial grimicing in response to a noxious stimulus. Cranial nerves IX an X may be evaluated with the gag reflex. The motor system is assessed by testing deep tendon reflexes, feeling the resistance of the patient's limbs to passive movements, and testing the strength of posturing and local withdrawl movements. Local withdrawl movements may be elicited by pressing a pen hard on the patient's fingernail and observing if the patient withdrawls the respective limb from the noxious stimulus. Upper motor neuron lesions are characterized by spasticity. Spasticity is increased muscle tone leading to resistance of the limbs to passive manipulation. This spasticity classically results in the clasp-knife response. The clasp-knife response is when the spastic limb is passively moved with great resistance, when suddenly the limb "gives", becoming very easy to move. The clasp knife response is most prominent in the muscle groups least affected by the upper motor lesion, e.g., flexors in the upper extremities or extensors in the lower extremities. The sensory system can only be evaluated by observing the patient's response, or lack of response, to noxious stimuli in different parts of the body. In addition to withdrawing from noxious stimuli, patient's may localize towards noxious stimuli. Localization indicates a shallower coma compared to the patient that withdraws. A common prognostic assessment, called the Glascow Coma Scale, is often used to measure the depth of coma. The Glascow Coma Scale is often used serially as a means to follow a comatose patient clinically. It has 3 sections: I. best motor response, II. best verbal response, and III. eye opening. Glascow Coma Scale: I. Motor Response 6 - Obeys commands fully 5 - Localizes to noxious stimuli 4 - Withdraws from noxious stimuli 3 - Abnormal flexion, i.e. decorticate posturing 2 - Extensor response, i.e. decerebrate posturing 1 - No responseII. Verbal Response 5 - Alert and Oriented 4 - Confused, yet coherent, speech 3 - Inappropriate words, and jarbled phrases consisting of words 2 - Incomprehensible sounds 1 - No soundsIII. Eye Opening 4 - Spontaneous eye opening 3 - Eyes open to speech 2 - Eyes open to pain 1 - No eye openingGlascow Coma Scale = I + II + III. A lower score indicates a deeper coma and a poorer prognosis. Patients with a Glascow Coma Scale of 3-8 are considered comatose. Patients with an initial score of 3-4 have a >95% incidence of death or persistent vegetative state. http://www.mona.uwi.edu/fpas/courses/physi...eSpasticity.htm Decerebrate/Decorticate rigidity is actually a form of spasticity. That is, the hypertonicity of the muscles, and their resistance to passive manipulation, is due to hyperactivity of the stretch reflexes. Hypertonia due to excessive a -motor neurone activity does not involve the stretch reflexes and is more properly termed rigidity. The stretch reflex hyperactivity appears to be due to loss of cerebral cortical input into the medullary reticular formations (medial reticular extensor inhibitory area). This area inhibits mainly the g-motor neurones, and to a lesser extent the a -motor neurones, of the extensor muscles. The activity in the pontine reticular formations (lateral reticular extensor facilitatory area), which receives input mainly from ascending collaterals of sensory afferents, remains undiminished. Reticulospinal fibres from this area facilitate the g -motor neurones of the extensor muscles. Normal tone depends upon the maintenance of normal, continually varying balance between the inhibitory and facilitatory influences, respectively, of the medullary and pontine reticular formations. This allows varying levels of promotion or suppression of the reflexes under different circumstances. Disruption of the normal balance between the excitatory and inhibitory areas, with a shift toward unbalanced excitation from the pontine area, leads to hyperactivity of the extensor g-motor neurons. This, in turn, causes hyperactivity of the stretch reflexes, with hypertonus and clonus. It can be shown that the stretch reflex loop is essential for maintenance of spasticity, since section of the dorsal roots of the spinal nerves will abolish it. The strong facilitatory influence of the vestibular nuclei upon mainly the extensor a-motor neurones, is also essential for sustenance of this spasticity, and lesion of the vestibular system will abolish spasticity and lead to hypotonia. The spasticity accompanying decerebration should be distinguished from that resulting from spinal transection. Clonus Clonus is an automatic oscillatory contraction/relaxation/contraction cycle, induced by sustained stretch on a hypertonic (spastic) muscle. Typically, this can be seen if the foot is quickly dorsiflexed and held in this position (ankle clonus). In individuals with spastic paralysis, who retain some capacity for movement, the stiffness due to the spasticity may interfere with effective use of the little voluntary power that they have remaining. Efforts to move, may also precipitate clonus of the limb involved. Lastly see this link:: http://assets.cambridge.org/052149/6888/sa...496888wsn01.pdf , and this PPT: [web:8d25abc475]http://neurosurgery.uthscsa.edu/presentations/Herniation%20Syndromes.pdf[/web:8d25abc475] IVCCS? Inferior Vena Cava Compression Syndrome?[/font:8d25abc475]
Scaramedic Posted July 20, 2006 Author Posted July 20, 2006 From Wikipedia... Inferior vena cava syndrome (IVCS) is a result of obstruction of the inferior vena cava. It can be caused by invasion or compression by a pathological process or by thrombosis in the vein itself. Grey Turner's sign Peace, Marty :joker:
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