Módulo 8 Med. Interna Flashcards

Question

A 25-year-old, apparently healthy man undergoes a complete physical as part of screening for health insurance. The physical is negative, but chemistry screening shows plasma bilirubin of 2.1 mg/dL as the only abnormal finding. The man is referred to an internist for further evaluation. The internist notes that all the serum liver enzymes are within normal limits and that there is no evidence on complete blood count of anemia or reticulocytosis. The urine is negative for bile compounds. Fractionation of the plasma bilirubin demonstrates a predominance of unconjugated bilirubin. Which of the following is the most likely diagnosis? (A) Alcoholic hepatitis (B) Crigler-Najjar syndrome (C) Gilbert syndrome (D) Hepatitis A infection (E) Hepatitis B infection

Answer 1

**Respuesta: C** The correct **answer is C**. As many as 3 to 5% of the general population has Gilbert syndrome, which is a completely benign condition (not even really a disease) in which there is a deficit in the liver’s rate of conjugation of bilirubin due to a slightly low glucuronyl transferase activity. No true clinically significant liver disease is present, but there is a risk of being misdiagnosed with chronic hepatitis. Alcoholic hepatitis (**choice A**) would be accompanied by elevated liver transaminases with the aspartate aminotransferase (AST) about twice as high as the alanine aminotransferase (ALT). Crigler-Najjar syndrome (**choice B**) is a true liver disorder characterized by a more severe glucuronyl transferase deficiency. It occurs in an autosomal recessive form that is fatal by age 1 and in a somewhat milder autosomal dominant form that permits survival into adulthood. Infection with hepatitis A (**choice D**) or hepatitis B (**choice E**) would be accompanied by elevated serum liver enzymes.

Answer 2

**Respuesta: D** The correct **answer is D**. The clinical picture is that of a patient with progressive congestive heart failure. The specific manifestations leading to the correct diagnosis include increased jugular pressure, especially during inspiration, and the calcific deposits in the pericardial sac. Restrictive pericarditis is due to a fibrocalcific transformation of the pericardium, which encases the heart and impairs ventricular filling. In the past, the most common etiology was tubercular pericarditis; nowadays, radiation therapy, cardiac surgery, and viral pericarditis represent the most frequent causes. Dilated cardiomyopathy (**choice A**) is associated with cardiomegaly, resulting in an enlarged cardiac silhouette on chest x-ray. Impaired inotropism is the principal pathophysiologic mechanism of congestive heart failure due to dilated cardiomyopathy. Hypertrophic cardiomyopathy (**choice B**) may not be associated with an enlarged heart, but a thickened left ventricular wall, especially the interventricular septum, would be demonstrated by echocardiography. Pericardial tamponade (**choice C**) results from accumulation of fluid within the pericardial sac and consequently impaired diastolic filling. The course is acute or subacute, and concomitant symptomatology (e.g., precordial pain in case of pericarditis, or history of penetrating trauma or infarction in case of hemorrhage) is present. The clinical manifestations of tricuspid regurgitation (**choice E**) may simulate restrictive pericarditis or cardiomyopathy, but this valvular defect would be associated with right ventricular enlargement and a pansystolic murmur, which are not present in this case.

Answer 3

**Respuesta: B** The correct **answer is B**. Basal cell carcinomas are the most frequent skin malignancies. They develop on sunexposed areas, often in fair-skinned individuals, grow slowly for years, and finally develop a central ulceration. Although nearly entirely devoid of metastatic potential (the cases of proven metastatic basal cell carcinoma are publishable), they may erode into adjacent structures, resulting in cosmetic and/or functional alterations. In fact, the designation of these tumors in the old literature was ulcus rodens (“erosive or destructive ulcer”). Actinic keratosis (**choice A**) is related to ultraviolet sun damage and thus occurs in sun-exposed skin of fair individuals. It appears as small, flesh-colored or slightly pigmented papules that have a characteristic sandpaperlike surface. Actinic keratosis is a premalignant lesion, which may transform into squamous cell carcinoma in 1 of 1000 cases. Hemangioma (**choice C**) is a benign vascular tumor, of which the capillary type is the most frequent. Capillary hemangiomas appear in infancy, grow rapidly in the first year of life, and undergo spontaneous regression by age 5-7. These tumors are bright red to blue and are covered by intact skin. Keratoacanthoma (**choice D**) is histologically extremely similar to squamous cell carcinoma but grows rapidly over a period of weeks and regresses spontaneously within 4-6 weeks. Usually, it presents a central, crater-like ulceration, which is keratin-filled. Melanoma (**choice E**) manifests de novo or on a preexisting mole as a pigmented lesion with asymmetric and irregular borders and variegated color. Ulceration is an infrequent feature. Psoriasis (**choice F**) presents as silvery plaques on typical locations such as knees, elbows, and scalp. Lesions tend to occur frequently on sites of repetitive trauma. Seborrheic keratosis (**choice G**) is an extremely common form of benign tumor of the elderly. The lesions of seborrheic keratosis are brown to black plaques with a velvety or warty surface. The lesions appear as if “stuck on” the epidermal surface, and indeed they can be easily lifted off the skin.

Answer 4

**Respuesta: D** The correct **answer is D**. This patient’s physical examination and history are suggestive of pericarditis. The ECG finding of PR depression alone nearly confirms this diagnosis. A triphasic pericardial friction rub may be heard on cardiac auscultation. Causes of pericarditis include uremia, viral infection, lupus, drugs such as hydralazine and isoniazid, and malignancy. This patient has missed her dialysis sessions and is probably uremic. Nonsteroidal antiinflammatory drugs (NSAIDs), such as indomethacin, are useful for decreasing the inflammation. Ultimately, this patient will require dialysis. Beta-blockers (**choice A**) have no value in the acute management of pericarditis. This patient’s chest pain is probably not from an ischemic event. Morphine (**choice B**) can be given to patients in heart failure to act as a sedative. It decreases the sensation of drowning, thus suppressing the adrenergic drive that can worsen ischemia. Nitroglycerin (**choice C**) is a vasodilator. It relieves acute chest pain by preload reduction and coronary artery dilation. Since the patient does not appear to be having cardiac ischemia, nitroglycerin will not be helpful. Steroids (**choice E**) may be used in pericarditis if NSAIDs are not effective. However, NSAIDs should be the first-line therapy

Answer 5

**Respuesta: A** The correct **answer is A**. Hepatitis viruses known to be spread orally, thereby potentially causing epidemics, include A and E. Outbreaks of hepatitis E have been identified only in developing countries, so you are unlikely to encounter this form of hepatitis in the U.S. Hepatitis A virus is usually spread by fecal-oral contamination, although blood and secretions can also be infectious. Fecal shedding is particularly significant since it typically occurs during the prodromal period when the patient has undiagnosed disease. Water- and food-borne (including raw shellfish) epidemics occur most frequently in undeveloped countries with poor sanitation. Subclinical infections are common during epidemics, again favoring the spread of the virus. Hepatitis A causes acute hepatic disease but does not cause chronic infection and cirrhosis. Hepatitis B (**choice B**) and C (**choice C**) are spread by blood and do not cause conventional epidemics, although they are becoming widely distributed through needle use and, especially for hepatitis B, sexual contact. Hepatitis D (**choice D**) is a defective blood-borne virus, requiring co-infection with hepatitis B. Hepatitis G (**choice E**) is a rare form of viral hepatitis that has been identified in a few cases of hepatitis transmitted by blood.

Answer 6

**Respuesta: E** The correct **answer is E**. One of the basic principles of emergency medicine is that you stabilize a crashing patient as rapidly as possible, even if that causes some delay in doing other reasonable things. In this case, the patient’s blood pressure is dangerously low, and he is obviously bleeding. Starting an IV line with saline and then getting appropriately typed blood into him as fast as possible is the best way to begin. Coagulation studies and liver function tests (**choice A**) are appropriate in helping to define the basis of the patient’s bleeding (coagulopathy or bleeding varices), but should be done after getting the blood (or other fluids if the blood is delayed) started. Complete physical examination (**choice B**) is also important but should be done after stabilizing the patient. A detailed history (**choice C**) is also important but should be done after stabilizing the patient. Endoscopy (**choice D**) may be necessary to identify the site of bleeding and stop it; however, this procedure is much easier and safer to do when the patient is stabilized.

Answer 7

**Respuesta: A** The correct **answer is A.** Total abstinence from alcohol is a fundamental prerequisite for the success of any therapeutic measure for cirrhosis. Transjugular intrahepatic portosystemic shunt (TIPS) is a frequently used alternative to surgical portosystemic shunting procedures in cases of recurrent variceal bleeding refractory to conventional treatments. Liver transplantation has a success rate as high as 80% in specialized centers, but patients must abstain from alcohol for at least 6 months before the procedure. TIPS has a lower success rate in patients with concomitant renal insufficiency (hepatorenal syndrome). Coexistence of infection with hepatitis C virus (**choice B**) does not affect the outcome of either TIPS or the majority of liver transplants. In fact, hepatitis C recurs in virtually all HCV-positive patients receiving a liver transplant, but the effects appear to be negligible in the majority, at least for the first 5 years. Lactulose treatment (**choice C**) is for hepatic encephalopathy. It decreases the flora of ammonia-forming bacteria in the colon. Lactulose treatment has no influence on TIPS or liver transplantation success. Low-protein diet (**choice D**) is used to decrease the amount of ammonia formed by colonic bacterial flora in the treatment of hepatic encephalopathy. Severity of ascites (**choice E**) is related to the severity of portal hypertension and the degree of hypoalbuminemia, both of which are associated with cirrhosis. TIPS is also used for patients with ascites refractory to diuretics or sodium restriction.

Answer 8

**Respuesta: C** The correct **answer is C**. Severe pain that is significantly better when the patient lies quietly should specifically suggest peritonitis to the examining physician. Other features of peritonitis include abdominal guarding, localized or diffuse tenderness, and, in severe cases, absent peristalsis. Acute peritonitis may have a wide variety of etiologies, including ruptured or infarcted viscera (intraabdominal esophagus, stomach, duodenum, bowel, appendix, gallbladder or biliary tree, urinary bladder), trauma, foreign bodies, pelvic inflammatory disease, infected blood in peritoneum, and pancreatitis. Emergency exploratory laparotomy is often required for diagnosis and therapy, with exceptions including acute pancreatitis and pelvic inflammatory disease. The pain of cholelithiasis (**choice A**) may be relieved by walking and may be referred to the right scapula. Peptic ulcer disease (**choice B**) may be relieved by antacids and tends to produce burning pain. Pyelonephritis (**choice D**) may cause dull, aching pain over the kidneys or may be referred to the pubis or vagina. A rupturing aortic aneurysm (**choice E**) causes severe, knifelike, tearing pain in the mid-back that may move downward as the tear evolves.

Answer 9

**Respuesta: C** The correct **answer is C**. The most common cause (>80%) of amenorrhea is pregnancy. Once this option has been excluded, a thorough physical exam is performed, and a well-established ACOG (American College of Obstetrics and Gynecology) algorithm is used. This patient gives a history suggestive of an intracranial process (headache and specific visual deficits). The one diagnosis that could explain both these symptoms and her lack of menses is a prolactin-secreting adenoma of the pituitary. A 17-β estradiol level (**choice A**) is not indicated in the evaluation of amenorrhea. Serum LH and FSH (**choice B**) is indicated only if PRL levels are normal and polycystic ovarian disease or gonadal dysgenesis of some variety is being considered. MRI of the brain (**choice D**) is indicated only if prolactin is elevated, since brain masses are an uncommon cause of headache and the reason for her amenorrhea will typically lay elsewhere. A visual evoked potential study (**choice E**) is not indicated in the evaluation of a patient with amenorrhea. This study is used in patients with suspected multiple sclerosis or retinal nerve damage.

Answer 10

**Respuesta: B** The correct **answer is B** This question relates to infectious diseases, their manifestations, and their geographic distribution. Coccidioides immitis, a fungus that exists as a spherule in the tissue, is endemic to the southwestern U.S., and infection is caused by inhalation. Some people develop a influenza-like illness that often resolves spontaneously. Candida albicans (**choice A**) causes cutaneous infections and mucosal infections. It appears as pseudohyphae. Cryptococcus neoformans (**choice C**) typically causes meningitis or pneumonia in immunocompromised patients. India ink preparation shows budding yeast forms. Histoplasma capsulatum (**choice D**) is endemic in the central and eastern U.S. Spores are engulfed by macrophages. Diagnosis is made by tissue examination showing oval budding yeasts inside macrophages.

Answer 11

**Respuesta: D** The correct **answer is D**. Normal pressure hydrocephalus (NPH) must be considered in any elderly patient with a subacute onset of mild dementia, urinary incontinence, and gait disturbance. NPH is a communicating hydrocephalus presumed to be due to defective reabsorption of CSF by subarachnoid villi. The etiology is unknown, but some have suggested that obstruction of the normal flow of CSF over the cerebral convexity and delayed absorption into the venous system may be causative. Intracranial pressure is generally normal or high normal. Ventriculoperitoneal shunting is sometimes beneficial. Alzheimer disease (**choice A**) is characterized by a slowly progressive decrease in cognitive functioning and memory over time in elderly patients. Huntington disease (**choice B**) causes dementia, but is also associated with a choreoathetotic movement disorder that was not observed in this patient. In addition, Huntington disease generally presents around age 45-50. Multi-infarct dementia (**choice C**) is characterized by a step-wise decrease in cognitive function associated with hypertension, atrial fibrillation, smoking, and transient ischemic events (TIAs) or strokes. Pick disease (**choice E**) is rare and characterized by progressive dementia (similar to Alzheimer disease) associated with circumscribed cerebral atrophy (lobar sclerosis).

Answer 12

**Respuesta: B** The correct **answer is B**. Atrial fibrillation may be the first sign of hyperthyroidism, especially in the absence of any cardiac anomalies or coronary artery disease. In such cases, thyroid hormone levels should be evaluated. The TSH level is a more sensitive parameter for the evaluation of thyroid dysfunction, as long as a sensitive (second- or third-generation) assay is used. Maintaining the patient on the same medication (**choice A**) would be inappropriate without clarifying the underlying etiology. The dexamethasone suppression test (**choice C**) is used to confirm a clinical suspicion of hypercortisolism. The patient is given 1 mg of dexamethasone at 11 PM. At 8 AM the next morning, after overnight fasting, the cortisol level is measured in a serum sample. Failure to suppress cortisol secretion is evidence of Cushing syndrome/disease. This patient does not have clinical evidence of hypercortisolism, i.e., truncal obesity, dermal striae, and “moon face.” Anticoagulation with Coumadin (**choice D**) would be appropriate if electrical or pharmacologic cardioversion were planned. This measure is necessary to prevent the formation of clots within the atria, with subsequent embolization when the heart resumes its normal rhythm. Coronary arteriography (**choice E**) is useless since there is no clinical evidence of coronary artery disease, namely a history of anginal pain. On the other hand, hyperthyroidism can itself cause anginal pain, as well as atrial fibrillation.

Answer 13

**Respuesta: C** The correct **answer is C**. The clinical presentation is consistent with osteogenesis imperfecta, which is due to mutations in one of the two genes that encode procollagen I. Type I collagen is the most abundant form in the body. Different mutations associated with osteogenesis imperfecta have been identified, some causing structurally abnormal collagen, others leading to decreased expression of procollagen I gene. There are two main clinical variants. The fetal type leads to in utero fractures and congenital deformities. The adult type results in extreme bone brittleness and frequent fractures and is also associated with a characteristic constellation of signs including bluish sclerae, brown or bluish misshapen teeth, and conductive hearing loss. Family history is usually positive since the disorder is usually transmitted as autosomal dominant. Mutations resulting in defects in fibrillin (**choice A**) cause Marfan syndrome. Fibrillin protein forms the scaffold for the deposition of elastin in tissues of the heart valves, aorta, and lens suspensory ligaments. Major clinical manifestations include mitral valve prolapse, aortic dissection, aortic insufficiency, and dislocation of the lens. Body habitus is characteristic, with long arms and legs, long fingers (arachnodactyly), pectus excavatum, and bossing of frontal eminence. A point mutation in the gene coding for FGF-receptor 3 (**choice B**) is the molecular defect causing achondroplasia, one of the most common causes of dwarfism. This mutation results in abnormal cell signaling that impairs proliferation of chondrocytes in the growth plate. Activation of FGFR3 inhibits normal proliferation of chondrocytes. Mutations associated with achondroplasia cause this receptor to be in constant activation. Mutations affecting procollagen III (**choice D**) account for the majority of Ehlers-Danlos syndrome, characterized by hyperextensible skin and hypermobile joints. Accumulation of mucopolysaccharides (**choice E**), as occurs in mucopolysaccharidoses, is often associated with short stature, chest wall deformities, and various bone malformations. Chondrocytes are among the cells most severely affected by these disorders.

Answer 14

**Respuesta: A** The correct **answer is A**. Cryptococcal meningoencephalitis is one of the most frequent opportunistic infections in patients with AIDS. Cryptococcal organisms invade the subarachnoid space and extend into the perivascular (Virchow-Robin) spaces in the brain parenchyma, often without eliciting a significant inflammatory reaction. Cryptococcal meningitis presents with fever and headache, but nuchal rigidity may be minimal. Very high CSF cryptococcal antigen titers are characteristic of this condition. IV administration of amphotericin B is necessary, followed by oral fluconazole. The clarithromycin-rifabutin combination (**choice B**) is currently recommended to treat infections caused by Mycobacterium aviumintracellulare (MAI). MAI infections are exceptionally rare in immunocompetent hosts but occur frequently in AIDS patients. Oral fluconazole (**choice C**) alone can be used to treat cryptococcal CNS infections in the absence of significant neurologic compromise. Sulfadiazine-pyrimethamine (**choice D**) is an effective combination for treatment of cerebral toxoplasmosis, one of the most common opportunistic infections in AIDS. Trimethoprim-sulfamethoxazole (**choice E**) is currently the treatment of choice for Pneumocystis carinii pneumonia, the most common opportunistic infection in AIDS.

Answer 15

**Respuesta: C** The correct **answer is C.** Marfan syndrome is characterized by long limbs and fingers (arachnodactyly), ectopia lentis (dislocation of the lens), and proximal aortic dilatation resulting in aortic insufficiency, mitral valve prolapse (hence, the midsystolic click), and laxity of joints. Patients with Marfan syndrome are usually very tall: most of the height is due to the long lower extremities. Pectus excavatum and pectus carinatum (pigeon breast), and protuberant forehead are frequent associated skeletal anomalies. A mutation in the fibrillin gene is the underlying molecular defect. Cardiovascular complications, particularly aortic dissection, represent the most common cause of death in Marfan patients. Ehlers-Danlos syndrome (**choice A**) is a heterogeneous group of disorders related to mutations in the genes encoding one of several types of collagen, most commonly collagen III. Clinically, it is characterized by laxity of joints and ligaments. The skin can be abnormally stretched. Klinefelter syndrome (**choice B**) is a chromosomal disorder due to a 47,XXY karyotype. Patients are phenotypically males, but show hypogonadism and a characteristic eunuchoid habitus, with gynecomastia and long legs. Klinefelter syndrome is one the most frequent causes of male infertility. McCune-Albright syndrome (**choice D**) or Albright syndrome is a rare hereditary condition caused by somatic mutations in the c-fox gene. It leads to multiple endocrinopathies, unilateral skin hyperpigmentation, multifocal fibrous dysplasia (on the side of the body with hyperpigmented skin), and precocious puberty. Osteogenesis imperfecta (**choice E**) is an inherited condition, usually autosomal dominant, due to mutations in the gene for collagen type I. The resulting clinical picture is characterized by bone fragility, leading to multiple fractures in utero (fetal form) or adult life (adult form)

Answer 16

**Respuesta: E** The correct **answer is E**. Virtually all patients with adult respiratory distress syndrome (ARDS) have reduced lung compliance. ARDS begins with compromise of capillary integrity, which causes extravasation of fluid, fibrin, and protein into the alveoli. Thus, the lungs become wet and stiff, causing reduced lung compliance. Clinical features include progressive tachypnea. Specific physical features are usually absent, except for bilateral diffuse rales. ARDS can be initiated by many different events and conditions, including shock, aspiration of fluid, disseminated intravascular coagulation (DIC), sepsis, trauma, blood transfusion, pancreatitis, smoke inhalation, and heroin overdose. The ultimate goal of treatment is to provide adequate tissue perfusion and oxygenation while addressing the precipitating event. ARDS leads to tachypnea and increased ventilation. Thus, arterial Pco2 is reduced (compare with **choice A**). Chest x-ray films typically show patchy, diffuse, bilateral fluffy infiltrates, rather than a localized mass (**choice B**). ARDS is characterized by severe hypoxia caused by extreme ventilation-perfusion (V/P) imbalance and shunting of blood in the fluid-filled areas of the lung. Oxygenation is severely reduced, not normal (compare with **choice C**). A pulmonary embolism (**choice D**) may result from prolonged immobilization, but is not necessarily a direct sequelae of ARDS.

Answer 17

**Respuesta: C** The correct **answer is C**. Treatment with steroids is standard for polymyositis. Prednisone is used daily in single doses of 1 to 2 mg/kg. In responsive patients, muscle strength usually improves in 1 or 2 months, and the creatine phosphokinase (CPK) level normalizes in 3 months. Daily high-dose steroids are continued until the CPK has remained normal for a period of 3 to 6 weeks. Once the patient is in remission, the steroids should be tapered off slowly. Intravenous fluid replacement (**choice A**) and plasma exchange (**choice B**) play no role in the management of polymyositis. Neostigmine (**choice D**) is used in the treatment of myasthenia gravis. Azathioprine (**choice E**) is used in patients whose condition is refractory or in those who continue to require high doses of steroids. It is not used as an initial therapy.

Answer 18

**Respuesta: A** The correct **answer is A**. Hemolytic disease is associated with the production of black pigment gallbladder stones. Brown pigment stones (**choice B**) form in the common duct, in the presence of infected bile. Calcium stones (**choice C**) are found in the urinary tract rather than the biliary tract. Pigment stones in the biliary tract often have enough calcium to be radio-opaque, but they are not pure calcium stones. Mixed stones (**choice D**) are the usual gallbladder stones, seen in obese females who have had multiple pregnancies. They are not associated with hemolysis. Pure cholesterol stone (**choice E**) is occasionally seen as a single large stone filling the entire gallbladder.

Answer 19

**Respuesta: D** The correct **answer is D**. Urinary 5-hydroxyindoleacetic acid (5- HIAA), a serotonin metabolite, is increased in patients with carcinoid syndrome. Calcitonin levels (**choice A**) would be elevated in patients with medullary thyroid carcinoma. Serum gastrin levels (**choice B**) are elevated in patients with gastrinoma. Levels greater than 1000 pg/mL in patients with typical clinical features of gastrinoma are sufficient to establish the diagnosis. Upper gastrointestinal tract endoscopy (**choice C**) might reveal multiple peptic ulcers, implying Zollinger-Ellison syndrome. Urine vanillylmandelic acid (**choice E**), a catecholamine metabolite, would be elevated in pheochromocytoma.

Answer 20

**Respuesta: A** The correct **answer is A**. The young woman has a brain tumor. MRI will provide the best diagnostic images. Skull x-rays (**choice B**) rarely are used nowadays. When patients sustain head trauma, CT scan is much more valuable. When we suspect brain tumor, x-rays are completely worthless. They cannot penetrate past the bone to show the brain. Spinal tap (**choice C**) is absolutely contraindicated. The patient has increased intracranial pressure. A tap might produce herniation and death. Pheochromocytomas produce headaches, but they do so as part of a pattern of pounding headache, palpitations, perspiration, pallor, and blood pressure elevation. In that case, measuring catecholamines (**choice D**) is indicated. In this vignette, it is not. Visual fields (**choice E**) might help establish if the chiasma or the optic nerves or tracts are involved, but they would be completely normal if the tumor is elsewhere. This is obviously not the correct answer.

Answer 21

**Respuesta: D** The correct **answer is D**. The patient is in diabetic ketoacidosis (DKA). The precipitant is probably the recent infection. The patient has become hyperglycemic, leading to an osmotic diuresis. The low insulin levels have induced a fasting state, leading to catabolism of fatty acids into ketones. She needs continuous short-acting insulin to reverse this process. Regular insulin is short-acting and can be administered via continuous intravenous infusion, with monitoring of the patient’s blood glucose response. This patient is also dehydrated because of the osmotic diuresis; the dehydration is the cause of the observed orthostasis. Therefore, fluid replacement with regular insulin infusion is the ideal treatment. Severe dehydration can produce lactic acidosis from decreased perfusion and ischemia. Thus, isotonic solution replacement (**choice A**) is a partial, but not complete, treatment for this patient. Her acidosis is significantly worsened by her diabetes, and the underlying problem will be corrected by insulin administration. NPH insulin would be too erratic in maintaining euglycemia (**choice B**). Her dehydration needs to be corrected rapidly. NPH effects peak after 4 to 6 hours, which will not allow the adequate and immediate reversal of this patient’s DKA. Although administration of continuous IV regular insulin is part of the solution (**choice C**), it is not the complete solution, since the lost fluids must be replaced as well. In the initial stages of DKA, this patient needs continuous insulin infusion. Administration of regular insulin every 4 hours (**choice E**) might not prove adequate, since her DKA control will be too episodic and erratic.

Answer 22

**Respuesta: C** The correct **answer is C**. The diagnosis is obvious: bony metastasis from the recent breast cancer, but the question is to what extent the spinal cord is involved. MRI is the best study to evaluate the spinal cord. Lumbar puncture (**choice A**) will not provide useful information unless it is done to provide access for contrast material for x-rays. One of the advantages of the MRI is that detailed information can be seen without resorting to invasive studies. She may well have a second cancer in her other breast, but looking for it (**choice B**) is not going to influence what we do for the current problem that is affecting her back. By the same token, she could have bony metastasis elsewhere, but a bone scan of the thoracic area (**choice D**) would be redundant. We already know from the x-ray that she has a metastasis in the thoracic spine. The MRI will show other metastasis in that region if they are present. Bone scan of the whole body might add information, but it would not be critical for the management of the current symptomatic lesion. MRI is better than CT scan (**choice E**) when the target of our studies is the spinal cord.

Answer 23

**Respuesta: B** In the correct **answer is B**. Most mucosa-associated lymphoid tissue lymphoma is related to Helicobacter pylori infection. Studies have shown that eradication of infection of H. pylori results in regression of such infection. This treatment involves a prolonged course of antibiotic therapy aimed at eliminating the bacteria. Combination chemotherapy has been used in the diffuse aggressive lymphoma that arises from mucosa-associated lymphoid tissue lymphoma (**choice A**). Because MALT lymphomas can progress to diffuse, large, B-cell lymphomas, observation is not appropriate (**choice C**). Primary management for most lymphoma is combination chemotherapy, not radiation therapy (**choice D**). Gastric mucosa-associated lymphoid tissue lymphomas can progress to diffuse, large, B-cell lymphomas. Many forms of treatment produce responses, but until recently most therapies were considered palliative and had not been shown to extend survival. Combination chemotherapy regimens that include fludarabine have shown improvements in response rate and durability of response (**choice E**)

Answer 24

**Respuesta: B** The correct **answer is B**. This patient has cold autoimmune hemolytic anemia, a disease primarily seen in the elderly although it is classically associated with mycoplasma (and other pulmonary pathogens) infection and lymphoproliferative disorders. IgM antibodies are created, which react with polysaccharide antigens on the erythrocyte surface only at temperatures below that of the core temperature of the body. In severe cases, acral cyanosis (often easily reproducible) and livedo reticularis are both present. Anemia is usually Coombs-positive, which reveals surface complement and antibody attached to the erythrocyte membrane. The indirect Coombs test (**choice D**) looks for circulating antibodies (such as in testing blood before transfusion) and is not commonly used in evaluating autoimmune hemolytic anemias. The usual treatment centers on staying warm. A bone marrow biopsy (**choice A**) will show nonspecific erythroid hyperplasia and some lymphocytoplasmic aggregates. It is not necessary for the diagnosis, unless there is other evidence to suspect a lymphoproliferative disorder (lymphoma is associated with cold agglutinins). This patient has a normocytic anemia with laboratory work consistent with hemolysis. LDH, an intracellular enzyme, is elevated, indicating cell lysis. Indirect bilirubin, also elevated, indicates increased heme catabolism, further suggesting hemolysis. The haptoglobin, which binds free hemoglobin, is low, suggesting that extracellular hemoglobin is present. Given these findings, it is not necessary to first rule out iron deficiency anemia by ordering a ferritin and iron binding capacity (**choice C**). If, in the course of this patient’s treatment, there appears to be an iron deficiency component to his anemia, then these would be appropriate tests. Mycoplasma is one of a handful of conditions that have well described associations with cold autoimmune hemolytic anemia. However, this patient’s current condition exists independent of any obvious precipitating factor. As such, mycoplasma pneumonia titers (**choice E**) are unlikely to be helpful because the current condition exists independent of any precipitating cause.

Answer 25

**Respuesta: K** The correct **answer is K**. This is the characteristic clinical presentation of schwannomas of the acoustic nerve (AKA acoustic neurinomas). Loss of speech discrimination is an early sign, often associated with tinnitus. In the Weber test, the tuning fork is applied to the forehead: the sound will appear louder in the deaf ear because of a conductive deficit. In this case, the sound appears louder in the good ear, which indicates sensorineural loss. Botulism (**choice A**) manifests with sudden development of diplopia, dysphagia, and nasal speech, followed by paralysis of respiratory muscles and limbs. Charcot-Marie-Tooth disease (**choice B**) is an autosomal dominant polyneuropathy that manifests in childhood with distal weakness and wasting of calf muscles. The most common form of diabetic neuropathy (**choice C**) is a distal symmetric polyneuropathy, manifesting with depressed tendon reflexes, reduced sensation, paresthesias, and burning pain in the legs. Lead neuropathy (**choice E**) follows chronic lead poisoning, manifesting with learning disorders (in children) and motor deficits (wrist drop). Meniere syndrome (**choice F**) consists of recurrent attacks of vertigo, tinnitus, and a characteristic sensation of pressure in the ear. Fluctuating sensorineural hearing loss is also present. Neurofibromatosis (**choice G**) type 2 (the “central” type) is associated with intracranial tumors. Bilateral schwannomas are pathognomonic of this condition. Otosclerosis (**choice H**) affects the footplate of the stapes, leading to increased rigidity of the ossicular chain and producing conductive hearing loss (usually bilateral and symmetric). Otosclerosis has a strong familial basis. Polyarteritis nodosa (**choice I**) may involve the vasa nervorum and manifests with random involvement of single peripheral nerves (mononeuritis multiplex), with sensory-motor disturbances. Presbyacusis (**choice J**) is the progressive hearing loss associated with aging. It is symmetric and preferentially affects high-frequency sounds. Impaired speech discrimination in a noisy environment is characteristic. Traumatic neuroma (**choice L**) is a tumor-like nodule resulting from haphazard regeneration of the distal end of a peripheral nerve following transection. It manifests with acute pain. Vertebrobasilar insufficiency (**choice M**) is a common cause of vertigo in old age. It may result from atherosclerosis of the posterior cerebral circulation or osteoarthritis of the cervical column.

Answer 26

**Respuesta: D** The correct **answer is D**. Guillain-Barré syndrome is an acute/subacute demyelinating inflammatory polyneuropathy manifesting with typical “ascending” paralysis. This condition may be fatal if respiratory muscles are involved. It is probably of autoimmune origin and is often triggered by an upper respiratory infection occurring a few weeks before the onset of the neurologic symptoms. Typical CSF findings include elevated protein with a normal cell count or mild lymphocytosis. Botulism (**choice A**) manifests with sudden development of diplopia, dysphagia, and nasal speech, followed by paralysis of respiratory muscles and limbs. Charcot-Marie-Tooth disease (**choice B**) is an autosomal dominant polyneuropathy that manifests in childhood with distal weakness and wasting of calf muscles. The most common form of diabetic neuropathy (**choice C**) is a distal symmetric polyneuropathy, manifesting with depressed tendon reflexes, reduced sensation, paresthesias, and burning pain in the legs. Lead neuropathy (**choice E**) follows chronic lead poisoning, manifesting with learning disorders (in children) and motor deficits (wrist drop). Meniere syndrome (**choice F**) consists of recurrent attacks of vertigo, tinnitus, and a characteristic sensation of pressure in the ear. Fluctuating sensorineural hearing loss is also present. Neurofibromatosis (**choice G**) type 2 (the “central” type) is associated with intracranial tumors. Bilateral schwannomas are pathognomonic of this condition. Otosclerosis (**choice H**) affects the footplate of the stapes, leading to increased rigidity of the ossicular chain and producing conductive hearing loss (usually bilateral and symmetric). Otosclerosis has a strong familial basis. Polyarteritis nodosa (**choice I**) may involve the vasa nervorum and manifests with random involvement of single peripheral nerves (mononeuritis multiplex), with sensory-motor disturbances. Presbyacusis (**choice J**) is the progressive hearing loss associated with aging. It is symmetric and preferentially affects high-frequency sounds. Impaired speech discrimination in a noisy environment is characteristic. Traumatic neuroma (**choice L**) is a tumor-like nodule resulting from haphazard regeneration of the distal end of a peripheral nerve following transection. It manifests with acute pain. Vertebrobasilar insufficiency (**choice M**) is a common cause of vertigo in old age. It may result from atherosclerosis of the posterior cerebral circulation or osteoarthritis of the cervical column.