Módulo 2 Med. Interna Flashcards
A 25-year-old man comes to the physician because of the rapid onset of pain and swelling of his left knee, which began 24 hours ago. His temperature is 38.5 C (101.3 F), blood pressure is 125/70 mm Hg, pulse is 95/min, and respirations are 20/min. His personal history is significant for IV drug abuse. He denies a history of sexually transmitted diseases. The left knee is tender, swollen, and warm to the touch. Chest auscultation is normal. Which of the following is the most appropriate next step in management?
(A) Blood studies including complete blood count (CBC)
(B) HIV testing prior to instituting any treatment
(C) Plain x-ray films of the joint
(D) Nonsteroidal anti-inflammatory and empiric antibiotic therapy
(E) Diagnostic arthrocentesis
Respuesta: E
The correct answer is E. This clinical picture is consistent with septic arthritis. IV drug abusers are prone to developing joint infections (as well as endocarditis) due to Staphylococcus aureus. Fever and local inflammatory changes restricted to a single joint (i.e., monoarthritis) are sufficient clues to the correct diagnosis. Swelling of the joint indicates that there is probably an effusion within the articular cavity. The next step is to confirm the diagnosis and isolate the offending agent by performing aspiration of the joint fluid. Microscopic examination will allow confirming the nature of the effusion (transudate versus exudate) and ruling out crystal- related joint disease (gout and pseudogout). Culture of the fluid will most likely yield S. aureus in this case.
Blood studies, including complete blood count (CBC; choice A), are useful additional investigations. However, arthrocentesis is more important in management.
HIV testing (choice B) is appropriate in this case, considering the high frequency of HIV infection among IV drug abusers. However, the results would not have any influence on the specific therapy for septic arthritis.
Plain x-ray films of the joint (choice C) are not helpful in diagnosis or management of infectious arthritis.
Nonsteroidal anti-inflammatory and empiric antibiotic therapy
(choice D) prior to arthrocentesis would be a mistake in this context, since isolation of the pathogen is necessary to institute appropriate antibiotic therapy.
A 28-year-old man presents to the emergency department with complaints of fever, chills, and malaise for the past 3 days. He also complains of nausea, headaches, and anorexia. The patient denies any homosexual practices but admits to occasional IV drug use. Examination of his palms and soles reveals painless macules; on auscultation, a loud holosystolic murmur is noted. Which of the following is the most appropriate next step in diagnosis?
(A) ECG
(B) Echocardiogram
(C) Chest CT scan with contrast
(D) RPR for syphilis
(E) Cardiac catheterization
Respuesta: B
The correct answer is B. This patient is displaying signs and symptoms of acute bacterial endocarditis (ABE), with fever, chills, a heart murmur, Janeway lesions, and a positive history of drug use. A thoracic echocardiogram is the most appropriate first step for finding the vegetations of ABE on heart valves, which are diagnostic. Blood cultures are also diagnostic, but take 2 days for a result and confirm only the bacteremia itself, not its source. Since the mortality is great for ABE, empiric antibiotics should be initiated after three sets of blood cultures are drawn. The organism is most likely Staphylococcus aureus, and the right-sided valves are more commonly affected in IV drug users. The tricuspid regurgitation murmur (a holosystolic murmur along the sternal border that increases with inspiration) should always suggest the diagnosis of S. aureus endocarditis.
ECG findings (choice A) are not sensitive for diagnosing endocarditis.
There is no role for CT (choice C) or cardiac catheterization (choice E) in this case. The findings do not suggest syphilis; however, both an HIV test and an RPR (choice D) would provide useful information, although neither would aid in the diagnosis of ABE.
A 71-year-old man is brought to the emergency department with acute onset of headache, vomiting, and confusion. The family reports that he has a long history of poorly controlled hypertension with hypertensive renal disease and eye disease that were diagnosed 3 years ago. They report that, a few hours ago, he rapidly developed a very severe headache, and over the next half hour, became more lethargic and confused, and had five episodes of vomiting. His blood pressure is 235/140 mm Hg in both arms, and he appears to have a lateral gaze paralysis on the right. There is no nuchal rigidity, and the pupils appear reactive bilaterally; however, papilledema is evident on funduscopic exam. Which of the following is the most likely diagnosis?
(A) Cerebellar hemorrhage
(B) Epidural hematoma
(C) Putamenal hemorrhage
(D) Subarachnoid hemorrhage
(E) Subdural hematoma
Respuesta: C
The correct answer is C. This patient is having a hypertensive hemorrhage. The caudate and the putamen are the most common sites for such bleeds (70%), which can lead to dangerous elevations in intracranial pressure (ICP), as in this patient. The signs and symptoms of increased ICP, when present, portend imminent herniation of the brain and certain death. These patients require urgent intervention to lower their blood pressure.
The cerebellum (choice A) is an uncommon site (< 5%) for
hypertensive hemorrhage. When cerebellar hemorrhages occur,
urgent intervention is required because they can cause brainstem compression and/or obstructive hydrocephalus.
Epidural hematoma (choice B) is usually the result of trauma to the squamous portion of the temporal bone of the skull and is not associated with hypertension.
Subarachnoid hemorrhage (SAH; choice D) is infrequently
associated with severe hypertension and is usually accompanied by meningismus. Once the SAH is identified, neurosurgical
intervention to stop the bleeding can be performed, and the patient thereafter has a normal life expectancy. The most common nontraumatic cause for SAH is a berry aneurysm in the anterior portion of the circle of Willis.
Subdural hematoma (choice E) results from tearing of the bridging subdural veins, most often due to trauma or shearing forces. It is uncommon without trauma and, even when present, does not tend to produce headache and increased ICP unless very severe.
A 55-year-old woman presents to the emergency department because of chest pain. The pain, which has lasted 3 hours, is substernal and dull in nature, with no relation to respiration or position. The pain does not radiate and is accompanied by weakness, lightheadedness, and nausea. She has received oxygen, aspirin, a continuous infusion of nitroglycerin, and a beta blocker. Her chest x-ray film is normal, and her ECG is remarkable for inverted T waves in leads II, III, and aVF. Which of the following is the most important next step in management?
(A) Nifedipine
(B) IV heparin
(C) IV thrombolytic therapy
(D) Cardiac catheterization
(E) Percutaneous coronary angioplasty
Respuesta: B
The correct answer is B. The patient has unstable angina. Unstable angina with ECG changes is associated with critical coronary artery stenosis in most cases. One goal of therapy is to prevent thrombus formation on complex atherosclerotic plaques; heparin is the most effective proven treatment to prevent progression of unstable angina to myocardial infarction. Heparin is also required to maintain vessel patency when using relatively fibrin-specific thrombolytics, such as tPA. Heparin may cause delayed thrombocytopenia in about 10% of cases.
Nifedipine (choice A), a calcium-channel blocker, has no proven benefit in the therapy of acute myocardial infarction. The drug decreases afterload and may cause a reflex tachycardia.
The patient does not meet the criteria for thrombolytic therapy (choice C). The best candidate for thrombolytic therapy is one in whom the ECG has distinct regional ST segment elevation or new left bundle branch block. Thrombolytic therapy has not been shown to benefit patients with inverted T waves, ST segment depression, or nonspecific ST-T waves changes and chest pain.
The patient may eventually require catheterization (choice D) to see the extent of the coronary artery disease, but it is not the appropriate next step in management.
Angioplasty (choice E) should be considered if chest pain refractory to medical management persists, but it is not the appropriate next step in management.
A 40-year-old man consults a physician because of dizziness. The patient has noticed that every time he lays with the right side of his head down, he develops a whirling sensation within a few seconds. This symptom will last as long as the position is maintained, but resolves when a new head position is taken. He does not experience tinnitis or hearing changes during these episodes. Otoscopic examination is within normal limits. Which of the following is the most likely diagnosis?
(A) Benign paroxysmal positional vertigo
(B) Cholesteatoma
(C) Herpes zoster oticus
(D) Meniere disease
(E) Presbyacusis
Respuesta: A
The correct answer is A. This patient has benign paroxysmal positional vertigo. The pathophysiology appears to involve granular masses (tiny rocks) that sit on the cupola in the inner ear, pushing the cilia (hairs) on the sensory cells down. Certain positions compress the cells more, producing vertigo. Patients should be instructed to avoid the position that sets off the vertigo. A canalith repositioning maneuver is effective in most cases, but chronic cases may require surgical treatment. Some cases resolve spontaneously within a year.
Cholesteatoma (choice B) is a tumor-like, benign lesion that can destroy the middle ear and occurs in the setting of chronic otitis media.
Herpes zoster oticus (choice C), or herpes infection of the ganglion of CN VIII, causes severe ear pain, vertigo, hearing loss, and sometimes facial nerve paralysis.
Meniere disease (choice D) causes the cluster of vertigo, tinnitis, and fluctuating hearing loss, but is usually not triggered by positional changes.
Presbyacusis (choice E) is a progressive loss of sensitivity to high frequencies with age.
A 62-year-old woman with a history of depression and hypertension presents complaining of recurrent falls over the past 6 months. She had been having difficulty with complex tasks at work and was recently asked to leave. On examination, her mental status is unremarkable. Her cranial nerve examination is notable for limited downward gaze. She has prominent, symmetric bradykinesia with more axial than limb rigidity. There is no resting tremor. Her gait is stiff with “en bloc” turning. Reflexes are normal, with downgoing toes. An MRI of the brain is read as showing a small lacunar infarct in the left putamen. She has recently been started on L- dopa/carbidopa but has had little to no improvement in her symptoms. Which of the following is the most likely diagnosis?
(A) Basal ganglia stroke
(B) Carbon monoxide poisoning
(C) Cervical stenosis
(D) Parkinson disease
(E) Progressive supranuclear palsy
Respuesta: E
The correct answer is E. Progressive supranuclear palsy is a degenerative disorder that predominantly affects the midbrain and basal ganglia. The clinical hallmarks are symmetric parkinsonism with vertical gaze limitation and axial rigidity. These patients tend to have falls as their earliest symptoms. There is an associated mild-to-moderate dementia that usually involves frontal lobe functions more than hippocampal/memory systems. These patients tend to show a very modest response, if any, to L-dopa/carbidopa. Imaging is typically unremarkable.
The basal ganglia (choice A) is a common site of small lacunar strokes in patients with hypertension and/or diabetes. Most of these tend to be asymptomatic, and vascular parkinsonism requires a heavier burden of disease in the basal ganglia. In addition, a unilateral left putamenal lacunar infarct would result in right-sided, rather than symmetric, symptoms.
Carbon monoxide poisoning (choice B) results in bilateral pallidal (globus pallidus) necrosis. These patients develop symmetric parkinsonian symptoms but would not be expected to have vertical gaze problems. In addition, an MRI would demonstrate bilateral lesions in the putamen.
Cervical stenosis (choice C) with impingement on the spinal cord can present with falls and a spastic gait but should not affect eye movements or cognition. These patients should have hyperreflexia and upgoing toes.
Idiopathic Parkinson disease (choice D) typically begins asymmetrically, with resting tremor and rigidity worse on one side of the body. Vertical eye movements are not usually affected. Falls occur but normally a few years into the course of the disease. Patients with idiopathic Parkinson disease will usually experience a pronounced improvement in symptoms when started on Sinemet.
A 22-year-old man presents with burning on urination and a milky urethral discharge for 3 days. He had unprotected sex 5 days prior to the onset of these manifestations. A smear of the urethral discharge demonstrates gram-negative diplococci in neutrophilic granulocytes. The patient reports no allergies. Which of the following is the most appropriate treatment?
(A) Amoxicillin
(B) Azithromycin
(C) Ceftriaxone
(D) Doxycycline
(E) Penicillin G
Respuesta: C
The correct answer is C. This is the typical presentation of gonorrhea in men. The infection may regress spontaneously, progress to involve the epididymis and prostate, or become chronic, resulting in urethral strictures. In women, the infection is more often clinically silent, but when symptomatic, the manifestations frequently begin during menses, with frequency, dysuria, and urethral discharge. Chronic cervicitis is an important reservoir of gonococci. If gonococci cannot be demonstrated in smears of the discharge, cultures become necessary. For uncomplicated urethritis or cervicitis, a single intramuscular injection of ceftriaxone, 125 mg, is the treatment of choice and guarantees compliance.
Amoxicillin (choice A) and penicillin G (choice E) are no longer recommended because of the increasing prevalence of penicillin-resistant strains of gonococcus.
Chlamydial infection develops frequently in association with gonorrhea. Thus, therapy with ceftriaxone should be combined with a drug effective against chlamydia. Erythromycin, 500 mg 4 times daily for 1 week, or alternatively azithromycin (choice B) in a single oral dose of 1 g, may be used.
Doxycycline (choice D) is also effective against chlamydia and should be administered at a dosage of 100 mg twice daily for 1 week.
A 50-year-old woman presents with a chief complaint of dizziness when she gets out of bed in the morning. During the episodes of dizziness, she feels very warm and flushed. She admits to frequent episodes of abdominal cramping and severe watery diarrhea during the past year, and she recently began having dry, itchy skin. On physical examination, she has a 2/6 systolic murmur best heard at the left lower sternal border. No wheezing, rhonchi, or crackles are apparent on lung examination. Laboratory results are unremarkable. Which of the following is the most appropriate next step in diagnosis?
(A) Barium examination of the bowel
(B) Measurement of serum lipase and amylase levels
(C) Ultrasound of the abdomen
(D) Urinalysis for 5-hydroxyindoleacetic acid (5-HIAA)
(E) Small bowel biopsy
Respuesta: D
The correct answer is D. This woman has carcinoid syndrome. The classic triad of this disorder is flushing (present in 85%), watery diarrhea, and valvular heart disease. The first test for screening carcinoid syndrome is the determination of 5-HIAA (metabolite of serotonin, 5-HT) in a 24-hour urine sample (carcinoid patients may excrete more than 25 mg/day). Carcinoid syndrome is also associated with hypotension, bronchospasm, telangiectasia, and abdominal cramps due to the release of serotonin and vasoactive peptides, especially in bronchial carcinoid. There may also be a secondary niacin deficiency, causing dermatitis, depression, and diarrhea. Symptomatic treatment of carcinoid syndrome consists of giving the synthetic peptide octreotide.
Barium examination of the bowel (choice A) will often not
demonstrate the primary carcinoid tumor, most commonly located in the distal ileum.
Measurement of serum lipase and amylase levels (choice B) is indicated in the diagnosis of pancreatitis.
Ultrasound examination (choice C) would be indicated if she had symptoms pointing to an abdominal mass or gallbladder disease.
Small bowel biopsy (choice E) is invasive and would not aid in the diagnosis.
A 40-year-old woman consults a physician about a “mole” on her neck. The lesion is 2 cm in diameter and slightly irregular, and has a variegated dark red to brown to black color. Wide excision of the lesion demonstrates a malignant neoplasm that extends to a depth of 3 mm. This tumor would be most likely to stain for which of the following tumor markers?
(A) Alpha-fetoprotein
(B) CA-125
(C) Leukocyte common antigen (LCA)
(D) Prostate specific antigen (PSA)
(E) S-100
Respuesta: E
The correct answer is E. The tumor is a malignant melanoma, which is a neoplastic proliferation of melanocytes. The cells in these tumors are related to neuroendocrine cells and often stain immunohistochemically for S-100. The prognosis in malignant melanoma is closely related to the depth of the lesion, since shallow lesions are much less likely to metastasize than are lesions of 1 mm or more thickness, which have reached the rich lymphatic plexus of the superficial dermis. The result is that shallow melanomas have a close to 100% cure rate with wide (typically 1 cm) excision, whereas deep melanomas have a dreadful prognosis since they typically have already metastasized by the time of surgical removal and usually fail to respond to chemotherapy.
Alpha-fetoprotein (choice A) is a marker for testicular and ovarian tumors with a yolk sac component, as well as hepatocellular carcinoma.
CA-125 (choice B) is a marker for some ovarian tumors.
LCA (choice C) is a marker for some lymphoid neoplasms.
PSA (choice D) is a marker for prostatic carcinoma.
A 19-year-old homosexual college freshman presents to the student health clinic complaining of diarrhea of 2 days’ duration. He returned 9 days ago from a spring break trip to Mexico. His diarrhea is accompanied by prominent bloating, flatulence, nausea, and general malaise. On physical examination, he appears to be well hydrated, with a temperature of 36.9 C (98.4 F), blood pressure of 130/86 mm Hg, pulse of 89/min, and respirations of 18/min. Examination of the abdomen reveals diffusely hyperactive bowel sounds without tenderness or masses. A stool sample is negative for red and white blood cells. Which of the following is the most appropriate next step in management?
(A) Supportive care with IV fluids
(B) Treatment with ciprofloxacin
(C) Treatment with mebendazole
(D) Treatment with metronidazole
(E) Treatment with trimethoprim-sulfamethoxazole
Respuesta: D
The correct answer is D. This patient probably has giardiasis, caused by Giardia lamblia. The diagnosis of giardiasis can often be made clinically on the basis of symptoms of flatulence and bloating appearing several days after a trip to Mexico (and endemic zones). Metronidazole is the treatment of choice for giardiasis.
Supportive care with IV fluids (choice A) is used for patients with Escherichia coli “traveler’s diarrhea” who are severely dehydrated. Patients generally have diarrhea the day after they return from their trip, rather than 1 week later.
Ciprofloxacin (choice B) is effective for Shigella and Salmonella infections. Patients usually have fever and blood or leukocytes in the stool, since these agents are invasive.
Mebendazole (choice C) is indicated for infection with helminths.
Trimethoprim-sulfamethoxazole (choice E) is not effective against Giardia lamblia.
A 26-year-old woman has a 10-year history of type 1 diabetes mellitus. She has maintained strict glycemic control and has had no significant diabetic complications so far. On her last routine examination, her blood pressure is 125/78 mm Hg. Blood chemistry studies are within normal limits. Funduscopic examination reveals no evidence of diabetic retinopathy. Which of the following is the most appropriate next step in management to prevent diabetic nephropathy?
(A) Periodic measurement of serum creatinine levels
(B) Screening for microalbuminuria with dipstick examination of urine
(C) Screening for microalbuminuria with 24-hour urine collection
(D) Administration of ACE inhibitors
(E) Renal biopsy
Respuesta: D
The correct answer is C. Diabetes mellitus is the most common cause of chronic renal failure in the U.S. (and probably in all industrialized countries). Diabetic nephropathy is one of the most severe complications and manifests on average 10-15 years after the onset of diabetes. The earliest expression of diabetic nephropathy is microalbuminuria, while the patient is otherwise asymptomatic. This is the rationale for screening diabetic patients for microalbuminuria, which should be performed by 24-hour urine collection or on an early morning urine sample. In the latter case, dipstick screening (choice B) may not be sufficiently sensitive. The albumin:creatinine ratio in an early morning urine sample is a convenient alternative to 24-hour collection. A ratio < 3.5 is normal and >10 is abnormal; between these two values, reevaluation is recommended. During the phase of microalbuminuria, aggressive treatment, including strict glycemic and blood pressure control, is in order.
Measurement of serum creatinine levels (choice A) would not be valuable in detecting preclinical renal damage.
Treatment with ACE inhibitors (choice D) has been shown to slow progression of renal nephropathy, possibly because of the reduction of intraglomerular pressure. This treatment is not widely used if microalbuminuria absent and the patient is normotensive.
Renal biopsy (choice E) is not indicated in asymptomatic diabetic patients as a method for prevention of renal disease.
A 45-year-old woman consults a physician because of chronic fatigue. A review of systems reveals long-standing stomach problems characterized by slow digestion and delayed emptying of her stomach. A complete blood count demonstrates a moderately severe megaloblastic anemia. Serum vitamin B12 level is 85 pg/mL; serum folate is 3 ng/mL; and serum iron is 105 mg/dL. Autoantibodies to intrinsic factor are detected in the serum. A biopsy of the stomach is most likely to show which of the following?
(A) Acute erosive gastritis
(B) Gastric atrophy
(C) Linitis plastica
(D) Menetrier disease
(E) Peptic ulcer
Respuesta: B
The correct answer is B. The patient has pernicious anemia, in which gastric atrophy is associated with megaloblastic anemia due to vitamin B12 deficiency. The gastric atrophy characteristically involves the corpus, with sparing of the antrum. Most cases appear to have an autoimmune basis, with antibodies to parietal cells detected in 90% of patients; antibodies to intrinsic factor and the proton pump (H+/K+ ATPase) are also commonly present. The lack of parietal cells and the damage to the proton pump lead to markedly decreased acid secretion by the stomach. Lack of intrinsic factor leaves the small bowel unable to absorb vitamin B12, leading to megaloblastic anemia.
Acute erosive gastritis (choice A) is seen most often in severely ill patients, who develop multiple small gastric ulcers.
Linitis plastica (choice C) is an aggressive form of adenocarcinoma of the stomach that produces a “leather bottle” stomach.
Menetrier disease (choice D) is characterized by markedly
thickened gastric folds with mucous gland hyperplasia. It presents with weight loss and severe protein wasting because of protein loss from the gastric mucosa.
Peptic ulcer disease (choice E) usually occurs in the setting of Helicobacter pylori infection or NSAID use and is very rare in pernicious anemia, since gastric acid secretion is markedly diminished.
A 72-year-old man who was recently diagnosed with lymphoma has been undergoing chemotherapy for the past 3 weeks. He now develops acute renal failure. His laboratory studies reveal a creatinine of 4 mg/dL, urea nitrogen of 15 mg/dL, and uric acid level of 20 mg/dL. Which of the following would most likely have prevented this patient’s acute renal failure?
(A) Allopurinol
(B) Diphenhydramine
(C) Furosemide
(D) N-acetylcysteine
(E) Nifedipine
(F) Urinary acidification
Respuesta: A
The correct answer is A. Instituting chemotherapy in this patient has resulted in tumor lysis syndrome (TLS). TLS results from the the acute lysis of lymphoma cells and the acute renal failure from the precipitation of uric acid and hypoxanthine in the renal collecting tubules. Patients should receive allopurinol, a xanthine oxidase inhibitor that reduces the synthesis of uric acid, and should be aggressively hydrated prior to the initiation of chemotherapy to reduce the incidence of TLS.
Diphenhydramine (choice B) is an antihistamine that may be used in allergic conditions. Because TLS is not due to a drug allergy, diphenhydramine has no role in its prevention or management.
Furosemide diuretic (choice C) is reserved for well hydrated patients with insufficient diuresis. It increases the excretion of water but has not been proven to be beneficial as front-line therapy in TLS. It may contribute to uric acid or calcium phosphate precipitation in renal tubules in volume-contracted patients.
N-acetylcysteine (choice D) is used in the treatment of acetaminophen overdose and may be used to reduce hemorrhagic cystitis due to cyclophosphamide and ifosfam. However, it has no role in the prevention of TLS.
Nifedipine (choice E) is a calcium channel blocker used to treat hypertension and angina. It has no role in the prevention of TLS.
Urinary alkalinization, not urinary acidification (choice F), is a method of managing TLS. Intravenous sodium bicarbonate promotes alkaline diuresis and acts to solubilize (and thus minimize) intratubular precipitation of uric acid.
A 30-year-old man consults a physician because of weight loss and fatigue. A complete blood count demonstrates an erythrocyte count of 2.2 million/mm3, a leukocyte count of 105,000/mm3, and a platelet count of 100,000/mm3 . The peripheral smear shows many abnormal white cells containing multiple Auer rods. Remission is achieved with chemotherapy, and the decision is made to treat the patient with total body irradiation followed by allogeneic bone marrow transplantation. Depletion of which of the following cells in the transplanted marrow tends to decrease the incidence of subsequent graft-versus-host disease?
(A) B cells
(B) Megakaryocytes
(C) Promyelocytes
(D) Pronormoblasts
(E) T cells
Respuesta: E
The correct answer is E. The patient has acute myeloid leukemia (AML). Auer rods are pathognomonic for AML. Patients who have this disease and undergo bone marrow transplantation in the first remission have a 50 to 60% chance of long-term, disease-free survival. The major complications of allogeneic bone marrow transplantation are infection, failure of graft survival, recurrent leukemia, and graft-versus-host disease. The incidence of graft-versus-host disease can be reduced by removal of T cells from the donor marrow by using monoclonal antibodies, rosetting techniques, or mechanical separation.
B cells (choice A) are not as important as T cells in graft-versus- host disease.
Megakaryocytes (choice B), promyelocytes (choice C), which are granulocyte precursors, and pronormoblasts (choice D), which are erythrocyte precursors, play no role in graft-versus-host disease.
A 40-year-old woman presents to her physician’s office with a rash on her legs for the past 4 days. She recalls a recent respiratory infection. On examination, there is a small amount of blood in her nostrils. There are several hemorrhagic bullae in her oral cavity. Her lungs are clear, cardiac examination is unremarkable, and her abdomen is soft with no palpable spleen or liver. Both lower extremities have multiple dark blue ecchymoses.
Laboratory analysis reveals:
Leukocyte count: 9000/mm3
Hemoglobin: 10.1 g/dL
Platelets: 9000/mm3
Peripheral smear: Reticulocytosis with normal erythrocytes and megathrombocytes
An ultrasound examination is negative for masses or fluid collections. Which of the following is the most appropriate next step in management?
(A) Cryoprecipitate
(B) Immunoglobulins
(C) Prednisone
(D) Plasmapheresis
(E) Splenectomy
Respuesta: C
The correct answer is C. This woman most likely has idiopathic thrombocytopenic purpura (ITP). ITP is most common in adults (women > men) aged 20-40 years. Bleeding, epistaxis, oral bleeding, or menorrhagia can occur, and isolated thrombocytopenia (< 10,000) is characteristic. Ten percent of patients will have coexistent autoimmune hemolytic anemia (note the reticulocytosis and anemia). The first-line therapy is prednisone if the patient is not actively bleeding. Patients who are bleeding may require IV immunoglobulin (choice B) to block phagocytic activity; in severe cases, splenectomy (choice E) may be required.
Cryoprecipitate (choice A) is effective treatment for von Willebrand disease.
Plasmapheresis (choice D) is the treatment of choice for hemolytic uremic syndrome (HUS) in a coagulation disorder setting. The most striking features of HUS are fever, fragmented RBC, and renal failure without neurologic signs. HUS is often seen after a diarrheal illness, particularly after infection with Escherichia coli 0157:H7.
A 30-year-old man presents with a rapidly enlarging, single, stony hard, palpable 2.5-cm nodule in his thyroid gland. Thyroid isotope scanning demonstrates the nodule to be “cold.” On resection of the thyroid gland with subsequent pathologic examination, the nodule is found to contain follicular structures, some of which have inwardly protruding fibrovascular branching cores covered by epithelial cells. Many of the epithelial cells have “orphan Annie” nuclei. Which of the following is the most likely diagnosis?
(A) Follicular carcinoma of the thyroid
(B) Graves disease
(C) Hashimoto disease
(D) Nontoxic goiter
(E) Papillary carcinoma of the thyroid
Respuesta: E
The correct answer is E. Papillary structures within follicles that have epithelial cells with nuclei with cleared centers (“orphan Annie eyes”) indicate the presence of papillary carcinoma of the thyroid. It does not matter whether the papillary structures are present in only a percentage of the follicles; the condition is still considered to be papillary carcinoma. Of all thyroid cancers, 60% to 70% are papillary carcinomas. The condition is more frequent in younger patients but tends to be more aggressive in the elderly. There is usually a single dominant nodule that is “cold” (does not take up radioactive iodine) on thyroid scan. Among the different types of thyroid cancers, papillary carcinoma tends to be the one with the best prognosis overall, and smaller lesions can be treated with thyroid lobectomy alone. Large or more diffusely spreading lesions require complete thyroidectomy, sometimes with ablation of any residual thyroid tissue with large doses of 131I.
Follicular carcinoma of the thyroid (choice A) would not exhibit the papillary structures or orphan Annie nuclei seen in this case. Well- differentiated follicular carcinoma can be very difficult to distinguish from normal thyroid tissue.
Graves disease (choice B) would be characterized by prominent hyperthyroid symptoms and would show smaller than normal amounts of colloid on biopsy. This disease is not characterized by a single hard nodule; a symmetric, diffusely enlarged goiter may be found.
Hashimoto disease (choice C) would produce diffuse goiter and would show an intense lymphocytic infiltrate with destruction of follicles on biopsy. Symptoms of hypothyroidism are often apparent.
Nontoxic goiter (choice D) produces a goiter that may be either smooth or multinodular, but does not usually have a single dominant nodule. On biopsy, the follicles are typically of a wide range of sizes, and the patient is usually clinically euthyroid.
A 38-year-old man is admitted to the hospital after sustaining a pulmonary embolism. The patient has a past medical history significant for two idiopathic deep venous thromboses and takes only an aspirin daily. Three hours ago, he developed acute shortness of breath, pleuritic chest pain, and palpitations. He was taken by ambulance to the hospital. In the emergency department, he was diagnosed with a pulmonary embolus on the basis of clinical signs and symptoms and a ventilation-perfusion scan. He was started on IV unfractionated heparin at that time. Which of the following laboratory tests would be most appropriate to guide therapy with this drug?
(A) Bleeding time
(B) Factor Xa levels
(C) Platelet count
(D) Prothrombin time (PT)
(E) Partial thromboplastin time (PTT)
Respuesta: E
The correct answer is E. The dose of traditional unfractionated heparin required for anticoagulation can be determined by following the partial thromboplastin time (PTT). Heparin prolongs the PTT. This test is performed by adding particulate matter to a patient’s blood sample to activate the intrinsic coagulation cascade; the PTT therefore reflects activity of the intrinsic coagulation pathways.
Bleeding time (choice A) reflects the interaction of platelets with the vascular endothelium leading to the formation of an initial clot. An abnormal bleeding time usually reflects abnormal or diminished platelets.
Factor Xa levels (choice B) are used to follow the dosing of the newer, low-molecular-weight heparins.
Platelet count (choice C) may be followed while giving IV heparin, since a significant minority of patients will develop heparin-induced thrombocytopenia. The platelet count, however, is not the test used to monitor efficacy of heparin therapy and any dosing changes.
Prothrombin time (PT; choice D) is a measure of the extrinsic coagulation system. This value, and the corresponding international normalized ratio (INR) of patient and normal PTs, is particularly sensitive to deficiencies in factor VII. It is usually used to help guide Warfarin therapy.
A 48-year-old man presents to the physician’s office with progressive hearing loss in his right ear for the past several months. He describes a ringing and hissing sound in his right ear, and he feels unsteady on his feet, as if he is losing his sense of balance. His past medical history includes syphilis, which was treated at age 20, and bronchial asthma, which is controlled with medications. On physical examination, right-sided facial numbness is noted, and a Rinne test shows air conduction that is greater than bone conduction. Routine laboratory profile is normal, and rapid plasma reagin is negative. Which of the following is the most likely diagnosis?
(A) Acoustic neuroma
(B) Benign positional vertigo
(C) Lyme disease
(D) Ménière disease
(E) Tertiary syphilis
Respuesta: A
The correct answer is A. Acoustic neuroma, also known as neurilemoma or schwannoma, is a benign tumor that typically arises from the neurilemmal sheath of the vestibular portion of the acoustic nerve in the auditory canal. Symptoms are produced by compression or displacement of the cranial nerves, brainstem, and cerebellum and by obstruction of CSF flow. The trigeminal (CN V) and facial (CN VII) nerves are often affected because of their anatomic location and relationship to the acoustic nerve. Clinical findings include insidiousonset of sensorineural hearing loss, tinnitus, and a sensation of fullness in the ear. Facial numbness, facial weakness, headache, and gait ataxia may also be present; vertigo ultimately develops in 20% to 30% of patients. The most useful diagnostic test is MRI of the cerebellopontine angle. Treatment is surgical excision of the lesion.
Patients with benign positional vertigo (choice B) experience vertiginous symptoms only when the head is in a specific position. Symptoms are usually most severe when the patient is in the lateral decubitus position with the affected ear down. Hearing loss is not a feature of this condition.
There is no specific reason at this time to suspect Lyme disease (choice C), although it should be included in the differential.
Ménière disease (choice D) is characterized by repeated episodes of vertigo lasting minutes to days, tinnitus, and progressive sensorineural hearing loss.
Tertiary syphilis (choice E) or neurosyphilis presents 3 to 10 years after untreated syphilis, with personality changes, ataxia, blurred vision, headache, dizziness, and hearing loss. Pupillary response to light is lost (Argyll Robertson pupils), and there is loss of proprioception and vibration sense. Although this patient has a history of syphilis at age 20, he was treated and his present rapid plasma reagin test is negative. Therefore, neurosyphilis is unlikely.
A 22-year-old woman comes to the physician for her first physical health examination in several years. She says that she has always been in good health except for irregular menses in the past year. She does not take any medication or smoke. Her blood pressure is 137/80 mm Hg. Her height is 160 cm (63 in), and her weight is 83 kg (185 lb). Physical examination reveals a slight increase in upper lip and chin hair. She reports that she has been gaining weight since the age of 15 despite all attempts to both limit calorie intake and exercise. Which of the following is the most appropriate next step in management?
(A) No intervention needed at this time
(B) Explanation of risks of obesity and benefits of weight loss
(C) Laboratory investigations to exclude secondary causes of obesity
(D) Referral to weight reduction program for very-low-calorie diet
(E) Pharmacologic treatment with the serotonin reuptake inhibitor sibutramine
Respuesta: C
The correct answer is C. Obesity can be defined by using the nomograms based on the statistical studies of the National Center for Health Statistics on large population samples in the U.S. These data allow estimating the body mass index (BMI) from height (in inches) and weight (in pounds) [To calculate this index more rigorously, BMI = weight/(height)2 , where weight is in kilograms and height is in meters]. Most authors agree that obesity is present when the BMI is higher than 30 kg/m2. This patient has a BMI of 33 kg/m2. Once obesity is identified, the most appropriate next step is to determine whether obesity is secondary to underlying pathologic conditions. Physical examination and history should focus on detecting signs and symptoms of the three most common causes of secondary obesity, namely hypothyroidism, Cushing syndrome, and genetic conditions. In this case, menstrual irregularities and slight hirsutism are features that suggest the need to undertake additional investigations to rule out endocrinologic or genetic causes. Stein-Leventhal syndrome (in addition to those mentioned) should be considered in this case.
No intervention at this time (choice A) would not be appropriate. Active diagnostic and therapeutic interventions are needed for all patients whose BMI is >30 kg/m2 , and patients with BMI >27 kg/m2 should be encouraged to lose weight. In fact, it is well established that obesity is associated with increased risk of developing hypertension, diabetes, cardiovascular disease, cholelithiasis, pulmonary dysfunction, osteoarthritis, and some forms of cancer.
The physician should explain the risks of obesity and benefits of weight loss (choice B) to all overweight patients, although most of them are already painfully aware of the disadvantages inherent to obesity, with regards to both health risks and social stigma.
Treatment options for obese patients include decreasing calorie intake and/or increasing energy expenditure, variably combined with techniques of behavioral modification. A weight reduction program for a very-low-calorie diet (choice D) is an aggressive approach that replaces the whole daily food intake with a diet or a beverage containing no more than 800 kcal/day, 1 g protein/kg of body weight, plus all of the necessary vitamins and minerals. This diet is used as part of a comprehensive weight-loss program, in which the patient is closely monitored by a medical specialist to prevent possible serious adverse effects.
Pharmacologic treatment with the serotonin reuptake inhibitor sibutramine (choice E) has been approved by the FDA for treatment of obesity. However, the long-term effects of this therapy are still under investigation. Hypertension has been observed in some patients. In any case, this type of treatment should be used only after secondary obesity has been excluded.
A 55-year-old man presents to a physician because of a 2-month history of difficulty swallowing. At first, the difficulty was only with large bites of solid food, and he was able to limit it by taking smaller bites and washing them down with drinks. However, he now has trouble with small bites and liquids. He has a long history of heavy use of both alcohol and cigarettes. Esophagoscopy demonstrates a large, irregular polypoid mass that is nearly occluding the upper third of the esophagus. A biopsy of the tumor is most likely to show which of the following?
(A) Anaplastic squamous epithelial cells with numerous mitotic figures
(B) Large, lymphocytic cells with large, prominent nucleoli
(C) Mucin-producing glandular tissue with signet ring cells
(D) Small, lymphocytic cells with irregular nuclei and condensed chromatin
(E) Small, polygonal cells with neurosecretory granules
Respuesta: A
The correct answer is A. Cancers involving the upper third of the esophagus are usually squamous cell in origin; histologically, they are described as anaplastic squamous cells with numerous mitotic figures. Lower esophageal cancers may be either squamous cell carcinomas or adenocarcinomas (usually arising in Barrett esophagus). Esophageal cancer has a very poor prognosis (most patients die within 2 years) because the cancer usually has advanced through the esophageal wall by the time the patient presents with dysphagia. Because the esophageal wall is thin, it is easy for the cancer to penetrate to the level of the lymphatics (less than 1 mm), where metastasis can occur, or penetrate completely through the esophagus (2 to 4 mm) to directly involve nonresectable mediastinal structures, such as the aorta, heart, or vicinity of the carina of the bronchial tree. Predisposing factors for squamous cell carcinoma of the esophagus include alcohol and tobacco use, human papillomavirus, esophageal scarring (lye ingestion, irradiation), sclerotherapy, and chronic achalasia.
Large, lymphocytic cells with large, prominent nucleoli (choice B) describe large cell lymphoma, whereas small, lymphocytic cells with irregular nuclei and condensed chromatin (choice D) describe small cell lymphoma. Both of these cancers are unlikely to be found in this patient.
Mucin-producing glandular tissue with signet ring cells (choice C) is the classic description of adenocarcinoma, which is unlikely to be found in the upper third of the esophagus. It usually arises in patients who have had long-standing metaplastic changes of Barrett esophagus.
Small, polygonal cells with neurosecretory granules (choice E) describe small cell carcinoma of the lung, which is also called oat cell carcinoma. This cancer is strongly associated with cigarette smoking and usually presents as a central or hiker lung tumor.
A 19-year-old African American woman with sickle cell anemia has had palpitations and dizziness for 3 days. She works part-time in a daycare center. Her temperature is 38.1 C (100.5 F), pulse is 110/min, and respirations are 18/ min. The cardiac examination is significant for a systolic murmur heard best at the apex. Her lungs are clear, and her abdominal examination is unremarkable. Laboratory studies reveal a hemoglobin of 6.0 g/dL. A blood smear stained with Wright’s stain demonstrates Howell-Jolly bodies and the absence of reticulocytes. Which of the following is the most likely pathogen?
(A) Influenza virus
(B) Parainfluenza virus
(C) Parvovirus
(D) Salmonella
(E) Streptococcus pneumoniae
Respuesta: C
The correct answer is C. This patient is experiencing an aplastic crisis due to parvovirus infection. Parvovirus exposure is common in daycare centers. Individuals with sickle cell disease, like those with other chronic hemolytic diseases, are susceptible to infection with parvovirus. Patients usually present with weakness, lethargy, and severe anemia often preceded by a few days of nonspecific symptoms. These patients have intense reticulocytopenia, and the bone marrow contains no erythroid precursor cells, despite a normal myeloid series. A transient aplastic crisis due to parvovirus infection may produce life-threatening anemia and may require urgent transfusion. Note that Howell-Jolly bodies are consistent with asplenism.
Influenza virus (choice A) and parainfluenza virus (choice B) present with fever and systemic symptoms, including myalgia, headache, and malaise. Sudden development of severe anemia with reticulocytopenia is not seen in these infections.
Salmonella infection (choice D) is more common in sickle cell patients because of splenic hypofunction, but it presents either as typhoidal illness or diarrhea. Selective red cell aplasia is not a feature of Salmonella infection. Note that osteomyelitis due to
Salmonella is more common in sickle cell patients.
Infection due to Streptococcus pneumoniae (choice E), although common in sickle cell disease patients because of splenic hypofunction, more frequently manifests as pneumonia or, less commonly, as meningitis.
A healthy 20-year-old man presents with a history of recurrent episodes of severe throbbing headache. The headaches are triggered or aggravated by noise and stress and last for several hours. The pain is frequently preceded by visual disturbances, such as luminous stars or zigzags of light, and accompanied by nausea and vomiting. His father experienced a similar form of headache. The patient has found no relief with aspirin and ibuprofen. Which of the following is the most appropriate drug treatment during the acute attacks?
(A) Acetaminophen
(B) Calcium-channel antagonists
(C) Carbamazepine
(D) Ergotamine
(E) Prednisone
Respuesta: D
The correct answer is D. The clinical picture is virtually
pathognomonic of migraine, especially considering the premonitory visual symptoms (the aura), the throbbing quality of the pain, and the positive family history. However, migraine does not always present classically. A common form of migraine may be more frequent, with diffuse (not unilateral) throbbing pain of moderate intensity, which is not preceded by visual disturbances or associated with nausea. Acute treatment is based on the administration of antimigraine drugs at the onset of symptoms. Effective drugs include ergotamine tartrate or similar compounds, and sumatriptan.
Prophylactic treatment is aimed at decreasing the frequency of
attacks. Calcium-channel blockers (choice B), for example, have been used for prophylaxis.
Acetaminophen (choice A) is very unlikely to provide relief in classic migraine, especially if aspirin and ibuprofen have already failed to do so.
Carbamazepine (choice C) has been found particularly helpful in the treatment of trigeminal neuralgia (tic douloureux), but not in migraine.
Prednisone (choice E) should be used to treat patients manifesting signs and symptoms strongly suggestive of giant cell arteritis (temporal arteritis), which may lead to blindness in the absence of effective anti-inflammatory therapy. However, temporal arteritis is much more common in the elderly and would not be in the differential diagnosis in this 20-year-old.
A 55-year-old man consults a physician because of weight loss and severe abdominal pain of several months’ duration. The pain radiates to the mid-back and is slightly relieved when he assumes a bent forward position. On physical examination, the man appears emaciated, with mild jaundice. The liver edge is palpable and smooth; the liver depth is not increased. The clinician suspects pancreatic cancer. Which of the following tests is the most appropriate next step in diagnosis?
(A) CT scan
(B) MRI scan
(C) Ultrasound
(D) Arteriography
(E) Endoscopic retrograde pancreatography
Respuesta: A
The correct answer is A. Ductal carcinoma of the pancreas is often devastating because, in roughly 90% of cases, it presents late in the clinical course, when it is no longer resectable. Therefore, the first step when this disease is suspected on clinical grounds is a CT scan, which is now recommended as the most cost-effective method of both diagnosing and staging the tumor (i.e., determining whether it is potentially resectable). If unresectable disease is detected, then definitive tissue diagnosis (for choice of chemotherapy) can be made on the basis of CT-guided percutaneous needle aspiration or biopsy. If a potentially resectable lesion is identified, endoscopic ultrasound (not yet widely available) can be used to search for small metastatic lesions not visible with CT.
MRI (choice B) is no more accurate than CT in detecting and staging pancreatic cancer, and is more expensive.
Ultrasound (choice C) is still frequently used, but usually is followed by CT scan. Therefore, the current thinking is to eliminate this test and go directly to CT, since the ultrasound is less sensitive.
Arteriography (choice D) is rarely used and is primarily for
determining vascular invasion and tumor resectability.
Endoscopic retrograde pancreatography (choice E) is still commonly used in working up pancreatic cancer. However, this is an invasive procedure and would not be the first step in diagnosis.
A 70-year-old man presents to his physician with complaints of blurred vision in his right eye along with intermittent loss of vision, which has been occurring for the past 3 days. He describes it as a “curtain passing vertically” across the visual field. He does not have any pain, fever, headache, nausea, or vomiting. He has a history of hypertension and diabetes and is a smoker. Current medications include captopril and twice-daily insulin. On examination, the conjunctivae are pink, the sclerae are clear, and the pupils bilaterally are 3-4 mm and reactive. Cranial nerves II-XII are intact, and there are no focal neurologic deficits. Which of the following is most likely diagnosis?
(A) Amaurosis fugax
(B) Diabetic retinopathy
(C) Retinal artery occlusion
(D) Retinal detachment
(E) Retinal vein occlusion
Respuesta: A
The correct answer is A. A sensation of a curtain passing across the visual field can be characteristic of either amaurosis fugax or retinal detachment (choice D). In this case, the phenomenon is transient, so amaurosis fugax is more likely than retinal detachment. Fleeting blindness is characteristically caused by retinal emboli from ipsilateral carotid disease. The visual loss is described as a curtain passing vertically across the visual field, with complete monocular visual loss lasting a few minutes. Amaurosis fugax may be due to cholesterol plaque release and is a precursor of retinal artery occlusion.
Diabetic retinopathy (choice B) is the most common cause of blindness in the U.S. in adults aged 20-65 years, but the clinical description favors a diagnosis of amaurosis fugax.
Retinal artery occlusion (choice C) is characterized by sudden profound visual loss. Pupils are unreactive to direct light, and there is a cherry-red spot on the fovea.
Retinal detachment (choice D) causes progressive, unilateral, and painless blurred/loss of vision in one eye. There is often a sensation of a curtain passing down over the eyes.
Retinal vein occlusion (choice E) produces a sudden decrease or loss of vision; the pupils react sluggishly to light. Younger patients may present with near normal vision, whereas older patients may have significant obscuration.
