Questions 201-240 Flashcards
(40 cards)
- For several years, a hypertensive 65-year-old female has been treated with hydrochlorothiazide, 25 mg/day; atenolol (Tenormin), 100 mg/day; and hydralazine, 50 mg 4 times/day. Her blood pressure has been well controlled on this regimen. Over the past 2 months she has experienced malaise, along with diffuse joint pains that involve symmetric sites in the fingers, hands, elbows, and knees. A pleural friction rub is noted on examination. Laboratory testing shows that the patient has mild anemia and leukopenia, with a negative rheumatoid factor and a positive antinuclear antibody (ANA) titer of 1:640.
Which one of the following would be the most appropriate INITIAL step?
A) Replace hydrochlorothiazide with furosemide (Lasix)
B) Discontinue hydralazine
C) Start prednisone, 40 mg/day orally
D) Start hydroxychloroquine (Plaquenil), 400 mg/day
E) Order renal function studies and anticipate that a renal biopsy will be needed
ANSWER: B
There are many drugs that can induce a syndrome resembling systemic lupus erythematosus, but the most common offenders are antiarrhythmics such as procainamide. Hydralazine is also a common cause. There is a genetic predisposition for this drug-induced lupus, determined by drug acetylation rates. Polyarthritis and pleuropericarditis occur in half of patients, but CNS or renal involvement is rare. While all patients with this condition have positive antinuclear antibody titers and most have antibodies to histones, antibodies to double-stranded DNA and decreased complement levels are rare, which distinguishes drug-induced lupus from idiopathic lupus.
The best initial management for drug-induced lupus is to withdraw the drug, and most patients will improve in a few weeks. For those with severe symptoms, a short course of corticosteroids is indicated. Once the offending drug is discontinued, symptoms seldom last beyond 6 months.
- A 52-year-old mechanic complains of an irritation in his right eye lasting for 2 days. On direct visualization you see a small, dark foreign body on the periphery of the cornea and are able to remove it with no complications. However, there is a patch of reddish-brown discoloration extending several millimeters around the area where the foreign body had been.
Which one of the following is most appropriate for this patient?
A) Watchful waiting
B) Irrigation with 0.9% saline solution under pressure
C) An antibiotic ointment to be used every 2–4 hours
D) Gentle debridement with a #11-blade scalpel
E) Prompt ophthalmologic evaluation
ANSWER: E
If a metal foreign body is present on the cornea for more than 24 hours a rust ring will often be present in the superficial layer of the cornea. This material is toxic to the cornea and should be removed as soon as possible, but it is not an emergency. The proper removal of a rust ring requires the use of a slit lamp and specialized ophthalmic equipment. Referral to an eye specialist within 24–48 hours is the best management in this case.
- A mother calls to ask your advice because her healthy 3-year-old, who has not been immunized against hepatitis A, attends day care with a child who was just diagnosed with the illness. You advise her that her child should receive
A) no prophylactic treatment
B) hepatitis A vaccine only
C) immunoglobulin only
D) hepatitis A vaccine and immunoglobulin
E) hepatitis A vaccine, along with other family members
ANSWER: B
Workers and children at child care centers should receive postexposure prophylaxis if one or more cases of hepatitis A is found in a child or worker. Hepatitis A vaccine is preferred over immunoglobulin because of its long-lasting effect, ease of administration, and efficacy. Children younger than 1 year of age should receive immunoglobulin. Family members should receive prophylaxis only during an outbreak and if their child is still in diapers.
- A 74-year-old male with hypertension, diabetes mellitus, and stage 3 chronic renal insufficiency presents to your office with a request from a consulting ophthalmologist for risk assessment prior to cataract surgery. His medications include lisinopril (Prinivil, Zestril), 20 mg daily; amlodipine (Norvasc), 5 mg daily; aspirin, 81 mg daily; pravastatin (Pravachol), 20 mg daily; and glipizide (Glucotrol), 5 mg daily. His blood pressure is 126/72 mm Hg. His most recent laboratory tests from 2 months ago show a hemoglobin A1c of 7.2% (N 4.0–5.6) and a serum creatinine level of 1.8 mg/dL (N 0.6–1.3). He is in his normal state of health, and is able to walk 1–2 blocks before having to stop to rest.
Which one of the following would be most appropriate with regard to preoperative medical testing for this patient?
A) No preoperative medical testing
B) ACBC
C) An EKG and cardiac stress testing
D) An EKG, and if results are abnormal, stress testing or echocardiography
ANSWER: A
In general, recommended preoperative testing is based on the patient’s medical history and risk factors, the risk associated with the planned surgery, and the patient’s functional capacity. In the case of cataract surgery, however, randomized, controlled trials have established a lack of benefit from preoperative testing for patients in their normal state of health (SOR A).
- In a patient without allergies who is admitted to the hospital for hip joint replacement, which one of the following is the recommended prophylactic antibiotic?
A) Ampicillin B) Ampicillin/sulbactam (Unasyn) C) Cefazolin D) Clindamycin (Cleocin) E) Vancomycin (Vancocin)
ANSWER: C
Cefazolin is the recommended prophylactic antibiotic for most patients undergoing orthopedic procedures such as total joint replacement, unless the patient has a B-lactam allergy (SOR A).
- A 45-year-old female presents to your office with knee pain. She was playing volleyball yesterday when she collided with another player and was unable to continue playing because of pain in her knee. The knee was swollen this morning. She is able to walk but not without pain, and she also has pain when she attempts to bend her knee. On examination there is medial joint line tenderness and a positive Thessaly test.
Which one of the following is the most likely cause of her knee pain?
A) Osteoarthritis B) Anterior cruciate ligament tear C) Collateral ligament tear D) Medial meniscus tear E) Tibial plateau fracture
ANSWER: D
A medial meniscus tear is the most likely diagnosis in a patient older than 40 who was bearing weight when the injury occurred, was unable to continue the activity, and has a positive Thessaly test. This test is performed by having the patient stand on one leg and flex the knee to 20°, then internally and externally rotate the knee. The presence of swelling immediately after the injury makes an internal derangement of the knee more likely, so osteoarthritis is less probable. This patient is able to bear weight, so a fracture is also not likely. Either a collateral ligament tear or an anterior cruciate ligament tear is possible, but these are not as common in this situation.
- You suspect orthostatic hypotension in an elderly male who reports “dizziness” when standing up, and you decide to obtain recumbent and standing blood pressure measurements. After the patient rests in a supine position for 5 minutes, you measure his baseline blood pressure and then ask him to stand, which he does without a problem.
For how long should his blood pressure be periodically measured before considering the test complete?
A) 30 seconds B) 60 seconds C) 90 seconds D) 3 minutes E) 5 minutes
ANSWER: D
Orthostatic hypotension is defined as a documented drop in blood pressure of at least 20 mm Hg systolic or 10 mm Hg diastolic that occurs within 3 minutes of standing. When symptomatic it is often described as lightheadedness or dizziness upon standing. Etiologies to consider include iatrogenic, neurologic, cardiac, and environmental causes, plus many others alone or in combination. Since orthostatic hypotension may result in syncope, leading to falls and substantial injury, identifying it and taking corrective steps can produce a significant benefit.
- Which metabolic disturbance is most likely to cause the EKG findings shown below?
A) Hyperkalemia
B) Hypercalcemia
C) Alkalosis
D) Hypothermia
ANSWER: A
Peaked T waves are most commonly associated with acute myocardial infarction and hyperkalemia (SOR A). Other causes include intracranial bleeding, left ventricular hypertrophy, and left bundle branch block. Hypocalcemia can cause peaked T waves on rare occasions, but hypercalcemia has no effect on T waves. Metabolic alkalosis is not associated with a particular EKG pattern, but it is associated with hypokalemia and can lead to the patterns resulting from the potassium deficit. Hypothermia causes an elevation at the J point, called either a J wave or an Osborn wave.
- A 30-year-old female asks about her contraceptive options. She has polycystic ovary syndrome and is currently being treated with spironolactone (Aldactone) for hirsutism.
Which one of the following should be used with caution, due to an increased risk of hyperkalemia?
A) Oral drospirenone/ethinyl estradiol (Yaz, Yasmin)
B) Oral norethindrone/mestranol (Necon 1/50)
C) Oral norgestimate/ethinyl estradiol (Ortho Tri-Cyclen)
D) Transdermal norelgestromin/ethinyl estradiol (Ortho Evra)
E) Depot medroxyprogesterone acetate (Depo-Provera)
ANSWER: A
Spironolactone is commonly used to treat hirsutism in women with polycystic ovary syndrome. One of its side effects is hyperkalemia. Using an oral contraceptive at the same time as spironolactone has a synergistic effect for treating hirsutism due to the low androgenic effects of oral contraceptives. Contraceptives containing drospirenone should be used with caution in patients taking spironolactone, however, because they can also lead to hyperkalemia. The other contraceptive options listed do not increase the risk for hyperkalemia.
- The etiologic agent that causes erysipelas is
A) Staphylococcus aureus B) Haemophilus influenzae C) Streptococcus pyogenes D) Pseudomonas aeruginosa E) Rubivirus
ANSWER: C
Erysipelas is caused primarily by group A Streptococcus, with a rare case caused by group C or G. Most cases of erysipelas involve the face, but the lesions can occur anywhere on the body. Penicillin is an effective treatment.
- A 45-year-old female is being treated for hypothyroidism with levothyroxine (Synthroid), 112 Xg daily. She is still having persistent fatigue and weight gain despite her TSH value of 1.5 XU/mL (N 0.5–5.5).
In addition to evaluating this patient for other causes of her symptoms, which one of the following would be appropriate management of her thyroid medication at this time?
A) Continuing the current therapy
B) Increasing the dosage
C) Adding liothyronine (Cytomel)
D) Switching to desiccated thyroid hormone (Armour Thyroid)
ANSWER: A
Some hypothyroid patients who are treated with appropriate dosages of levothyroxine and whose TSH levels are in the appropriate range continue to have persistent symptoms such as fatigue, depressed mood, and weight gain. If the TSH is in the appropriate range then no adjustment is necessary and annual serum TSH testing is recommended. Patients who remain symptomatic on an appropriate dosage of levothyroxine, as determined by a TSH less than 2.5 mIU/L, are not likely to benefit from combination triiodothyronine/thyroxine therapy (SOR A). Desiccated thyroid hormone preparations are not recommended by the American Association of Clinical Endocrinologists for the treatment of hypothyroidism. A meta-analysis of 11 randomized, controlled trials of combination T3/T4 therapy versus T4 monotherapy showed no improvements in pain, depression, or quality of life (SOR A).
- Which one of the following basal cell carcinomas is associated with the highest risk of recurrence?
A) A 7-mm lesion on the nose
B) A 9-mm lesion on the forehead
C) A 12-mm lesion on the shoulder
D) A 17-mm lesion on the arm
ANSWER: A
Treating basal cell carcinoma with Mohs micrographic surgery leads to the lowest recurrence rate. Because of its cost and limited availability, however, this procedure should be limited to tumors with a higher risk for recurrence. Risk factors include larger size, more invasive histologic subtypes (micronodular, infiltrative, and morpheaform), and sites associated with a higher risk of recurrence.
High-risk locations include the “mask” areas of the face, which include the central face, eyelids, eyebrows, periorbital area, nose, lips (cutaneous and vermilion), chin, mandible, preauricular and postauricular skin/sulci, temple, and ear. Other high-risk sites include the genitalia, hands, and feet. Moderate-risk locations include the cheeks, forehead, scalp, and neck. All other areas, including the trunk and extremities, are low-risk areas.
Even with a low-risk location, a lesion that is greater than or equal to 20 mm in size has a high risk of recurrence. With a moderate-risk location a lesion greater than or equal to 10 mm in size carries a higher risk of recurrence, and a lesion greater than or equal to 6 mm in size is considered high risk in a high-risk location.
- A 52-year-old male presents for a routine physical examination. His laboratory results reveal an AST (SGOT) level of 124 U/L (N 10–40) and an ALT (SGPT) level of 36 U/L (N 10–55). His y-glutamyl transpeptidase (GGTP) level is also elevated.
The most likely cause of this abnormality is
A) hepatitis C B) hemochromatosis C) nonalcoholic fatty liver disease D) alcoholic liver disease E) statin-induced liver disease
ANSWER: D
In a study of 256 asymptomatic Swedish patients with mildly elevated liver transaminase levels, alcohol was found to be the cause in 10% of cases. An accurate history is important for making the diagnosis. A biopsy alone cannot differentiate alcoholic liver disease from nonalcoholic fatty liver disease. An AST/ALT ratio >2 supports a diagnosis of alcoholic liver disease. Elevated @-glutamyl transpeptidase (GGTP) is also associated with alcohol abuse, especially in a patient with an AST/ALT ratio >2.
- Which one of the following is an appropriate treatment for tinea capitis?
A) Oral cephalosporins B) Oral griseofulvin C) Topical acyclovir (Zovirax) D) Topical ketoconazole (Nizoral) E) Topical miconazole (Monistat)
ANSWER: B
Tinea capitis is an infection of the scalp caused by a variety of superficial dermatophytes. The treatment of choice for this infection is oral griseofulvin. It has the fewest drug interactions, a good safety record, and anti-inflammatory properties. Terbinafine has equal effectiveness and requires a significantly shorter duration of therapy, but it is only available in tablet form. Since tinea capitis most commonly occurs in children, tablets would have to be cut and/or crushed prior to administration. Oral itraconazole, fluconazole, and ketoconazole have significant side effects. Topical antifungals such as ketoconazole and miconazole are ineffective against tinea capitis. Topical acyclovir is used in the treatment of herpesvirus infections, and oral cephalosporins are used in the treatment of bacterial skin infections.
- An 88-year-old male nursing-home patient is having problems with constant overflow incontinence. Intermittent catheterization has proven difficult due to urethral obstruction and his resistance to such procedures. He has dementia and generalized weakness as a result of multiple strokes and is bedbound, requiring total care for most activities of daily living. Examination shows a grade 3 coccygeal ulcer that has been present for several months, and a digital rectal examination demonstrates a large, irregular prostate.
Which one of the following is the best choice to quickly correct his incontinence?
A) Doxazosin (Cardura)
B) Finasteride (Proscar)
C) Tolterodine (Detrol)
D) Long-term indwelling Foley catheter placement
E) Referral for transurethral prostatectomy
ANSWER: D
While it would increase the risk of urinary infection, indwelling catheter placement is most likely to provide immediate relief of this patient’s urinary retention. It will minimize or prevent further contamination of his decubitus ulcer with urine. Prostatectomy may relieve the urethral obstruction, but this patient is likely to remain incontinent due to his vascular dementia. Doxazosin or finasteride would likely be inadequate in this situation. Tolterodine is not indicated for overflow incontinence.
- A 45-year-old female presents to an urgent care center complaining of left-sided chest pain for the past 2 days. The pain is nonradiating and sharp in character, and increases with deep inspiration. She has no associated shortness of breath, cough, nausea, diaphoresis, or dizziness. She has no significant past medical history or recent travel history.
On examination she is afebrile, with a pulse rate of 102 beats/min, a blood pressure of 116/72 mm Hg, and a respiratory rate of 22/min. Her lungs are clear and her heartbeat is regular with no murmurs. Her lower extremities have no edema, tenderness, or varicosities.
Which one of the following is the most appropriate next step in her evaluation?
A) A high-sensitivity D-dimer test B) A troponin I level C) An antinuclear antibody level D) Ultrasound examination of the veins of the lower extremities E) Multidetector helical CT of the chest
ANSWER: A
This patient has a low pretest probability of pulmonary embolism based on the Wells criteria. She would be a good candidate for a high-sensitivity D-dimer test, with a negative test indicating a low probability of venous thromboembolism. In patients with a low pretest probability of venous thromboembolism, ultrasonography or helical CT would not be the recommended initial evaluation. Neither troponin I nor an ANA level would be part of the recommended initial evaluation.
- Which one of the following organisms is the most common cause of cutaneous infections associated with intertrigo?
A) Candida albicans B) Pseudomonas aeruginosa C) Staphylococcus aureus D) Group A B-hemolytic Streptococcus E) Trichophyton mentagrophytes
ANSWER: A
Intertrigo is skin inflammation caused by skin-on-skin friction. It is facilitated by moisture trapped in deep skinfolds where air circulation is limited. When intertrigo does not respond to usual conservative measures, including keeping the skin clean and dry, evaluation for infection is recommended. A Wood’s light examination, KOH preparation, and exudate culture can assist in identifying causative organisms.
The moist, damaged skin associated with intertrigo is a fertile breeding ground for various microorganisms, and secondary cutaneous infections are commonly observed in these areas. Candida is the organism most commonly associated with intertrigo. In the interdigital spaces dermatophytes (e.g., Trichophyton rubrum, Trichophyton mentagrophytes, Epidermophyton floccosum) are more common. Staphylococcus aureus may present alone or with group A B-hemolytic Streptococcus (GABHS). Pseudomonas aeruginosa, Proteus mirabilis, or Proteus vulgaris also may occur alone or simultaneously.
- A 4-year-old male presents with a 1-week history of a fever at or slightly above 38°C (101°F) that has responded poorly to antipyretics. The patient complains of photophobia, burning eyes, and a sore throat. On examination his eyes look red, his lips are red and cracked, and he has a “strawberry tongue.” In addition, his palms and soles are erythematous and there is periungual desquamation on his fingers and toes. He has minimally painful nodes located in the anterior cervical region, about 2×2 cm in size. A Streptococcus screen is negative.
The most appropriate management at this time would be
A) intramuscular benzathine penicillin G (Bicillin L-A), 600,000 U
B) intravenous nafcillin
C) aspirin and intravenous immune globulin
D) prednisone, 2–3 mg/kg daily
E) a fine-needle biopsy of the lymph nodes
ANSWER: C
Kawasaki disease, or mucocutaneous lymph node syndrome, is a common form of vasculitis most often seen in children under 5 years of age. It is typically self-limited, with fever and acute inflammation lasting 12 days on average without therapy. However, if untreated, this illness can result in heart failure, coronary artery aneurysm, myocardial infarction, arrhythmias, or occlusion of peripheral arteries. This diagnosis requires that fever be present for 5 days or more with no other explanation. In addition, at least four of the following symptoms must be present: (1) nonexudative conjunctivitis that spares the limbus; (2) changes in the oral membranes such as diffuse erythema, injected or fissured lips, or “strawberry tongue”; (3) erythema of the palms and soles, and/or edema of the hands or feet followed by periungual desquamation; (4) cervical adenopathy in the anterior cervical triangle with at least one node larger than 1.5 cm in diameter; and, (5) an erythematous polymorphous rash, which may be targetoid or purpuric in 20% of cases. The disease must be distinguished from toxic shock syndrome, streptococcal scarlet fever, Stevens-Johnson syndrome, juvenile rheumatoid arthritis, measles, adenovirus infection, echovirus infection, and drug reactions.
- A 48-year-old male presents with a 4-week history of rectal pain associated with minimal rectal bleeding. On examination there is a small tear of the anorectal mucosa at the 6 o’clock position.
The most appropriate initial treatment would be topical
A) botulinum toxin
B) clobetasol (Temovate)
C) capsaicin (Capzasin-HP, Zostrix)
D) nitroglycerin
ANSWER: D
This patient has classic findings for acute rectal fissure. Although patients often require an internal sphincterotomy, nonsurgical measures that relax the sphincter have proven helpful. Botulinum toxin injected into the internal sphincter has proven most beneficial, but topical preparations are not yet available and have not been shown to be effective for this problem. Corticosteroid creams may decrease the pain temporarily, but potent fluorinated corticosteroid creams such as clobetasol are not indicated in the treatment of fissure. Capsaicin cream can be helpful for pruritus ani, but not for anal fissures. Drugs that dilate the internal sphincter, including diltiazem, nifedipine, and nitroglycerin ointment, have proven to be beneficial in healing acute fissures, but usually have to be compounded by a pharmacist.
- A 3-year-old male is brought to your office the day after he was stung by a honeybee. He developed a significant local reaction, with redness and swelling around the site of the sting on his forearm. He also had some swelling of his lips which lasted 2–3 hours. He was treated with oral diphenhydramine (Benadryl) at home and now his symptoms have completely resolved.
Which one of the following should be recommended for this patient?
A) An epinephrine autoinjector (EpiPen)
B) Corticosteroids as needed for stings
C) Immunotherapy for 1–2 years
D) Reassurance only
ANSWER: A
Children generally have a benign course after insect stings, but those who have a moderate to severe systemic reaction have a high risk of future reactions. Local reactions may initially look like cellulitis, but antibiotic therapy is not needed. The treatment of choice for anaphylaxis subsequent to an insect sting is systemic epinephrine. Corticosteroids may be given as adjunctive treatment. Immunotherapy may induce cellular suppression after 4 or 5 years. Patients who stop venom immunotherapy after 1 or 2 years continue to be at moderate risk for systemic allergic reaction to future stings.
- A 54-year-old male sees you for a 6-month follow-up visit for hypertension. He feels well, but despite the fact that he takes his medications faithfully, his blood pressure averages 150/90 mm Hg. He has had an intensive workup for hypertension in the recent past, with normal repeat laboratory results, including a CBC, serum creatinine, an electrolyte panel, and a urinalysis. His medications include chlorthalidone, 12.5 mg daily; carvedilol (Coreg), 25 mg twice daily; amlodipine (Norvasc), 10 mg daily; and lisinopril (Prinivil, Zestril), 40 mg daily. He has been intolerant to clonidine (Catapres) in the past.
Which one of the following medication changes would be most reasonable?
A) Adding isosorbide mononitrate (Imdur)
B) Adding spironolactone (Aldactone)
C) Substituting furosemide (Lasix) for chlorthalidone
D) Substituting losartan (Cozaar) for lisinopril
ANSWER: B
Spironolactone is now recommended for treating resistant hypertension, even when hyperaldosteronism is not present. A longer-acting diuretic such as chlorthalidone is also recommended for treating hypertension, particularly in resistant cases with normal renal function. There is no benefit to switching from an ACE inhibitor to an ARB. Nitrates have some effect on blood pressure but are recommended only for patients with coronary artery disease.
- Which one of the following occurs with delirium tremens but is not usually seen with less severe forms of alcohol withdrawal?
A) Fever B) Hypertension C) Tachycardia D) Seizure E) Visual hallucinations
ANSWER: A
Chronic excessive alcohol intake produces functional changes in neurotransmitter activity that can lead to a net increase in excitatory neuroreceptor activity when the person stops drinking. Withdrawal can be divided into four levels of severity: minor, major, seizures, and delirium tremens. Minor alcohol withdrawal is characterized by tremor, anxiety, nausea, vomiting, and/or insomnia 6–24 hours after the patient’s last drink. Major withdrawal occurs 10–72 hours after the last drink and can include the signs and symptoms of minor withdrawal, as well as visual and auditory hallucinations, diaphoresis, tachycardia, and elevated blood pressure. Alcoholic seizure generally occurs within 2 days of the last drink and may be the only sign of withdrawal, although approximately one-third of these patients will progress to delirium tremens. The onset of delirium tremens can occur anytime within 3–10 days following the last drink. The defining clinical finding is delirium, but the findings seen in milder forms of alcohol withdrawal can also be present, and may be more severe. Fever is most often seen with delirium tremens and is less common with less severe forms of alcohol withdrawal.
- You attend the cesarean delivery of a full-term male infant with no prenatal risk factors other than breech position. The infant was received from the operating team crying and vigorous, with Apgar scores of 8 at 1 minute and 9 at 5 minutes.
An hour later, the infant becomes ashen-blue in color with an O2 saturation of 82%. He is alert and tachypneic, with a heart rate of 140 beats/min and a normal temperature. You order supplemental oxygen.
Which one of the following is the most appropriate next step in managing this patient?
A) Bag-mask ventilation with 100% oxygen B) Endotracheal intubation C) Prostaglandin E1 infusion D) An EKG E) A chest radiograph and laboratory studies
ANSWER: E
Cyanosis and tachypnea may be a sign of transient tachypnea of the newborn (TTN), or may be the first signs of a more serious health condition. Many of the severe conditions may be ruled out through the history (hyaline membrane disease is unlikely in this full-term infant) and physical examination (choanal atresia may be ruled out at the bedside). After these initial steps are taken, a chest radiograph and laboratory studies will help rule out many urgent and life-threatening conditions, such as pneumothorax, pneumonia, severe anemia, sepsis, etc. An EKG is less helpful in determining causes since it cannot differentiate defects that cause cyanotic heart disease. Infusion of prostaglandin E1 should be started only if the condition is determined to be ductal dependent; this is not the case in this scenario. Bag-mask ventilation is not warranted in this child, who is alert and breathing and has a normal heart rate. At this time it is reasonable to start investigations into the cause of the child’s problems before resorting to more extreme measures such as intubation.
- A 26-year-old African-American male presents with diffuse abdominal and back pain 5 days after being diagnosed with streptococcal pharyngitis. He appears mildly ill, with slight scleral icterus.
Laboratory Findings
Unconjugated bilirubin . . . . . . 3.2 mg/dL (N less than 0.2)
Hemoglobin . . . . . . . . . . . . . . . 9.6 g/dL (N 13.0–18.0)
Hematocrit . . . . . . . . . . . . . . . . 29.4% (N 37.0–49.0)
Peripheral blood smear . . . . . keratocytes, blister cells, and
polychromatic macrocytes
Which one of the following is the most likely diagnosis?
A) Thalassemia B) Sickle cell anemia C) Spherocytic hemolytic anemia D) Microangiopathic hemolytic anemia E) G6PD deficiency
ANSWER: E
A peripheral blood smear revealing the presence of keratocytes, blister cells, and polychromatic macrocytes is consistent with an oxidative hemolytic process. Hemolysis is seen in glucose-6-phosphate dehydrogenase (G6PD) deficient persons, such as this patient, following an acute insult triggered by drugs, infection, or fava bean ingestion. A blood smear suggests the diagnosis even if an assay for G6PD is normal, which is frequently the case in heterozygous men of African ancestry. Peripheral blood smears showing spherocytes suggest spherocytic hemolytic anemia. Sickle-shaped red blood cells indicate sickle cell anemia, whereas hypochromic and teardrop-shaped red blood cells may be seen in thalassemia. Red blood cell fragments are found in microangiopathic hemolytic anemia.
