A 26-year-old man presents with new-onset confusion, tremor, and “clumsiness” for the last 3 to 4 weeks. He decided to come in after he could not remember the name of his long-term girlfriend. He has no significant past medical history and denies alcohol or illicit drug use. Physical examination shows stable vital signs and hepatomegaly. Laboratory studies reveal the following:
Which of the following is the next best step in the diagnostic workup for this patient?
Serum ceruloplasmin levels. The patient in this question is presenting with neuropsychiatric symptoms and hepatomegaly consistent with a likely diagnosis of Wilson disease. Wilson disease is an autosomal recessive disorder in which copper accumulates in tissues due to mutations in the Wilson disease protein (ATP7B) gene; this causes a defect in incorporation of copper in hepatic lysosomes. Clinical symptoms range from an asymptomatic state to tremor, depression, and memory impairment. The diagnosis is confirmed by low serum ceruloplasmin levels (normally <20 mg/dL), increased urinary copper, and Kayser–Fleischer rings (so a slit lamp examination of the eye should also be performed). (A) Liver biopsy in Wilson disease often shows inflammation, portal fibrosis, and necrotic hepatocytes. Macrovesicular steatosis and Mallory bodies may also be present. A less invasive test (such as a blood test) should be ordered before a liver biopsy is performed. (B) α-1 antitrypsin levels would be ordered if α-1 antitrypsin deficiency were suspected, but this disease is associated with liver and lung (emphysema in young patients) disease. (C) Lumbar puncture (LP) for CSF analysis is not useful in Wilson disease. Even though the neurologic symptoms in Wilson disease are caused from copper accumulation in the basal ganglia, this would not generate positive CSF findings.
A 24-year-old woman presents with a history of diarrhea. She reports returning 2 months ago from a church-affiliated hiking trip. Since returning, she has developed diarrhea, abdominal pain, and increased flatulence. Of note, she just finished taking one of her friend’s ciprofloxacin for 7 days without any improvement.
Which of the following antibiotics should be prescribed to this patient?
Metronidazole. The patient in this question is presenting with classic giardiasis caused by Giardia lamblia. The Internal Medicine shelf examination might ask a similar question that offer clues to the diagnosis of giardiasis (history of recent travel, exposure to river water, or day care centers). This organism is common in unsanitary conditions and most often transmitted via water (although it can also be transmitted via food). In this condition, the organism (trophozoites) sticks to the mucosa of the gut and causes malabsorption. This causes diarrhea (patients typically note foul-smelling watery stools), flatulence, abdominal pain, and sometimes weight loss. Diagnosis can be confirmed with stool studies looking for ova and parasites. Treatment is with oral metronidazole. (A, C, D) These antibiotics are not used in the treatment of giardiasis. Although ciprofloxacin is usually the best antibiotic in infectious diarrhea, it is not helpful in giardiasis.
A 51-year-old woman with a history of diabetes mellitus type 2 presents for her annual physical examination. The patient denies alcohol or drug use. Physical examination reveals an obese woman with hepatomegaly. Laboratory studies reveal the following:
A liver biopsy is performed and demonstrates macrovesicular steatosis and necrotic hepatocytes, in addition to centrilobular zone fatty accumulation.
Which of the following is the most likely diagnosis in this patient?
Nonalcoholic steatohepatitis. The patient in this question is presenting in an asymptomatic state, but has elevated AST, ALT, and alkaline phosphatase levels on laboratory testing. Given her history of hyperlipidemia, diabetes, and obesity, she likely has hepatomegaly and transaminitis secondary to underlying nonalcoholic steatohepatitis (NASH). The histology is further confirmation of this diagnosis given the macrovesicular steatosis and centrilobular zone fatty accumulation findings. (C) Of note, alcoholic hepatitis can present with similar histologic findings, so it cannot be distinguished from NASH solely on pathology. However, this patient denies alcohol use. (B) This patient has a negative smooth muscle antibody, making autoimmune hepatitis unlikely to be the diagnosis. (D) This patient is asymptomatic and does not report any symptoms consistent with cholelithiasis. Even though cholelithiasis can be asymptomatic, the history and pathologic findings in this patient support a diagnosis of NASH.
A 21-year-old man presents with flatulence, abdominal pain, and diarrhea for the last 2 years. He has noticed that these symptoms occur after drinking milk or eating yogurt. The diarrhea is nonbloody, watery, and explosive. The patient denies fever, chills, or weight loss. Physical examination is unremarkable.
Which of the following is the best next step in the diagnostic workup of this patient?
Hydrogen breath test. The patient in this question is presenting with classic findings associated with lactose intolerance, a condition in which individuals have insufficient levels of lactase. Lactase is an enzyme that breaks down lactose into glucose and galactose, permitting carbohydrate absorption. If patients are unable to hydrolyze lactose, they develop diarrhea, bloating, and flatulence. The most accurate test is the hydrogen breath test, in which the hydrogen level is measured in one’s breath after lactose ingestion. If the lactose cannot be digested, enteric bacteria metabolize it and produce hydrogen that is detected in the test. (A) Acid steatocrit testing evaluates for fat malabsorption; however, lactose intolerance involves carbohydrate malabsorption. (C) The patient in this question is not febrile and is not showing signs of infection, so blood cultures are not warranted. (D) Intestinal biopsy is sometimes performed after hydrogen breath test confirms elevated hydrogen levels. However, this is not the best initial step in diagnosis.
A 59-year-old man with a history of hypertension presents with a 2-month history of weight loss (9.1 kg (20 lb)), malaise, and “yellow skin.” The patient denies any abdominal pain. He drinks alcohol socially (three beers per week on average) and has never used illicit drugs. He has a temperature of 36.8°C, blood pressure of 124/90 mmHg, heart rate of 96 beats per minute, and a respiratory rate of 18 breaths per minute. Physical examination reveals jaundice, but no hepatomegaly or abdominal tenderness. Laboratory results reveal a severely elevated alkaline phosphatase (910 U/L) and negative anti-mitochondrial antibodies.
Biliary obstruction secondary to malignancy. The patient in this question is presenting with a severely elevated alkaline phosphatase in the setting of weight loss, jaundice, and malaise. Elevated alkaline phosphatase indicates obstruction, and given the systemic symptoms of weight loss and malaise, the most likely diagnosis is malignancy causing biliary obstruction, specifically pancreatic adenocarcinoma. Remember: the combination of weight loss, painless jaundice, and elevated alkaline phosphatase is highly suggestive of pancreatic cancer! (A) This patient presents with a negative anti-mitochondrial antibody, making primary biliary cirrhosis highly unlikely. (C) Biliary obstruction secondary to gallstones (choledocholithiasis) can present with similar laboratory values (elevated alkaline phosphatase) but usually is accompanied by right upper quadrant pain (not painless jaundice like this patient). (D) Chronic viral hepatitis would not solely elevate the alkaline phosphatase levels; you would also expect elevated aminotransferases. Furthermore, there is no history of hepatitis B or C in this patient’s history.
Click to expand