A 6-year-old girl is brought to a walk-in clinic for evaluation of growth. The patient and her family immigrated to the United States from Haiti 2 months ago. For the past 3 months, decreased appetite has led to the loss of several pounds. The patient has had occasional episodes of abdominal discomfort and diarrhea. The family denies any recent changes to her diet. There is no gross blood or mucus in the stool, and the patient has no fever. A mild cough early in the course of symptoms has since resolved. The patient received all age-appropriate vaccinations prior to immigration. She was also immunized in infancy for bacille Calmette-Guérin. Skin tuberculin testing at the time of immigration showed 2 mm induration. Temperature is 36.7 C (98.1 F), pulse is 102/min, and respirations are 18/min. Height is 120 cm (4 ft, 10th percentile) and weight is 19 kg (41.9 lb,

Question

A 6-year-old girl is brought to a walk-in clinic for evaluation of growth.  The patient and her family immigrated to the United States from Haiti 2 months ago.  For the past 3 months, decreased appetite has led to the loss of several pounds.  The patient has had occasional episodes of abdominal discomfort and diarrhea.  The family denies any recent changes to her diet.  There is no gross blood or mucus in the stool, and the patient has no fever.  A mild cough early in the course of symptoms has since resolved.  The patient received all age-appropriate vaccinations prior to immigration.  She was also immunized in infancy for bacille Calmette-Guérin.  Skin tuberculin testing at the time of immigration showed 2 mm induration.  Temperature is 36.7 C (98.1 F), pulse is 102/min, and respirations are 18/min.  Height is 120 cm (4 ft, 10th percentile) and weight is 19 kg (41.9 lb, <5th percentile).  Physical examination shows a slightly distended abdomen with soft, hyperactive bowel sounds.  There is generalized mild tenderness to deep palpation.  No guarding, rebound tenderness, or hepatosplenomegaly is present.  Fecal occult blood test is positive.  Laboratory results are as follows:  Which of the following diagnostic studies is most likely to be abnormal in this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bfa8_bd70_8f63_5383016a81c7_MD0005_00 This child's abdominal symptoms, poor growth, eosinophilia, and anemia are highly suggestive of a parasitic infection by hookworms. Hookworms are intestinal nematodes (eg, Ancylostoma duodenale, Necator americanus) prevalent in developing tropical or subtropical nations. Their eggs are shed into the ground, where they hatch during periods of increased moisture. Larvae subsequently invade human hosts, either through bare feet or by ingestion, and migrate through the lungs (often causing a transient, nonproductive cough, as in this case) to the pharynx, where they are swallowed and complete their maturation in the gut. Adult worms attach to epithelial cells in the small intestine and feed on capillary blood. Hookworm infection is often asymptomatic. With increasing worm burden, patients may experience nonspecific gastrointestinal symptoms (eg, diarrhea, abdominal pain, distension) or, rarely, obstruction. After several months, iron deficiency anemia develops. Eosinophilia is commonly a part of the body's immunologic response to these organisms, so it can be a helpful in distinguishing hookworm infection from other causes of chronic diarrhea. Stool ova and parasite testing is very sensitive for this infection due to the high worm (and therefore egg) burden in symptomatic hosts. Antiparasitic treatment (eg, albendazole, nitazoxanide) is curative, although reinfection is common in endemic areas. (Choice A) Interferon-gamma release assays are serum tests for tuberculosis exposure. They are particularly useful for patients with a history of bacille Calmette-Guérin immunization, which may cause false-positive tuberculin skin tests. However, this child has a negative (<5 mm) skin test and does not have a fever or an active cough, and tuberculosis does not cause diarrhea or microcytic anemia. (Choice B) Folate deficiency can present with weight loss, anemia, and diarrhea. However, the red blood cells in folate deficiency are characteristically macrocytic rather than microcytic, making it unlikely in this child. (Choice C) Anti-tissue transglutaminase antibodies are used to screen for celiac sprue. Although celiac sprue can present with gastrointestinal symptoms, weight loss, and anemia, this patient's recent immigration and significant peripheral eosinophilia make a parasitic infection more likely. (Choice E) A stool culture can identify bacterial causes of diarrhea, including pathogenic Escherichia coli, Salmonella, Shigella, Yersinia enterocolitica, and Campylobacter. However, diarrhea associated with bacterial gastroenteritis is rarely prolonged and is not associated with eosinophilia. Stool cultures do not identify parasitic infections. Educational objective: Hookworm infections are encountered worldwide, particularly in tropical areas, and present with abdominal symptoms and failure to thrive. Common laboratory findings include microcytic anemia and eosinophilia. Examination of the stool for hookworm eggs is diagnostic. References: Epidemiology and control of human gastrointestinal parasites in children. (http://www.ncbi.nlm.nih.gov/pubmed/20109051) Effect of sanitation on soil-transmitted helminth infection: systematic review and meta-analysis. (http://www.ncbi.nlm.nih.gov/pubmed/22291577)

A 6-Year-Old Girl Is Brought to a Walk-In Clinic for Evaluation