Pediatric Bulimia Workup

Updated: Feb 17, 2015
  • Author: Maggie A Wilkes, MD; Chief Editor: Caroly Pataki, MD  more...
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Workup

Laboratory Studies

Bulimia nervosa (BN) requires a clinical diagnosis. No single laboratory test can be diagnostic. The laboratory tests listed below may be helpful in assessing the medical complications that arise from bulimia nervosa.

Routine laboratory tests [6, 3, 7, 8, 19]

  • CBC count: Malnutrition can cause neutropenia and, rarely, anemia or thrombocytopenia.
  • Biochemistry panel: If dehydration or electrolyte imbalances are suspected, electrolytes, calcium, magnesium, phosphorous, glucose, creatinine, and BUN levels may be obtained to measure liver, kidney, and pancreatic functioning. Common findings include the following:
    • Dehydration
    • Hypokalemia - Secondary to purging, or use of diuretic or laxatives
    • Hypochloremia - Secondary to purging and laxative or diuretic use
    • Hypocalcemia
    • Hypomagnesemia - Due to diarrhea resulting from laxative use
    • Hypophosphatemia
    • Hyponatremia - Secondary to use of diuretics
    • Metabolic acidosis - Secondary to laxative use
    • Metabolic alkalosis - Secondary to purging
    • Increased BUN levels
  • Endocrine studies in patients with bulimia nervosa may exhibit the following abnormal findings:
    • Decreased follicle-stimulating hormone (FSH), leuteinizing hormone (LH), and estradiol levels
    • Prolactin levels: Studies have documented both increased and decreased basal serum prolactin in association with bulimia nervosa.
    • Increased cortisol levels; positive dexamethasone suppression test result
  • Thyroid and parathyroid panels
    • Hypothyroidism can occur as a mechanism of energy conservation.
    • Decreased free triiodothyronine (FT3) and free thyroxine (FT4) levels may be observed.
  • Gastrointestinal laboratory tests may reveal the following:
    • Increased amylase secondary to vomiting
    • Esophagitis, pancreatitis, or delayed gastric emptying
    • Liver function test results usually normal

Situational laboratory tests [7, 20, 8]

  • A drug screen may be indicated for patients with possible drug use. Attention should be paid to adolescent confidentiality anytime drug testing involves an adolescent patient. [21]
  • Ipecac use can cause emetine cardiomyopathy, hepatic toxicity, or peripheral myopathy. Hypokalemia can also result, and the following laboratory studies may be indicated for patients suspected of using ipecac:
    • Stool and urine analyses for emetine (a byproduct of ipecac)
    • Cardiac assessment - Muscle enzyme values, lipid levels, magnesium, zinc, electromyography
    • Electrocardiography (Findings may include cardiac arrhythmias, a prolonged QT interval, ipecac cardiomyopathy.)
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Other Tests

ECG should be considered in the following conditions:

  • Hypokalemia: This condition can cause cardiac conduction defects that may lead to heart arrhythmias or seizures. [8]
  • Severe purging behaviors or suspected ipecac use
  • Symptoms and signs of arrhythmias

Gastric motility studies should be considered in the following conditions:

  • Prolonged history of bulimia
  • History of constipation (often due to chronic use of laxatives)
  • Recent weight loss: Consider other causes of vomiting such as superior mesenteric artery (SMA) syndrome
  • Other unexplained abdominal pain
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