Pediatric Bulimia Workup

Updated: Feb 28, 2020
  • Author: Maggie A Wilkes, MD; Chief Editor: Caroly Pataki, MD  more...
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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 [7, 4, 8, 9, 20]

  • 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 [8, 21, 9]

  • 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. [22]

  • 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.)


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. [9]

  • 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