Can bulimia nervosa (BN) cause elevated bilirubin levels in a young adult patient?

Can Bulimia Cause Elevated Bilirubin?

Bulimia nervosa does not directly cause elevated bilirubin through its pathophysiology, but patients with bulimia who have underlying Gilbert's syndrome may manifest unconjugated hyperbilirubinemia due to the fasting state induced by their eating disorder. 1

Direct Relationship Between Bulimia and Bilirubin

• Bulimia nervosa itself is not recognized as a cause of elevated bilirubin in standard medical literature or clinical guidelines 2, 3, 4
• The comprehensive medical complications of bulimia nervosa include electrolyte abnormalities (particularly hypokalemic alkalosis), elevated serum amylase, dental erosion, salivary gland hypertrophy, and gastrointestinal complications—but elevated bilirubin is not listed among these typical complications 4, 5, 6
• Laboratory evaluation for bulimia nervosa should include a complete blood count and comprehensive metabolic panel with attention to electrolytes, liver enzymes, and renal function, but bilirubin elevation is not an expected finding 3

The Gilbert's Syndrome Connection

• A documented case report demonstrates that patients with anorexia nervosa (and by extension, eating disorders involving fasting states) who are homozygous for mutations in the bilirubin UDP-glucuronosyltransferase gene (UGT1A1) can develop unconjugated hyperbilirubinemia due to their fasting state 1
• This represents an interaction between an underlying genetic condition (Gilbert's syndrome) and the behavioral pattern of food restriction, rather than a direct complication of bulimia itself 1
• Gilbert's syndrome causes impaired bilirubin conjugation via reduced glucuronyltransferase activity and is the most common cause of isolated elevated bilirubin 7

Clinical Approach to Elevated Bilirubin in a Patient with Bulimia

When encountering elevated bilirubin in a patient with bulimia nervosa, consider this algorithmic approach:

• First, determine if the hyperbilirubinemia is conjugated or unconjugated by fractionating the bilirubin 7
• If predominantly unconjugated (and no evidence of hemolysis), suspect Gilbert's syndrome, which is exacerbated by the fasting/starvation state common in eating disorders 7, 1
• If predominantly conjugated, investigate for parenchymal liver disease or biliary obstruction unrelated to the bulimia itself 7
• Rule out other causes of liver dysfunction including medication effects, viral hepatitis, or alcohol use (which may be comorbid with bulimia) 6

Important Clinical Caveats

• The presence of hyperbilirubinemia in isolation, without other abnormal hepatic studies, is NOT helpful in diagnosing eating disorder-related complications and may suggest an alternative liver problem 7
• Patients with bulimia commonly have metabolic and endocrine changes suggestive of semistarvation, but these do not typically include bilirubin elevation 6
• If a patient with bulimia has elevated unconjugated bilirubin and Gilbert's syndrome is suspected, genetic analysis of UGT1A1 can confirm the diagnosis and rule out hepatic damage 1
• The fasting state in eating disorders can unmask or worsen pre-existing Gilbert's syndrome, leading to moderate unconjugated hyperbilirubinemia that resolves with nutritional rehabilitation 1