Expanding the differential diagnosis for transaminitis in patients with anorexia nervosa

Aminotransferase elevations have been described in patients with anorexia nervosa. Hypothesized etiologies have included ischemic hepatitis, refeeding-induced transaminitis, and the process of autophagy. Supervised enteral nutrition is the mainstay of treatment for severe anorexia, but an increase in aminotransferase levels after initiation of enteral feeding presents clinicians with a diagnostic dilemma. We present a 31-year-old woman with anorexia nervosa (body mass index [BMI] of 13.5 kg/m²) who experienced a worsening of aminotransferase elevations even after the initiation of enteral feeding. Despite nutritional supplementation, the patient's weight continued to fall for 6 days. Peak aminotransferase concentrations correlated with the patient's lowest weight and improved only after an increase in BMI was eventually achieved. Secondary causes of severe transaminitis were investigated, and after no cause was found, a liver biopsy was performed. Pathology was consistent with liver injury secondary to severe malnutrition rather than from refeeding syndrome. This case highlights malnutrition as an important cause of aminotransferase elevations and underscores the need for judicious early weight restoration in patients with anorexia and abnormal liver chemistry.