Case Presentation: A 46-year-old woman with no past medical history presented with right upper quadrant pain, jaundice, and pruritus after undergoing a liver biopsy at an outside hospital. At the outside hospital, she had these same symptoms with hyperbilirubinemia and transaminitis. HIDA scan was negative. The liver biopsy showed marked portal and pan-lobular inflammatory infiltration consistent with active hepatitis. She was discharged with outpatient follow up and oxycodone. She presented to the ED two weeks later for persistent symptoms. Labs showed total bilirubin 3.0 mg/dl, alkaline phosphatase 273 U/L, AST 720 U/L, and ALT 699 U/L. CT abdomen showed a subcapsular hematoma at the biopsy site.On admission, she had sharp 8/10 right upper quadrant pain, pruritus, and jaundice. She denied excessive alcohol use, vitamin or herbal supplements, or illicit drug use. She had no family history of autoimmune conditions. She received nitrofurantoin for a UTI approximately three months ago. Vital signs were T 36.5 C, HR 66, BP 125/62, RR 18, SpO2 100%. On exam, she had right upper quadrant tenderness, scleral icterus, jaundice, and photosensitive hyperpigmentation over her cheeks. MRCP was negative for biliary stricture. EBV, CMV, hepatitis A, B, C, and E testing showed no infection. Anti-dsDNA antibody was positive. Autoimmune hepatitis was diagnosed when IgG was elevated at 2059 mg/dl, ANA was 1:640, and review of liver histology from the outside hospital was consistent with autoimmune hepatitis.Prednisone 30 mg PO daily was initiated. AST and ALT decreased to 306 U/L and 533 U/L. Her pain improved. She was discharged on prednisone 30 mg PO daily for 4 weeks. On follow up, she had completed her steroids and liver enzymes were only mildly elevated with an AST 43 U/L and ALT 49 U/L. IgG was within normal limits.
Discussion: Patients suspected of autoimmune hepatitis (AIH) may require inpatient work up for close monitoring and symptom control. This requires an organized approach to efficiently exclude alternative causes and justify immunosuppression. A simplified scoring system for autoimmune hepatitis with a high sensitivity and specificity can be used to characterize patients with autoimmune hepatitis. Our patient scored a 7, indicating definite autoimmune hepatitis.Nitrofurantoin is a known cause of drug-induced autoimmune hepatitis (DIAIH). The clinical, pathological, and serological features of AIH and DIAIH are very similar. Nitrofurantoin was a likely trigger in our patient. Also, our patient had anti-dsDNA antibodies, a chronic photosensitive facial rash, and intermittent joint pains. This suggests a possible undiagnosed autoimmune condition or predilection.Data suggests that patients with DIAIH generally have a better prognosis and usually do not relapse after completing glucocorticoid treatment, whereas most patients with AIH will relapse after discontinuation of immunosuppression. A trial off of steroids would seem appropriate in our patient given her prior exposure to nitrofurantoin.
Conclusions: Autoimmune hepatitis poses a diagnostic challenge. Scoring tools are helpful for determining probable to definite autoimmune cases for early initiation of immunosuppressive therapy. Drug-induced autoimmune hepatitis is a very similar entity. It is important to take a thorough history of prior drug exposures and know which drugs, such as nitrofurantoin, have been implicated as causes. Differentiating AIH from DIAIH will inform prognosis and guide decisions regarding treatment duration.