Joo Hee Chang, et al. Fig. 1. Chest X-ray shows increased bronchial wall thickening and diffuse infiltration on both lungs. fields. The liver was slightly enlarged and palpated 2 cm below costal margin. The spleen was not pal- pable. An erythematous papular rash was noted on both extremities. Chest X-ray showed diffuse bronchopneumonia in both lungs (Fig. 1). The abdominal sonography showed hepatomegaly with wall thickening of gallbladder. The laboratory tests showed Hb 12.2 g/dL, Hct 35.2%, WBC 4,300/mm3 with 49% neu- trophil, 32% lymphocytes, and platelets 237,000/ mm3. The serology testing for M. pneumoniae IgM class antibody titer was 4,377 Units/mL (normal range: < 770 Units/mL). The bedside cold agglu- tinin test was positive. The specific antibody test was done by the ELISA method (Immuno Well, GenBio, San Diego, CA, USA). The alanine amino- transferase (ALT) was 100 IU/L and aspartate aminotransferase (AST) 169 IU/L. The total biliru- bin was 0.5 mg/dL and the direct bilirubin 0.3 mg/dL. The total protein was 6.2 g/dL, albumin 3.5 g/dL, ammonia 81 μg/dL, and the C-reactive protein was 1.32 mg/dL. The patient was treated with azithromycin (10 mg/kg/day) for 3 days. On the fourth hospital day, he developed abdominal pain at the upper- right quadrant. Tenderness was noted at the upper-right quadrant. The liver was markedly enlarged and was palpated 8 cm below costal margin, compared to the admission examination. Yonsei Med J Vol. 49, No. 6, 2008 Fig. 2. Progression of the disease. The liver enzymes increased acutely; AST 2,985 IU/L and ALT 2,725 IU/L. Prothrombin time (PT) was 15.6 seconds (INR: 1.28) and partial throm- boplastin time (PTT) was 50.7 seconds (normal range: 30 - 45 seconds) and increased up to 82.1 seconds a few days later (Fig. 2). The serology testing for HAV, HBV, HCV, cytomegalovirus, and Ebstein-Barr virus were negative. Wilson disease and autoimmune hepatitis were excluded. Factor VIII was 31.0%, factor IX 23.0%, factor XI 43.0%, and factor XII 42.0%. The PTT mixing test failed to correct prolonged PTT. A bleeding ten- dency was not observed. On the eighth hospital day, a liver biopsy was performed. The hepatic lobules showed features of acute hepatitis such as ballooning degeneration, spotty necrosis and in- creased Kupffer cell activity, consistent with acute hepatitis, but was unremarkable otherwise (Fig. 3). A week later, the pneumonia was nearly resolved, and the liver enzymes were decreased; AST was 51 IU/L and the ALT 237 IU/L. The patient was discharged in good condition. A week after discharge, the liver enzymes were normalized; AST 28 IU/L and ALT 43 IU/L. Several months later, the coagulation factors were nearly nor- malized without specific treatment. Factor VIII was 55.0%, Factor IX 65.0%, Factor XI 84.0%, and Factor XII 41.0%. The PTT mixing test was 38.1 seconds.