In August, 2007, a 60-year-old man who had had bipolar disorder since 1990 was admitted to our hospital with recurrence of mania. Remission was achieved with lithium carbonate (400 mg/day) and zotepine (125 mg/day), and in November he was moved to an open ward. 1 week later we increased his lithium dose to 800 mg following relapse of mania. 4 days later, he developed a fever (39ยฐC). He was alert, had pressure of speech, tachycardia, unstable blood pressure, and diaphoresis, but had no muscle rigidity. Blood test results showed mild anaemia, slight leucocytosis (9โข6ร10โน/L), high creatine kinase (CK, 330 U/L), slightly high aspartate transaminase (38 U/L) and alanine transaminase (33 U/L), and normal concentrations of thyroid hormones and electrolytes. CT of the head and chest radiography showed no foci of infection. Serum lithium concentration (0โข57 mEq/L) was not suggestive of toxicity. We discontinued lithium, suspecting neuroleptic malignant syndrome from the rapidly increased dose 4 days earlier.
The next day, physical signs and white-cell count normalised, and 3 days later, CK concentration dropped to 210 U/L. However, CK isoenzyme MB rose to 103 U/L (normal <25 U/L) despite a negative cardiac troponin-T test. Electrocardiography and echocardiography showed no abnormalities. CK isoenzyme electrophoresis showed the presence of macro-CK type II, prompting us to search for malignancy. Faecal occult blood was positive, and our patient had high values of serum carcinoembryonic antigen (125 ng/mL; normal <5 ng/mL); an ulcerated tumour with infi ltration 10 cm above the anal verge was seen on colonoscopy (fi gure A), which was identifi ed as a well-diff erentiated adenocarcinoma on histopathological examination. Contrast-enhanced abdominal CT showed fi ve low-density areas over 4 cm in diameter and seven smaller areas in the liver (fi gure B).