Isolated involvement of corpus callosum in metronidazole-induced encephalopathy with concomitant peripheral...

Metronidazole is widely used for treating infection of anaerobic bacteria and protozoa. Metronidazole is generally well tolerated, although metronidazole-associated peripheral neuropathy (PN) and metronidazole-induced encephalopathy (MIE) have been reported as rare side effects. The most common sites of MIE involve the bilateral dentate nucleus of the cerebellum. Herein, we present a rare case of MIE with isolated corpus callosum involvement, with concomitant metronidazole-associated PN.

A middle-aged man with ulcerative colitis was diagnosed with amoebic dysentery because of unhygienic eating. After receiving metronidazole (1.8 g/d, cumulative dose 61.2 g) for >1 month, he started to complain of continuous paresthesia of the limbs, and intermittent speech problems. Magnetic resonance imaging demonstrated an isolated lesion in the splenium of the corpus callosum.

A diagnosis of reversible splenial lesion syndrome and PN was made. Given the patient's medical history, MIE and metronidazole-associated PN were considered.

Metronidazole was stopped. Mecobalamine and vitamin B1 were used for adjuvant treatment.

At 1.5 months after stopping metronidazole, his symptoms of numbness and hyperesthesia had not improved, although he felt less ill. The isolated lesion disappeared on follow-up magnetic resonance imaging. At 6 months later, the hyperesthesia symptoms remained, and he was unable to resume his previous work.

Physicians should consider MIE in their differentials for reversible splenial lesion syndrome when encountering a patient with a history of metronidazole medication and symptoms of encephalopathy, especially with concomitant PN. Early identification of this metronidazole-related complication and early cessation of the drug are essential for treatment.