00:01 Let's start with a case to understand why this information is important. 00:05 This is a 53-year-old man with liver disease and recent hospitalization for osteomyelitis, who was placed on metronidazole and moxifloxacin for six weeks. 00:17 The patient was recovering well until about two weeks ago, when he began to develop gait ataxia and dysarthria. 00:23 So some cerebellar signs. 00:26 This is slowly worsened to the point that he is having trouble walking. 00:29 Exam shows truncal ataxia, difficulty with keeping himself upright dysarthric speech, saccadic overshoot on eye movement examination, so he's having trouble coordinating his eye movements. 00:41 Otherwise, neurologic exam is unremarkable. 00:44 MRI is performed and reveals T2-weighted hyperintense lesions in the bilateral deep cerebellar gray matter. 00:52 So what's the most likely diagnosis? Well, as with other cases of the brain and cerebellum, the timeline of onset is important. 01:00 This is a subacute onset condition. 01:03 It's not acute like a stroke, or an intoxication or trauma, not chronic, like a degenerative cerebellar disease. 01:09 This sounds like something more in the inflammatory, toxic, or metabolic category. 01:16 The patient's description is that of cerebellar disequilibrium. 01:20 There's prominent gait ataxia and imbalance, dysarthric of speech. 01:24 And on examination, we find all of those cerebellar findings. 01:28 So this isn't vertigo. It's not syncope, we're dealing with disequilibrium. 01:34 And then importantly, for this case, are the imaging findings. 01:37 We see edema or problems in the deep cerebellar nuclei, not in the hemispheres of the white matter, but in those deep cerebellar nuclei. 01:46 So we're looking for a problem that has a predilection for the nuclei of the cerebellum. 01:52 So what is the most likely diagnosis? Is this metronidazole-induced to cerebellar toxicity? Is this a post-infectious cerebellitis? Is this a cerebellar stroke? Or could this be hepatic encephalopathy? We don't like hepatic encephalopathy. 02:08 In liver disease, which the patient has can cause hyperammonemia and hepatic encephalopathy. 02:14 But that's an encephalopathy syndrome. 02:17 Patients are confused and altered with varying degrees of sedation. 02:21 This patient has no encephalopathy, and isolated cerebellar signs. 02:26 So this is inconsistent with hepatic encephalopathy. 02:30 This doesn't sound like a cerebellar stroke. 02:32 Strokes again, are acute in onset, and this was more subacute in its onset. 02:37 In addition, the MRI changes are very specific to the deep cerebellar gray matter nuclei. 02:42 Their bilateral and symmetric. 02:44 And typically we think of a stroke as being asymmetric on one side of the other, and often affecting the circumferential vessels as they course around the cerebellum and affecting the hemispheres and hemispheric function. 02:58 Post infectious cerebellitis can be seen after an infection, but that's typically not something we see after an osteomyelitis. 03:05 Typically, we see this after some type of viral infection. 03:08 And importantly, post-infectious cerebellitis affects the hemispheres. 03:13 Sometimes one or the other hemispheres, and sometimes bilaterally, but the hemispheres of the predominant area that are affected. 03:20 And here we have a specific process that has a tropism or predilection for the deep gray matter of the cerebellum. 03:28 And this is a typical case of metronidazole-induced cerebellar neurotoxicity. 03:34 This is an uncommon condition, but we see it frequently. 03:37 Metronidazole has a predilection for the dentate nucleus, and the deep gray matter structures. 03:42 And so as neurologist, and when evaluating neurologic patients with neurologic disease, this is a condition we want to understand. 03:50 Let's talk for a minute about Metronidazole-Associated Cerebellar Neurotoxicity. 03:55 It's one of those conditions that reminds us of the importance for understanding, what those deep cerebellar nuclei are? This is a subacute onset cerebellar ataxia. 04:05 That presents in patients who have been taking metronidazole. 04:08 Often at moderate to high doses for a extended period of time. 04:12 Patients present in a subacute fashion over several days to weeks, with primary ataxia. 04:18 Both affecting the trunk, as well as appendicular function. 04:22 And symptoms occurred during a prolonged course of metronidazole. 04:27 Imaging is very specific and shows us the T2-weighted or FLAIR hyperintensity, as we saw in this case, that affects the bilateral dentate nuclei. 04:35 Those are susceptible to this metronidazole induced toxicity. 04:40 What's going on pathologically? Well we see edema or swelling within the dentate nuclei that caused this characteristic imaging finding. 04:47 Typically this resolves with removal of the offending agent stopping the metronidazole, and in patients improve gradually, over the next several weeks and sometimes months. 04:57 Many returning back to normal function.
The lecture Case: 53-year-old Man with Ataxia by Roy Strowd, MD is from the course Vertigo, Dizziness, and Disorders of Balance.
Which of the following is most closely associated with metronidazole-induced cerebellar toxicity?
Which of the following is the most accurate with respect to metronidazole-induced cerebellar toxicity?
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