Toxic and Metabolic Polyneuropathies

00:01 When we think about the toxic/metabolic polyneuropathies.

00:05 These are patients presenting often with sensorimotor polyneuropathies.

00:11 The vast majority of these are length-dependent.

00:13 They start in the most, in the longest nerves out in the legs and work their way proximally.

00:18 They often follow a stocking glove distribution and present chronically and progressively over time.

00:24 Immunologic work-up for AIDP or CIDP is negative.

00:29 There's no increased inflammation in the body that is precipitating the attack.

00:34 This is the result of a chronic toxic ingestion or a metabolic deficiency or overload.

00:40 Some of the things that we consider on the differential diagnosis for a toxic metabolic polyneuropathy is alcoholism which presents with prominent sensory findings and often a paucity of motor weakness.

00:52 Diabetes is the most common cause of distal symmetric polyneuropathy in the United States, and presents with a sensorimotor polyneuropathy with some demyelinating, as well as a prominent axonal features.

01:06 Uremia can present with a polyneuropathy that has a sensory predominance and is reversible and can be treated and is important to recognize.

01:14 Vitamin B12 may often present in the combination of neuropathy and myelopathy, It's a Myeloneuropathy.

01:22 Rarely patients will present with neuropathic symptoms early and slow development of myelopathy and so this needs to be a consideration in patients presenting with a polyneuropathy.

01:33 Vitamin B1 deficiency as well as others vitamin B6 can also present with polyneuropathy.

01:40 Importantly, vitamin B6 presents with a sensory neuropathy that is a result of an overdose of vitamin B6 and needs to be a consideration in selected patients.

01:51 There's a long list of drugs or medications that can present with side effects of polyneuropathy.

01:57 You can see a short list on the slide and any patient presenting with a chronic onset, length-dependent, symmetric sensorimotor polyneuropathy should have a robust medication review to evaluate any potential offending agents.

02:11 Heavy metals can present with a polyneuropathy, arsenic with a sensorimotor neuropathy and lead or plumbism with a motor predominant polyneuropathy.

02:21 And then lastly, porphyric polyneuropathy is can be present in some patients, this presents with a motor predominant often proximal involving polyneuropathy.