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New Treatments for Systemic and Toxic Diseases

Heavy metal poisoning. Now lead obviously gives you moderate neuropathy, predominantly a demyelinating neuropathy. Clinical features, if somebody comes to you with a wrist drop, radial nerve palsy, on the exam they want you to think lead neuropathy. Lead exposure. Wrist drop is very common. We have distal wasting. Sometimes this mimics ALS. So it’s a predominantly a motor problem.

Let’s move on to mercury. We talked about it. Mercury can give you a lot of things. Mercury. You all know about the "mad hatters" disease in organic mercury? Tremor, dementia, psychosis. Now the organic mercury poisoning now is much more common. The Minamata disease I mentioned … who knows about Minamata disease? Where are you from? Okay, so you can’t answer this question. Actually, this was discovered in Minamata Bay.

Now arsenic produces a predominantly axonal sensory neuropathy. Dark hyperkeratotic skin changes. It also produces a lot of fingernail changes. You get what’s called Mees line. It’s a white line in the nail. They are all due to arsenic toxicity.

Now thallium is pretty uncommon but for some strange reason this keeps showing up in the exam, in part one. All I know about thallium is what I read in the textbook. But the unique thing is alopecia. Remember that.

Organophosphate. Basically you get cholinergic problems, small pupils, salivation, diarrhea, cramps. You may want to remember this; pralidoxime, it just kicks the chemical out.

Manganese fumes can give you Parkinson’s disease. There are apparently more manganese mines in Montana. Until recently they were seeing people who were exposed to manganese and they came down with Parkinson’s disease, or parkinsonian syndrome sometimes. Pretty uncommon.

Here’s a multiple choice question. Renal failure, the least common complication in current day practice? No, headache is common. No. Seizures is very common. We all see seizures. Dialysis dementia. Now why is that? No aluminum. So dialysis dementia is the least common in fact … how many of you are not in practice? Okay. The ones of you who are in practice, how many of you have seen dialysis dementia in the last five years? It’s pretty uncommon. Now that brings up one point. Sensory neuropathy is common, myoclonus is very common.

One page on the neurology of renal failure. Now the encephalopathy, the take-home message is that it is not due to the severity of the renal failure but it is the acuteness with which the kidney fails. That’s a very important point you need to remember. The findings are very non-specific. Drowsy, confusion, agitation, little hallucinations, coma, tremor, myoclonus, asterixis. There’s really nothing specific about it at all. Now, this statement here, when you treat seizures in someone with renal failure, remember that the binding sites for phenytoin and valproic acid.

A lot of the patients that we see are on dialysis and they have seizures. So how do you manage? Phenytoin, a lot of times, you can give once a day dosage because of its long half life. But in someone with renal failure, you can handle the seizures in a good majority of them.

Disequilibrium syndrome we do not see a lot, but when I finished training over ten years ago we were still seeing them. Basically what happened was that the way the renal guys dialyzed, they were much more vigorous ten or 15 years ago.

Neuropathy in renal failure is painful neuropathy. It’s an axonal neuropathy, it’s predominantly sensory neuropathy. Sometimes in part two this may show up as a patient quiz. It’s a differential diagnosis for restless leg syndrome. Now Clonopin, clonazepam, works wonders in renal failure.

We talked about headache, there is really nothing more I need to tell you except the fact that it is a common problem.

Transplantation, I think I am going to skip. Except, remember there is a new entity some of you may have seen. Immediately after transplant there is rejection encephalopathy. The electrolytes are fine, the renal function is probably okay, but they get an encephalopathy.

Just one half minute on cyclosporine. Cyclosporine of course can give you seizures. Cyclosporine level can be peri-normal. Cyclosporine does another unique thing. How many of you have seen leukoencephalopathy?

Now incidence of all these is increased in renal failure. B1 gets dialyzed so if you don’t eat enough B1 you may get Wernicke’s encephalopathy. So in your part II, if your renal failure patient gets increasingly confused and drowsy, the differential diagnosis will be Wernicke’s encephalopathy. The differential diagnosis will be chronic bilateral subdural.