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Porphyria Educational Services


Porphyric Polyneuropathy

There are many neuropathies, but a porphyric based neuropathy is a severe,
rapidly advancing neuropathy.

Quite often it begins with the onset of an acute attack of porphyria.
It is often associated with the abdominal pain, psychosis may be part of
this in the form of delirium or confusion, and may result in convulsions.

Such neuropathy may be more or less symmetrical polyneuropathy.

It is not a disease, but is rather a symptom or sign of a disease, and in
this case, being one of the acute types of hepatic porphyria.

PN, as it is known, is always a likely manifestation of AIP [acute
intermittent porphyria] pyrroloporphyria or Swedish porphyria. It is also
found in the the Chester type or the sub type dubbed as Dobson's Complaint.

The types are porphyria giving way to PN ware inherited as an autosomal
dominant trait. It is not associated associated with cutaneous sensitivity
to sunlight.

The metabolic defect is in the liver. It is marked by an increased
[rpduction and urinary excretion of porphobilingen and of the porphyrin
precusor, ALA. ALA is delta aminolevulinic acid.

In the VP and the HCP types, the p[eripheral and central nervous systems
may also be affected with the PN. In the CEP the nervous system is not
affacted by PN. Studies in relation to the ALAD have not been completed in relation to PN.

The neurologic manifestations in the acute porphyrias are usually those of
a polyneuropathy involving the motor nerves, more than the sensory ones.
Less often both sensory and motor nerves are affected.

The symptoms may begin in the feet and legs and ascend, or they may begin
in the hands and arms and spread in a few days to the trunk and legs. This
may happen asymmetrically.

Occasionally the weakness predominates in the proximal muscles of the limbs
and limb girdles.

Sensory loss, often extending to the trunk, is present in more than 50% of
the cases.

Facial paralysis, dysphagia, and ocular palsies are features of the most
severe cases, and often simulate Guillian Barre Syndrome.

The CSF protein content is normal or slightly elevated.

The course of the polyneuropathy is variable.

In mild cases the symptoms may regress in a few weeks.

If the condition is severe, it may progress to a fatal respiratory or
cardiac paralysis in a few days. It can also advance in a saltatory
fashion over a period of several weeks, resulting in a severe sensorimotor
pararlysis that improves only after many months and the avoidance of
further acute porphyria attacks.

A disturbance of cerebral function (ie., confusion, delirium, visual field
defects [fuzzy vision and brain fog]) is likely to preced the severe rather
than the mild forms of PN. Sometimes they will not appear at all.

Death may result from respiratory paralysis or cardiac arrest and sometimes
from uremia and cachexia.

Rarely the PN developes without the other symptoms of an acute attack.

Asbury, Dr. A. and Thomas Dr. P.K. "Peripheral Nerve Disorders:
2nd Edition, London, Butterworth & Hennemann, 1995.

Principles of Neurology, Adams, Dr,. Raymond D. et. al. Porphyric
Neuropathy, New York, McGraw-Hill, 1997.

*Provided by Porphyria Educational Services
Porphyrin Press