Signs of neuropathy in the lower legs and feet of patients with acute intermittent porphyria

Abstract

Objective. To assess signs of distal neuropathy in patients with acute intermittent porphyria (AIP). Design. A population-based study. Subjects. All patients with DNA-verified AIP ≥ 18 years of age in the four most northerly counties of Sweden. Intervention. Validated neuropathic signs and tests such as monofilament test, neuropathic pain, dry feet, extensor digitorum brevis (EDB) test, loss of forefoot arch, hammer toes and ulceration. Results. A total of 356 patients were registered and 339 of them (95%) participated in the neuropathy study. The chronic neurological signs were symmetrical and similar to those in type 1 diabetic patients. Significant impairment was found concerning perception, EDB test, lower leg pain, ankle and knee tendon reflexes, but not concerning dry feet, loss of forefoot arch and hammer toes, on comparing patients with manifest versus latent AIP. The neurological signs were more severe in the diabetic patients (n = 298). Five AIP patients had permanent quadriplegia after severe attacks. Conclusions. Patients with manifest AIP had significantly more signs of distal chronic, symmetrical neuropathy of axonal type than did patients with latent AIP. More grave neurological lesions appear to develop after severe attacks.