Diphtheritic neuropathy is the commonest complication of diphtheria and generally occurs during childhood. Diphtheria toxin is neurotoxic and results in segmental demyelination.
Earliest symptom is paralysis of soft palate which occurs within a few days of the illness. It leads to hasal character of voice and regurgitation of fluids through the nose.
There is loss of palatal reflex. This is followed by paralysis of accommodation which usually develops during the third week of illness.
Pupillary reflexes are unaffected but paralysis of oculomotor and abducent nerves nay develop. Rarely facial and hypoglossal nerves may be affected.
Generalized polyneuritis occurs between 5th and 7th week after the infection and resembles acute infective polyneuritis. Lower extremities are more severely affected than the upper extremities.
Motor weakness is predominant and there may be foot or wrist drop. Sensory loss is present and there is glove and stocking type of anesthesia with tenderness of calf muscles. Postural sensibility may be grossly impaired leading to ataxia.
Deep reflexes are lost early and may remain so for long period. Sphincters are usually not effected. As the disease progresses respiratory and diaphragmatic paralysis may develop. Diphtheritic myocarditis is an important complication.
Diagnosis of Diphtheritic neuropathy
It is primarily of diphtheria, CSF proteins are increased while there is no increase in cell count. If one fails to detect diphtheria bacillus, SCHICK test may be employed.
Treatment of Diphtheritic neuropathy
It is primarily of diphtheria. Anti diphtheritic serum (ADS) should be administered at the earliest.
Care should be taken to manage palatal, and respiratory paralysis on the lines of management of infective polyneuritis.
Patients who survive respiratory paralysis, recovery is good. Inter current respiratory infections shall carry bad prognosis. Recovery from paralysis may take several weeks to months.