Acute dysautonomia following mumps.

PS Mathuranath, J Duralpandian, A Kishore 
 Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, 695011, India., India

Correspondence Address:
P S Mathuranath
Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, 695011, India.
India

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::   Introduction

Autonomic dysfunction as a component of peripheral neuropathy is a common occurrence. However, a pure acute autonomic neuropathy is rare. [Table I] lists the causes of autonomic dysfunction complicating neurological disorders. We report here a case of pure acute dysautonomia following mumps and a brief review of the entity.

::   Case report

A 30 year old lady developed fever and bilateral parotid swelling with dryness of mouth. She was clinically diagnosed to have mumps. Seven days after the swelling subsided she acutely developed transient burning paraesthesias extending below the neck. It was followed by incapacitating postural syncope. A day later she developed severe abdominal colic, associated with vomiting and intermittent diarrhoea. The following day she had intermittent profuse generalized diaphoresis and urinary retention requiring catheterisation. At the time of admission she was conscious and complained of increased thirst. Higher mental functions, optic fundi and cranial nerve examination were unremarkable except for small pupils, sluggishly and symmetrically reacting to both light and accommodation. Horner's sign was not detected. Muscle bulk, tone and power in all the limbs were normal. Objective sensory examination did not reveal any superficial or deep sensory loss, hyperaesthesias or trunkal sensory level. All deep tendon jerks were absent. There were no cerebellar signs or peripheral nerve thickening. There was marked symptomatic postural hypotension unaccompanied by cardioacceleration. The supine blood pressure was 150/100mm of Hg which fell on standing to 60 mm of Hg (systolic) with unrecordable diastolic pressure. The heart rate remained unchanged at 88 beats/min irrespective of the postural alterations.



The blood biochemistry, haemogram and serum protein electrophoresis were normal. Urinary porphobilinogen was negative. Cerebrospinal fluid (CSF) cytology and biochemical studies, done in the 1st and 3rd week of neurological illness were within normal limits. CSF viral cultures were negative for mumps virus. Complement fixation tests for mumps `S' and `V' antigens were not performed. Motor and sensory nerve conduction studies done on the median, ulnar, peroneal, tibial and sural nerves during the 1st and 3rd week of neurological illness were essentially normal except for an absent F-response on peroneal nerve stimulation in the 3rd week's study. Electromyographic examination was not done.



The bedside autonomic tests revealed absent sympathetic skin response (SSR) ; RR ratio of 1.1 in response to valsalva maneuver, (valsalva ratio) (normal > 1.4); expiration : inspiration RR ratio of 1.0 (normal > 1.2); no response in heart rate to standing (normally increases by 5-30 beats/min); documentation of postural drop (mentioned earlier). All the tests thus showed abnormal responses. Secretomotor and gastrointestinal motility tests were not performed.



The patient was initiated on symptomatic treatment with fludrocortisone (0.1mg daily) and omeprazole to which she showed good response. In view of this response and the stable course of her illness, plasmapheresis was not initiated. Six weeks later she was asymptomatic except for occasional postural giddiness and continued to require fludrocortisone. Her supine blood pressure was 110/70 mm of Hg. On standing it fell to 100/56 mm of Hg though she remained asymptomatic. There was no cardioacceleration.

::   Discussion

Young et al briefly reported a patient in 1969 and described the results of autonomic tests on him in 1975,[1] giving the first detailed description of pure pandysautonomia. Autonomic dysfunction associated with various conditions mentioned in [Table I], are excluded from the entity of pure pandysautonomia[2],[3]



The additional characteristics which qualify for the diagnosis of pure pandysautonomia include acute or subacute onset; monophasic course; and gradual partial or complete recovery.[3] Majority of patients presenting with pandysautonomia have a preceding infection,[3],[4] which includes herpes simplex, infectious mononucleosis, rubella and coxsackie B infection.[4],[5]



A variety of neurological sequelae to mumps have been reported including meningitis, encephalitis, myelitis and rarely polyneuropathy of a Guillain-Barre syndrome type.[6] Muscle weakness associated with a lymphocytic pleocytosis mimicking poliomyelitis has also been reported to accompany the acute illness.[7] Polyneuropathy reported with mumps develops one to three weeks following the viral infection[8] and in the majority of cases is preceded by mumps orchitis.[9]



To the best of our knowledge, there is no previous report of mumps preceding acute pure dysautonomia. Our patient, by clinical consideration, had mumps, though CSF viral culture was negative. It is well known that the virus is detectable only upto 4 days after the infection. Our patient also had sensory symptoms and absent F-response in the peroneal nerve which raises the possibility of a proximal involvement of the somatic nerve. In other postinfectious acute pure dysautonomias, mild sensory symptoms have been reported though objective sensory signs or electrophysiological evidence for somatic nerve involvement were extremely rare.



The definite aetiopathogenesis of acute pure dysautonomia remains uncertain, though a possible postganglionic immune-mediated inflammatory mechanism has been suggested by Suarez et al.[3] Some authors have reported electroencephalographic abnormality and a transient hypothalamic dysfunction.[10] Okada and Shintomi reported abnormal eye movements in a few patients. Based on all these reports, they postulates an affection of cholinergic neurons within the CNS that share antigenic similarities to the postganglionic autonomic neurons.[11]



As a general rule, almost all patients slowly recover over months, though some may show only partial recovery. Management is essentially symptomatic. On the basis of their findings, Suarez et al[3] have suggested a trial of plasmapheresis or steroids as a specific management during the acute phase, if symptoms are severe.

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