Spontaneous Periodic Hypothermia

A rare neurologic disorder characterized by spontaneous periodic hypothermia and hyperhidrosis in the absence of hypothalamic lesions.

Epidemiology

Spontaneous periodic hypothermia (SPH) prevalence is unknown but to date more than 50 cases of spontaneous periodic hypothermia have been described in the world literature.

Clinical description

SPH can occur at any age (ranging from 6 months to 62 years). The clinical manifestations of the disease comprise recurrent episodes of hypothermia (core temperature <35°C) with profuse sweating, nausea and vomiting, that occur in the absence of any detectable infectious or endocrine cause. Periodicity of hypothermic episodes may range from hours to years and the episodes themselves may last from hours to weeks. The sensation is usually experienced as a ''funny feeling'' in the head and is described as powerful, consuming and combined with a sense of weakness, incoordination and gait unsteadiness. Additional features include drowsiness, deep sleep, hypothermic syncope, mild bradycardia, and pale and cool skin. There are usually no associated complaints of diarrhea, confusion, wheezing, rash, seizure activity, shivering or shakiness. Polyuria and polydipsia during the attacks have been described in only one case. Recurrent hypothermia attacks were reported in two siblings.

Etiology

The exact pathophysiological mechanism for this syndrome is still not understood. Postulated mechanisms include hypothalamic dysfunction, neurochemical abnormalities, inflammatory processes, and epileptic activity.

Diagnostic methods

Diagnosis includes physical and systemic examinations which show a pale, cold skin and normal blood count and electrolyte levels. Imaging studies may in some cases reveal confluent lesions in the corpus callosum and a circumscribed lesion in the right posterior thalamus. 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) levels in cerebrospinal fluid may be below the normal ranges.

Differential diagnosis

Differential diagnosis of SPH severe hypothyroidism, hypoglycemia or attacks of diabetic ketoacidosis.

Management and treatment

There is no cure for SPH. Management is mainly supportive and includes re-warming with a warm blanket. Carbamazepine, clonidine, cyproheptadine, glycopyrrolate, bromocriptine, chlorpromazine, beta1 blockers or sympathectomy are used with varying responses.

Prognosis

SPH is a benign disease and may cease spontaneously. Some patients have been reported to have hyperthermia attacks during the course of the disease.