Diagnosis and management of periodic hypothermia

Abstract

Hypothermia, defined as a core temperature below 35°C, can occur in a variety of clinical settings, including environmental exposure, shock, infection, metabolic disorders (such as hypothyroidism, adrenal insufficiency, and Wernicke encephalopathy), malnutrition, and alcohol or drug toxicity. Typically, hypothermia should resolve with treatment of the underlying disorder. However, in rare cases patients experience recurrent episodes of hypothermia in the context of a stereotyped syndrome due to a hypothalamic lesion, which can be either congenital or acquired. The episodes are characterized by progressive confusion and a decreased level of arousal, hypothermia, and eventual resolution with a return to baseline. Additional clinical findings during episodes may include diaphoresis, asterixis, bradycardia, and thrombocytopenia. These recurrent episodes represent periodic hypothermia.

MRI findings in patients with periodic hypothermia Figure 1. (A) T1 sagittal and (B) coronal MRI of a 70-year-old man with agenesis of the corpus callosum and periodic hypothermia. (C) T1 sagittal and (D) T2 fluid-attenuated inversion recovery axial MRI of a 54-year-old man who had rupture and clipping of an anterior communicating artery aneurysm 6 months prior. C demonstrates an area of encephalomalacia in the anterior corpus callosum (arrow). Metal artifact obscures the hypothalamic region. D demonstrates encephalomalacia of the genu of the corpus callosum (arrow), with gliosis of the frontal paraventricular white matter due to wallerian degeneration. (E) T1 sagittal and (F) coronal postcontrast MRI of an 82-year-old man with a suspected renal cell carcinoma metastasis to the hypothalamic region. The tumor appears as a homogeneously enhancing mass lesion (arrow).

Classification of the periodic hypothermia syndromes Figure 2. Congenital periodic hypothermia with a structural lesion may occur in cases of partial or complete agenesis of the corpus callosum. Congenital periodic hypothermia without a structural lesion is seen exclusively in pediatric cases, where the etiology may be a neurotransmitter disorder. Acquired, stereotyped periodic hypothermia may occur after an intracranial hemorrhage or remote traumatic brain injury. Acquired, non-stereotyped periodic hypothermia may occur in cases of advanced multiple sclerosis or tumors in the hypothalamic region.