Pituitary Dysfunction Following Snakebite Envenomation: A Clinico-Radiological Assessment of 15 Cases and Review of the Literature.

BACKGROUND

Snakebite envenomation (SE) is an important tropical disease in India, causing significant morbidity and mortality among patients. The hormonal deficiencies due to the involvement of the pituitary in case of SE can present in either acute or delayed setting. Hypopituitarism (HP) is often an underrecognized and relatively rarely reported complication of this neglected disease.

METHODS

We present here the data of 15 patients diagnosed to have HP following systemic SE and are being currently followed-up in the Endocrinology outpatient department of a tertiary care hospital of South India. The study was approved by the Institute ethics committee, and informed onsent was taken from all the study patients. The study was a record-based retrospective analysis of the patients with HP following SE. Clinical data including lag time in diagnosis and type of snake were determined. Further, hormonal data including all the anterior pituitary functions (thyroid stimulating hormone, free T4, cortisol, insulin-like growth factor (IGF-1) luteinizing hormone, follicular-stimulating hormone, testosterone; prolactin) and water deprivation test to determine diabetes insipidus (DI) in patients with polyuria on follow-up were extracted from the records and the hospital information system. An experienced neuroradiologist examined the magnetic resonance imaging (MRI) findings of the pituitary.

RESULTS

The mean age of the patients was 43 ± 9 years and 80% were male. Around 90% of patients belonged to upper-lower socioeconomic status according to the modified Kuppuswamy scale. The commonest snake species reported was Russell's viper. Thirteen patients had delayed HP. The median duration from snakebite to onset of HP symptoms was 1 year (range 0.33-10 years). However, the median time from snakebite to the diagnosis of HP was 7 years (range 1-13 years). Central hypothyroidism and hypogonadism were present in all subjects. However, central hypocortisolism was noted in 93% of patients. Low IGF-1 was noted in all the six patients where data were available. One patient had partial central DI. Thirteen out of 15 patients had reduction of pituitary volume in MRI.

CONCLUSION

HP in patients with SE can appear slowly and the diagnosis is frequently delayed for years. Following snakebite, multiple pituitary hormone deficiencies associated with radiological abnormalities like a significant reduction in the pituitary volume are common.