Monday, January 23, 2012
Daboia Envenomation and the Pituitary Gland
In 2011, Antonypillai and colleagues found people envenomed by Russell’s vipers suffer coagulopathy, bleeding, shock, neurotoxicity, acute kidney injury and local tissue damage leading to severe morbidity and mortality; and report the unusual complication of hypopituitarism. They described the first case of hypopituitarism following Russell’s viper bite in Sri Lanka. A 49-year-old man bitten and seriously envenomed by D. russelii in 2005 was treated with antivenom, recovered from the acute effects but remained unwell. Three years later hypopituitarism, with deficiencies of gonadal, steroid and thyroid axes was diagnosed and he showed marked improvement after replacement of anterior pituitary hormones. The authors attributed the hypopituitarism to Daboiai envenomation. Russell’s viper venom is known to cause acute and chronic hypopituitarism and diabetes insipidus, possibly through deposition of fibrin microthrombi and hemorrhage in the pituitary gland that result from the action of procoagulant enzymes and haemorrhagins in the venom. Forty nine cases of hypopituitarism following Russell’s viper bite have been described in the literature. More than 85% of these patients suffered acute kidney injury immediately after the bite, but steroid replacement in acute hypopituitarism is lifesaving.
Although the pituitary gland regulates puberty, it continues to function throughout a person's life and damage can result in failure of the gland to produce the needed hormones. Envenomation by Russell's Vipers often result in significant damage to the gland and hypopituitarism or Sheehan's Syndrome, as suggested by these two studies. Both conditions have symptoms, such as a constant feeling of cold and an unusual amount of fatigue, but what distinguishes them is a loss sex drive, fertility, body hair, and muscle mass (especially pubic hair), while women lose their body shape as they lose weight, and some may lose cognitive skills as the condition progresses.
Antonypillai CN., Wass, JAH., Warrell, DA, and Rajaratnam, HN. 2011. Hypopituitarism following envenoming by Russell’s Vipers (Daboia siamensis and D. russelii) resembling Sheehan’s syndrome: first case report from Sri Lanka, a review of the literature and recommendations for endocrine management. Oxford Journal of Medicine, 104: 97-108.
Tun-Pe, Warrell DA., Tin Nu, S. Phillips, RE., Moore, RA. 1987. Acute and chronic pituitary failure resembling Sheehan's syndrome following bites by Russell's Vipers in Burma. The Lancet 330: 763-767.