Deep coma and hypokalaemia of unknown aetiology following Bungarus caeruleus bites: Exploration of pathophysiological mechanisms with two case studies

Case Report


J Venom Res 
(2010), Vol 1, 71-75

doi:

Published online: 14 December 2010

Full Text: (html | XML | pdf ~437kb)

Deep coma and hypokalaemia of unknown aetiology following Bungarus caeruleus bites: Exploration of pathophysiological mechanisms with two case studies

Indika Bandara Gawarammana †‡*, Senanayake Abeysinghe Mudiyanselage Kularatne †, Keerthi Kularatne ¥, Roshita Waduge €, Vajira Senaka Weerasinghe §, Sunil Bowatta ¶, Nimal Senanayake †

† Department of Medicine, Faculty of Medicine, University of Peradeniya, Sri Lanka

‡ South Asian Clinical Toxicology Research Collaboration, Faculty of Medicine, University of Peradeniya, Sri Lanka

¥ Poisons and Snake bite management Unit, Teaching Hospital Peradeniya, Sri Lanka

€ Department of Histopathology, Faculty of medicine, University of Peradeniya, Sri Lanka

§ Departments of Physiology and Neurophysiology, Faculty of Medicine, University of Peradeniya, Sri Lanka

¶ Base Hospital, Nawalapitiya, Sri Lanka

*Correspondence to: Indika Gawarammana, Email: indika@sactrc.org, Tel: +94 714225081, Fax: +94 814479822

Received: 29 November 2010, Accepted: 13 December 2010

© Copyright The Authors

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ABSTRACT

Bungarotoxin present in Bungarus caeruleus (BC) causes life threatening respiratory muscle paralysis. Deep coma and hypokalaemia have been observed in a significant proportion of patients, but the cause is unknown. We postulate the likely mechanism behind these two phenomena. We studied clinical details of two patients admitted with deep coma and performed electroencephalograms (EEG) and brain stem auditory and visual evoked potentials (BAEP and VEP). Daily serum potassium was measured along with urinary potassium excretion as a marker of total extracellular body potassium. Both patients had no brain stem reflexes on admission and the EEG revealed absent alpha and delta activity and presence of dominant theta activity. Alpha rhythm returned on the 3 rd day in one patient, while in the other it did not, and the latter patient died on the 13 th day due to disseminated intravascular coagulation. BAEP were delayed and VEP were absent in the deceased patient. Both had low serum potassium and low urinary potassium excretion. Replacement of potassium (up to 1.5mmol/kg/day) did not improve serum potassium and urinary potassium excretion. Absent alpha and delta activity in EEG and delayed BAEP and absent VEP are suggestive of a central action of the venom on both the cortical and brain stem neurones. Persistently low serum potassium and reduced urinary potassium excretion are suggestive of intracellular shift as the causative mechanism of hypokalaemia.

KEYWORDS: Deep coma, hypokalaemia, Bungarus caeruleus, EEG, evoked potentials

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