Three cases of severe neurotoxicity after cobra bite (Naja kaouthia).

Abstract

Snakebites represent a health-care problem in Africa and Asia [1, 2]. In Africa, for example, snakes are responsible for hundreds of deaths each year and thousands of cases of permanent physical handicap [2]. In Switzerland, venomous snakes enjoy a growing popularity as domestic animals. For that reason the number of cases of illnesses caused by snake bites is rising [3]. We report on three patients with severe neurotoxic symptoms of poisoning after a bite by the Thai cobra Naja kaouthia (Figure 1). In 1964, an investigation of 47 patients bitten by Malayan cobra Naja naja subspecies observed the occurence of neurotoxic symptoms in only 4 of the 47 cases [4]; whereas a study in 1986 showed 14 of 24 cases exhibited neurologic deficiencies after a bite by the Thai cobra Naja kaouthia. An ELISA test detected the presence of Naja kaouthia poison antigen in the serum of 22 of these Thai victims [5]. In both publications mentioned all patients who exhibited a local necrosis at the area of the bite wound developed signs of neurotoxicity. Our three patients were all hospitalised as emergencies and monitored in the intensive care unit. The time interval between the snake bite and the first detectable neurologic symptoms varied from a few minutes to four hours (Table 1). All patients had a local inflammation and a swelling around the bite wound (Figure 2); laboratory findings documented an elevation of inflammatory parameters. Patients 1 and 3 exhibited ptosis, dysphagia, dysarthria, and somnolence after four and two hours respectively. One of them had to be intubated and ventilated mechanically because of a respiratory insufficiency resulting from an increasingly shallow breathing. Patient 2 developed signs of anaphylactic shock a few minutes after the snake bite. During the transport to the hospital a cardiac arrest occurred. The patient was successfully resuscitated, intubated and ventilated mechanically. In this case (Patient 2, Table 1) it was impossible to assess how far the life threatening symptoms were neurotoxic or rather allergic, or both. The two patients who required intubation received a treatment with a Naja kaouthia specific monovalent antivenom (Thai Red Cross Society, Queen Saovabha Memorial Institute [QSMI], Bangkok). In one case the course was complicated by a phlegmona of the hand that made surgical debridement necessary. The isolated germ was Morganella morganii, a bacterium naturally resistant to amoxycillin/clavulanic acid [6] and frequently detected in the flora of a snake’s mouth [7]. In the patient who had the anaphylactic shock at the initial phase, extubation was delayed despite regained consciousness and spontaneous breathing activity because of an extensive swelling of the tongue and the pharyngeal area. The third patient developed a deep vein thrombosis. All our patients recovered completely without further sequelae. 227 Letter to the editor S W I S S M E D W K LY 2 0 0 1 ; 1 3 1 : 2 2 7 – 2 2 8 · w w w. s m w. c h