Helen M. Pope

Bites by the saw-scaled or carpet viper (Echis carinatus): trial of two specific antivenoms.

Echis carinatus is the most important cause of morbidity and mortality from snake bite in Nigeria and in many other parts of the world. Forty-six patients with systemic poisoning by this snake were given echis antivenom made either by the South African Institute for Medical Research (S.A.I.M.R.) or by Behringwerke (North and West African polyvalent antivenom). A simple test of blood coagulability was used to assess whether an adequate neutralizing dose of antivenom had been given. An average of 15·2 ml S.A.I.M.R. antivenom restored normal coagulability permanently in all 23 patients in one group, but in the other group receiving an average dose of 37·9 ml Behringwerke antivenom normal clotting resulted in only 18 out of 23 patients. Local tissue swelling was similar in both groups, but local necrosis occurred in three patients treated with Behringwerke antivenom and in none given S.A.I.M.R. antivenom.

Dangerous reactions to treatment of onchocerciasis with diethylcarbamazine.

Nine Nigerians with severe onchocerciasis who were treated with diethylcarbamazine developed clinical changes, ranging in severity from mild itching to distress, cough, and syncope. Physiological changes (fever, tachypnoea, tachycardia, or hypotension) were seen in eight. In five patients the systolic blood pressure fell by more than 25 mm Hg, and one patient collapsed on attempting to sit up. Circulating eosinophils decreased profoundly in all cases, reaching their lowest levels just before or during the clinical and physiological changes. A fall in serum complement (c3) accompanied the reaction but there was no fall in antibody titre. Diethylcarbamazine probably acts on the parasites cuticle, thus exposing it to the bodys defence mechansims. The reaction coincides with the death of microfilariae, and the accompanying physiological changes may be so severe, even in generally healthy patients, the treatment should perferably be started in hospital.

Pathophysiologic studies in human rabies

Six patients with proved rabies were studied with a combination of clinical, physiologic and pathologic technics. Three were given a type of intensive care but died with evidence of respiratory failure. Although circulatory failure did not develop in any of the six patients, three had supraventricular arrhythmias: interstitial myocarditis was found in one of these and rabies virus was isolated from the myocardium of another. Inspiratory muscle spasm was the dominant clinical feature in all cases. This occurred as part of the hydrophobic response and followed stimulation of the upper respiratory tract and skin. Hydrophobia may represent an exaggerated respiratory tract irritant reflex with associated arousal. Later in the course of the disease, various patterns of periodic and ataxic breathing were observed. Widespread brain stem encephalitis was discovered at autopsy, with particular involvement of the neighborhood of the nucleus ambiguous in two of three patients examined. In one patient cerebral metabolism was grossly abnormal, with greatly reduced cerebral oxygen consumption suggesting irreversible brain damage. Respiratory and circulatory disturbances may well be immediate causes of death in patients with rabies, but the present studies reemphasize the severity of the encephalitis which remains the ultimate barrier to survival. In the developing countries in which rabies is still a major problem and in which the cost precludes intensive care, the clinical management of rabies can aim only to reduce suffering by heavy sedation.

Disseminated Intravascular Coagulation Caused by the Carpet Viper (Echis carinatus): Trial of Heparin

Summary. Heparin has been advocated for the treatment of poisoning by Echis carinatus, a snake whose venom causes disseminated intravascular coagulation. Fourteen patients with proven E. carinatus bite who had incoagulable blood were treated with specific Echis antivenom, Seven of them were also given low‐dose heparin, initially 50 units/kg body weight by i.v. injection, followed by 10 units/kg/h by i.v. infusion for 22 h. Response to treatment was assessed clinically and by repeated tests of blood coagulation. All patients showed a rapid return to normal blood coagulability after treatment and the heparinized group were not significantly different in any respect from the group given antivenom alone. Heparin did not reduce the local effects of envenoming. There appears to be no place for heparin in the treatment of E. carinatus poisoning provided that potent antivenom is available. The in vivo results were supported by in vitro studies in which it was found that Echis‐induced thrombin was less sensitive to the inhibitory effect of heparin than physiological thrombin.

SILICOSIS AMONG GRINDSTONE CUTTERS IN THE NORTH OF NIGERIA

Many of the grindstones used in Nigerian homes are quarried from sandstone in a small group of villages near Kano in the extreme north of the country. Of an unselected group of 126 stonecutters from two of these villages 49 were found to have radiographic evidence of silicosis, with progressive massive fibrosis in 17. Those with silicosis had worked longer in the quarries than 77 whose radiographs showed no evidence of silicosis. Sixty-three per cent of the silicotics had respiratory symptoms, the commonest being breathlessness on moderate exertion. Cough was the earliest symptom in 42%. Only 35% had abnormal physical signs in the cardiorespiratory system, 18% had clearly reduced ventilatory capacity, and airways obstruction was evident in 16%. The prevalence of silicosis in these open-cast sandstone quarriers is unexpectedly high. This is probably explained by the intensity of exposure and the particular kind of sandstone being worked. Reduction of dust exposure in these quarries raises severe practical problems, but the inhabitants of this drought-ridden area can scarcely be expected to abandon their traditional livelihood.

Physiologic changes during the Jarisch-Herxheimer reaction in early syphilis: A comparison with louse-borne relapsing fever

Abstract In twelve of fifteen patients with early syphilis body temperature increased by more than 0.8 °C after treatment with penicillin. In all cases the blood leukocyte count increased; the lymphocyte count fell in seven of eight patients, but neutropenia was never observed. In four of the patients detailed cardiorespiratory measurements were made. During the Jarisch-Herxheimer rection (J-HR) metabolic rate increased, but pulmonary ventilation and cardiac output exceeded metabolic requirements. There was evidence of impaired pulmonary oxygen uptake, and systemic arterial blood pressure fell due to decreased vascular resistance. The role of leukocyte pyrogen in the Jarisch-Herxheimer reactions of secondary syphilis and louse-borne relapsing fever (LBRF) is discussed, and possible reasons are suggested for the differences in timing and intensity of the reactions in the two diseases and for the absence of an early neutropenia in syphilis.