Infection with Epstein-Barr virus.
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Antibodies, Viral↗
Biomedical subjects
D A Warrell
Publications and source records attributed to D A Warrell.
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 parasite's cuticle, thus exposing it to the body's 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.
Adolescent↗
Poisoning by bites of the saw-scaled or carpet viper (Echis carinatus) in Nigeria.
The Saw-scaled or Carpet Viper (Echis carinatus) whose range extends from Senegal to Bengal probably bites and kills more people than any other species of snake. One hundred and fifteen patients with poisoning caused by its bite were studied in the savanna region of Nigeria, where victims of this snake may occupy 10 per cent of hospital beds. Patients showing no signs of envenoming were excluded. All patients had local swelling at the site of the bite. Other features included local blistering (13 per cent), local necrosis (11 per cent), incoagulable blood (93 per cent), and spontaneous systemic bleeding (57 per cent). There was evidence of disseminated intravascular coagulation in all cases; fibrinogen was severely depleted, fibrin degradation products were increased (mean 1711 +/- 904 micron per ml), but significant thrombocytopenia (less than 103 000 per mm3) was seen in only ten severe cases. Clotting factors V, VIII, II and XIII were depleted, while X and VII were usually normal. Fibrinolytic activity was rarely increased, so it seems likely that a procoagulant action (direct activation of prothrombin) is principal effect of E. carinatus venom on blood coagulation in man. Development of the haemostatic defect was observed as early as 75 minutes and as late as 27 hours after the bite. Spontaneous haemorrhage is clinically the most important effect of E. carinatus venom, causing the five deaths in this series. The relative importance of procoagulant and haemorrhagic components of the venom in causing haemorrhage is discussed. Complement activation via the classical and alternative pathways may have contributed to vascular damage. Mortality was reduced from the untreated level of between 10 and 20 per cent to 2.8 per cent in a group of 107 patients treated with 10 to 110 ml of specific antivenom. The dose was controlled using a simple clotting test. Blood coagulability was restored in two to 39 (mean 12) hours after the first dose of antivenom. Immediate-type serum reactions were observed in 21 per cent of cases. Additional treatment included blood transfusion for patients in haemorrhagic shock and ealry surgical débridement of necrotic tissue at the site of the bite.
Adolescent↗
Effects of venom in eye from spitting cobra.
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Adult↗
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.
Adolescent↗
Neurotoxic effects of bites by the Egyptian cobra (Naja haje) in Nigeria.
Two patients were bitten by Egyptian cobra (Naja haje). One became drowsy and developed transient ptosis 24 hours later. The other lost consciousness and died within two hours of the bite, but no cause was revealed by autopsy. A third patient developed severe transient neurological signs after being bitten by an unidentified snake. The small literature on bites by this species is discussed.
Adolescent↗
The clinical picture of rabies in man.
After an incubation period of one to two months rabies presents with non-specific prodromal symptoms and often with paraesthesiae of the bitten area. As in canine rabies there are furious and dumb forms of the disease. In man, furious rabies is characterised by hydrophobia: terror and excitation with spasms of inspiratory muscles, larynx and pharynx precipitated by attempts to drink and by a variety of other stimuli. Hydrophobia may represent an exaggerated respiratory tract irritant reflex with associated arousal potentiated by the selective destruction of brain stem inhibitory systmes. Also typical of furious rabies are intermittent episodes of excitement, hallucinations and maniacal behaviour. Focal neurological abnormalities are surprisingly uncommon. Other signs include hypersalivation, tachycardia and hyperpyrexia. Paralysis and coma supervene after a few days: survival rarely exceeds seven days. Dumb or paralytic rabies is an ascending flaccid paralysis with sphincter involvement and sensory disturbances. Death from respiratory and bulbar paralysis occurs after a longer illness than furious rabies. In a minority of cases hydrophobia develops before the terminal coma. Complications include respiratory arrest, pneumonitis, cardiac arrhythmias and interstitial myocarditis, posterior pituitary disorders, and gastrointestinal bleeding. Differential diagnoses of furious rabies include hysterical pseudo hydrophobia, tetanus, other encephalitides, delirium tremens and various other intoxications. Paralytic rabies may have to be distinguished from postvaccinal encephalomyelitis, poliomyelitis and other causes of Landry-type ascending paralysis. Intensive care has produced some promising results: life-threatening complications can be prevented but there is some evidence that the severity of the encephalitis is the ultimate barrier to survival.
Arrhythmias, Cardiac↗
Disseminated intravascular coagulation caused by the carpet viper (Echis carinatus): trial of heparin.
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.
Antivenins↗
Bites by the night adder (Causus maculatus) and burrowing vipers (genus Atractaspis) in Nigeria.
Nineteen patients proven to have been bitten by the small African adders Causus maculatus, Atractapis dahomeyensis and A. microlepidota were studied in the Nigerian savanna region. One of the patients bitten by C. maculatus was drowsy, hypotensive and flaccid on admission but recovered without treatment. Mild or moderate local swelling, local lymphadenitis and mild fever were the only other features in this group. None of the patients bitten by Atractaspis had signs of systemic envenoming apart from moderate fever. Local blistering appeared in two cases but did not progress to necrosis. No patient showed any disturbance of blood coagulation, or evidence of spontaneous hemorrhage or of cranial nerve lesions. The small literature on the effects of Causus and Atractaspis venoms in man and in laboratory animals is reviewed. It appears that bites by these species are very unlikely to cause serious ill effects. A few deaths from Atractaspis bites have been reported, but the danger from these species has been exaggerated.
Adolescent↗
Snake venom ophthalmia and blindness caused by the spitting cobra (Naja nigricollis) in Nigeria.
Venom entered the eyes of 9 patients spat at by the spitting cobra, Naja nigricollis. In 5 the only effect was a simple conjunctivitis but 4 had corneal ulceration, 1 developed anterior uveitis indicating absorption of venom in the anterior chamber, and 2 were permanently blinded. Treatment of this rare emergency is discussed: immediate irrigation of the eye with water, careful examination for corneal abrasion, and prevention of secondary infection are recommended. The value of local specific antivenom is unproven.
Adult↗
Pneumococcal meningitis: a clinical and laboratory study.
Forty-two patients who were admitted consecutively with pneumococcal meningitis during an 18-month period were studied in Ahmadu Bello University Hospital, Zaria, Nigeria. The disease was seen most frequently in older children and young adults. A predisposing condition was found in only four patients. Counter-current immunoelectrophoresis was found to be a rapid and effective method of diagnosis: pneumococcal polysaccharide antigen was found in the initial cerebrospinal fluid (CSF) sample from all but one of the patients. Detailed physiological studies carried out in two patients showed profound disturbances of cerebral carbohydrate metabolism and an increase in cerebral vascular resistance. Twenty patients died (48 per cent) in spite of treatment with large doses of penicillin. A fatal outcome was associated with impairment of consciousness on admission, a low CSF white cell count and a high CSF antigen titre. It is suggested that marked changes in cerebral carbohydrate metabolism, and perhaps vascular damage, play important roles in producing severe brain damage in patients with pneumococcal meningitis and that defective CSF polymorphoneutrophil leukocyte function may contribute to the failure of the infection to respond satisfactorily to antibiotic therapy.
Adolescent↗
The importance of bites by the saw-scaled or carpet viper (Echis carinatus): epidemiological studies in Nigeria and a review of the world literature.
The incidence of Echis carinatus (saw-scaled or carpet viper) bite and its mortality have been investigated in the Nigerian savanna region. A geographical area was defined in which the snake was particularly abundant and bites were frequent. Perennial and seasonal fluctuations in incidence and mortality, the circumstances in which bites occurred and the types of people bitten were studied at Bambur, Zaria, Kaltungo and Gombe hospitals. Peak incidence coincided with the increase in farming during the rains whereas percentage mortality seemed to be greatest during the cold dry season. The majority of the patients were young males bitten on the foot while walking or farming. A review of the world literature indicated that E. carinatus was the principal cause of snake bite morbidity wherever data were available throughout its wide geographical range. Official statistics have seriously underestimated this important rural health problem.
Adolescent↗
Necrosis, haemorrhage and complement depletion following bites by the spitting cobra (Naja nigricollis).
The Spitting Cobra, Naja nigricollis, is widely and densely distributed in Africa. Fourteen patients with proven N. nigricollis bites, who were seen in the savanna region of Nigeria, did not exhibit the neurological signs, such as cranial nerve lesions and respiratory paralysis, expected following Elapid poisoning. All had local swelling, in eight cases involving the entire limb, and ten developed local tissue necrosis. Spontaneous haemorrhage was detected in three cases and was the probable cause of death in one of them; the other death in this series was unexplained. Haematological abnormalities included prolonged clot lysis anf failure of clot retraction due to a platelet defect. There was no specific deficit in clotting factors and a delayed rise in fibrin degradation products was attributed to extensive tissue damage at the site of the bit. Most patients showed depletion of complement component C3 and glycine-rich beta-glycoprotein (GBG), suggesting activation of the alternative pathway of complement fixation. There was evidence of hepatocellular damage in two out of six patients investigated. There was no evidence that specific polyvalent antivenoms, used in doses of up to 80 ml, prevented any of the effects of N. nigricollis venom. Clinical laboratory diagnosis is discussed. In the past many bites were wrongly classified as viper bites on the basis of clinical findings. Immunodiagnosis is a promising method for assessing the true importance of N. nigricollis bite in West Africa.
Adolescent↗
Bites by puff-adder (Bitis arietans) in Nigeria, and value of antivenom.
Ten patients bitten by the puff-adder (Bitis arietans) were studied in the North of Nigeria. Six showed severe local signs, and four also had evidence of systemic envenoming, including spontaneous bleeding with thrombocytopenia, hypotension, and bradycardia. Two patients died after developing circulatory collapse and renal failure. Antivenom and intravenous fluid restored blood pressure in two hypotensive patients, and antivenom probably prevented the development of local necrosis in four others with massive local swelling. Victims of B arietans who have swelling of more than half the bitten limb or show signs of systemic envenoming should be given at least 80 ml of specific polyvalent antivenom and watched carefully for signs of circulatory collapse. Debridement of necrotic tissue may be necessary.
Adolescent↗
Proceedings: Haemostatic changes following snake bite by Echis carinatus; trial of heparin.
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Blood Coagulation↗
Meningococcal antigen in diagnosis and treatment of group A meningococcal infections.
Meningococcal antigen was measured by countercurrent immunoelectrophoresis in the blood and cerebrospinal fluid of 200 patients with group A meningococcal meningitis. Antigen was detected in the blood of 27 (13.5 per cent) patients. These patients had a worse prognosis and a higher incidence of allergic complications, such as arthritis and vasculitis, about 5 days after the start of antibiotic treatment. Antigen was found in the CSF of 129 (67.5 per cent) patients); antigen often persisted in the cerebrospinal fluid despite antibiotic treatment before admission. A combination of immunoelectrophoresis and routine bacteriologic study was used in the diagnosis of 162 (84.8 per cent) patients with meningococcal meningitis. High levels of antigen and a slow antigen disappearance were associated with neurologic damage. The antigen is stable and may be detected from specimens of cerebrospinal fluid dried on filter paper.
Antigens, Bacterial↗