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Biomedical subjects

D G Lalloo

Publications and source records attributed to D G Lalloo.

30 records · Page 2Linked to original sources
PubMed1995

Snake bites by the Papuan taipan (Oxyuranus scutellatus canni): paralysis, hemostatic and electrocardiographic abnormalities, and effects of antivenom.

One hundred sixty-six patients with enzyme immunoassay-proven bites by taipans (Oxyuranus scutellatus canni) were studied in Port Moresby, Papua New Guinea. One hundred thirty-nine (84%) showed clinical evidence of envenoming: local signs were trivial, but most developed hemostatic disorders and neurotoxicity. The blood of 77% of the patients was incoagulable and 35% bled spontaneously, usually from the gums. Fifty-one per cent had microscopic hematuria. Neurotoxic signs (ptosis, ophthalmoplegia, bulbar paralysis, and peripheral muscular weakness) developed in 85%. Endotracheal intubation was required in 42% and mechanical ventilation in 37%. Electrocardiographic abnormalities (sinus bradycardia and septal T wave inversion) were found in 52% of a group of 69 unselected patients. Specific antivenom raised against Australian taipan venom was effective in stopping spontaneous systemic bleeding and restoring blood coagulability but, in most cases, it neither reversed nor prevented the evolution of paralysis even when given within a few hours of the bite. However, early antivenom treatment was associated statistically with decreased incidence and severity of neurotoxic signs. The low case fatality rate of 4.3% is attributable mainly to the use of mechanical ventilation, a technique rarely available in Papua New Guinea. Earlier use of increased doses of antivenoms of improved specificity might prove more effective.

Adolescent↗
PubMedDate not supplied

Analysis of referral letters to assess the management of poisonous snake bite in rural Papua New Guinea.

A prospective series of patients envenomed after snake bite was seen at Port Moresby General Hospital (PMGH), Papua New Guinea, between January 1991 and December 1992. Referral letters were received with 60 of the patients who had been initially seen at a health centre. These letters were analysed in conjunction with our own clinical observations. The importance of non-clotting blood and local lymphadenopathy as early signs of systemic poisoning did not appear to be universally recognized by staff in health centres. In some cases, no attempt was made to transfer the patient to hospital until signs of neurotoxicity were established with potentially dangerous delay. Analysis of both hospital and health centre records suggests that the majority of deaths which occurred in Central Province, Papua New Guinea, during the period of the study were due to delay in transfer to hospital. We suggest that all patients with unequivocal signs of envenoming in Central Province, Papua New Guinea, should be transferred to PMGH as soon as possible. Antivenom should also be given as soon as possible, but this does not remove the need for immediate transfer.

Antivenins↗
PubMedDate not supplied

Electrophysiological findings in patients envenomed following the bite of a Papuan taipan (Oxyuranus scutellatus canni).

Electrophysiological studies were done on patients with systemic neurotoxicity following the bite of a Papuan taipan (Oxyuranus scutellatus canni). Evoked compound muscle action potentials decreased and increased in tandem with clinical deterioration and recovery. Nerve conduction velocities did not change in envenomed patients and were consistent with control studies. Repetitive nerve stimulation studies showed decremental responses in envenomed patients with post-tetanic potentiation followed by post-tetanic exhaustion. The findings are consistent with studies in vitro which suggested that the major action of neurotoxins in Australian taipan venom is at the synapse. The observation that electrophysiological data correlate closely with the clinical condition of the patient has potential application in the assessment of interventions in the management of snake bite victims.

Action Potentials↗
PubMedDate not supplied

Failure of 3,4-diaminopyridine and edrophonium to produce significant clinical benefit in neurotoxicity following the bite of Papuan taipan (Oxyuranus scutellatus canni).

Progressive systemic neurotoxicity is a common feature in patients envenomed following the bite of a Papuan taipan (Oxyuranus scutellatus canni). Respiratory paralysis, which commonly results, accounts for considerable morbidity and mortality. Established neurotoxicity does not respond to antivenom. In this study, a combination of clinical and electrophysiological variables was used to assess the effect of edrophonium and 3,4-diaminopyridine in patients with significant neurotoxicity. Both drugs produced minor electrophysiological and clinical changes in envenomed patients. This effect was maximal when the 2 drugs were used in combination, but was insufficient to be of significant clinical benefit. Neither drug can be recommended for use in the management of Papuan taipan bite.

4-Aminopyridine↗
PubMedDate not supplied

The epidemiology of snake bite in Central Province and National Capital District, Papua New Guinea.

Snake bite is an important medical problem in some areas of Papua New Guinea and appears to be most common in the Central Province and National Capital District. The overall incidence for Central Province is 215.5 per 100,000 population, but Kairuku subprovince has an incidence of 526 per 100,000, which is amongst the highest in the world. The clinical pattern of envenoming also varies within the Province, suggesting that different species of snake may be responsible for bites in different areas. Most envenomed patients are bitten during daylight on the lower limb and are rarely able to describe the snake. The mortality rate in Central Province is 7.9 per 100,000; most patients die from ventilatory failure due to severe neurotoxicity. Mortality might be reduced by increased use of compression bandaging as a first aid measure, earlier treatment with antivenom and earlier referral to hospital.

Adolescent↗
PubMedDate not supplied

The efficacy of antivenom in the treatment of bites by the Papuan taipan (Oxyuranus scutellatus canni).

A prospective series of 156 patients systemically envenomed following the bite of a Papuan taipan (Oxyuranus scutellatus canni) were studied. All patients were treated with appropriate antivenom and clinical course and outcome were compared. The proportion of patients requiring intubation was significantly smaller, and the time to resolution of neurotoxicity and discharge from hospital significantly shorter, in patients receiving antivenom no more than 4 h after the bite. No significant difference in outcome was demonstrated between patients receiving antivenom at various times after 4 h. No difference was demonstrated in the times to restoration of coagulability between the 2 groups. The only significant difference between a small number of patients given 2 vials of antivenom and patients given a single vial at the same time after envenoming was a marginally shorter duration of intubation in those who required it. The study suggests that, to achieve significant clinical benefit in Papuan taipan bite, antivenom must be given as early as possible.

Animals↗
PubMedDate not supplied

Meningitis caused by Cryptococcus neoformans var. gattii and var. neoformans in Papua New Guinea.

Eleven cases of cryptococcal meningitis were diagnosed and biotyped from September 1991 to August 1992 in Papua New Guinea (PNG). Seven isolates were Cryptococcus neoformans var. gattii from paediatric and adult patients, one with diabetes mellitus and 4 were C. neoformans var. neoformans from adults, of whom 2 had human immunodeficiency virus type 1 (HIV-1) infection, and one each had tuberculosis and Plasmodium vivax malaria. Significant clinical findings were headache, fever, meningism, vomiting, photophobia, papilloedema and cranial nerve lesions. Five patients (45.5%) died; 3 of these were adults with var. gattii and 2 were men with both var. neoformans and HIV-1 infections. This prospective tropical study documents the emergence of C. neoformans var. neoformans in patients with HIV-1 infection in a country where previously var. gattii had predominated in the immunocompetent. There has been no earlier report of cryptococcosis in an HIV-1 seropositive patient in PNG. Despite presumed exposure to both varieties of C. neoformans, var. gattii infections had been most frequent. As HIV-1 spreads, the proportion of hosts infected with var. neoformans may rise. The course of meningitis caused by the 2 varieties of C. neoformans may differ, with mortality in the tropics remaining particularly high. In PNG the environmental source of C. neoformans remains elusive.

Adolescent↗
PubMedDate not supplied

Electrocardiographic abnormalities in patients bitten by taipans (Oxyuranus scutellatus canni) and other elapid snakes in Papua New Guinea.

Envenoming by a number of species of snake may affect the myocardium or cause electrocardiographic changes; several different mechanisms have been proposed. In a prospective study of snake bite in Papua New Guinea, electrocardiographic changes were observed in 36 of 69 patients (52%) envenomed by the taipan (Oxyuranus scutellatus), 2 of 6 (33%) envenomed by death adders (Acanthophis sp.) and one envenomed by the brown snake (Pseudonaja textilis). Septal T wave inversion and bradycardias, including atrioventricular block, were the commonest abnormalities. There was no haemodynamic deterioration. The cause of these changes is uncertain; only 2 of 24 patients (8.3%) with electrocardiographic changes had markedly elevated plasma concentrations of cardiac troponin T, a sensitive and specific marker of myocardial damage. This suggests that myocardial damage is uncommon following bites by these species. Electrocardiographic abnormalities are most likely to have been caused by a direct toxic effect of a venom component upon cardiac myocyte function; in taipan bites, taicatoxin, a calcium channel blocker, might be responsible.

Animals↗
PubMedDate not supplied

Cryptococcus neoformans in Papua New Guinea: a common pathogen but an elusive source.

Around Port Moresby, Papua New Guinea (PNG), the annual incidence of cryptococcal meningitis is estimated to be up to 42.8 per million population; Cryptococcus neoformans var. gattii is the predominant causative agent. In Australia and California, environmental isolations have established an ecological association of C. neoformans var. gattii with Eucalyptus camaldulensis, E. tereticornis, and more recently E. rudis and E. gomphcephala. In PNG few E. camaldulensis survive experimental planting, E. tereticornis is endemic and there are no records of planting of the non-endemic E. rudis and E. gomphcephela. Despite extensive sampling of eucalypt-associated and other sources, we were unable to identify the ecological niche of C. neoformans var. gattii and neoformans in this region.

Cryptococcus neoformans↗