Electrophysiological correlates of respiratory failure in acute organophosphate poisoning: Evidence for differential roles of muscarinic and nicotinic stimulation

Background. Respiratory failure in acute organophosphate (OP) poisoning can occur early and also relatively late in the clinical course, and the pathophysiology of respiratory failure at these different phases may have important clinical implications. Objective. To compare the electrophysiological findings in patients with early and late respiratory failure following acute OP poisoning. Methods. A prospective observational case series of consenting symptomatic patients with acute OP poisoning were assessed with daily physical examinations and repetitive nerve stimulation (RNS) studies. RNS was done on right and left median and ulnar nerves at 1, 3, 10, 15, 20, and 30 Hz. Outcomes such as need for ventilation and development of intermediate syndrome (IMS) were noted. Early respiratory failure was defined as occurring within 24 hours of ingestion. Results. Seventy-eight patients were recruited for the clinical and electrophysiological study and of those 59 (75.6%) patients had ingested chlorpyrifos. Seven patients developed respiratory failure within 24 hours of ingestion with overt muscarinic signs. They had no electrophysiological abnormalities at median and ulnar nerves before intubation. Three of them later developed “forme fruste” IMS. Five other patients developed late respiratory failure after 24 hours of ingestion, and all of them showed progressive RNS changes indicating severe IMS prior to intubation. Conclusion. The normal RNS in all patients developing early respiratory failure suggests that it is due to a central nervous system (CNS) and muscarinic effect. This emphasizes the need for early rapid atropinisation as a priority, combating the nicotinic effects being less urgent. This is in contrast with the late respiratory failure, which has been shown to be associated with neuromuscular dysfunction. Further studies are needed to quantify CNS and muscarinic dysfunction to assist in the development of better treatments for the severe and early OP poisoning

The Spectrum of Intermediate Syndrome Following Acute Organophosphate Poisoning: A Prospective Cohort Study from Sri Lanka

Jayawardane and colleagues evaluate a cohort of 78 patients with organophosphate poisoning from Sri Lanka, and identify changes in repetitive nerve stimulation that precede, and may help predict, the onset of intermediate syndrome

Neurological manifestations of malaria

The involvement of the nervous system in malaria is reviewed in this paper. Cerebral malaria, the acute encephalopathy which complicates exclusively the infection by Plasmodium falciparum commonly affects children and adolescents in hyperendemic areas. Plugging of cerebral capillaries and venules by clumped, parasitized red cells causing sludging in the capillary circulation is one hypothesis to explain its pathogenesis. The other is a humoral hypothesis which proposes nonspecific, immune-mediated, inflammatory responses with release of vasoactive substances capable of producing endothelial damage and alterations of permeability. Cerebral malaria has a mortality rate up to 50%, and also a considerable longterm morbidity, particularly in children. Hypoglycemia, largely in patients treated with quinine, may complicate the cerebral symptomatology. Other central nervous manifestations of malaria include intracranial hemorrhage, cerebral arterial occlusion, and transient extrapyramidal and neuropsychiiatric manifestations. A self-limiting, isolated cerebellar ataxia, presumably caused by immunological mechanisms, in patients recovering from falciparum malaria has been recognized in Sri Lanka. Malaria is a common cause of febrile seizures in the tropics, and it also contributes to the development of epilepsy in later life. Several reports of spinal cord and peripheral nerve involvement are also available. A transient muscle paralysis resembling periodic paralysis during febrile episodes of malaria has been described in some patients. The pathogenesis of these neurological manifestations remains unexplored, but offers excellent perspectives for research at a clinical as well as experimental level

Reflex epilepsy : clinical and neurophysiological studies in a tropical country in Asia

Contains fulltext : 18643.pdf (publisher's version ) (Open Access)Promotor : H. MeinardiXII, 126 p

Development of a mini core collection from Sri Lankan traditional rice for flowering time variation

Sri Lankan traditional rice germplasm (Oryza sativa indica) consists of a wide variety of morphology and days to flowering (DF). The objective of this research was to develop a mini core collection representing the DF variation of the total collection. Three hundred and eighty four rice accessions from 53 Sri Lankan traditional rice varieties were evaluated for morphological and flowering time variation. The experiment was carried at Rice Research and Development Institute, Bathalagoda, Sri Lanka during the late short day season (Maha), 2012/2013.Three hundred and forty five accessions flowered and 39 accessions did not flower during the experimental period of 210 days. Two principal component analyses (PCA) were performed and subsequently 2 dendograms were developed for flowered and not flowered accessions. Sixty eight percent of total observed variation was explained through 6 principal components (PC’s) by DF and fourteen quantitative morphological characters of 345 flowered accessions. Seventy nine percent of total observed variation of not flowered 39 accessions was explained through 4 PC’s by 9 quantitative morphological characters. Ninety accessions were selected from 2 dendograms for development of a mini core collection; out of which 85 accessions represented flowered accessions based on minimum and maximum DF variation in each cluster of the dendogram. Five randomly selected accessions represented each cluster of not flowered accessions. Minimum and maximum DF values of both total collection and mini core collection were 56 and 189 days, respectively. Average DF of total flowered collection and mini core collection was 79.16 ± 0.95 and 87.95 ± 3.1, respectively. A similar trend in the regression relationship between DF and plant height and, DF and leaf length of the leaf prior to flag leaf was observed in total flowered collection and mini core collection, indicating the representation of mini core collection for flowering time variation