Thursday, 25 August 2016

Pathophysiology of Malaria



Malaria is a communicable disease characterized by rigor, fever caused by plasmodium parasite. Malaria occurs whenever the female anopheles mosquito injects the sporozoites of these parasites into the blood stream for about 30 minutes, these sporozoites then enters the liver cells to stay. In this stage it is called pre-erthrocytic phase of development. The presence of the sporozoites in the liver inflamed the cells causing hepatitis.


There is also proliferation of the reticulo-endothelial cell (especially in the liver, spleen and bone marrow) leading to enlargement of the liver (hepatomegally) and spleen (splenomegally) with tenderness. The liver cell then burst to release merozoites and toxins into the blood stream. Some of these merozoites enter fresh red blood cell to start up the erythrocytic phase. The red blood cells then mature to release these parasites into the blood stream. The destruction of red blood cells leads to anaemia causing tiredness and the clients complains of pain in the legs and joints due to the inflammatory phase of the parasite toxins in the body.

The rigor starts with intense cold leading to a feeling of hotness and dryness of the skin. The body temperature may rise to 39.40C to 40.00C.This is due to parasites and their toxins acting as pyrogens and endogenous pyrogens resetting the thermostat in the in the heat regulating centre in the hypothalamus, causing more production of body heat which may lead to the irritation and poisoning of the brain tissue by parasite toxins.

In malaria caused by falciparum (plasmodium), the severe haemolysis can lead to jaundice, the presence of toxins along the gastrointestinal tract through the systematic circulation irritate the muscular layers causing increased peristalsis lead to diarrhoea; in some people the toxins can also irritate the gastric mucosa and vomiting centre in the hypothalamus causing vomiting. In severe terminal stage, individual present with cerebral manifestation like delirium leading to coma due to blockage of the tiny cerebral blood vessels by the parasite toxins and debris of the impaired red blood cells.

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