TYPHOID FEVER [Symptoms and Signs / Cause / Pathogenesis / Complication]


       Typhoid, also called typhoid fever, occurs all over the world. In 2015, 12.5million new cases worldwide were reported. The risk of death may be as high as 20% without treatment. In 2015, it in about 149,000 deaths worldwide. The disease is endemic in India , southeast Asia , Africa and south America.

  Symptoms and signs           

        *In the first week, the body temperature rises slowly, and fever fluctuations are seen with malaise, headache, and cough.

        *In the second week, high fever around 40 degree Celsius. The abdomen is distended and painful in the right lower quadrant. The spleen and liver are enlarged [hepatosplenomegaly]. 

        *In the third week of typhoid fever, a number of complications can occur;

              👉Intestinal haemorrhage due to bleeding in congested Payer's patches;

              👉Intestinal perforation in the distal ileum, a very serious complication and is frequently fatal.

              👉Septicaemia or peritonitis.

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Causes

       Typhoid fever is caused by virulent bacteria called Salmonella typhi. The bacteria that cause typhoid fever spread through contaminated food or water. The patient or the carrier passes bacteria in the faeces. You can contract the infection if you eat food handled by someone with typhoid fever who hasn't washed his hands carefully after using the toilet. You can also become infected by drinking water contaminated with the bacteria.



Pathogenesis 

          Salmonella organisms penetrate the mucosa of small intestine and proliferate in the mucosal epithelial cells. Next, the bacteria proliferate in the payer's patches [sub-mucosal collection of lymphoid tissue] of the lower small intestine from where systemic dissemination occurs to the reticuloendothelial system of liver and spleen. 


       

        For a period varying from 1 to 3 weeks, the organism multiplies within these organs. Invasion of the mucosa cause the epithelial cells to synthesise and release various proinflammatory cytokines responsible for the most of the symptoms of typhoid fever. Ulceration over payer's patches account for complications such as bleeding, perforation and paritonitis. Proliferation in reticuloendothelial system leads to enlargement and congestion of the spleen and live. illustrates the pathophysiology of typhoid fever.


Typhoid ulcer in small intestine 


             Pathophysiology of typhoid fever

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Complication

        *Intestinal hemorrhage                 *Peritonitis

        *Intestinal perforation                  *Death

        *Septicaemia