Typhoid Fever Flashcards
Typhoid Fever is a marker for what problem?
Public Health Infrastructure
Where are the highest number of cases?
India and SE Asia
What are the three basic zones?
Endemic-children and young adults
Pseudo-endemic-imported cases due to e.g. workers coming into a country
Non-endemic-Travelers and visitors
Is typhoid sexually transmitted?
Yes, anal sex, esp MSM
What are some characteristics of the bacteria?
It shares antigens with E Coli It has 2 plasmids It can be distinguished by serologies infection requires more than 1000 organisms It can evade a low pH barrier
What are the distinguishing serologies?
LPS(endotoxin)-Ag 9 and 12
Flagellar Protein- ag Hd
Capsular Polysaccharide- Ag Vi
What is the Pathophysiology of infection?
The capsular polysaccharide conceals the endotoxin from the T Lymphocytes.The organism adheres to the M cells in Peyers patches. It then translocates to the lymphoid follicles and lymph nodes within 24 hrs. It remains there for 1 to 2 weeks and then is released into the blood stream. This leads to infection of the Liver, GB, bone marrow and Spleen.
How does the organism enter the epithelial cell?
Via the Type III secretion system (SP-1) and the zipper mechanism, an interaction of the host cell and bacterial ligands
What is the result of LPS (endotoxin) release?
the release of cytokines which results in inflammation and necrosis of host cells. There is also increased apotosis and persistent infection of macrophages
What are the sx/signs of Typhoid Fever in Adults?
Apathetic Facies/ fog
stepwise increment to sustained high fever by week 2
Dry cough
Constipation with anorexia, n/v
Rose Spots- 2 to 4 mm spots of chest and abdomen-evanescent
What are the sx/signs in children?
Short and sharp course Febrile Seizure as first indication Hepatomegaly Acute Abdomen Diarrhea concurrent infection with H. Flu (e.g. meningitis) Sickle Cell kids have more susceptibility Vertical Transmission occurs
What are some complications of Typhoid Fever?
Hepatitis Acalculous Cholecystitis GI Bleed Intestinal Perforation Salmonella Meningitis(Encephalopathy with Psychosis and Delirium) Pneumonia and Bronchitis due to S. Typhi and Pneumococcus Myo/Pericarditis Osteomyelitis Pyelonephritis Abscesses of Skin, Liver and Spleen
Who become carriers?
women, elders and those with cholelithiasis. 25% have not had Typhoid Fever, Those with abn GU tracts and Schistisomiasis can carry in GU tract.
How do you dx. S Typhosa?
Look for left shift of WBCs and elevated LFTs 2x-3x nl
Blood Cultures
Bone Marrow cultures ( most sensitive)
Buffy coat cultures
What is the Widal test?
measures IgM against somatic O ag.and H ag IgM and IgG. It reflects past infection
