12 Facts about Typhoid Fever
Typhoid fever is a life-threatening disease that is caused by bacteria known as Salmonella Typhi. This bacteria is usually spread through contaminated food. The bacteria once they are eaten multiply and spread into the bloodstream.
The following are the 12 facts that you need to know about typhoid fever.
“Slow rising, non-localizing, fever for a few days or a few weeks and without Rigors is likely enteric or brucellosis”.
1: Typhoid may start as a sore throat which doesn’t respond to treatment for sore throat and fever keeps progressing (Salmonella Typhi proliferates in lymphoid tissue of oropharynx and then ileum).
2; Slow rising temperature due to slowly increasing bacteremia. With passing time, fever severity increases. So it’s more on day two, goes even higher on day 3 and so on. The patient will not have Rigors due to slow-onset bacteremia.
3: Non-localising Fever. As it’s a bacteremia infection, it doesn’t give any localizing symptoms or signs in the first week. Localizing symptoms may happen later in the late second or third week if bacteria are not controlled and it starts settling in body organs. But localizing symptoms in the first week is not Typhoid. So by the third week, either infection will be controlled by the immune system, etc or it may start complicating.
4: Ileal features are not seen in the first week. The ileum is the site of proliferation not the site of actual infection (Ileum is like a cantonment area for the bacteria, not the border area to fight). In the late second or third week, Ileum may be attacked by the immune system if the infection is still going on. So ileal symptoms are seen late, not in the first week.
The presence of ileal symptoms in the first week is not Typhoid but it can be other bugs infecting ileum such as campylobacter or yersinia or E.Coli etc. So Diarrhea, abdominal pain or constipation are not seen in the first week. Even when Ileum is involved, subacute obstruction or perforation is more common than Diarrhea.
5: Blood culture is the investigation of choice in the first week. Bone marrow culture is also very rewarding but often not needed as it’s an invasive test.
6: Serology such as the Widal test may be positive in the second week onward. So negative widal, especially in the first week, doesn’t exclude enteric. However, people living in endemic areas often have positive serology and only rising antibody titer is useful than a single one-time test.
Positive widal test doesn’t mean it’s Typhoid unless we document it with a rising titer of antibodies in febrile patient OR it’s positive in the proper clinical context of non-localising fever in a person who isn’t living in an endemic area. If a patient is afebrile, widal has no significance.
If the clinical picture isn’t suggestive of typhoid, widal has no significance. If it’s not a rising titer of antibodies on repeating the test with an interval of 2-3 days, it’s not significant for patients living in endemic areas. Please don’t treat the widal test, treat the clinical picture.
Practically it’s more of a useless test than a useful test as by the time we document rising titer, it takes 4-5 days, false-negative and false-positive results and lack of specificity in an endemic area where Typhoid actually exist.
7: Urine, fecal or bile culture may also be positive when bacteria start seeding kidneys or bile in the late second or third week.
8: Unlike tuberculosis, Typhoid is an acute infection, doesn’t last for months. Also, weight loss is either not there or not significant.
9: Being a gram-negative bacteria, endotoxins mediated marrow suppression, myocardial suppression, etc may be evident. Hence neutrophilia etc may not be seen or even patients may have leucopenia etc.
10: Skin rash is rare but the classic one is rose pink macules mainly on the abdominal wall, which may be easily missed in non-white populations.
11: Complicated Typhoid Fever, seen after the late second week or third week, can cause organ infections by bacterial seeding. These may be pneumonia, brain infection, bone and joint infections, kidney infection such as pyelonephritis, cholecystitis, hepatitis, etc. Abscess formation is also possible.
12: Typhoid means “up in the clouds” so altered sensorium out of proportion to the severity of infection may be seen and doesn’t necessarily mean meningitis or encephalitis. However focal neurological signs do indicate brain tissue involvement.