Typhoid fever: cause, symptoms, tests, treatment and vaccines

Typhoid is also called Enteric fever. It is an infectious bacterial illness caused mainly by drinking contaminated water or contaminated food. It is largely seen most commonly In developing world and includes areas of India and south east asia. It is also a common illness in africal countries. Its prevalence has been reduced in the developed world as the accessibility to safe drinking water improved there in the last century. Worldwide 22 million people get affected by typhoid each year.

What is the cause of Typhoid fever?

Typhoid fever is caused by Salmonella typhi or Salmonella paratyphi. These are bacterias that are gram negative. These bacteria affect mainly the gastrointestinal tract and also infect other organs like heart, brain, liver and kidneys.

How does typhoid spread?

Typhoid is an infectious illness that spreads from person to person. Salmonella typhi and Salmonella paratyphi bacteria can contaminate drinking water and food. If the susceptible person consumes such food he may get infected by the bacteria causing typhoid.

So typhoid is spread by following modes:

  • Through contaminated drinking water
  • Through contaminated food
  • If the hands are not washed with soap water before having food
  • If the hands are not washed with soap water after using toilet
  • Poor sanitary facilities leading to mixing of the fecal matter with drinking water
  • Consuming street foods sold on open streets

What are symptoms of Typhoid fever?

Symptoms of Typhoid fever range from mild symptoms initially to very severe life threatening symptoms if left untreated. Most common symptoms of typhoid fever include:

  • At the initial stages sometimes Typhoid fever can present as cough, cold, fever hich are typically symptoms of upper respiratory tract infection.
  • Fever is a common symptom of typhoid fever. Fever may be mild, initially progressing to  moderate to high grade. This fever may be associated with chills.
  • Abdominal pain is mild initially, if left untreated and there is intestinal rupture it may progress to severe pain.
  • Constipation and diarrhea both can occur because of Typhoid fever.
  • Weakness and fatigue.
  • Loss of appetite.
  • Headache.
  • General body ache and pain.

Above all are common symptoms of typhoid. If the complications of typhoid occur and other organs like brain, kidneys, bones, liver get affected and intestine may get perforated following symptoms may occur.:

  • Loss of consciousness.
  • Vomiting and stool containing blood.
  • Lowering of blood pressure.
  • Breathlessness.
  • Increasing cough.
  • Loss of power in limbs.
  • Pale skin.
  • Back pain.
  • Jaundice.

What tests are needed for diagnosis of Typhoid?

From the clinical examination of the patient and history given by the patient, if diagnosis of  the typhoid is suspected then the following investigations are needed for confirming  the diagnosis:

  • Blood culture examination: This is the gold standard test for the diagnosis of Typhoid fever. In this test ml of blood is taken and it is mixed in culture medium. If the salmonella typhi or paratyphi bacteria is present in blood its colonies can be detected after 3 to 5 days in culture medium. This test also detects the resistance pattern to antibiotics shown by some strains of the bacteria. This test helps to guide the selection of appropriate antibiotics and further line of treatment.
  • Urine culture test: Salmonella typhi and paratyphi bacteria all also excreted in the urine of the infected person. Those can be detected on urine culture examination tests.
  • Stool culture examination: Salmonella typhi bacteria also excreted in the stool of the patient. Those bacteria excreted in stool can be detected on stool culture examination.
  • Hemogram or CBC: This is a non-specific test that does not confirm the diagnosis but helps as a supportive test. This stage shows hematological changes because of typhoid. In typhoid various hematological changes occur. Some of them are anaemia that is decreased hemoglobin, leukopenia, thrombocytopenia, eosinophilia and decreased ESR. These all changes occur because of suppression of bone marrow caused by toxins of the Salmonella typhi.
  • Bone marrow culture test: Though this paste is invasive it is a most sensitive test for the diagnosis of typhoid fever. Bone marrow is inside your long bones. So to get the sample of bone marrow one has to  insert a needle in the bone marrow.
  • Widal test: Widal test detects the antibodies in your blood that act on upSalmonella typhi and Salmonella paratyphi bacteria. This test though has low sensitivity, also has a high false positivity rate. It may come falsely positive in many other illnesses.
  • Rapid diagnostic test: In these tests serum from patients is used to detect infection of typhoid. These tests give results in a few minutes. These tastes have moderate sensitivity and require almost no technical skills. Typhidot is one such test used for the diagnosis of Typhoid fever. This test detect igg and IGM what type of antibodies against Salmonella typhi and paratyphi. The drawbacks of these tests are high cost and storage requirements at low temperatures. Though these tests are useful they still are not the gold standard for the diagnosis of Typhoid fever.
  • Renal function test: Because of ongoing illness and reduced appetite patients may develop electrolyte imbalance. Also in complications of typhoid fever kidneys may get directly affected. Renal function test detects blood urea level and creatinine level along with serum electrolytes.
  • Liver function test: In some patients of the Typhoid fever liver may get affected because of illness. Liver function tests detect Bilirubin level and other liver enzyme levels. This test is also useful to exclude other liver diseases as the symptoms of typhoid may mimic hepatitis in some patients.
  • USG abdomen: Ultrasonography abdomen is a non-invasive method of imaging by sonography. In this test hepatosplenomegaly, thickening ileo-cecal junction and enlarged mesenteric lymph nodes can be seen in typhoid fever.

So these are the common tests required in the illness of Typhoid fever.

What is the treatment of typhoid fever?

Typhoid fever if left adequately treated or untreated it may be life threatening for the patient. It is important to start the treatment early. After the diagnosis of Typhoid fever the treatment is started.

Patients who are not severely ill can be treated on OPD basis with oral antibiotics at home. Those patients who are suffering from severe typhoid are to be admitted in the hospital and antibiotics are given by intravenous route. Antibiotics are only the effective treatment for the Typhoid; it has no alternative.

Selection of antibiotics is very important as typhoid has been found to be resistant to many antibiotics.

A broad spectrum antibiotic is started depending upon the local resistant pattern in the area. The therapy can be modified or altered depending upon the culture result. The antibiotic therapy should be given for the adequate number of days to avoid the patient left in-adequately treated or going into stage of carrier.

Fluoroquinolones, cephalosporins and macrolides are good choices for the treatment of the Typhoid fever. Single or combinations of many antibiotics may be needed for the treatment of Typhoid fever. In many parts of the world Salmonella typhi has developed resistance to fluoroquinolones.

Decades back Salmonella typhi was sensitive to chloramphenicol. Now this drug is avoided considering the side effects of it. Surprisingly in many cases multidrug resistance of typhoid chloramphenicol is still useful for the treatment of the Typhoid fever.

Along with these antibiotics supportive treatment is necessary till the patient recovers from the illness. Supportive treatment is given to treat the symptoms as required. In case of fever and body ache and headache antipyretic drug like paracetamol can be used in appropriate doses. 

Along with supportive treatment it is very important to maintain the water and electrolyte balance of the patient. For patients who are not able to Eid IV fluids are used to maintain the hydration and electrolyte balance.

For patients who are very severely affected and not able to eat main lead parenteral nutrition, till they are able to eat.

Which is the best antibiotic for Typhoid fever?

The selection of antibiotics for the treatment of typhoid fever is a tricky business. Salmonella typhi and paratyphi have developed resistance to many antibiotics over the course of a few decades.

Selection of antibiotics depends upon the resistance pattern in the area in which the patient is residing. The selection of antibiotics is further guided by the reports of blood culture and bone marrow culture.

Fluoroquinolone was the antibiotics of choice a few years ago. Salmonella typhi and paratyphi have developed resistance to fluoroquinolones in recent times. Part of the world in which resistance is not developed yet can use fluoroquinolone as first line treatment for the Typhoid fever.

If the fluoroquinolone resistance is well known in your area, fluoroquinolones may not be useful for you. Combination of fluoroquinolones with cephalosporin or combination of cephalosporin with macrolide like azithromycin may be useful in this case.

No single antibiotic can be labelled as the best antibiotic for the treatment of Typhoid fever. The selection of antibiotics should depend upon the local resistance pattern to antibiotics. Antibiotics best for one part of the world may not be best in the other part of the world.

Selection of the antibiotics may also depend upon the age of the patients. Some antibiotics that are well tolerated by adults may not be useful in children because of their side effects. Fluoroquinolones are generally avoided in children.

Some facts about Typhoid vaccines

Typhoid is a vaccine preventable illness. Many types of vaccines are available to prevent typhoid disease.

These vaccines can be live attenuated vaccines or killed vaccines.

Live attenuated vaccines for Typhoid can be taken orally in the form of a capsule. This vaccine contains live Salmonella like bacteria which do not have capacity to cause typhoid disease. When these vaccines are given they actually in fact you’re like real Salmonella typhi. Your immunity gets trained to fight against typhoid.

Killed vaccines for Typhoid can be given as a shot by injection. This vaccine contains killed bacteria or the parts of bacteria. When these vaccines are injected your immunity recognises them and gets trained to fight against the real bacteria. These vaccines can be of polysaccharide type or conjugated polysaccharide type. Conjugated polysaccharide vaccines are more effective than simple  polysaccharide vaccines.

No matter what vaccine was given you should remember that vaccines do not give protection with the hundred percent surety. 

You still can get the disease after vaccination though with low frequency. Eating clean food and drinking clean water and washing hands with soap water before food and after using the toilet are still needed even after getting vaccinated. You can further read prevention of monsoon illnesses.


Sources
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