Typhoid fever

Introduction

Many times in Medical practice we come across patients who often complain of “Typhoid fever”. These patients have also been on treatment previously at peripheral centres for this diagnosis, commonly by unqualified personnel, or on a basis of non specific laboratory tests and often on clinical suspicion. This kind of practice has led to Overtreatment and irrational use, and thus potentially abuse, of antibiotic medications.

Other names

Enteric fever,Typhoid.

But what exactly is Typhoid fever?

Typhoid is a bacterial infection that is characterized by fever and abdominal pain and caused by dissemination of Salmonella Typhi or Salmonella Paratyphi types of bacteria. It is a clinically distinct diagnosis, though clinical features may resemble those of many other tropical diseases such as Malaria, Amoebiasis, Dengue fever, hepatitis, bacterial enteritis, Ricketsial infection, and Acute HIV infection among others.

It is thus important for you to note that there are many clinical scenarios similar to typhoid, thus it’s the duty of trained medical personnel to differentiate which one it is.

How is typhoid transmitted?

Salmonella that cause typhoid reside only on Humans, no Known Animal reservoir.
Infection is acquired by direct contact with an infected individual or indirectly via contaminated food or water. There is a story of “typhoid Mary” the cook in early 20th century NewYork who infected approximately 50 people, with 3 persons reported to have died,  highlights the person to person spread of this infection and role of asymptomatic carriers maintaining the cycle of infection.

Factors predisposing to infection include:

1. Conditions increasing the PH of the stomach like
   • Increased use of Antacids
   • Low levels of hydrochloric acid in the stomach (Achlohydria)
   • Age of <1 year
2. Inflammatory conditions such as Inflammatory bowel disease,
3. Previous gastric surgery,
4. Altered intestinal Normal Flora due to antibiotic usage.

What are the symptoms of Typhoid fever?

Following infection with Salmonella, there is an Incubation period of between 3 to 21 days, with average 10-14 days. There are no signs of disease at this time.

The length of this duration reflects the inoculum size and a person’s health and immune status. Infection leads to an onset of fever with other non specific symptoms. There non specific symptoms that often precede fever such as chills, headache, anorexia, cough, weakness, sore throat, dizziness, and muscle pains.

The Classic presentation of Typhoid in untreated person is divided into weeks is as follows:

First week of illness

Nonspecific symptoms including:

• Persistent headaches
• Malaise,
• Rising remittent fevers also called the Step ladder fever. This is fever that rises exponentially over a tie period without remittion
• Constipation
• Mild nonproductive cough.

Second week

• The patient looks toxic and apathetic
• There is a sustained high temperature.
• The abdomen slightly distended
• There is an enlarged spleen (Splenomegally)

Third week

• The patient becomes more toxic and ill.
• There are persistently high fever episodes.
• There may be intestinal bleeding and perforation, resulting in peritoneal infection (peritonitis).
• There is abdominal distension that on auscultation, there are pronounced  scanty bowel sounds.
• Diarrhoea common with liquid, foul smelling green-yellow stools.
• The patient becomes delirious and a confusional state sets in (typhoid state)

Fourth week

• Patients who survive have considerable weight loss.
• Fever, mental state, and abdominal distension slowly improve.
• Convalescence is slow.

How is Typhoid Fever Diagnosed?

Other than a positive culture, no specific laboratory test is diagnostic for enteric fever.
Cultures can be done on the following specimen:

• Blood
• Stool
• Urine
• Rose spots
• Gastric or intestinal secretions
• Bone Marrow; these remains positive in more than 90% of cases even after 5 days of good antibiotics.

Other tests that may give clues to the diagnosis of typhoid fever include a Complete Blod Count, Liver Function tests, Kidney function tests all which may change in various other disease states.

How about the Widal test?

The classic Widal test is widely available however, it has high rates of false positive and false negative, and thus this test is not clinically useful.

How is Typhoid fever treated?

Several Antibiotics are available for treatment of Typhoid fever, and since they are prescription only medicines, it’s wise to present to the doctor whenever you suspect Typhoid fever.