What is typhoid fever and what are its symptoms?

In our daily life, we must always pay attention to food hygiene. If we are not careful, we may accidentally deal with intestinal diseases. So what is typhoid fever? What are the clinical manifestations?

What is typhoid fever?

Typhoid fever is an intestinal infectious disease caused by Salmonella enterica subspecies Typhi serotype. Paratyphoid fever is a typhoid-like illness caused by Salmonella enterica subspecies paratyphi serotypes A, B, or C. The symptoms of paratyphoid A and B are similar to those of typhoid fever, but the condition is generally milder, the course of the disease is shorter, and the mortality rate is lower. Symptoms of paratyphoid C vary and may present as mild typhoid fever, acute gastroenteritis, or sepsis. Typhoid and paratyphoid fever can cause outbreaks due to contamination of water and food. The disease is distributed throughout my country and occurs sporadically throughout the year, with the highest incidence in summer and autumn. It occurs more frequently in children and young adults.

Causes

Both Salmonella typhi and Salmonella paratyphi belong to the genus Salmonella. They are short rod-shaped, do not form spores, have flagella, and are easy to grow in bile culture. Bacterial lysis produces endotoxins that cause disease.

Clinical manifestations

The natural course of typical typhoid fever lasts about 4 weeks and can be divided into 4 stages:

Phase 1.1

This is equivalent to the first week of the disease. The onset is usually slow, with fever being the earliest symptom, often accompanied by general discomfort, fatigue, loss of appetite, sore throat and cough. The condition gradually worsens and the body temperature rises in a step-like manner to 39-40°C within 5-7 days. There may be chills before the fever but less chills, and there is no obvious sweating when the fever subsides.

Phase 2.2

This corresponds to the 2nd to 3rd week of the disease, and typical symptoms of typhoid fever often help with diagnosis.

(1) The high fever persists and presents as a persistent fever type. A few cases present as a remittent fever type or an irregular fever type, which lasts for about 10 to 14 days.

(2) Digestive system symptoms: loss of appetite is more obvious than before, the tongue tip and tongue edge are red with thick and greasy coating (the so-called typhoid tongue), abdominal discomfort, abdominal distension, most of them have constipation, and a few have diarrhea. Since intestinal diseases are mostly in the terminal ileum and ileocecal region, there may be mild tenderness in the right lower abdomen.

(3) Neurological symptoms, which are proportional to the severity of the disease, are caused by the action of Salmonella typhi endotoxin on the central nervous system. The patient may be in a trance, have a dull expression, slow reaction, and hearing loss. In severe cases, there may be delirium, coma, or signs of meningeal irritation (asthenic meningitis). These neurological symptoms usually recover gradually as the body temperature drops.

(4) Circulatory system symptoms, often with a relatively slow pulse or sometimes a heavy pulse, are one of the clinical features of this disease. However, when toxic myocarditis occurs, the bradycardia is not obvious.

(5) Starting from the sixth day of the disease, an enlarged spleen with soft texture or tenderness can often be felt under the left hypochondrium. A small number of patients may also have an enlarged liver, which may be soft or accompanied by severe tenderness and jaundice. Obvious abnormalities in liver function suggest the presence of toxic hepatitis.

(6) During the 7th to 13th day of the disease, some patients develop small pink maculopapular rashes (roseola), about 2 to 4 mm in diameter, which fade when pressed. There are fewer than 12 of them, and they appear in batches. It is mainly distributed in the chest and abdomen, and can also be seen on the back and limbs. It disappears within 2 to 4 days. Crystalline prickly heat rash (or white prickly heat) is also not uncommon and often occurs in people who sweat a lot.

3.3 Period

This is equivalent to the 3rd to 4th week of the disease. The human body's resistance to Salmonella typhi gradually increases, body temperature fluctuates and begins to decline, appetite gradually improves, abdominal distension gradually disappears, and spleen enlargement begins to shrink. However, there is a risk of intestinal bleeding or intestinal perforation during this period, so you need to be particularly vigilant.

4.4th phase

At the fourth week of the disease, body temperature begins to return to normal and appetite improves, and the patient usually recovers completely in about a month.