Introduction
Typhoid is also known as Enteric fever. It is an infection caused by a bacteria called the salmonella bacillus. Salmonella typhi causes typhoid fever and Salmonella paratyphi A & B cause paratyphoid fever.
Mode of Infection
Humans are the only natural reservoirs of S. Typhi. Ingestion of food or water contaminated with human feces is the most common mode of transmission. The salmonella organisms after ingestion attack the intestine and enter into the bloodstream. These organisms than the bone marrow, liver, spleen, and other organs. The bacteria again enter the blood from these organs and again reach the intestine through the bile by local multiplication in the walls of the gall bladder. Circulating endotoxin (a part of the bacterial cell wall) is thought to be the cause of prolonged fever and toxic symptoms.
Some patients may excrete S. Typhi for three months or longer after infection leading to a chronic carrier state.
Clinical features
Onset: Gradual onset fever, anorexia, malaise, diarrhea in the early stages, and then constipation.
2nd week: High fever, toxic child, delirium, enlarged liver and spleen, diffuse abdominal tenderness. A rash may be seen around 7th to 10th day on the chest and the abdomen. The fever usually resolves within 2-4 weeks but malaise and lethargy persist for a longer time.
Complications
- Severe intestinal hemorrhage and intestinal perforation - seen usually in 1st week of illness.
- Heart involvement in the form of shock and psychosis may also be seen.
- Rare complications - Hepatitis (inflammation of liver), Cholecystitis (inflammation of gall bladder), pancreatitis (inflammation of pancreas), pneumonia, bone marrow involvement, pyelonephritis (inflammation of kidneys), meningitis.
Diagnosis
Blood tests in the form of a Widal test and culture may help in the diagnosis. In some patients' urine, stool, and bone marrow culture may also be positive.
Treatment
Your doctor will prescribe antibiotics for 7-10 days. In patients with high fever, intravenous antibiotics may be required. In children with malnutrition, antibiotic therapy can be extended for 21 days to reduce the rate of complications.
In patients with shock, obtundation, stupor, or coma a short course of steroids improves survival.
To eradicate chronic carrier stage: High dose antibiotics for 4-6 weeks are required.
Prevention: Vaccines
Presentation
Onset: Gradual onset step ladder fever, anorexia, malaise, diarrhea in early stages and then constipation
2nd week: High fever, toxic child, delirium, relative bradycardia, hepatomegaly, splenomegaly, diffuse abdominal tenderness. Rose spots may be seen around 7th to 10th day (Maculopapular erythematous rash) on the chest and the abdomen. The fever usually resolves within 2-4 weeks but malaise and lethargy persist for a longer time.
Investigations
- Blood culture: positive early in course of diseases.
- Stool/Urine culture: becomes positive after 1st week of disease.
- Bone marrow cultures are often positive even when blood cultures are sterile and are less influenced by prior antibiotic therapy.
- Widal test: It measures antibodies against 'O' and 'H' antigens of typhi. It becomes positive only in the 2nd week of illness.
- Typhidot M test
Treatment
Your doctor will prescribe antibiotics for 7-10 days. In patients with high fever, intravenous antibiotics may be required. In children with malnutrition, antibiotic therapy can be extended for 21 days to reduce the rate of complications.
In patients with shock, obtundation, stupor or coma a short course of steroids improves survival.
To eradicate chronic carrier stage: High dose antibiotics for 4-6 weeks are required.
Due to multidrug resistance to chloramphenicol, ampicillin and TMP-SMX, 3rd generation cephalosporins and fluoroquinolones are drugs of choice.
Ciprofloxacin (10-15 mg/kg/d) for 7-10 days is effective and has a low recurrence rate.
Cefotaxime (200 mg/kg/d) intravenously in 3-4 divided doses or ceftriaxone (100 mg/kg/d IV in 1 or 2 divided doses) for 7-10 days have also been successful in treating enteric fever caused by resistant strains. Cefixime (8 mg/kg/d PO in BD doses) for 7-10 days have also been successful.
Other antimicrobial agents useful are:
- Chloramphenicol (50 mg/kg/d PO or 75 mg/kg/d IV in 4 equal doses) for at least 14 days.
- Ampicillin (200 mg/kg/d IV in 3-4 doses) for 14 days.
- Amoxicillin (100 mg/kg/d PO in 3 doses) for 14 days.
- TMP- SMX (10 mg of TMP/kg/d PO in 2 doses) for 14 days.
- In children with malnutrition, antibiotic therapy can be extended for 21 days to reduce the rate of complications.
Complications
- Severe intestinal hemorrhage and intestinal perforation - seen usually in 1st week of illness. Perforations occur in distal ileum and lead to acute peritonitis.
- Myocarditis - Seen as arrhythmias, Cardiogenic shock.
- CNS psychosis - also seen as transverse myelitis, cerebellar ataxia and deafness.
- Rare complications - Hepatitis, Cholecystitis, pancreatitis, pneumonia, bone marrow necrosis, pyelonephritis, meningitis, orchitis and lymphadenitis. Septic arthritis and osteomyelitis may be seen in children with hemoglobinopathies.