Typhoid FeverDr. Hafiz Muhammad Aeymon

Typhoid Fever• Typhoid fever or simply typhoid is a common worldwide bacterial disease transmitted by the ingestion of food or water contaminated with the feces of an infected person, which contain the bacterium Salmonella Enterica Serotype Typhi / paratyphi A/B.

Epidemiology• S. Typhi (75.7%) is the predominant

serotype followed by S. Paratyphi A (23.8%)

• Over 21.7 million cases annually.• >2 lacs death every year.• Developed countries- <15 cases / lac

population• Developing countries- 100-1000 / lac.• Pakistan ranks 7th for the no. of typhoid

cases annually all over the world.

Prevalence

Risk FactorsPoor sanitationExtremes of ageAntacids or suppression of acid secretionAltered intestinal functionImpaired phagocytic functionImpaired cell-mediated immunityAIDSCorticosteroid use Prior antibiotic therapy

Pathogen• Salmonella typhi is a Gram-negative bacteria.• Similar but often less severe disease is caused by

Salmonella serotype paratyphi A.• The ratio of disease caused by S. typhi to that

caused by S. paratyphi is about 10 to 1.• Many genes are shared with E. coli and at least

90% with S. typhimurium,• Polysaccharide capsule Vi: present in about 90%

of all freshly isolated S. typhi and has a protective effect against the bactericidal action of the serum of infected patients.

Pathogenesis• Entry in GIT localization in Gut associated lymphoid tissue Lymphatic channel thoracic duct circulation primary silent bacteremia localization in macrophages of RES in spleen, liver, bone marrow (incubation period 8-14 days) secondary bacteremia

Pathogenesis

Signs & Symptoms• Prolonged fever, classic stepladder rise is

uncommon. • Relative Bradycardia• Disturbances of bowel function • Pain abdomen• Headache• Anorexia and Malaise.• Bronchitic cough.• Exanthem (rose spots appear in 25% cases

during 2nd week) on the chest, abdomen and back

Rose spots

Diagnosis• In endemic area, fever without evident cause for

more than 7 days should be considered Typhoid until proved otherwise.

• Blood culture – standard diagnostic method . +ve in only 40-60% cases

• Blood Cultures are positive in

1st week in 90% cases2nd week in 75% cases3rd week in 60% cases

4th week and later in 25% cases

Diagnosis• Bone marrow aspirate culture is the

gold standard for the diagnosis of typhoid fever+ve 80-95% of cases Inspite on antibiotics.

• Stool culture +ve in 30% with acute Typhoid fever. Positivity rate increases with duration of illness.• Widal Test• Typhidot

Widal Test• Measures antibody against O & H

antigens of S.typhi.• >1:160 titre against O & H highly

suggestive with relevant clinical findings• Sensitivity-60%; specificity-80%.• O antibodies appear on days 6-8 and H

antibodies on days 10-12• Negative in up to 30% of culture-proven

cases of typhoid fever

Typhidot•Rapid serological test, detects IgM & IgG antibody of S.typhi.•Becomes +ve within 2-3 days of infection.•Sensitivity- 90-98% ; specificity-75-90%.

Management• Where resistance is uncommon, the treatment

of choice is a fluoroquinolone such as ciprofloxacin.

• Otherwise, a third-generation cephalosporin such as ceftriaxone or cefotaxime is the first choice. Cefixime is a suitable oral alternative.

• Antibiotics, such as ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole & amoxicillin have been commonly used to treat typhoid fever.

Complications• CNS: Encephalopathy, Typhoid meningitis,

encephalomyelitis, Guillain-Barre syndrome, cranial or peripheral neuritis and psychotic symptoms, Coma Vigil.

• GIT: occult blood, intestinal hemorrhage, Intestinal perforation.

• Others: Hepatitis, myocarditis, pneumonia, Empyema, DIC, Osteomyelitis

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