References:
- Global Infectious Diseases and Epidemiology Online Network: Infectious Diseases of the Philippines, 2013 eBook Edition, ISBN 978-1-61755-582-4, by Stephen Berger. Accessed here.
| Agent | BACTERIUM. Salmonella serotype Typhi (other Salmonella species cause ‘paratyphoid’ fever) A facultative gram-negative bacillus |
| Reservoir | Human |
| Vector | None |
| Vehicle | Fecal-ral Food Fly Water |
| Incubation Period | 15 to 21 days (As early or late as 5 to 34 days) |
| Diagnostic Tests | Culture (blood, urine, sputum culture); stool usually negative unless late untreated infection Serology |
| Typical Adult Therapy | Ceftriaxone 2 g IV q12h to q 24h X 5 to 7d. OR Ciprofloxacin 750 mg PO (400 mg IV) Q12h X 2w. OR Azithromycin 1 gram PO on day 1; then 500 mg days 2 to 7. Add corticosteroids if evidence of shock or decreased mental status. |
| Typical Pediatric Therapy | Ceftriaxone 50 to 80 mg/kg IV daily X 5 to 7d. OR Azithromycin 15 mg/kg PO on day 1; then 7.5 mg/kg on days 2 to 7. |
| Vaccines | Typhoid - injectable Typhoid - oral |
| Clinical Hints | Transient diarrhea followed by fever, splenomegaly, obtundation, rose spots (during second week of illness); leukopenia and relative bradycardia often observed; case fatality rate = 0.8% (treated) to 15% (untreated) |
| Synonyms | Abdominal typhus, Abdominaltyphus, Buiktyphus, Enteric fever, Febbre tifoide, Febbre tifoidea, Fiebre tifoidea, Paratifoidea, Paratyfus, Paratyphoid, Salmonella serotype Typhi, Tyfoid, Typhoid, Typhoide |
Enteric fever is a defined syndrome of systemic illness associated with Salmonella infection.
- Enteric fever caused by S. typhi is referred to as “typhoid fever,” and that caused by S. paratyphi, is referred to as “paratyphoid fever.”
- Symptoms are often nonspecific and insidious in onset.
- The differential diagnosis of fever, abdominal pain with hepatosplenomegaly also includes malaria, amebic liver abscess, brucellosis, visceral leishmaniasis, and dengue fever.
- The clinical features of scrub typhus and melioidosis may also mimic those of enteric fever.
Acute Illness
Following an incubation period of 5 to 21 days, an initial enterocolitis may develops without associated fever.
- Constipation is present in 10 to 40% of patients; abdominal pain 20 to 40%; hepatosplenomegaly in 50%.
- Such symptoms as chills, diaphoresis, headache, anorexia, cough, sore throat, vertigo and myalgia often precede the onset of fever.
- Psychosis or confusion (“muttering delirium”) occur in 5 to 10%, encephalopathy in 21%, and seizures and coma in less than 1%.
- Patients appear acutely ill.
- Cervical lymphadenopathy develops in some patients, and pulmonary disease is rare at this stage.
- 3% have signs and symptoms of cholecystitis, and jaundice is reported in as many as 12% of cases.
- Instances of “typhoid hepatitis” appear to represent super-infection by hepatitis virus, rather than a complication of typhoid fever.
Prognosis and Complications
Symptoms resolve by the fourth week of infection without antimicrobial therapy.
- Weight loss, and debilitation may persist for months, and 10% of patients will experience a relapse.
- Relapse is more common among antibiotic-treated than non-treated patients.
- Intestinal perforation is characterized by recurrent fever, abdominal pain, intestinal hemorrhage and tachycardia occurring in the 3rd to 4th week of illness. 65.7% of perforations are solitary and involved the anti-mesenteric border of the terminal ileum. There is a male predominance among patients with typhoidal perforation. During a typhoid fever outbreak in Uganda, 43% of patients presented with intestinal perforation.
- 70% of pregnancies will end in miscarriage when complicated by untreated typhoid.
- Rare instances of acalculous cholecystitis, gall-bladder perforation, pancreatitis, intestinal intussusception, rhabdomyositis, renal failure, genital ulceration, spondylitis/spondylodiscitis, transverse myelitis, cranial nerve palsy, cerebral venous sinus thrombosis, endophthalmitis and ectopic abscesses have been reported in typhoid patients.
- The case-fatality rate is 10% to 15%
Carrier State
The carrier state is defined as persistent shedding of Salmonella typhi in stool and/or urine for ≥12 months.
- Approximately 5% of people who contract typhoid continue to carry the disease after they recover.
- Long-term carriage is associated with an increased incidence of cancers of the gallbladder, pancreas, colo-rectum, and lung.
Laboratory findings include leukopenia (albeit an initial leucocytosis is common), thrombocytopenia, coagulopathy and hepatic dysfunction.
- The most sensitive laboratory test for enteric fever is blood culture.
- Serum transaminase elevations appear to reflect myopathy rather than hepatic disease in most cases