Can u tell .w about enteric fever from ak tripati

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Note on source: The textbook library does not contain a book by "AK Tripathi." You may be thinking of KD Tripathi (Essentials of Medical Pharmacology) - also a very popular Indian textbook - which is likewise not in the library. The content below is drawn from Harrison's Principles of Internal Medicine, 22nd Edition (2025), which covers enteric fever in the same depth.

Enteric Fever (Typhoid Fever)

Definition

Enteric (typhoid) fever is a systemic disease caused by Salmonella Typhi or S. Paratyphi, characterized by prolonged fever and abdominal pain resulting from dissemination of the organism. The term "enteric fever" was coined in 1869 to anatomically distinguish it from typhus; both names are still used interchangeably.

Etiology and Transmission

Caused by Salmonella enterica serovar Typhi (typhoid fever) and serovar Paratyphi A, B, C (paratyphoid fever)
Humans are the only reservoir - no animal hosts
Spread by fecal-oral route - contaminated food or water; rarely via sexual transmission or healthcare exposure
Risk factors: fecally contaminated drinking water or ice, flooding, street food, raw produce fertilized with sewage, prior Helicobacter pylori infection (reduced gastric acidity), lack of handwashing

Epidemiology

9.2-21 million cases of typhoid and ~5 million paratyphoid cases per year globally; 110,000-280,000 deaths annually
Highest incidence in the Indian subcontinent (India, Pakistan, Bangladesh, Nepal), Eastern Mediterranean, and African regions - exceeding 1,000 cases per 100,000 children in some urban areas
Strongly correlates with mixing of drinking water with human sewage
More common in poor urban neighborhoods and in children/adolescents

Drug resistance:

MDR strains emerged in 1980s - resistant to chloramphenicol, ampicillin, and trimethoprim
Decreased susceptibility to ciprofloxacin (DSC) and full fluoroquinolone resistance emerged on the Indian subcontinent (clone H58)
XDR S. Typhi emerged in Sindh, Pakistan in 2016 - resistant to all first/second-line agents plus third-generation cephalosporins; susceptible only to azithromycin and carbapenems

Pathogenesis

After ingestion, S. Typhi invades via Peyer's patches in the ileum. The organism is phagocytosed by macrophages but survives intracellularly. It then:

Disseminates through lymphatics to mesenteric lymph nodes
Enters the bloodstream (primary bacteremia)
Seeds the liver, spleen, bone marrow, and gallbladder
Multiplies intracellularly, then causes secondary bacteremia (producing clinical illness)
Re-enters the intestine via bile, infecting Peyer's patches again (risk of ulceration/perforation)

Clinical Course

Incubation period: 5-21 days (mean 10-14 days), depending on inoculum size and host status.

Symptoms (from a prospective study of 669 cases in Nepal):

Symptom	Frequency
Fever (38.8-40.5°C, prolonged)	>75%
Headache	80%
Chills	35-45%
Anorexia	55%
Abdominal pain	30-40%
Diarrhea	22-28%
Nausea	18-24%
Vomiting	18%
Cough	30%
Constipation	13-16%
Myalgias	20%

Physical Findings:

Coated tongue: 51-56%
"Rose spots": ~30% - faint, salmon-colored, blanching maculopapular rash on trunk and chest, appearing at end of week 1, resolving in 2-5 days. Salmonella can be cultured from biopsy of these lesions.
Hepatosplenomegaly: 3-6%
Relative bradycardia at peak of fever (<50%)
Epistaxis

Rose spots - the characteristic rash of enteric fever due to S. Typhi or S. Paratyphi

Complications (~27% of hospitalized patients)

GI (most common, occurring in weeks 3-4):

Intestinal perforation (1%) - at ileocecal Peyer's patches; life-threatening, requires surgery
GI bleeding (6%)

Neurologic (2-40%):

Meningitis, Guillain-Barré syndrome, peripheral neuritis
"Muttering delirium" / "coma vigil" (neuropsychiatric)

Other (rare):

DIC, hemophagocytic syndrome, pancreatitis, hepatitis
Myocarditis, endocarditis, pericarditis
Hemolytic-uremic syndrome, glomerulonephritis
Osteomyelitis, arthritis

Relapse: Up to 10% of patients, within 2-3 weeks of fever resolution, with same strain and susceptibility.

Chronic carriage: 2-5% of untreated patients shed S. Typhi >1 year (more common in women, infants, those with biliary abnormalities). Chronic carriage is associated with increased risk of gallbladder cancer.

Diagnosis

A high index of suspicion is needed since clinical features are non-specific. Consider in any febrile traveler from a developing country.

Differential diagnosis: malaria, viral hepatitis, dengue fever, bacterial enteritis, rickettsial infections, leptospirosis, amebic liver abscess, acute HIV.

Lab findings:

Leukopenia and neutropenia in 15-25% (leukocytosis in children or if perforation occurs)
Elevated liver enzymes, mildly elevated muscle enzymes
Widal test - serological (poor sensitivity and specificity; not recommended as sole diagnostic)

Definitive diagnosis - Culture (gold standard):

Specimen	Yield
Bone marrow	~90% (highest) - unaffected by prior antibiotics
Blood	40-80% (best in weeks 1-2)
Intestinal secretions (string test)	~58%
Stool	~30% (best in weeks 3-4)
Rose spot biopsy	Positive
Urine	Lower yield

Treatment

Antibiotic Therapy:

Clinical Setting	Drug of Choice	Alternatives
Fully susceptible	Fluoroquinolone (ciprofloxacin 500 mg BID x 7-10 days)	Amoxicillin, chloramphenicol, TMP-SMX
MDR (resistant to ampicillin, chloramphenicol, TMP-SMX)	Fluoroquinolone	3rd-gen cephalosporin (ceftriaxone)
DSC / Fluoroquinolone-resistant (Indian subcontinent)	Azithromycin (1 g/day x 5 days) or Ceftriaxone (2 g/day x 7-14 days)
XDR (Pakistan strains)	Azithromycin (oral) or Carbapenem (IV)
Severe/complicated disease	Ceftriaxone 2 g/day IV x 10-14 days	+ dexamethasone if severe toxicity

Dexamethasone (3 mg/kg initial dose, then 1 mg/kg q6h x 8 doses): Used in severe typhoid with delirium, obtundation, stupor, or shock - reduces mortality from ~55% to ~10%.

Chronic carriage treatment:

Ciprofloxacin 500 mg BID x 28 days (if susceptible) - ~80% cure
Cholecystectomy if gallbladder disease present and antibiotics fail

Prevention

Vaccines:

Ty21a (oral, live attenuated): Days 1, 3, 5, 7; booster every 5 years; minimum age 6 years; ~50% efficacy at 2.5-3 years
Vi CPS (parenteral polysaccharide): Single dose; booster every 2 years; minimum age 2 years; ~55% efficacy at 3 years
Typhoid Conjugate Vaccines (TCV) - WHO recommended: Typbar TCV (Bharat Biotech) and TYPHIBEV (Biological E); single IM 0.5 mL dose; 79-95% effective; protection up to 7 years; effective in children <2 years. Introduced in Pakistan, Nepal, Liberia, Zimbabwe, Malawi, Samoa.

Public health:

Enteric fever is a notifiable disease
Food handlers and health care workers must be cleared before returning to work
Safe water supply, sewage treatment, and handwashing are the mainstay of prevention

Source: Harrison's Principles of Internal Medicine, 22nd Edition (2025), Chapter 171 - Salmonellosis, pp. 1359-1362

The library does not contain a book specifically by "AK Tripathi." If you meant KD Tripathi's Essentials of Medical Pharmacology, that is also not in the library, but the pharmacological treatment details above cover the same content taught in that textbook.

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