TYPHOID FEVER

Definition of Typhoid fever

Acute enteric infectious disease

caused by Salmonella typhi (S.Typhi).

prolonged fever, Relative bradycardia,

apathetic facial expressions, roseola,

splenomegaly, hepatomegaly, leukopenia.

intestinal perforation, intestinal

hemorrhage

Etiology

Serotype: D group of Salmonella

Gram-negative rod non-spore flagella Culture characteristics

Antigens: located in the cell

capsule

H (flagellar antigen).

O (Somatic or cell wall antigen).

Vi (polysaccharide virulence)

“widel test”

A schematic diagram of a single A schematic diagram of a single Salmonella typhi Salmonella typhi cell showing the locations of the H (flagellar), 0 cell showing the locations of the H (flagellar), 0 (somatic), and Vi (K envelope) antigens.(somatic), and Vi (K envelope) antigens.

Endotoxin

A variety of plasmids

Resistance: Live 2-3 weeks in

water. 1-2 months in stool. Die

out quickly in summer

Resistance to drying and

cooling

Epidemiology

continues to be a global health problem

areas with a high incidence include Asia, Africa and Latin America

affects about 6000000 people with more than 600000 deaths a year. 80% in Asia .

sporadic occur usually, sometimes have epidemic outbreaks.

Transmission

fecal-oral route

close contact with patients or

carriers

contaminated water and food

flies and cockroaches.

Susceptibility and immunity

all people equally susceptible to infection

acquired immunity can keep longer, reinfection are rare

immunity is not associated with antibody level of “H”, “O”and “VI”.

No cross immunity between typhoid and paratyphoid

All seasons, usually in summer and autumn.

Most cases in school-age children and young adults.

both sexes equally susceptible

Major findings in lower ileum

Hyperplasia stage(1st week): swelling lymphoid tissue and

proliferation of macrophages. Necrosis stage(2nd week): necrosis of swelling lymph nodes or

solitary follicles. Ulceration stage(3rd week): shedding of necrosis tissue and

formation of ulcer ----- intestinal hemorrhage, perforation .

Stage of healing (from 4th week): healing of ulcer, no cicatrices and

Clinical manifestations

Incubation period: 3 ～ 60 days(7 ～ 14).

The initial period (early stage) First week. Insidious onset. Fever up to 39~400C in 5~7 days chills 、 ailment 、 tired 、 sore

throat 、 cough ,abdominal discomfort and constipation et al.

The fastigium stage

second and third weeks. Sustained high fever 、 partly remittent

fever or irregular fever. Last 10 ～ 14 days.

Gastro-intestinal symptoms: anorexia 、 abdominal distension or pain 、diarrhea or constipation

Neuropsychiatric manifestations: confusion 、 blunt respond even delirium and coma or meningism

Circulation system:

relative bradycardia or dicrotic pulse.

splenomegaly 、 hepatomegaly

toxic hepatitis.

roseola :30%, maculopapular rash

a faint pale color, slightly raised

round or lenticular, fade on pressure

2-4 mm in diameter, less than 10 in number

on the trunk, disappear in 2-3 days.

fatal complications:

intestinal hemorrhage

intestinal perforation severe toxemia

Diagnosis

Epidemiology data

Typical symptoms and signs

Laboratory findings.

TREATMENT

General treatment

isolation and rest

good nursing care and supportive treatment

close observation T,P,R,BP,abdominal condition and stool .

suitable diet include easy digested food or half-liquid food.drink more water

intravenous injection to maintain water and acid-base and electrolyte balance

Symptomatic treatment:

for high fever: physical measures firstly

antipyretic drugs such as aspirin should

be administrated with caution

delirium,coma or shock,2-4mg

dexamethasone in addition to antibiotics

reduces mortality.

Etiologic and special treatment

1.Quinolones:

first choice

it’s highly against S.typhi

penetrate well into macrophages,and achieve

high concentrations in the bowel and bile lumens

Norfloxacin (0.1 ～ 0.2 tid ～ qid/10 ～ 14 days).

Ofloxacin (0.2 tid 10 ～ 14days).

ciprofloxacin (0.25 tid)

caution: not in children and pregnant

2.Chloramphenicol:

For cases without multiresistant S.typhi.

Children in dose of 50 ～ 60mg/kg/per day.

adult 1.5 ～ 2g/day. tid.

Unable to take oral medication, the same dosage

given introvenously

after defervescence reduced to a half. complete a

10 ～ 14 day course.

But ,drug resistance, a high relapse rate,bone

marrow toxicity.

3.Cephalosporines: Only third generation effective

Cefoperazone and Ceftazidime.

2 ～ 4g/day .10~14 days.

4.Treatment of complication. Intestinal bleeding:

bed rest, stop diet,close observation T,P,R,BP.

intravenous saline and blood transfusion,and attention to acid-base balances.

sometimes,operative.

Perforation:

early diagnosis.

stop diet.

decrease down the stomach pressure.

intravenous injection to maintain

electrolyte and acid-base balances.

use of antibiotics.

sometimes operative.

Toxic myocarditis:

bed rest, cardiac muscle protection drugs,

dexamethasone, digoxin.

5.Chronic carrier: Ofloxacin 0.2 bid or ciprofloxacin 0.5 bid, 4 ～ 6

weeks. Ampicillin 3 ～ 6g/day tid plus probenecid 1 ～

1.5g/day. 4 ～ 6 weeks. TMP+SMZ

2 tabs. Bid. 1 ～ 3 months. Cholecystitis may require cholecystectomy.