Typhoid

INTRODUCTION
  • Typhoid fever is caused by Salmonella typhi.
  • Paratyphoid fever is caused by Salmonella paratyphi A, B and C.
  • The term enteric fever encompasses both typhoid and paratyphoid fevers.
  • Infection acquired by ingestion of faecally contaminated food or water
  • Man is the only known reservoir
  • Most common among males
  • IP: 7 - 14 days, but ranges from 3 days to 3 weeks
CLINICAL FEATURES
  • Coated tongue
  • Step ladder pyrexia
  • Relative bradycardia Soft palpable spleen
  • Rose spots(appears at 2nd week on trunk)
  • Rose spots are bacterial emboli to the skin and occur in 1/3 of cases of typhoid fever
  • There may be marked constipation in the early stage or "pea-soup diarrhea"
  • Typhoid ulcers 
  1. They are longitudinal and subsequent strictures do not occur( Tuberculous ulcers are transverse that lead to stricture formations)
  2. The margins of the ulcer are slightly raised, and the base of the ulcers is base black due to sloughed mucosa
  3. Multiple ulcer found in terminal ileum
  4. Perforation appears clinically as Pyrexia for greater than ten days ,acute pain in periumblical region spreading all over the abdomen.
  5. Erythrophagia and Mononuclear cell infiltration ulcers are seen
  • Paratyphoid fever caused by S.paratyphi C more often leads to septicemia with suppurative complications
  • To prevent the spread of infection, the patients are kept in isolation till three bacteriologically negative stools and urine reports, are obtained on three separate days.
COMPLICATIONS OF TYPHOID:
  • GI bleeding is the most common complication
  • Neurologic manifestations: meningitis, Guillain-Barre syndrome, neuritis, and neuropsychiatric symptoms (muttering delirium or Coma vigil), with picking at bedclothes or imaginary objects.
  • Intestinal perforation( less common in children below 5yrs) a hemorrhage are the commonest complications seen in 3rd or 4th week
  • Cholangiocarcinoma
  • Splenomegaly
  • Neutropenia
CARRIERS
  • 2 - 4% become chronic carriers at the end of 1 year
  • Convalescent carriers: shed bacilli in feces for 3 weeks to 2 months after clinical cure
  • Temporary carriers: shed bacilli for more than 3 months but less than 1 year
  • Chronic carriers: shed bacilli for more than a year
  • Chronic carrier state is associated with presence of bacilli in gall bladder
  • Carriers of avirulent organisms in typhoid are called pseudo-carriers
  • Bacilli persist in gall bladder (excreted in feces) or kidney (excreted in urine)
  • Carrier state more common in women, infants, older age groups (> 40 years) and biliary abnormalities
  • In breast fed infant less chance of enteric infection is due to Ig & nutrients in breast milk
  • Fecal carriers are the most common
  • Healthy carriers in typhoid emerge from subclinical cases
  • Urinary carriers are more dangerous, common among those with calculi or schistosomiasis
LAB DIAGNOSIS
  • Blood culture (gold standard) - 90% positive in the first week
  • Clot culture has higher rate of isolation
  • Typhoid perforation is diagnosed by Plain X-ray of abdomen in erect posture
  • Fecal and bone marrow culture - valuable in patients on antibiotics
  • Urine culture - positive in 2nd and 3rd week
  • Bile culture - detection of carriers (Bile is a good culture medium for the bacillus)
  • Vi antibody can be used for detecting carrier
  • Demonstrated of circulating antigen - staphylococcal coagglutination test (Staph.aureus-Cowan I strain)
  • New diagnostic tests
  1. IDL tubex test - detects IgM09 antibodies in few minutes
  2. Typhidot test - detects IgM and IgG antibodies
  3. Leukopenia and neutropenia in 25% cases
  4. Leukocytosis - children during first 10 days of illness, cases complicated by intestinal perforation or secondary infection
WIDAL REACTION:
  • Dreyer's tube - Conical bottom, H agglutination[DCH]
  • Felix tube - Round bottom, O agglutination [FOR]
  • H and O antigens of S.typhi and H antigens of S.paratyphi are employed (Paratyphoid 0 antigens not used)
  • H-antigen titre remains positive for several months after infection
  • Most immunogenic in typhoid is H antigen
  • Usually positive at the end of 1st week, titre increases till 4th week and then declines
  • Widal test is the investigation of choice in 3rd week.
  • Demonstration of rise in titres is more meaningful than a single test
  • Significant titres > 1/320 for O; 1/640 for H is considered positive
  • Widal positive should not be taken as proof of typhoid fever as agglutinins may be present on account of prior disease, inapparent infection or immunization
  • No role in the detection of carriers
  • Those who had prior infection or immunization may develop and anamnestic response (transient rise in antibody titres) during an unrelated fever

Exam Question
  • Healthy carriers in typhoid emerge from subclinical cases
  • In typhoid fever, the urinary carrier is more dangers than an intestinal carrier
  • Carriers of avirulent organisms in typhoid are called pseudo-carriers
  • Typhoid is Most common among males
  • IP: 7 - 14 days, but ranges from 3 days to 3 weeks
  • Chronic case of typhoid carrier is a risk factor for cholangiocarcinoma
  • To prevent the spread of infection, the patients are kept in isolation till three bacteriologically negative stools and urine reports, are obtained on three separate days. Widal test is the investigation of choice in 3rd week.
  • Step ladder pyrexia, Rose spots on trunk & pea-soup diarrhea are the common findings of typhoid fever
  • Chronic carrier state is associated with presence of bacilli in gall bladder 
  • Convalescent carriers excrete the organism for 3 – 8 weeks
  • Chronic carriers excrete bacilli for many years
  • Splenomegaly , neutropenia & positive urine & stool culture after 2weeks of infection may be seen in Typhoid in children Vi antibody can be used for detecting carrier
  • Blood culture (gold standard) - 90% positive in the first week
  • H-antigen titre remains positive for several months after infection
  • Person with prior infection or immunization may show anamnestic response
  • Infection acquired by ingestion of faecally contaminated food or water
  • Culture of feces, Bile, urine is useful in detection of carrier state in Typhoid
  • Man is the only known reservoir
  • Multiple ulcer found in terminal ileum
  • Perforation in typhoid ulcer occurs in 3rd week
  • Intestinal Perforation in typhoid is less common in children below 5yrs
  • Erythrophagia and Mononuclear cell infiltration ulcers are seen in typhoid ulcer
  • Perforation,Haemorrhage,Sepsis are the complications of typhoid ulcers
  • In breast fed infant less chance of enteric infection is due to Ig & nutrients in breast milk
  • Perforation appears clinically as Pyrexia for greater than ten days ,acute pain in periumblical region spreading all over the abdomen.
  • Typhoid perforation is diagnosed by Plain X-ray of abdomenin erect posture
  • Enteric Fever is caused by salmonella typhi & paratyphi
  • Enteric fever diagnosis in 2nd week is best made by widal test
  • Most immunogenic in typhoid is H antigen
  • Rose spots are bacterial emboli to the skin and occur in 1/3 of cases of typhoid feverHealthy carriers in typhoid emerge from subclinical cases
  • In typhoid fever, the urinary carrier is more dangers than an intestinal carrier
  • Carriers of avirulent organisms in typhoid are called pseudo-carriers
  • Typhoid is Most common among males
  • IP: 7 - 14 days, but ranges from 3 days to 3 weeks
  • Chronic case of typhoid carrier is a risk factor for cholangiocarcinoma
  • To prevent the spread of infection, the patients are kept in isolation till three bacteriologically negative stools and urine reports, are obtained on three separate days.
  • Widal test is the investigation of choice in 3rd week.
  • Step ladder pyrexia, Rose spots on trunk & pea-soup diarrhea are the common findings of typhoid fever
  • Chronic carrier state is associated with presence of bacilli in gall bladder 
  • Convalescent carriers excrete the organism for 3 – 8 weeks
  • Chronic carriers excrete bacilli for many years
  • Splenomegaly , neutropenia & positive urine & stool culture after 2weeks of infection may be seen in Typhoid in children
  • Vi antibody can be used for detecting carrier
  • Blood culture (gold standard) - 90% positive in the first week
  • H-antigen titre remains positive for several months after infection
  • Person with prior infection or immunization may show anamnestic response
  • Infection acquired by ingestion of faecally contaminated food or water
  • Culture of feces, Bile, urine is useful in detection of carrier state in Typhoid
  • Man is the only known reservoir
  • Multiple ulcer found in terminal ileum
  • Perforation in typhoid ulcer occurs in 3rd week
  • Intestinal Perforation in typhoid is less common in children below 5yrs
  • Erythrophagia and Mononuclear cell infiltration ulcers are seen in typhoid ulcer
  • Perforation,Haemorrhage,Sepsis are the complications of typhoid ulcers
  • In breast fed infant less chance of enteric infection is due to Ig & nutrients in breast milk
  • Perforation appears clinically as Pyrexia for greater than ten days ,acute pain in periumblical region spreading all over the abdomen.
  • Typhoid perforation is diagnosed by Plain X-ray of abdomen in erect posture
  • Enteric Fever is caused by salmonella typhi & paratyphi
  • Enteric fever diagnosis in 2nd week is best made by widal test
  • Most immunogenic in typhoid is H antigen
  • Rose spots are bacterial emboli to the skin and occur in 1/3 of cases of typhoid fever

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