Typhoid

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 

  • They are longitudinal and subsequent strictures do not occur( Tuberculous ulcers are transverse that lead to stricture formations)
  • The margins of the ulcer are slightly raised, and the base of the ulcers is base black due to sloughed mucosa
  • Multiple ulcer found in terminal ileum
  •  Perforation appears clinically as Pyrexia for greater than ten days ,acute pain in periumblical region spreading all over the abdomen.
  • 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) 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

  • IDL tubex test – detects IgM09 antibodies in few minutes
  • Typhidot test – detects IgM and IgG antibodies
  • Leukopenia and neutropenia in 25% cases
  • 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 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
Don’t Forget to Solve all the previous Year Question asked on Typhoid

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