This presentation deals with pathogenesis of Enteric fever

1. TYPHOID FEVER
(ENTERIC FEVER)
Dr Akshay Shetty
Assistant Professor
SSRAMC&H Inchal

2. Contents
• Objectives
• Definition
• Epidemiology
• Pathogenesis
• Clinical features
• Complications
• Investigations
• Summary
• References
13/10/2020Typhoid Fever (Dr Akshay Shetty) 2

3. Objectives
By the end of the presentation the students must be able to
1. DefineTyphoid fever
2. Discuss epidemiology ofTyphoid fever
3. Describe Pathogenesis ofTyphoid fever
4. Illustrate clinical features ofTyphoid fever
5. State complications ofTyphoid fever
6. Quote investigations ofTyphoid fever
13/10/2020Typhoid Fever (Dr Akshay Shetty) 3

4. Definition
Typhoid fever is a systemic infection caused by SalmonellaTyphi, usually
through ingestion of contaminated food or water.The acute illness is
characterized by prolonged fever, headache, nausea, loss of appetite, and
constipation or sometimes diarrhoea.
-WHO
13/10/2020Typhoid Fever (Dr Akshay Shetty) 4

5. Epidemiology
• Typhoid fever is a systemic disease characterized by fever and abdominal pain and caused
by dissemination of S. Typhi or S. Paratyphi.
• The disease was initially called typhoid fever because of its clinical similarity to typhus.
• However, in the early 1800s, typhoid fever was clearly defined pathologically as a unique
illness on the basis of its association with enlarged Peyer's patches and mesenteric lymph
nodes.
• In 1869, given the anatomic site of infection, the term enteric fever was proposed as an
alternative designation to distinguish typhoid fever from typhus. However, to this day, the
two designations are used interchangeably
13/10/2020Typhoid Fever (Dr Akshay Shetty) 5

6. Cont…
• The enteric fevers are caused by infection with Salmonella typhi and S. paratyphi A
and B
• The serotypes S. typhi and S. paratyphi A, B, C have a purely human reservoir and
produce the septicaemic illness 'enteric fever' (typhoid or paratyphoid fever
• High levels of transmission continue in India, sub-Saharan Africa and Latin
America.
• The bacilli may live in the gallbladder of carriers for months or years after clinical
recovery and pass intermittently in the stool and less commonly in the urine.
13/10/2020Typhoid Fever (Dr Akshay Shetty) 6

7. Cont…
• Chronic carriers are generally over 50 years old are more commonly women
than men and often have gall stones
• S.Typhi resides in the bile ,intermittently reaches the lumen of the bowel
and is excreted in the stool there by contaminating food or water
• Global hotspots Peru, Egypt , Jakarta (Indonesia),India, Pakistan and Nepal
13/10/2020Typhoid Fever (Dr Akshay Shetty) 7

8. • Typhoid Mary, byname of Mary Mallon, (born September 23,
1869, Cookstown, CountyTyrone, Ireland—died November 11, 1938, North
Brother Island, Bronx, NewYork, U.S.), famous typhoid carrier who allegedly
gave rise to multiple outbreaks of typhoid fever.
13/10/2020Typhoid Fever (Dr Akshay Shetty) 8

9. Pathogenesis
• Infection is initiated by oral ingestion of organisms
• Which must pass the gastric acid barrier to establish infection.
• Salmonella exhibits a genetic adaptive acid tolerance response
• Bacteria successfully evades ‘Acid death’ in stomach pass on to the distal ileum and
colon
• Initial bacterial invasion results in transient asymptomatic bacteraemia as
organism are rapidly ingested by mononuclear phagocytes within they survive and
multiply
13/10/2020Typhoid Fever (Dr Akshay Shetty) 9

10. Cont…
• When intracellular multiplication has produced enough to pervade the
initiation of persistent bacteraemia ,the clinical patients of typhoid fever
begins with invasion of the gall bladder and Peyer patches of intestine.
13/10/2020Typhoid Fever (Dr Akshay Shetty) 10

11. 13/10/2020Typhoid Fever (Dr Akshay Shetty) 11

12. Clinical features
• The onset may be insidious.The temperature rises in a stepladder fashion for 4 or 5 days.
There is malaise, with increasing headache, drowsiness and aching in the limbs.
• Constipation may be present, although in children diarrhoea and vomiting may be
prominent early in the illness.
• The pulse is often slower than would be expected from the height of the temperature, i.e. a
relative bradycardia.
• At the end of the first week a rash may appear on the upper abdomen and on the back as
sparse, slightly raised, rose-red spots, which fade on pressure. It is usually visible only on
white skin.
13/10/2020Typhoid Fever (Dr Akshay Shetty) 12

13. Cont…
• Cough and epistaxis occur. Around the 7th-10th day the spleen becomes palpable.
• Constipation is then succeeded by diarrhoea and abdominal distension with
tenderness.
• Bronchitis and delirium may develop.
• By the end of the second week the patient may be profoundly ill unless the disease
is modified by antibiotic treatment.
• In the third week toxaemia increases and the patient may pass into coma and die
13/10/2020Typhoid Fever (Dr Akshay Shetty) 13

14. Ist week
•Fever
•Headache
•Myalgia
•Relative bradycardia
•Constipation
•Diarrhoea and vomiting
in children
End of Ist week
•Rose spots on trunk
•Splenomegaly
•Cough
•Abdominal distension
•Diarrhoea
End of IInd week
Delirium, complications,
then coma and death (if
untreated)
13/10/2020Typhoid Fever (Dr Akshay Shetty) 14

15. Complications
•Perforation
•Haemorrhage
•Bone and joint
infection
•Meningitis
•Cholecystitis
•Myocarditis
•Nephritis
13/10/2020Typhoid Fever (Dr Akshay Shetty) 15

16. Investigations
Blood
culture,Stool
cultureWIDAL
Test
IInd &IIIrd week
Diagnosis may be
difficult because in
the invasive stage
with bacteraemia
,leukopenia
Ist week
13/10/2020Typhoid Fever (Dr Akshay Shetty) 16

17. Summary
1.DefineTyphoid fever
Discuss epidemiology ofTyphoid fever
Describe Pathogenesis ofTyphoid fever
Illustrate clinical features ofTyphoid fever
State complications ofTyphoid fever
Quote investigations ofTyphoid fever
13/10/2020Typhoid Fever (Dr Akshay Shetty) 17

18. References
• Davidson's Principles and Practice of Medicine,23rd Edition
• https://www.who.int/immunization/diseases/typhoid/en/
13/10/2020Typhoid Fever (Dr Akshay Shetty) 18

19. Thank You
13/10/2020Typhoid Fever (Dr Akshay Shetty) 19