Enteric Fever (Typhoid Fever) PDF

Enteric Fever (Typhoid Fever) Prepared by Dr Walla September 5th, 2022  typhoid fever is still a big health-problem in developing countries. The WHO estimates that there are over 21.7 million typhoid cases with the vast majority of cases in Asia, with over 200,000...

Enteric Fever (Typhoid Fever) Prepared by Dr Walla September 5th, 2022  typhoid fever is still a big health-problem in developing countries. The WHO estimates that there are over 21.7 million typhoid cases with the vast majority of cases in Asia, with over 200,000 deaths. Typhoid Mary A famous example is “Typhoid” Mary Mallon, who was a food handler responsible for infecting at least 78 people, killing 5. These highly infectious carriers pose a great risk to public health.  Typhoid fever ETIOLOGY samEEn Typhoid fever is caused by Salmonella enterica serovar Typhi (S. Typhi), a gram-negative bacterium. A very similar but often less severe disease is caused by S. Paratyphi A and rarely by S. Paratyphi B and S. Paratyphi C. The ratio of disease caused by S. Typhi to that caused by S. Paratyphi is about 10 to 1.  _ Salmonellae are motile, 2-3 μm in length, nonsporulating, nonencapsulated, gram-negative rods that grow aerobically They are resistant to many physical agents but can be killed by heating to 54.4°C for 1 hr or 60°C for 15 min. They remain viable at reduced temperatures for days and may survive for weeks in sewage, dried foodstuffs, and fecal material. Like other members of the family Enterobacteriaceae, Salmonella possesses somatic O antigens and flagellar H antigens. % infect intestines Paratyph Typhi vs  mode of transmission Feco oval route contact with infected person direct or indirect contact with an infected person (sick or chronic carrier) is necessary for infection. Ingestion of foods or water contaminated with human feces is the most common mode of transmission. few oral - Water-borne outbreaks due to poor sanitation and direct fecal-oral spread due to poor personal hygiene are encountered, mainly in developing countries. Congenital transmission of enteric fever can occur by transplacental infection from a bacteremic mother to her fetus. Who Can Be Infected? Everyone Especially: the elderly, infants, immunocompromised patients (AIDS, sickle cell anemia) extremes CLINICAL FEATURES The incubation period of typhoid fever is usually 7–14 days but is also dependent on the infecting dose (range 3–30 days). The clinical presentation varies from a mild illness with low-grade fever, malaise, and slight dry cough to a severe clinical picture with abdominal discomfort and multiple complications. Many factors influence the severity and overall clinical outcome of the infection. They include: The duration of illness before the initiation of appropriate therapy, Choice of antimicrobial treatment, age, previous exposure or vaccination history, virulence of the bacterial strain, quantity of inoculum ingested, and other host factors. School aged children & adolescent The onset of symptoms is insidious. EFFETEinten Initial symptoms of fever, malaise, anorexia, myalgia, headache, and abdominal pain develop over 2-3 days. 1ˢᵗ 2 3 days diarrhea having constipation later becomes a more prominent symptom. constipation then diarrhea Cough and epistaxis may ensue. Severe lethargy may develop in some children. Temperature often reaching 40°C. During the 2nd week of illness, high fever is sustained, and fatigue, anorexia, L cough, and abdominal symptoms increase in severity. Patients appear acutely ill, disoriented, and lethargic.nff.tv Delirium and stupor may be observed.  I ↑ of ↑ HR by physicalfindings 10 each T win 156pm - , Physical findings should be opposite A relative bradycardia. ( Faget sign ) Pulse temperature dissociation - Hepatomegaly, splenomegaly, and distended abdomen with diffuse tenderness are very common. In about 50% of patients with enteric fever, a macular or maculopapular I rash (rose spots) appears on about the 7th-10th day. Cultures of the lesions have a 60% yield for Salmonella organisms. Rhonchi and scattered rales may be heard on auscultation of the chest. Nausea and vomiting if occurring in the 2nd or 3rd week suggest a complication. If no complications occur, the symptoms and physical findings gradually resolve within 2-4 wk. INFANTS AND YOUNG CHILDREN ( 1 in 160 H > 1 in 320 Testing a paired sample for raise of antibodies carries a greater significance Limitations of Widal test Classically, a four-fold rise of antibody in paired sera Widal test is considered diagnostic of typhoid fever. However, paired sera are often difficult to obtain and specific chemotherapy has to be instituted on the basis of a single Widal test. false positive reactions may occur as a result of non-typhoid salmonella (sharing of antigenic determinants with other Salmonellae). poorly standardized antigens.  Direct detection of S. ser. Typhi specific antigens S. ser. Typhi Vi antigen in the urine has been attempted by immunologic methods, often using monoclonal antibodies. Polymerase chain reaction has been used to amplify specific genes of S. ser. Typhi in the blood of patients, enabling diagnosis within a few hours. serotype Other lab. investigations Pancgtopeuia A normochromic, normocytic anemia often develops after several weeks of illness. Blood leukocyte counts are frequently low in relation to the fever and toxicity, but there is a wide range in counts; leukopenia, usually not less than 2,500 cells/mm3, is often found after the 1st or 2nd week of illness. When pyogenic abscesses develop, leukocytosis may reach 20,000 25,000/mm3. Thrombocytopenia may be striking and persist for 1 wk. Liver function test results are often disturbed. Proteinuria is common. Fecal leukocytes and fecal blood are very common. DIFFERENTIAL DIAGNOSIS During the initial stage of enteric fever, the "" " " " " ° " ✓◦ clinical diagnosis may mistakenly be: ganga ,