Typhoid Fever - Enteric Fever

Contents:
1- Definition
2- Microbiology
3- Epidemiology
4- Clinical Presentation
5- Management
6- Prevention

1. Typhoid Fever

2. Typhoid fever, also known as enteric fever, is a potentially fatal multisystemic illness transmitted by the ingestion of contaminated food or water by Salmonella enterica  serovar Typhi ( Salmonella  Typhi). A similar but often less severe disease, paratyphoid fever, is caused by  Salmonella enterica  serovars Paratyphi ( Salmonella  Paratyphi) A, B or C. “ Enteric Fever " is a collective term that refers to typhoid and paratyphoid

3. Microbiology The Genus Salmonella belong to Enterobacteriaceae. Facultative anaerobe. Gram negative bacilli. 1-3 / 0.5 microns. Motile by peritrichous flagella. H umans are the sole reservoir of this bacteria. Resistance of Salmonella Live 2-3 weeks in water. 1-2 months in stool.  55º c – 1 hour 60º c – 15 MT Boiling ,Chlorination, Pasteurization Destroy the Bacilli.

4. The organisms is ingested Bacilli attach to Microvilli, ileal mucosa, penetrate to Lamina propria and sub mucosa Phagocytosis by Polymorphs and Macrophages Then reach mesentric lymph nodes via Lymphatics Multiply, and Invade Blood stream via thoracic duct In 7 – 10 days through blood stream, it infect Liver , Gall Bladder, spleen, Kidney, Bone marrow. After multiplication bacilli passes again into the blood causing secondary and heavier bactermia Pathogenesis

5. Epidemiology An estimated 11–20 million people get sick from typhoid and between 128 000 and 161 000 people die from it every year. Poor communities and vulnerable groups including children are at highest risk. (WHO January 2018) This is a highly adapted, human-specific pathogen occurring more frequently in underdeveloped regions of the world where overcrowding and poor sanitation are prevalent. http://www.who.int/features/qa/typhoid-fever/en/ http://www.thelancet.com/journals/langlo/article/PIIS2214-109X(14)70301-8/fulltext

6. Clinical presentation 1 st week: The clinical syndromes associated with  S typhi  and  paratyphi  are indistinguishable . Typhoid fever begins 7-14 days after ingestion of the organism.  The fever pattern is stepwise means it gets higher over the day, and then drops by the morning again. Over the course of the first week of illness, the gastrointestinal manifestations of the disease develop. To Includes: Diffuse abdominal pain and tenderness and, in some cases, fierce colicky right upper quadrant pain. Monocytic infiltration inflames Peyer patches and narrows the bowel lumen, causing constipation.

7. The patient then develops a dry cough, dull frontal headache, delirium, and an increasingly stuporous malaise.   The patient develops rose spots , which are salmon colored, truncal, maculopapules usually 1-4 cm wide. these generally resolve within 2-5 days. At approximately the end of the first week of illness, the fever rise at 103-104°F (39-40°C).

8. 2 nd week: During the second week of illness, the presenting symptoms progress. The abdomen becomes distended, and soft splenomegaly is common. Relative bradycardia and dicrotic pulse (double beat, the second beat weaker than the first) may develop.

9. 3 rd week: The patient grows more toxic and anorexic with significant weight loss. The conjunctivae get infected, And the patient become tachypneic with a thready pulse and crackles over the lung bases. Abdominal distension is severe. Some patients experience foul, green-yellow, liquid diarrhea (pea soup diarrhea). The individual may descend into the typhoid state, which is characterized by apathy, confusion, and even psychosis. Necrotic Peyer patches may cause bowel perforation and peritonitis. This complication is often unheralded and may be masked by corticosteroids. At this point, overwhelming toxemia, myocarditis, or intestinal hemorrhage may cause death. If the individual survives to the fourth week, the fever, mental state, and abdominal distension slowly improve over a few days. Intestinal and neurologic complications may still occur in surviving untreated individuals. Weight loss and debilitating weakness last months. Some survivors become asymptomatic  S typhi  carriers and have the potential to transmit the bacteria indefinitely.  

10. Diagnosis “A severe nonspecific febrile illness in a patient who has been exposed to typhoidal salmonella should always raise the diagnostic possibility of typhoid fever (enteric fever)” Labs: 1-Cultures: Culture of bone marrow aspirate is 90% sensitive until at least 5 days after commencement of antibiotics. However, this technique is extremely painful, which may outweigh its benefit. Blood , intestinal secretions (vomitus or duodenal aspirate), and stool culture results are positive for  S.typi in approximately 85%-90% of patients with typhoid fever who present within the first week of onset. They decline to 20%-30% later in the disease course. Stool culture may be positive for  S typhi  several days after ingestion of the bacteria. Later in the illness, stool culture results are positive because of bacteria shed through the gallbladder Multiple blood cultures (>3) yield a sensitivity of 73%-97%. Large-volume (10-30 mL)

11. 2-Polymerase chain reaction: Polymerase chain reaction (PCR) has been used for the diagnosis of typhoid fever with varying success 3-Specific serologic tests Assays that identify  Salmonella  antibodies or antigens support the diagnosis of typhoid fever, but these results should be confirmed with cultures. Indirect hemagglutination, indirect fluorescent Vi antibody, and indirect enzyme-linked immunosorbent assay (ELISA) for immunoglobulin M (IgM) and IgG antibodies to  S typhi polysaccharide. Imaging Studies Radiography of the kidneys, ureters, and bladder (KUB) is useful if bowel perforation (symptomatic or asymptomatic) is suspected. CT scanning and MRI: may be warranted to investigate for abscesses in the liver or bones, among other sites

12. Management

13. 1-Medical Care If a patient presents with unexplained symptoms within 60 days of returning from an typhoid fever (enteric fever) endemic area or following consumption of food prepared by an individual who is known to carry typhoid, broad-spectrum empiric antibiotics should be started immediately. Treatment should not be delayed for confirmatory tests since prompt treatment drastically reduces the risk of complications and fatalities. Antibiotic therapy should be narrowed once more information is available. Compliant patients with uncomplicated disease may be treated on an outpatient basis. They must be advised to use strict handwashing techniques avoid preparing food for others during the illness course. Hospitalized patients should be placed in contact isolation during the acute phase of the infection. Feces and urine must be disposed of safely.  

14. Antibiotic Recommendations by Origin and Severity South Asia, East Asia   Uncomplicated Cefixime PO Azithromycin PO Complicated Ceftriaxone IV or Cefotaxime IV Eastern Europe, Middle East, sub-Saharan Africa, South America . Uncomplicated Ciprofloxacin PO or Ofloxacin PO Complicated Ciprofloxacin IV or Ofloxacin IV Unknown geographic origin or Southeast Asia   Uncomplicated Cefixime PO plus Ciprofloxacin PO or Ofloxacin PO Complicated Ceftriaxone IV or Cefotaxime IV, plus Ciprofloxacin IV or Ofloxacin IV

15. 2-Surgical Care Surgery is usually indicated in cases of intestinal perforation. Small-bowel resection is indicated for patients with multiple perforations. If antibiotic treatment fails to eradicate the hepatobiliary carriage, (carrier state) The gallbladder should be resected. Cholecystectomy is not always successful in eradicating the carrier state because of persisting hepatic infection.

16. Prevention Wash your hands frequently and thoroughly. practice proper body hygiene. Drink purified water (boiled or untampered bottled water) only eat well cooked foods. Use the mantra  Boil it, Cook it, Peel it, or Forget it! Vaccination There are two types of vaccines available; The inactivated contains capsular material and is delivered parenterally (lasting 2-3 years). The live attenuated strain of S.Typhi and is administrated orally (lasting 5-7 years).