Welcome APPLICANTS!

1. Morning Report: Thursday, January 12th Welcome APPLICANTS!

2. Shigella Infection

3. Epidemiology • Common cause of bacterial diarrhea worldwide (especially in developing countries) • In the US: • Third in frequency (after Salmonella and Campylobacter) • Primarily affects children • Peak incidence ages 1-4

4. The Details… • Gram-negative bacilli • Four species: • S. dysenteriae • S. boydii • S. flexneri • S. sonnei Only Shiga toxin-producing species! Most common subtypes in the US

5. Transmission • *Person-to-person via the fecal-oral route • Transmission in institutions • *Child care centers • Grouping of susceptible children • Lack of adherence to hand-washing procedures • Small inoculum required for disease production • Food borne transmission • Cold salads • Raw veggies • Sexual transmission

6. Clinical Presentation • Incubation period 1-7 days, average 3 days • Range of GI illness • Mild diarrhea life-threatening dysentary

7. Clinical Presentation • Course • Presentation: abrupt onset of high fever, generalized toxicity, crampy abdominal pain*, high-volume, watery stools • 24-48h later: Small-volume, bloody, mucoidstools* with tenesmus • Neurologic manifestations (40%) • Severe HA • Seizures • Meningeal signs • Lethargy • Delirium/ hallucinations

8. Physical Exam • VS: high fever (>102F) • Gen: toxic-appearing • Abd: lower quadrant abdominal pain, distension • GU: tenderness on rectal exam • +/- signs of dehydration

9. Laboratory Findings • Bandemia • Stool microscopy • Large number of PMNs • +/- RBCs • Stool culture • Send stool specimen promptly to lab • Can be grown on MacConkey or Hektoen-Enteric agars • Always want speciation and sensitivities

10. *Treatment • Mainstay= SUPPORTIVE CARE! • Correction of fluid and electrolyte losses • Substantial volume depletion uncommon • Hyponatremia • NO intestinal antimotility drugs • Early restoration of oral intake

11. *Treatment • Antibiotics • Lead to improvement in symptoms and decreased spread of infection to contacts • The problem…increasing antimicrobial resistance!! • Ampicillin • TMP-SMX • So, who do I treat and what do I use to treat them?

12. *Treatment • Who to treat? • Red Book • Severe disease • Underlying immunosuppressive conditions • Dysentery • In mild cases Rx to prevent spread of the organism

13. *Treatment • What to use? • Parenteral • Ceftriaxone • Cipro • Oral • Azithromycin • First-line oral Rx for children <18yo when Abx susceptibility is unknown • Fluoroquinolones • First-line oral Rx for children >17yo and adults

14. *Treatment • What to use? • Oral • Cefixime • Alternative to azithromycin in children <18yo • Ampicillin or TMP-SMX • Only if sensitivities are known

15. Control Measures • Most importantly…. • METICULOUS HAND HYGIENE!!!

16. Control Measures • Hospital • Contact precautions • *Day care • Notify local health department • Stool cultures should be performed on all symptomatic attendees and staff • Affected persons should be excluded until: • Initiation of appropriate ABx • ≥24 hours after diarrhea has resolved • Stool cultures are negative for Shigella

17. Complications • Intestinal • Proctitis or rectal prolapse • Toxic megacolon • Intestinal obstruction • Colonic perforation

18. Complications • Systemic • Bacteremia • Metabolic disturbances • Leukemoid reaction • Neurologic disease • Reactive arthritis • Alone or in association with conjunctivitis and urethritis (Reiter syndrome) • Hemolytic-uremic syndrome • Caused by EHEC (O157:H7), S. dysenteriae

19. A Question… • A previously healthy 3 ½ yo girl presents following 2 days of diarrhea, vomiting, and low-grade fever. Her symptoms began shortly after the family dined at a local fast-food restaurant. She has had 4-6 watery, mucoid stools per day. Her parents are very concerned because the have started to see some blood in her stool. On PE, the alert, somewhat irritable child has a T 38.6C, HR 100, RR 16. Her oral MM are dry. CRT~2 secs. Her abdomen is diffusely tender without distension. Labs show HgB 11.5, WBC 14.5, Na 136, K 4.5, Bicarb 18. Of the following, which is the most appropriate treatment? • A. A glucose-electrolyte solution • B. Cholestyramine • C. Loperamide • D. Metronidazole • E. TMP-SMX

20. A Question… • A 5yo girl presents after having a brief generalized seizure. Her mother reports that the child has had a 3 day h/o fever, tenesmus, and bloody diarrhea. On PE, you find a mildly toxic-appearing child who has a T104F and diffuse abdominal tenderness. The rectal exam produces significant pain. Stool from her rectum is guaiac-positive. You tell the mother that you believe the diarrhea has an infectious cause. Of the following, the MOST likely pathogen is: • A. Cryptosporidium sp • B. Rotavirus • C. Salmonella sp • D. Shigella sp • E. Yersinia sp

21. A Question… • You are evaluating a 2 yo boy with a 10h history of a temperature of 40.0C and progressively worsening diarrhea. Yesterday he attended a birthday party at the petting zoo, but he had no other history of ill contacts or unusual exposures. His mother states that he has had 8 watery bowel movements with mucus and streaks of blood in the last 10h. On PE, the boy is irritable and has a temp of 39.5C. His MM are slightly tacky, and his abdomen is diffusely TTP. The rest of the PE is normal. Labs show WBC 16.0 with 65% neutrophilsand 9% bands. Microscopic exam of the stool shows fecal leukocytes, blood and mucus. Of the following, the MOST likely etiologic agent for this patient’s condition is • A. Campylobacter • B. E. Coli • C. Salmonella • D. Shigella • E. Yersiniaenterocolitica

22. Infectious Diarrhea

23. Noon Conference: JIA, Dr. Brown Thanks for your attention!!