Morning Report: Thursday, January 12th Welcome APPLICANTS!

Shigella Infection

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 1-4 165 million cases occur worldwide annually, 1 million associated deaths; 70% of the cases and 60% of the deaths involve children <5yo

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 Shiga toxin produced most commonly by S. dysenteriae, and enterhemorrhagic E.coli

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 Inoculum: ingestion of as few as 10 organisms can cause illness

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

Clinical Presentation Course Presentation: abrupt onset of high fever, generalized toxicity, crampy abdominal pain*, high-volume, watery stools 24-48h later: Small-volume, bloody, mucoid stools* with tenesmus Neurologic manifestations (40%) Severe HA Seizures Meningeal signs Lethargy Delirium/ hallucinations Can also see emesis in 35%

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

Laboratory Findings Bandemia Stool microscopy Stool culture 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 Largely clinical diagnosis where the labs are confirmatory

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

*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?

*Treatment Who to treat? Red Book Severe disease Underlying immunosuppressive conditions Dysentery In mild cases Rx to prevent spread of the organism Most infections with Shigella are self-limited and resolve within 48-72h (7d) without antimicrobial therapy

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

*Treatment What to use? Oral Cefixime Ampicillin or TMP-SMX Alternative to azithromycin in children <18yo Ampicillin or TMP-SMX Only if sensitivities are known 5 day treatment regimen

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

Control Measures Hospital *Day care Contact precautions 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 General: use of safe drinking water

Complications Intestinal Proctitis or rectal prolapse Toxic megacolon Intestinal obstruction Colonic perforation Bacteremia: leukocytosis, hypothermia, T>39.5, severe dehydration, lethargy; occurs commonly in children <5

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

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

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

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% neutrophils and 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. Yersinia enterocolitica

Infectious Diarrhea Symptoms Labs Treatment Salmonella Shigella Transmission Symptoms Labs Treatment Salmonella Chicken, milk, eggs; exotic pets (reptiles) Fever, diarrhea with blood/ mucous High WBC with left shift, +stool WBC, RBC (?+ BCx) None with uncomplicated GE; at risk* Amoxil, Bactrim Shigella Person-to person; daycare! Fresh fruits and veges Fever, abd. pain, watery diarrhea that becomes bloody, szs High WBC and band ct, +stool WBC, RBC Azithromycin, quinolones Campylobacter jejuni Undercooked poultry or meat Fever, abd pain, diarrhea with blood, vomiting +stool WBC, RBC; Cx with chocolate agar Erythromycin E.Coli O157:H7 Undercooked beef, unpasturized milk +stool WBC, RBC; look for signs of HUS Abx not indicated! (increases risk for HUS) Yersinia enterocolitica Pork (chitterlings) Dysenteric syndrome, can mimic appy/ Crohns +stool WBC, RBC Bactrim, aminoglycosides, cephalosporins (3rd), quinolones Clostridium difficile ABx exposure Mild diarrhea dysentric syndrome Dx with toxin assay PO Flagyl (Vanc) *At risk population for Salmonella (and therefore should be treated): infants <3mos and children with malignancies, hemoglobinopathies, and immunodeficiencies HUS: renal failure, hemolytic anemia, thromboctopenia (don’t forget, can see with Shigella as well!) Campylobacter GBS

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