MHD II Session 3 STUDENT COPY

Transcription

1 MHD II, Session 3, Student Copy - Page 1 MHD II Session 3 January 15, 2016 STUDENT COPY

2 MHD II, Session 3, Student Copy - Page 2 CASE HISTORY 1 Cc: Terrible diarrhea for 1 ½ days A 66 year-old woman presents to the traveler's clinic complaining of profound weakness and severe diarrhea of one and one-half days' duration. She has just returned from Africa where she worked for two months in a refugee camp on the border of Zimbabwe. On the plane she developed abdominal bloating, intestinal gurgling and nausea followed by two loose bowel movements. Soon she was having profuse watery diarrhea occurring hourly. Stools were clear and without odor. She denies having any blood in her stool. She has no previous history of diarrhea. Her medications are levothyroxine 100mcg daily for hypothyroidism and monthly intramuscular cyanocobalamin injections for pernicious anemia. You meet her in the clinic. She looks very weak. She is afebrile. Blood pressure is 94/60 lying down and drops to 72/40 standing. Oral mucosa is dry. Her lungs are clear to auscultation and percussion. On heart exam the patient is tachycardic, normal S1, S2, no murmurs. Her abdomen is nondistended. There is mild diffuse abdominal tenderness to palpation; there is no rebound tenderness or guarding. She is admitted to the hospital. Admitting laboratory studies include the following: BASIC METABOLIC PROFILE Sodium 134 L [ ] mm/l Potassium 2.1 L [ ] mm/l Chloride 105 [98-108] mm/l CO2 15 L [20-32] mm/l Bun 34 H [7-22] mg/dl Creatinine 1.6 H [ ] mg/dl Calcium 10.4 H [ ] mg/dl Stool WBC NEG [NEG] Fecal Occult Blood NEG [NEG] Learning Objectives 1. Based on the information provided, what is the likely pathogenic mechanism of this patient s diarrhea?

3 MHD II, Session 3, Student Copy - Page 3 Bacterial stool culture is growing colonies of curved, Gram negative rods. 2. What organism is most likely represented by the culture results? 3. What is the mechanism of transmission of this organism? What factor(s) put this patient at risk for infection with this organism? 4. Describe the mechanism of action of this organism s toxin. 5. Besides toxin production, what other virulence determinant is essential for the development of infection with this organism? 6. Interpret the BMP.

4 MHD II, Session 3, Student Copy - Page 4 7. How would you manage the hypovolemia? Why can oral rehydration fluid be used in many cases of infection with this organism? 8. What advice would you provide to other travelers to Zimbabwe concerning avoidance of infection with this organism? 9. List potential public health solutions to the global problem of epidemic infections with this organism.

5 MHD II, Session 3, Student Copy - Page 5 Case History 2 Cc: Diarrhea, abdominal pain x 1 week An 8 year-old boy was admitted to the Pediatric Service with edema and high blood pressure. He had been well until 8 days prior to admission when he developed severe abdominal pain, nausea, vomiting and diarrhea. On the second day the diarrhea became bloody. The diarrhea continued but had lessened in amount, remaining bloody. The mother did not report any fever. On examination he appeared pale and had mild facial edema. Temperature was 37.6C, pulse 104 and regular and the blood pressure was 140/95. His abdomen was tender. Chest x-ray was clear. Abdominal x-ray disclosed edema of the transverse and descending colon with thumbprinting. Laboratory Studies CBC with Diff WBC 17.5 H [ ] k/ul RBC 2.33 L [ ] m/ul Hgb 8.5 L [ ] gm/dl Hct 25.0 L [ ] % MCV 96 H [85-95] fl MCH 32.9 H [ ] pg MCHC 36.5 H [ ] gm/dl RDW 16.0 H [ ] % Plt Count 42 L [ ] k/ul Diff Type Manual Gran 80 H [45-70] % Gran # 14 H [ ] k/mm3 Lymph 15 L [20-45] % Lymph # 2.6 [ ] k/mm3 Mono 3 [0-10] % Mono # 0.5 [ ] k/mm3 Eo 1 [0-7] % Eo # 0.1 [ ] k/mm3 Baso 1 [0-2] % Baso # 0.1 [ ] k/mm3 RBC Morphology SEE BELOW Mod Schistocytes BASIC METABOLIC PROFILE Sodium 136 [ ] mm/l Potassium 5.4 H [ ] mm/l Chloride 109 H [98-108] mm/l CO2 17 L [20-32] mm/l Bun 47 H [7-22] mg/dl Creatinine 5.4 H [ ] mg/dl Calcium 8.1 H [ ] mg/dl

6 MHD II, Session 3, Student Copy - Page 6 LDH 387 H [90-180] iu/l 1. Interpret the laboratory data. The pediatric team is concerned about an infectious cause of the patient s diarrhal illness and orders a stool culture to support their suspicion. The third year medical student on the team remembers that routine screening of stools for this organism is at the discretion of the individual laboratories and the microbiology lab should be contacted. 2. What enterohemorrhagic bacteria is most likey causing this infection? What complication did this patient develop? Define the complication. 3. List the virulence characteristics of the organism that are responsible for this syndrome. 4. Describe the pathogenic process. In your response address how the infectious microorganism might be responsible for hemorrhage, anemia, and renal failure.

7 MHD II, Session 3, Student Copy - Page 7 5. How is the infection acquired? Include in your answer an explanation of how the most common vehicle of transmission is likely to cause large outbreaks. 6. Should the child be isolated in the hospital? 7. How does one diagnose the infection? 8. Should antibiotics be used to treat the child? If so, which ones are used? 9. Review Case Images- Gastroenterology Set 3

8 MHD II, Session 3, Student Copy - Page 8 Case History 3 CC: I have been having stomach pains for about 1 week and I just threw up some blood A 49-year-old woman presented to the emergency department complaining that she had vomited up blood at home. She had been suffering with sharp epigastric pain, especially in the morning, for one week before the vomiting began. The pain was accompanied by mild nausea and was relieved by food or antacids. Her stools seemed darker than usual; she denies having bloody stools. She had been previously diagnosed with gastric or duodenal ulcers at ages 16, 23, and 32. She remembers being treated with ranitidine or cimetidine during those episodes. Previous work up for Zollinger-Ellison syndrome was negative. She takes no medications regularly aside from antacids as needed. She rarely drinks alcohol and does not smoke. A nasogastric tube was placed revealing blood in the stomach which cleared after gastric lavage with iced saline. Immediate endoscopy revealed scarring of the pylorus with a 2 cm ulcer in the first portion of the duodenum with adherent blood clot. She was admitted to the hospital and monitored. A gastric antral biopsy was done during the endoscopy and the results are below: Specimen #: S Physician(s): Lind, James, M.D. Source:Antrum bx FINAL DIAGNOSIS ANTRUM; BIOPSY: -ANTRAL MUCOSA WITH SUPERFICIAL MUCOSAL ULCERATION AND MODERATE ACTIVE CHRONIC GASTRITIS -GIEMSA STAIN REVEALS NUMEROUS CURVED BACILLI ALONG THE SURFACE OF THE MUCOSA ***Electronically Signed Out*** Anna Bardwell, M.D. Operation EGD Clinical History UGI bleeding Gross Description The specimen, received in formalin labeled with patient identification only, consists of multiple irregular fragments of tan soft tissue measuring in aggregate 0.5 x 0.4 x 0.2 cm. The entire specimen is wrapped in lens paper and submitted in one green cassette. Anna Bardwell, MD Microscopic Description The attending pathologist whose signature appears on this report has reviewed the diagnostic slides and has edited the gross and/or microscopic portion of the report in rendering the final microscopic diagnosis

9 MHD II, Session 3, Student Copy - Page 9 1. Describe the morphologic and microbiologic features of the microorganism seen on gastric antral biopsy. 2. What is the frequency of infection with this organism in the United States? How does the distribution of infection with this organism differ in populations from underdeveloped countries? 3. What phenotypic characteristics of this organism are thought to account for its virulence? Which of them appear to be most important? The nasogastric tube aspirate remained blood free and the tube was removed. She was started on a proton pump inhibitor. Her hemoglobin remained stable. 4. What further treatment is indicated. What long term benefits could she expect if she were to receive the additional treatment? 5. Why do think this patiet was previously evaluaed for Zollinger Ellison Syndrome. Cases 4 Unknown, Bacterial Enterocolitides Table Students will not have questions/table until the session meets.