Diarrhea

Question 1

Name the causative organism:

• Gastroenteritis w/ abdominal pain, fever, bloody diarrhea, nausea &/or vomiting
• Nonlactose fermenter
• Fecal/oral transmission
• Tends to affect preschool-age children & populations in nursing homes

Answer 1

Shigella typhi

(note: also causes Hemolytic uremic syndrome, which results in renal failure, thrombocytopenia, & microangiopathic hemolytic anemia)

Question 2

Name the causative organism:

• Dysentery (diarrhea w/ blood & Mucus), abdominal pain, nausea, &/or vomiting
• Gram-negative curved-shape rods

Answer 2

C. jejuni

note: also causes Guillaine Barre Syndrome

Question 3

Name the causative organism:

• Diarrhea, fever, headache, & rose spots on the abdomen
• Produces Hydrogen sulfide
• Fecal-oral transmission

Answer 3

Salmonella typhi

Sx characteristic of Typhoid fever

Question 4

Name the causative organism:

• Typhoid fever

Answer 4

Salmonella typhi

Question 5

Typhoid Fever:

Diagnosis & Treatment?

Answer 5

Diagnosis–Blood cultures are positive during the first 7-10 days of illness. After this time, stool and urine cultures become positive.

Treatment: Ceftriaxone, ciprofloxacin, trimethoprim-sulfamethoxazole are all generally effective

Question 6

Octreotide is a ____ analog that has what effects on the GI system?

Answer 6

Somatostatin-analog

Suppresses release of Gastrin, CCK, Secretin, VIP, & pancreatic fluids

Question 7

CCK is released by ____ cells in the _____ in response to ______.
What are its major effects (3)?

Answer 7

CCK is synthesized by I-cells of the Duodenum in response to chyme entering the duodenum from the stomach.

• decreases Gastric acid secretion, slowing release of chyme into the duodenum
• stimulates release of pancreatic digestive enzymes
• induces gall bladder contraction

Question 8

Gastrin is released by _____ cells in the _____ in response to what?
What are its major effects (2)?

Answer 8

Gastrin is released by G-cells of the stomach in response to stomach distention, vagal stimulation, & proteins.

• stimulates acid secretion from Parietal cells
• causes pepsinogen release from chief cells

Question 9

Secretin is released by ____ cells in the ____ in response to what?
What are its major effects?

Answer 9

Secretin is produced by S-cells in the Duodenum in response to inc’d duodenal fatty acids & acidity.

• Stimulates Bicarbonate secretion from pancreas

Question 10

VIP is released by _____ cells in the _____ in response to what?
What are its major effects?

Answer 10

VIP is produced by the intestines & pancreas.

• induces smooth muscle relaxation in the intestines
• stimulates Bicarbonate secretion from pancreas

Question 11

Peptic ulcer disease:

Duodenal ulcer- Age? Gastric acid levels? Risk of gastric/duodenal cancer?

Gastric ulcer- Age? Gastric acid levels? Risk of gastric/duodenal cancer?

Answer 11

Duodenal ulcer disease

• younger age patient
• higher gastric acid levels
• No risk of gastric/duodenal cancer

Gastric ulcer disease- multifactorial

• older age patients
• lower gastric acid levels
• associated w/ a higher risk of gastric cancer

Question 12

Causative Organism?

Diarrhea, abdominal cramps, & leukocytosis immediately following antibiotic regimen (likely in an older adult)

Answer 12

C. dificile – colonization & toxin release when large portion of commensal organisms are killed

Question 13

C. dificile Toxin(s) – MOA?

Answer 13

Toxin A = attracts neutrophils causing mucosal inflammation, loss of H2O into gut lumen (diarrhea), & mucosal death

Toxin B = Actin depolymerization, loss of cellular cytoskeleton integrity, cell death, & mucosal necrosis