pathogenic mechanisms of diarrhea

Question 1

what is diarrhea

Answer 1

an increase in frequency, fluidity, volume and water content of feces

Question 2

what causes diarrhea

Answer 2

• triggered by single strains of virulent pathogen, mixed infection or toxins
• host response due to disruption of physiology, leading to clinical signs

Question 3

list pathogenic mechanisms of diarrhea

Answer 3

• hypersecretion
• vilous atrophy
• infiltrative and proliferative distortion of mucosa
• mucosal necrosis

Question 4

explain how hypersecretion causes diarrhea

Answer 4

• a functional disturbance of the intestinal epithelial cells
• increased out flow or decreased re-absorption of water

Question 5

explain how vilous atrophy causes diarrhea

Answer 5

• destruction of the epithelial cells on vili or in the crypts
• vili become often stunted or fused

Question 6

describe how infiltrative and proliferative distortion of mucosa causes diarrhea

Answer 6

• recruitment of large numbers of macrophage and T lymphocytes in the lamina propria and sub mucosa
• leading to crypt compression and vilous distortion
• therefore reduce absorptive capacity

Question 7

explain how mucosal necrosis causes diarrhea

Answer 7

• infection leads to cell death
• severity and extent depend on virulence of pathogen
• majority of diarrhea from reduced absorption