EQ diarrhoea

Question 1

What areas of the GIT are affected in acute diarrhoea of the horse?

Answer 1

Colon/ caecum (colitis/ typhlocolitis)

Question 2

What risk factors are associated with acute diarrhoea?

Answer 2

Antibiotics, transport, competition, hospitalisation, surgery - ie stress

Question 3

What pathogens can cause acute diarrhoea in horses >9mo?

Answer 3

Salmonella, clostridium, cyathostomins, ehrlichia (also drug-related)

Question 4

Describe the pathophysiology of SIRS.

Answer 4

Endotoxins and exotoxins produced by pathogens lead to an overwhelming release of inflammatory mediators (TNF, IL, complement) which damage endothelium

Question 5

What clinical signs are associated with SIRS?

Answer 5

Haemodynamic alterations (shock, vasoconstriction/ dilation, oedema), coagulopathies, metabolic derangements (hypermetabolism, tissue hypoxia, acidosis), organ dysfunction (reduced GI motility, laminitis, renal dysdysfunction)

Question 6

Which species of Salmonella is most associated with diarrhoea in the horse?

Answer 6

Typhimurium

Question 7

What environmental factors can increase shedding?

Answer 7

High temperature, hospitalisation, transport, antibiotics, GI surgery, immunosuppression

Question 8

What pathogenic characteristics are employed by Salmonella?

Answer 8

Gram -ve (endotoxins), mucosal damage (cytotoxins), osmotic diuresis (enterotoxins)

Question 9

What results on a biochem may be associated with Salmonellosis?

Answer 9

Neutropenia (used in tackling Salmonella infection), hyponautraemia and dehydration (osmotic diuresis), septicaemia

Question 10

Describe the sampling procedure used to ensure a horse is free of Salmonella.

Answer 10

5x negative faecal cultures taken 12 hours apart

Question 11

What antibiotics are associated with antibiotic-induced diarrhoea?

Answer 11

Penicillin, ceftiofur, TMPS, oxytet, erythromycin

Question 12

What bacteria is associated with antibiotic-induced diarrhoea (via overload)?

Answer 12

Clostridium deifficile

Question 13

What antibiotic can cause fatal colitis as a side effect?

Answer 13

Oxytetracycline

Question 14

What type of diarrhoea may be seen with antibiotic-induced diarrhoea?

Answer 14

+/- haemorrhagic

Question 15

If a horse is >9% dehydrated how does this correlate with their fluid loss?

Answer 15

> 50L

Question 16

If a horse is 7-9% dehydrated how does this correlate with their fluid loss?

Answer 16

40-50L

Question 17

If a horse is 4-7% dehydrated, how does this correlate with fluid loss?

Answer 17

25-35L

Question 18

What is the mechanism of action of polymixins?

Answer 18

They bind to LPS in the cell wall of gram-ves

Question 19

What is the spectrum of activity of polymixins?

Answer 19

Enterobacteriaceae (salmonella), pseudomonas

Question 20

What is the spectrum of metronidazole?

Answer 20

Anaerobes (gram-ve and +ve), protozoa (treponemes etc)

Question 21

What oral protectants may be used in treatments of cases of diarrhoea?

Answer 21

Bismuth subsalicylate, activated charcoal, smectite (clay minerals)

Question 22

What infectious causes are associated with infectious chronic diarrhoea?

Answer 22

Salmonella, listeria, parasitism, abscessation, rhodococcus equi

Question 23

What non-infectious inflammatory causes are associated with chronic diarrhoea?

Answer 23

Sand ingestion, granulomatous enteritis, lymphosarcoma

Question 24

What non-infectious, non-inflammatory causes are associated with chronic diarrhoea?

Answer 24

Abnormal fermentation or motility

Question 25

What pharmacological agents may be associated with chronic diarrhoea in the horse?

Answer 25

NSAIDs (toxicity) causing right dorsal colitis

Question 26

What antimicrobial may be associated with chronic diarrhoea?

Answer 26

Tetracyclines