Diarrhea (key points only) Flashcards
What should you think of causing diarrhea with prior drug use in the history (NSAIDs)?
- Right dorsal colitis
What is a major component of the normal horse microbiome?
- Firmicutes
- Actinobacteria
- Spirochetes
What bacteria tend to be in greater abundance in horses with diarrhea?
- Fusobacteria
- VERY variable
Clinical signs associated with diarrhea
- Anorexia, obtundation, fever
- Diarrhea of variable severity
- Colic, abdominal distention
Do horses with enteritis have diarrhea?
- NO
- Often fever, colic, low WBC count
- NO DIARRHEA
What part of the horse GIT is dysfunctional in an adult horse with diarrhea?
- Colon dysfunction
- Colon, cecum or both
- Failure to absorb excess water or increased fluid secretion
Clinical pathologic changes in a horse with diarrhea
- Hemoconcentration
- pre-renal azotemia
- Neutropenia, left shift, toxic changes
- Hypoproteinemia, hypoalbuminemia
- Metabolic acidosis
- Hyponatremia, hypochloremia, hypokalemia
Abdominocentesis of a horse with diarrhea
- Generally normal
Infectious etiologies of horses with acute diarrhea
- Salmonella
- Clostridia
- Potomac horse fever
- 70% are unknown
Salmonella diarrhea
- Invasive in the cecum and colon
- +/- enterotoxic
- Endotoxin
Clinical signs of horses with Salmonella
- May show no clinical signs (carriers are quite common)
- Mild clinical disease
- Acute colitis (VERY sick)
- Small colon impaction
- Proximal enteritis
- Chronic diarrhea
How can a horse contract Salmonella?
- Contaminated feed or water
- Contaminated hands
- Ingestion of dead insects
- Contact with a contaminated surface
- Lots of ways basically
Risk factors for Salmonella
- younger
- Stress or transport
- Hospitalization
- NG tubing
- Antimicrobial treatment
Diagnosis of Salmonella
- Fecal culture (DIFFICULT)
- Fecal PCR (doesn’t let you know if it’s alive or not)
- Negative culture doesn’t rule it out (Take serial cultures)
- Necropsy (bowel, LN)
Treatment for Salmonella
- SUpportive
- MAYBE antibiotics?
- Prolonged shedding
- Zoonotic potential
What cell type is Potomac horse fever often invading?
- Monocytes and macrophages
- Colonic epithelium, mast cells
Season for Potomac horse fever
- May-Nov
Transmission of Potomac horse fever
- # 1 is ingestion of the aquatic insect that has picked up the metacercaria
- Could be ingestion of the egg
- Not the ingestion of a snail
- Ingestion of cercaria possible too
- Ingestion of the metacercaria in an aquatic insect larva/nymph or adult
Diagnosis of Potomac horse fever
- Paired samples (IFA, ELISA)
- PCR in blood or feces considered most definitive
Treatment of Potomac Horse Fever
- Oxytetracycline
- Typically rapid response
- Suppotive care
Vaccination with Potomac Horse Fever
- Different strains!
Clostridial diarrhea
C. perfringens
C. dificile
C. sordelli
Can have co-infections
What toxins do Clostridium spp produce?
- Enterotoxins
- Beta toxin - type C
- Toxin A is an enterotoxin
- Toxin B is a cytotoxin
Risk factors for Clostridial diarrhea
- Antibiotics
Stress
