Diarrhea Flashcards
What are the infectious causes of diarrhea in horses?
Bacteria: salmonella, C. perfringens or difficile (acute)
Viral: Equine coronavirus (acute)
Parasites: Neorickettsia risticii, cyathostomes (chronic)
What are the non-infectious causes of diarrhea in horses?
Abx, NSAIDs, grain overload (ACUTE), sand (chronic)
Toxins: blister beetle (acute), ionophore, IBD (chronic)
CS in a horse with acute salmonellosis
Abdominal pain, acute diarrhea, inappetence
Small colon impaction
Sepsis/ septic shock, laminitis
CS in a horse with acute clostridial colitis
Peracute, acute or gradual diarrhea (hemorrhagic, dark/ foul smelling) *
Colic, fever, inappetence, septic shock, sudden death
Abdominal distention, scant feces, bowel necrosis then death
Tx for a horse with clostridial colitis and acute salmonellosis
Metronidazole, di-tri- octahedral smectite, NSAIDs (polymixin B)
IV fluids with electrolytes
Plasma therapy, cryotherapy, colloid therapy
Plasma therapy
Commercial hyperimmune plasma with Abs and proteins (albumin) that maintain circulation, minimize edema and minimize endotoxemia effects
How would you differentiate between acute salmonellosis and acute clostridial colitis?
Salmonella: can dx with cx and PCR, could have a fever, small colon impaction, watery diarrhea, laminitis
Clostridium: hemorrhagic diarrhea, fever and sudden death
CS of Potomac Horse Fever
High fever (107F), 7-14d before colitis signs develop
Mild to moderate colic and ↓ GI signs
Edema: limbs, prepuce and ventral body
Abortion (transplacental trans)
What geographical areas is PHF found?
Swampy areas (summer dz)
Tx for PHF
Oxytetracycline (IV) and supportive therapy
DX PHF
PCR (sensitive and specific)
IFA (seroconversion, >30% false +)
CS of equine enteric coronavirus
Anorexia, lethargy, fever
Leukopenia secondary to neutropenia or lymphopenia
Hypoalbuminemia and neuro abnormalities
Hyperammonemia (severe cases)
Dx equine enteric coronavirus
PCR (chilled sample or frozen if testing delayed for more than 3-4 days)
What horses are predisposed to clinical dz in larval cyathostomiasis
Young adults <6yrs
CS of larval cyathostomiasis
Acute diarrhea → chr.
WL, colic and peripheral edema
Dx of larval cyathostomiasis
HY
Fecal exm (float and EPG)
CBC/ chemistry
Prognosis of larval cyathostomiasis if severe CS develop
???
Tx of horse with larval cyathostomiasis
Anthelmintics (adult larvae)
Corticosteroids (dexmeth, pred)
Which anthelminics are used for larval cyathostomiasis?
Fendendazole and avermectins
Repeated doses are needed to kill parasites as they emerge from arrested state leading to resistance
How would you use fecal egg counts and egg reappearance times to strategize anthelmintics?
???
Main site of GI damage with NSAIDs
Right dorsal colon
Right dorsal colitis pathophysiology
NSAIDs inhibit COX enzyme → reduction in cytoprotective effects from PGE2 → hypoxic or ischemic damage to the mucosa → phenylbutazone is bound to roughage and released after fermentation in large colon → slow transit time and narrowing of lumen @ junction
What factors contribute to right dorsal colitis?
Dehydration, enterotoxemia, inappropriate dosing or pre-existing lesions of the colon
Clinical pathology of right dorsal colitis
Hypoproteinemia
Hypocalcemia
Azotemia (prerenal or acute renal damage)
Anemia (chr. cases, mild)
CS of acute RDC
Profuse diarrhea, severe colic, dehydration, endotoxic shock and death
CS of chr. RDC
Mild to moderate intermittent colic
Ventral edema, WL
Weeks to months
RDC dx
US (colon wall thickened)
Scintigraphy
RDC tx
Pain management: opioids, xylazine
NSAIDs (avoid if possible but ketoprofen, firocoxib)
Low bulk diet and avoid roughage
Metro, sucralfate and glutamine (healing and repair)
Blister beetle toxicity (cantharidin)
Ingestion of dead beetles in alfalfa hay (males produce toxin)
4-6g of dead beetles is lethal
Vesicant and mucosal irritant
CS of BBT
Shock and death (massive dose)
Sweat profusely, ↑ HR, resp. and temp
Bright red mm, prolonged CRT, massive fasciculations, hematuria
Electrolyte abnormalities in BBT
Hypomagnesium, hypoproteinemia, elevated CK and mild azotemia
CS of sand enteropathy
40lb to cause colic
Diarrhea:
Dx sand enteropathy
Auscultation cd. to xyphoid cartilage: sand swirling in paper bag (20lb)
How do you tx sand enteropathy and prevent recurrence?
Sx- sand impaction
Laxatives- mineral oil, Mg sulfate, pelled complete feed ration
Combo of psyllium and MgSO4 via nasogastric intubation (4d)
Prevent with mowl horse feeder, or pre-vent horse feeder
