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How do clinical signs of pain and response to pain meds compare in strangulating and non-strangulating obstruction of small bowel?
- stang: mil-mod-severe pain w/little relief from pain meds
- non-strang: mild-mod pain; good response to analgesia
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How do cardiovascular parameters and peritoneal fluids compare in strangulating vs. nonstrangulating obstructions?
- strang: CV deterioration + abnormal fluid (hi WBC/TP; serosanginous)
- non-strang: minimal CV compromise + normal fluid
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what are some common places for abdominal incarceration of intestines?
- epiploic foramen
- mesenteric rent
- gastrosplenic ligament
- inguinal ring hernia
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what is signalment/history of horse with ascarid impaction?
- <1 year (horses 18-24 develop resistance)
- 3-6 month old recently dewormed who was not properly dewormed at 8 wks
- (hx of resp. infection dt worm's life cycle)
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what is the ascarid associated with equine impaction? what is the prepatency period?
- Parascaris equorum
- PPP 8-12 weeks
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life cycle/transmission of ascarids?
ingest - travel from SI to liver to lungs - up trachea - cough/swallow - mature in intestines - you deworm - massive die off/impaction
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what CS are associated with ascarid obstruction?
- colic
- depression, endotoxemia, tachycardia, tachypnea, fever
- gastric reflux +/-with worms!
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what is treatment for ascarid impaction?
- gastric decompression/lavage
- NSAIDs
- +/- surgery if worms have devitalized/ruptured bowel
- (foals don't usu. get laminitis so don't have to tx for this)
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what is prognosis for foal with ascarid obstruction?
guarded; more favorable outcome if can resolve with medical not sx
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when should foals be first dewormed to avoid ascarid obstruction? what is the most appropriate dewormer to use?
- begin at 60 days and repeat 2-4 months thereafter
- Benzimidazoles (resistance to Ivermectin reported)
- -base decision on the farms FECs
- -use less effective dewormer if suspect high worm burden to slow die off process
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what are two causes of ileal impaction?
- coastal bermuda grass hay
- tapeworms irritating ileocecal junction (Anaplocephal perfoliata)
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what age horse is associated with ileal impaction? what will rectal palpation reveal?
- any age, adults
- early in disease can feel enlarged ileum; as progresses SI loops distend and you only feel that
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is gastric reflux associated with ileal impaction? what will peritoneal fluid analysis reveal?
- ileum later in SI so may not see reflux; only if impacted long enough to back up (>8-10 hrs);
- normal peritoneal fluid (non-strangulating lesion)
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what is recommended treatment for ileal impaction?
- early (pain manageable and normal peritoneal fluid) = medical tx: mineral oil, IV fluids, analgesia
- later (pain escalates, deteriorating peritoneal fluid) = surgery
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what is prognosis for ileal impaction?
good (may have to address post-ob ileus)
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what is the most common place for intussusception? at what age?
- ileocecal most common - young; <3yr
- (jejuno-jejunal also common)
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what are inciting causes of intussusception?
- deworming, abrupt dietary changes
- GI parasites (ascarids -jejunal, tapeworms-ileocecal, cecocolic)
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is intussusception usually acute or chronic presention? what does rectal palpation reveal?
- acute (rarely intermittent)
- enlarged loops of bowel
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what will US show with intussusception? what about peritoneal fluid evaluation?
- target/bulls-eye lesions
- abnormal fluid - devitalized gut = sersanguinous, hi WBC/TP
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what is treatment for intussesception? what is prognosis?
- surgery - resection/anasthamosis
- simple obstruction = good
- ileocecal = guarded (jejunocecostomy; necrosis of ileocecal stump)
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what is the tapeworm with affinity for ileocecal junction? what is PPP? what is recommended tx for deworming?
- Anaplocephala perfoliata
- 4wk-4mo
- Tx: praziquantel
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when small intestine volvulus twists around root of mesentery, is arterial or venous supply obstructed first?
venous drainage occluded - engorged and thickened
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what age is volvulus usually seen? what causes volvulus?
- one of most common causes of colic in foals
- unknown cause (parasites? changing feeding habits?)
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what is treatment for volvulus? what is prognosis?
- surgical resection/anasthamosis
- good if only short section involved; euthanize if >50% involved - short bowel syndrome
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what fluids should be used when treating volvulus patient? should you treat for laminitis?
- aggressive therapy warranted - hypertonic saline (4ml/kg) then balanced IV fluids
- -yes, prophy for laminitis; NSAIDs, cryotherapy
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what are the landmarks for the epiploic foramen? does bowel usually pass from L to R or R to L?
- caudate lobe of liver
- caudal vena cava dorsally
- portal vein, pancreas
- Left to Right
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how old are horses with epiploic entrapment?
older than 8 years
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presenting signs of intestinal incarceration are consistent with any form of strangulating lesion, so how do you know which type you have?
all strangulating lesions require surgical correction - determine which type at surgery
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what signalment is associated with strangulating lipomas?
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what is treatment and prognosis for strangulating lipomas?
- surgical resection/anasthamosis
- good if addressed early
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both lipomas and large colon feed impaction present with dessicated feed in the colon. How do you determine which is the cause?
aged horses rarely get feed impactions; more likely lipoma if older
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feed impactions usu. do not cause CV deterioration;
strangulating lipomas: CV deterioration & abnormal peritoneal fluid
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what is the cardinal sign of colitis in adult horses?
diarrhea (considered an emergency)
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what are clinical signs of colitis?
- fever, endotoxemia
- diarrhea - PLE - edema
- colic pain that can mimic strangulating/surgical pain
- +/-gastric reflux
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what are expected lab parameters with colitis?
- neutro*penia* w/left shift
- toxic neutrophils
- hypOkalemia, *hypOnatremia*
- metabolic acidosis; azotemia
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what would US show with colitis patient?
thickened colon or cecal wall with fluid swirling within colon/cecum
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what would peritoneal fluid show with colitis?
nonseptic peritonitis: normal nucleated cell count and normal to mildly increased protein concentration
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what are some common causes of acute colitis/diarrhea?
- salmonella
- clostridium
- potomac horse fever
- grain overload
- cantharid toxicity
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what are some common causes of chronic colitis/diarrhea
- sand enteropathy
- right dorsal colitis (NSAIDs)
- cyathastomiasis
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Regardless the cause of colitis, what is treatment plan?
- fluids (crystalloid + colloids bc severe hypoproteinemia)
- NO hypertonic saline (bc hypOnatremic >24hr)
- NSAIDs + lidocaine CRI
- polymyxin B + cryotherapy + plasma (for endotoxemia)
- +/- anti diarrheal agents (bismuth salts, psyllium, probiotic)
- +/- Abs
- parenteral nutrition
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Usually antibiotics are not indicated in treatment of colitis except in which circumstances?
- foals less than 3 mo
- secondary infections; concurrent disease
- severe, persistent neutropenia
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what are common complications associated with colitis?
- laminitis
- thrombophlebitis
- coagulopathy (later)
- prolapsed rectum, infarcted bowel
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