GI DISEASES

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GI DISEASES

• LAM 1
• August 2005
• Amy Fayette

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SMALL INTESTINE
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Ascarid Impaction

• Clinical signs will typically mimic those of
  strangulating obstructions d/t severe necrosis
  and inflammation
• Signalment weanlings
• Risk factors recent administration of very
  effective anthelmintics
• CS
• Can get worms in gastric reflux
• Toxic, shocky, moderate to severe colic
• Tx
• Surgical intervention

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Feed or Foreign body impaction

• Ileal impaction is most common
• Risk factors GA, Fl, TX, and LA
• Feeds w high fiber content bermuda grass
• Fine hay particles w water squeezed out to form a
  firm mass
• CS
• Rectal SI distension, as impaction progresses
  gets pulled out of reach
• Tx
• Conservative mineral oil, IV fluids and
  analgesics
• Surgical intervention post op illeus usually
  occurs
• Prognosis fair survival
• Better if its fixed lt 17 hours after starting

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Muscular Hypertrophy

• Ileum
• Primary (idiopathic)
• Secondary (compensatory due to distal stenosis)
• Signalment
• Mature horses
• Can be associated w presence of tapeworms
• CS
• Intermittent colic after eating
• Tx
• Medical if associated w tapeworms
• Surgery
• Prognosis favorable after sx

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Abscesses

• Signalment lt 5 years old
• History weight loss and/or unthriftiness
• CS
• Depressed, anorectic and febrile
• Neutrophilia w left shift and hyperfibrinogenemia
• Abdominocentesis (elevated TP and WBC)
• EA S. equi, S. zooepidemicus, R. equi, C.
  pseudotuberculosis
• Tx
• Conservative long term ABs, treatment of choice
  but guarded prognosis
• Sx

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Adhesions

• D/t inflammation in the abdomen esp peritonitis
• History recurrent bouts of colic, often
  secondary to previous abdominal surgery
• Tx sx
• Prognosis guarded to poor (recurrence common)

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Neoplasia

• SCC and lymphosarcoma most common

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Volvulus

• Twist on the long axis of the mesentery at least
  180 degrees
• One of the most common causes of true
  strangulating obstruction in the SI
• Signalment lt3 years old
• lt1 year olds may be d/t diet change or ascarid
  infection
• Ileum is commonly involved

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Strangulating Lipoma

• Signalment older horses, overweight horses
• Pedunculated fat mass oin the end of a
  fibrovascular stalk
• History recurrent bouts of abdominal pain
• Prognosis guarded

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Internal Herniation

• Epiploic foramen
• Signalment older horses (possibly d/t reduction
  in size of the liver with age)
• CS
• Peritoneal fluid evaluation abnormal in 56 of
  cases
• Rectal exam SI distention in ¾ of cases
• Reflux in almost all cases
• Tx surgical correction can result in immediate
  death of horse d/t rupture of the caudal vena
  cava or portal vein
• Gastrosplenic ligament entrapment
• Mesenteric defects

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External Herniation

• Inguinal
• Indirect are present w/I the vaginal tunic
• Direct are those in which the intestines lie in
  the SQ tissues outside the vaginal tunic
• Signalment newborn colts, breeding stallions
• CS in stallion usu indirect and unilateral (left
  esp)
• CS in foal
• Indirect reducible, non painful, correct
  spontaneously
• Direct acute, painful

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External Herniation

• Umbilical
• Second most common congenital lesion in the horse
• Strangulation of SI associated w this lesion is
  rare
• Predisposing factors manual breaking of
  umbilical cord, umbilical infection, excessive
  straining, ligation of the cord
• Hernias in need of surgical correction increase
  in size, firmness, warmth, edema, pain on
  palpation
• Diaphragmatic rare
• Risk factors trauma, increased intraabdominal
  pressure (parturition)
• CS resp or GI signs (episodic colic)
• Prognosis guarded

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Intussusception

• Risk factors higher rate during times of fecal
  consistency change, tapeworm infestation,
  previous SI sx, anthelmintic administration,
  ascarids etc
• Signalment lt3 years (can occur in older horses)
• Ileum and ileicecal junction
• CS acute colic followed by intermittent colic
  lasting weeks to months
• peritoneal fluid change may not reflect the
  degree of intestinal necrosis b/c dead gut is
  isolated from the peritoneal cavity
• Prognosis with surgery fair to poor

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DPJ

• Aka Anterior enteritis
• Looks like strangulating disease
• Signalment all ages, mostly adults, those on an
  adequate to high plain of nutrition
• Pathophysiology
• Accelerated transmucosal fluid movement
• CS
• Moderate to severe abdominal pain (subsides after
  decompression, most horses remain very depressed)
• Lots of NG fluid
• Dehydration, injected MM
• Temp gt101 F but not high fever

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DPJ

• Tx decompression and fluid administration
• NSAIDS not enough to mask signs of pain in case
  it is a strangulating lesion
• Antiendotoxic therapy flunixin and antiserum
  administered IV
• Antibiotics cover systemic effects of altered
  mucosa
• Motility drugs if reflux for 7 or more days
• Sx if no resolution or to confirm absence of
  strangulating lesion
• Complications adhesions and laminitis
• Prognosis
• gt90 survive primary insult
• Usually succumb to complications

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CECUM
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Cecal tympany

• 2 types
• Primary- rapid gas production and decreased
  motility
• Secondary- associated w obstruction in the large
  or small colon
• CS
• bloated in right flank
• HR gt 100 bpm
• Silent abdomen but right flank has high pitched
  pinging
• Tx
• Decompression percutaneously
• Supportive therapy w fluids and analgesics

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Cecal impaction

• 2 types
• Dehydrated firm food mass filing cecum
• Cecal dysfunction idiopathic w ingesta of fluid
  conistency
• Risk factors dehydrated type associated w diet
  high in corn or coarse hay
• History orthopedic problems
• Signalment more common in adults
• CS
• mild to moderate intermittent pain w decreased
  gut sounds
• Cecal dysfunction type usually more severe pain
  and signs of endotoxemia

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Cecal impaction

• Tx
• Medical
• NG intubation w DSS
• IV fluids
• Walking
• Analgesia (xylazine and butorphanol)
• Sx if pain cannot be controlled

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Cecal perforation and rupture

• Risk factors tapeworms, parturition, ulceration
  etc
• Tx repair often imposible, removal of cecum
• Prognosis poor

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LARGE COLON
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Impaction

• Often in winter d/t worse hay, and horses drink
  less water when its cold
• Risk factors poor dentition, foreign materia,
  decreased water intake, altered colonic motility,
  adhesions
• CS intermittent colic, pain worsens if
  unresolved
• Tx
• IV fluids
• Analgesics can be worsened by multiple doses of
  alpha 2 agonists
• Laxatives mineral oil or DSS
• Walk frequently
• Off feed until a substantial amount of manure is
  passed
• Prognosis good unless evidence of bowel wall
  compromise

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Sand Enteropathy

• Risk factors
• Feeding on ground in sand stalls or sandy pasture
• CS
• Similar to Lg colon impaction
• Weight loss, diarrhea
• Lie on side or back to relieve tension on
  mesentary
• sand on beach sound may be heard in ventral
  abdomen
• Dx
• Float feces, find sand in the bottom
• Rads of ventral abdomen
• Tx
• Psyllium (binds and removes sand
• Sx may be necessary if complete obstruction, if
  unresponsive pain or if deterioration despite
  therapy

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Enterolithiasis

• Signalment 5-10 years (takes time to form)
• Risk factors
• California
• Nidus of undigestible material (twine/rubber
  fencing)
• Dietary magnesium
• Spherical (often single), tetrahedral (often
  multiple)
• CS
• Recurrent colic
• Rarely feel enterolith
• Tx
• Surgical removal
• Medical dissolution doesnt work

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Right Dorsal Displacement

• Idiopathic
• Signalment all horses (maybe large breed)
• CS
• insidious to moderate colic depending on degree
  of gaseous distention
• Reflux occurs if duodenum is obstructed by
  displacement

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Nephrosplenic Entrapment (LDD)

• Signalment warm bloods, large horses and drafts
• CS
• Pain (will lie down sternal to decrease the pull
  on mesentary)
• Dx
• Rectal The most overdiagnosed cause of colic in
  the horse (presence of gut in region may not be
  trapped)
• Ultrasound of nephrosplenic space
• Abdominoscentesis to look for other evidence of
  bowel compromise

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Nephrosplenic Entrapment (LDD)

• Tx
• Medical phenylephrine causes splenic
  contraction which will release colon (do PCV and
  TP before and after) or try rolling horse
• Surgical correction tack edge of spleen to
  nephrosplenic ligament (decrease space)
• Complications
• Recurrence etc

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Large Colon Torsion

• Signalment older brood mares, can be any age and
  any sex
• Risk Factors 1 month prior to 1 month after
  parturition
• Pathophysiology
• Exact cause unknown
• Root of mesentery is the location for
  constriction of the twist
• If torsion gt 180 degrees venous occlusion occurs
• If torsion gt 270 degrees arterial occlusion occurs

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Large Colon Torsion

• CS sudden severe pain, the most painful colic
• Pulse may be normal
• DOA d/t metabolic acidosis, resp compromise,
  endotoxemia etc
• Tx
• Fast surgical correction
• Possible lg colon removable
• Support for endotoxemia

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Inflammatory Collitis

• Look like strangulating disease
• Often associated with typhlitis
• Etiologies
• Infectious Salmonellosis, Potomac Horse Fever,
  Clostridiosis
• Nutritional Grain overload, blister beetle, Sand
  enteropathy
• Parasitic Cyathostomiasis
• Plant and chemical toxins
• Drug induced NSAIDS (phenylbutazone), antibiotics

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Inflammatory Collitis

• Pathophysiology inciting cause leads to mucosal
  damage results in inflammation which leads to
  further mucosal necrosis
• May progress to protein losing enteropathy
  (NSAIDs)
• Diarrhea in horse large colon disease
  
  
  
• CS
• Emergency d/t severe fluid losses and toxemia
• Looks like strangulating colic
• Fever, depression, shock, diarrhea

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Inflammatory Collitis

• CS
• Colic evaluation reflux- usually none rectal
  palpation- distended bowel but not usually tight
• Clin Path increased PCV and TP d/t dehydration
  hypoproteinemia depends on severity and inciting
  cause severe endotoxemia and stress pattern for
  WBC

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Inflammatory Collitis

• Dx
• Definitive dx only in 20-30 of cases
• CBC, chem profile
• Hct increased TP variable low normal
• WBC often low Total CO2 test for bicarb
• Renal fnct BUN, Creatinine d/t hypovolemia
• Fecal cultures/fecal flotation
• Serology
• Rectal mucosal biopsies
• Abdominocentesis, sand sedimentation

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Inflammatory Collitis

• Tx
• Supportive therapy
• Anti-inflammatories and analgesics
• NSAIDS- avoid if possible
• DMSO- use at 1/10th standard dose
• Analgesics not banamine, use alpha 2 agonists
  or butorphanol
• Antimicrobial
• Not indicated in uncomplicated cases
• For systemic issues in face of animal that is
  immunocompromised or showing signs of bacteremia
  etc
• Use Pen w gentamicin or potentiated sulfa (TMS
  may cause colitis)

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Inflammatory Collitis

• Tx
• GI protectants
• Impact of effect considered minimal in most cases
  
• Mineral oil, activated charcoal, bismuth
  subsalicylate
• Feeding
• May be anorexic initially
• Frequent small feedings, High quality
• Good management bedding, baths, tail wraps
• ICU care

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Salmonellosis

• Most frequently diagnosed infectious cause of
  diarrhea in horses
• Very contagious, potentially zoonotic
• Etiology
• No host adapted salmonella in the horse
• Epidemiology
• Fecal oral transmission
• Outbreaks more typical in warmer months
• Asymptomatic carriers under stress can shed
  organisms

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Salmonellosis

• Risk Factors
• Very STRESS related disease
• Risk factors concurrent GI disease, long
  transport, sudden feed cahnges, antimicrobial
  administration d/t disturbed GI microbial
  population etc
• Pathophysiology
• Produces endotoxin, cytotoxin (cell death in
  colonic mucosa), and enterotoxin

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Salmonellosis

• CS
• Malodorous profuse watery diarrhea
• Several syndromes
• Fever w leukopenia
• Colic w diarrhea
• Colic w/o diarrhea
• Proximal enteritis/jejunitis
• Septicemia (foals and neonates)
• Asymptomatic carriers

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Salmonellosis

• Dx
• Lab eval
• Leukopenia, neutropenia, met acidosis, decrease
  Na, Cl, HCO3
• Fecal eval
• Cultures minimum 3 usually 5 sequential culture
• Neg culture doesnt mean horse is negative it
  indicates that the horse isnt infective
• Can also culture reflux (if presents as DPJ) or
  abdominocentesis fluid
• Rectal mucosal biopsy/culture
• Tx same as general therapy for collitis
• Prevention/control strict isolation and
  disinfection

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Potomac Horse Fever (Equine Monocytic
Ehrlichiosis)

• Virtually indistinguishable from salmonellosis,
  can be infected with both
• Etiology neorickettsia risticii (aka E.
  risticii)
• Epidemiology
• No known horse to horse transmission
• Involves a trematode vector
• Pathophysiology
• Obligate intracellular parasite which infects
  trematode
• Trematode then infects snail

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Potomac Horse Fever (Equine Monocytic
Ehrlichiosis)

• CS
• Very high fever (104-106) 1-2 days prior to
  development of other signs
• High frequency of laminitis, often severe enough
  to warrant euthanasia
• Diarrhea cow like to watery feces, chronic
  diarrhea does not occur
• Dx
• Isolation/culture typically difficult
• Paired serum samples IFA or ELISA
• Tx
• Oxytetracycline
• Oxytet associated with development of
  salmonellosis in some horses
• Supportive therapy

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PHF VS SALMONELLA
PHF SALMONELLA
Very high fever for 2-3 days before onset of CS Fever but not typically very high
High incidence of laminitis Often early in the course At onset of fever or concurrent with onset of diarrhea Often severe and refractory Laminitis typically after onset of disease (after the first few days)
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Antibiotic associated colitis

• Antimicrobials can disrupt the normal flora and
  cause GIT disturbances
• Should never be used clindamycin, lincomycin and
  neomycin
• Associated with colitis tetracyclines, TMS,
  ceftiofur, erythromycin, pen, rifampin,
  metronidazole, enrofloxacin

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Clostridial Enterocolitis

• Etiology C perfringens, C difficile
• Epidemiology
• Risk factors foals or adults in training,
  altered GI flora (antibiotics) high protein or
  carb diets
• Clostridium is part of the normal flora, however
  those that inhabit GI are in low numbers and do
  not produce enterotoxins
• CS
• Necrotizing enterocolitis
• Severe toxemia and shock
• Hemorrhagic diarrhea in foals

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Clostridial Enterocolitis

• Dx
• Fecal gram stain
• Fecal culture
• Toxin ID (ELISA for C difficile toxin(
• PCR
• Necropsy smears of GI mucosa
• Tx
• Frequently unsuccessful
• Aggressive shock and symptomatic therapy
• Foals metronidazole if C difficile

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Cantharidin ToxicosisBlister Beetle Toxicosis

• Risk factors
• Ingestion of alfalfa hay (2nd cutting or later)
• Hay cut and crimped at the same time
• More frequent in hay harvested in midwest
• Most contaminated bales are at outer edge of the
  pasture
• CS
• Very severe unresponsive pain
• Polyuria, Pollakiuria, hematuria
• Severe hypocalcemua (may see SDF)
• SOME OF THE WORST COLICS YOU WILL EVER SEE

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Cantharidin ToxicosisBlister Beetle Toxicosis

• Pathophysiology
• Cantharidin (toxic principle) severely caustic
• Causes erosions and ulcerations in GIT
• Dx CS associated with risk in history
• Texas AM can id toxin (antemortem urine, post
  mortem GI contents)
• Tx
• Unresponsive to analgesics
• Supportive therapy
• Most will die