LA Sx Exam #2: Colic Flashcards
Colic vs. true colic vs. false colic
> Colic = broad category of ABDOMINAL PAIN
- True colic = pain originating from the GI tract
- False colic = diseases of other non-GI systems that manifest as apparent abdominal pain, Ex: pleuritis or pneumonia, granulosa cell tumor (rupture and bleed), urolith, pellet in urethral diverticulum, testicular torsion, tetanus, pre-pubic tendon rupture
Prevalence of colics and the need for surgical intervention
- Colics = 7% of practitioners calls
- 1% of colics = surgical
- Vast majority respond to initial medical tx or heal on their own
Questions to ask, as a practitioner, when presented with a colic case (4)
1) Does the horse require surgery for dx or tx?
2) Doesn’t need sx - what is the appropriate tx?
3) Does need sx - should it occur or should the animal be euthanized?
4) Does need sx - what should be done to prepare it for referral
Common cause of colic in 8 hour foal
Meconium impaction
Common cause of colic in a broodmare that foaled 4 weeks previously
Colonic displacement or volvuli
Common cause of colic in a 25 yo pony with mild/persistent signs of colic, with a serosanguineous abdominocentesis
Strangulating lipoma
Sedation recommended for colic cases
> Alpha-2 agonists = xylazine (shortest acting, less Ileus) or detomidine
+/- Butorphanol for additional analgesia
- NSAID’s
- Anti-spasmodics, Ex: buscopan
What sedative is not recommended for colic cases?
Acepromazine = provides minimal analgesia, will vasodilate and cause hypotension in already shocky/dehydrated animals
What emergency treatment might you need to use in a horse with colic (should really perform in any colic patient)? What can it tell you?
> Nasogastric tube (esp if there’s evidence of gastric reflux, Ex: ingesta coming out of nose, reverse esophageal peristalsis)
- Can’t eructate or regurgitate, prevents gastric rupture
- Reflux of 1-2 L is normal
- Gives you an idea of the nature and quantity of gastric contents
- Use a large tube = decreases chance of blockage
- Use the siphon effect
- DO NOT add large volumes of liquid to the already distended stomach
- Normal pH = 3.0 (more basic = indicative of SI reflex with bicarb)
- See reflux of medications already given? May indicate ileus
More rare = trocharize the flank
Questions to ask about in your history of a colic patient
1) Duration of clinical signs? How long?
2) Severity of colic signs? Stead, improving, worsening?
3) Passage and nature of feces? Small, hard, covered in mucus (impaction, prolonged time to excretion)? Diarrhea?
4) Feeding? Last meal? Off feed? Escaped and consumed highly fermentable apple or fresh grass?
5) Management changes? Exercise, stabling, transportation, fresh water availability
6) Age
7) Deworming history - ascarids, tapeworm, cyathostomiasis?
8) Vax history - rabies?
9) Previous strangles? Bastard strangles?
10) Regular dental care?
11) Recent injury or infection - hernia, edema, hemorrhage?
12) Breeding? - injury in mare during breeding, inguinal hernia in males
13) Recent colic or abdominal sx - aneurysms or adhesions, palpate ventral midline for scar
14) Pregnancy and uterine torsion
15) Color? Grey horses and melanomas
16) Medications - has anything been given (mask clinical signs?)
Main clinical sign we use to determine the need for surgery
PAIN and the response to treatment (medication)
- Related to rapidness of distension development, degree of intestinal compromise
- Ex: pelvic flexure obstrurction = mild, low grade discomfort as ventral colon distends
- Ex: large colon torsion w/ rapid distension and ischemia = severe and unrelenting pain
- Consider the age/breed and horse
- Ex: younger horses and smaller horses/ponies are far less stoic than older or draft breed hores
- Foals = difficult, progress from intense pain to becoming depressed and dull
Clinical signs of a mild colic
+ Yawning
+ Extended neck, stretch lip with Flehmen response
+ Teeth grinding
+ Anxiety
+ Looking at or biting at the flank w/ ears pinned back
+ Pawing at ground or abdomen
+ Groaning
+ Muscle tremors, esp in warm-blooded horses
+ Patchy sweating
+ Frequent posturing to urinate but only passing small amounts
+ Want to lean against a wall or lie on ground and frequently rise
+ Rolling
+ Resting in abnormal positions, Ex: dorsal recumbency, dog sitting (takes pressure off cranial abdomen)
+ Mild or intermittent signs of pain
+ Abnormal feces = diarrhea, foul smelling, hard, dry
Clinical signs of severe colic
\+ Continuous pain \+ Violent rolling, kicking at belly \+ Total disregard for handler or self \+ Self trauma - excoriations of legs (thrashing), supraorbital processes above the eye \+ Generalized and profuse sweating \+ Distended abdomen \+ Protrusion of perineum from straining \+ Profuse diarrhea \+ Dyspnea \+ Reverse peristalsis or nasal reflux
Reasons for pain in true colics (3)
1) Tension on hollow organs (distension)
2) Tension on the mesentery
3) Stretching of the parietal peritoneum
Should we allow horses to roll with colics?
- If they’re willing to just sit dorsal, may be ok (should probably get them up to walk)
- Risks = twisting GI tract, rupture internal organ, fracture spinous processes of withers
- DO NOT walk to the horse to the point of exhaustion
What may abatement of pain, accompanied by depression and deteriorating cardiovascular status suggest?
Non-viable intestine, no longer painful due to the destruction of its nerve supply
*Common causes = hypovolemia (sequestration of fluid in a 3rd space), endotoxic shock
What does the duration of the response to analgesia indicate?
- Low grade pain that is easily relieved with small doses of alpha-2 agonists = medical colic
- Short term or complete lack of response to analgesia = surgical lesion
Things to tell the owner/client to do before you get there
1) Remove all feed and water
2) Do not administer any home remedies (may mask clinical signs), with the possible exception phenylbutazone
3) Walk the horse WITHIN REASON (too much = exhaustion = poor anesthetic candidate)
4) DON’T GET HURT
Parameters that help you evaluate the cardiovascular status of the patient
- Heart rate and rhythm = HR will rise with more serious conditions
- Pulse quality
- Color of mucus membrane - icteric (off feed, liver), brick red (endotoxemic), pale (internal hemorrhage), blue/grey
- Capillary refill time
- Hydration status (>70% = poor prognosis) = skin tent, PCV or TP
- CBC = PCV, WBC counts (increased with infectious, increases late in spasmodics, impactions, compromised bowel)
*Thrashing around of the head may make the mucous membranes (conjunctiva) look hyperemic
Normal and abnormal heart rates for various colics, prognosis?
> > NORMAL = 36 bpm
- 40-60 bpm = likely a medical problem
- Nephro-splenic entrapment or colonic volvulus can be < 40 min (still serious)
- 60-80 bpm = consider laparotomy
- 80-100 bpm = almost certainly surgical
- > 100 bpm = very serious (indicative of endotemic shock)
Minimal blood work recommended to perform with colic patients (4)
- PCV (>70% = poor prognosis)
- TP (plasma total solids)
- Blood gas
- Electrolytes
True or false? Pain alone can increase heart rate and PCV?
True - splenic contraction = increased PCV (w/o dehydration)
True or false? Stronger the pulse = better prognosis
True - weaker pulses indicate a failing heart
Things to consider with abdominal auscultation and percussion
> 4 sections = dorsal, ventral, left, right
- Dorsal L = referred sounds from stomach and SI (often quiet in fasted horses)
- Ventral L & R = large colon, should have constant motility
- Borborygmi?
- Hypo or hypermotility?
- “Sand sounds” - like waves on a beach (absence is not exclusion)
- Tympany for distended sections of bowel
- Hypomotile = indicate ileus or obstruction
- Hypermotile = impending diarrhea, plus gas sounds
Things to consider with thoracic auscultation
- Abnormal sounds + fever - considered pleuritis or pneumonia?
- Recent trauma - diaphragmatic hernia?
What should you suspect if you’re getting large amounts of fluid (> 1-2 normal liters) out of the nasogastric tube?
- Obstruction of the small intestine
- Can be present with large colon distension (Ex: nephrosplenic displacement with pressure on descending duodenum)
How much fluid does the pancreas secrete with ileus?
4 L per hour - can produce gastric distension if not relieved (deflate every 2 hours)
Main diagnostic that helps us determine if the patient is surgical or not
Rectal palpation - assess bowel distension (tight taenial bands), thickness, position
- Only if it’s safe for you or the horse (small sized, fractious animals, animals in severe pain)
- Only permits you to examine 25-30% of the abdomen (relying on the fact that distension will push things caudally)
Pros and cons of using xylazine
+ Short acting
+ Less likely to cause ileus
- Not the most effective sedative = may want to use detomidine for more profound sedation
Things you should be palpating via rectum in colic patients
- Bladder = commonly full because horses don’t want to posture to urinate, check for wall thickening associated with cystitis or uroliths
- Vaginal ring in males = normal slits, ensure there’s no inguinal herniation of bowel
- Uterus = pregnant? rupture of middle uterine artery?
- Ovary - granulosa cell tumor
- Intestine character = thickness (mural edema?), more persistent indentation with impaction
- Spleen = caudal border for blunting with engorgement from entrapments, space between splenic base and kidney
- Peritoneum - gritty with adherent plant material following rupture or with peritonitis
- Scrotum in males for hernia or torsion
Medical or surgical? Distended small intestines that feels large/firm, or large colon pushing into the pelvic canal
Surgical - if unsure, re-rectal later
Other diagnostics, besides history, clinical signs, CBC, chem, or rectal palpation (3)
1) Abdominal U/S - amotile loops of bowel, increased wall thickness (> 3 mm), fluid pockets for centesis
- Ileum is thicker than normal duodenum/jejunum
- Abnormal viscera = distends, becomes heavy, and falls ventrally
- SI intussception = “bulls-eye” appearance
2) Abdominocentesis - for patients not responding to medical treatment (not recommended for every colic, often inconclusive)
- Use teat cannula or 18-g needle
* Reflects changes within the peritoneum
- TP increases within 1 hour
- RBC’s appear in 3-4 hours
- WBC’s appear in 6 hours
* False negatives can occur (no fluid)
* Tap at least 3 sites
- Not getting fluid? = rock horse, hold off nostrils (take a large breath)
- Use in conjunction with U/S
3) Abdominal radiograph = maybe in small horses or foals (see enterolithiasis, sand impactions, diaphragmatic hernias)
- Requires a powerful mounted unit with grid
Risks of abdominocentesis (3)
1) Enterocentesis = hitting a loop of bowel, common with distended ischemic bowel (less common with teat cannulas), see green plant material (not necessarily ruptured bowel)
2) Leakage from bowel
3) Amniocentesis of the mare is pregnant
Interpretation of normal and abnormal abdominocentesis fluids
- Normal = straw colored clear
- Normal cell count (WBC’s) = < 5 x 10^9 per L in an adult (less in foal)
- Normal total protein < 25 g/L
- Normal postpartum mares = WBC counts in normal ranges (may be higher in dystocias, fetotomies, assisted vaginal deliveries with NORMAL TP)
- Cloudy = WBC’s, not increases in TP
- Clot due to fibrinogen
- Small amount of RBC’s = secondary to centesis
- Large amount of RBC’s = intraperitoneal hemorrhage, splenic puncture, hitting a skin vessel
- Splenic rupture = higher PBC than venous blood with no phagocytosis
- Brown/bloody fluid, degenerative neutrophils = late stage necrosis
- High WBC’s and ingesta = ruptured viscous
- Enterocentesis > 450 x 10^9
Signs of ruptured bowel? Do you euthanize?
+ Degenerate neutrophils and bacterial presence from release of intestinal contents
+/- Plant material (may be walled off by omentum)
*Plant material on tap - may have performed an enterocentesis - REPEAT more caudally
*Requires other signs for euthanasia (not just green digesta)
Do we trocharize large bowel?
RARELY in general practice, but may do so prior to surgery
Locate distended viscous with percussion (commonly cecum in right paralumbar fossa)
Risk = leakage on ingesta, laceration of bowel
Criteria used for deciding when to perform abdominal surgery (8)
- PROMPT ID AND REFERRAL ARE CRUCIAL
1) Intractable pain not relieved by analgesics
2) Tympanitis that is not relieved medically
3) Abnormal rectal palpation (SI distension, colonic displacement)
4) Abnormal bowel on U/S (dilated, amotile)
5) Persistent nasogastric reflux
6) Abnormal abdominal fluid
7) Worsening clinical picture, Ex: markedly elevated HR, elevated PCV or TP
8) Impactions that don’t respond medically
Things, as a practitioner, to do before referring a colic
- Fluids - ideally hypertonic with water/saline afterwards
- Broad spectrum antibitoics, Ex: gentamicin or penicillin
- NSAID’s
- Nasogastric tube with gastric distension
- Sedation (degree depends on travel duration)
- Contact owner, WARN OF POTENTIAL COST
- Contact referral center
- Contact the insurance company
Can you see gastric distension?
No, enclosed in ribs
All about the small intestine (duodenum, jejunum)
- Duodenum = RIGHT SIDE, pass caudally near the right lobe of liver, right dorsal colon, right kidney
- Duodenum = short mesoduodenum, mostly fixed
- Jejunum = coiled and suspected by a LONG mesentery (trap in umbilical, inguinal, or epiploic foramens)
What helps us ID the ileum?
Terminal ilieum = anti-mesenteric band
*Only ID along the mesenteric portion of the SI
Sequence of viscera in the GI tract
Esophagus > stomach > duodenum > jejunum > ileum (cecum) > right ventral colon > sternal flexure, left ventral colon > pelvic flexure > left dorsal colon > diaphragmatic flexure > LARGE right dorsal colon > small colon > rectum
Which portion of the cecum is attached?
Base of the cecum - connective tissue to peritoneum, etc.
Common cause and sites of impactions (4)
> Occurs where we see changes in direction or diameter
- RIGHT = Terminal ileum to base of cecum
- RIGHT = Cecum = NOT DUE TO change in direction/diameter
- LEFT = Pelvic flexure (sharp turn) = MOST COMMONLY
- Right dorsal colon = narrows into small colon
- Transverse small colon
Difference between torsion and volvulus
- Torsion = twist along the longitudinal axis
- Volvulus = occurs along the root/longitudinal axis of the mesentery
