COLIC #1 - VET MED 578

Flashcards covering the anatomy of the equine gastrointestinal tract, the definition and causes of colic, clinical signs, diagnostic approaches, indications for surgery, and common medical treatments for colic in horses, based on lecture notes from VET MED 578.

Colic

Visceral abdominal pain in horses, an extremely common clinical problem.

Equine Foregut

Includes the Mouth, Esophagus, Stomach, and Pylorus.

Equine Small Intestine

Composed of the Duodenum, Jejunum, and Ileum, approximately 70-75 feet in length.

Equine Large Intestine Sections

Includes the Cecum, Right ventral colon, Sternal flexure, Left ventral colon, Pelvic flexure, Left dorsal colon, Dorsal diaphragmatic flexure, Right dorsal colon, Right colic flexure, Transverse colon, Descending colon (small colon), and Rectum.

Equine Stomach Capacity

Holds 8-15 liters; horses cannot vomit.

Equine Large Intestine Function

Site of breakdown by microbial enzymes into volatile fatty acids and ammonia, with a large capacity for storage and absorption of fluids.

Causes of Colic Symptoms

Intestinal distention (fluid, gas, ingesta), pulling on the root of the mesentery, ischemia/infarction, inflammation of viscera, and endotoxemia.

Idiopathic Colic

A common cause of colic, often referred to as 'gas' or 'spasmodic' colic, meaning the specific cause is unknown.

Strangulating Obstruction

A severe type of colic where a section of the intestine is obstructed and its blood supply is cut off, leading to tissue death.

Clinical Signs of Colic

Rolling, looking at side ('flank watching'), Flehman response, stretched out posture, lying down, and thrashing.

Signalment in Colic Workup

Patient characteristics like age, sex, and breed that can provide clues to potential colic causes (e.g., stallions for inguinal hernias, older horses for enteroliths).

Colic Risk Factors (History)

Deworming history, vaccination status, diet, stabling, dental care, environmental/weather changes (sandy area, freezing conditions), recent changes (feed, environment, exercise), previous colic episodes, reproductive history, and musculoskeletal issues.

Toxic Line

Injected, brick red mucous membranes, indicating endotoxemia, a severe sign in horses with colic.

Normal Equine Heart Rate (Colic Indicator)

If persistently greater than 80 bpm during colic, it indicates a poorer prognosis and strongly suggests surgical consideration.

Normal Net Reflux (Nasogastric Intubation)

Less than 2 liters; reflux greater than 4-6 liters indicates significant obstruction or anterior enteritis.

Nephrosplenic Entrapment

A condition detectable by rectal palpation where the left dorsal colon becomes displaced and entrapped around the nephrosplenic ligament.

Abdominocentesis Indications

Used to diagnose peritonitis, strangulating lesions, ruptured GI, and to help decide if surgery is necessary for colic cases.

Normal Abdominal Fluid Values (Abdominocentesis)

Protein < 2.5 g/dl, nucleated cell count < 5,000/ul, and lactate < 2.0 mmol/dl.

Packed Cell Volume (PCV) in Colic

Assesses hydration, with increases potentially due to splenic contraction (pain/stress) or endotoxemia. Normal range is ~32-43%.

Lactate (Peripheral)

An indicator of perfusion and tissue oxygenation, normal values are < 2 mmol/L. Elevated levels can suggest severe colic.

Indications for Colic Surgery

Persistent and uncontrollable pain, positive rectal findings of a potential surgical lesion, large volumes of nasogastric reflux, deterioration of clinical/metabolic parameters, and failure to pass manure for a long period of time.

Xylazine

An alpha-2 agonist sedative commonly used for colic pain, providing sedation for about 15-20 minutes.

Flunixin Meglumine (Banamine)

A non-steroidal anti-inflammatory drug (NSAID) commonly used to manage colic pain in horses.

N-butylscopolammonium bromide (Buscopan)

A spasmolytic drug used to relieve smooth muscle spasms, often administered during colic examinations, particularly for rectal palpation.

Mineral Oil (Colic Treatment)

Used as a lubricant only for impactions; it does not break them up, but can act as a marker for intestinal transport.

Magnesium Sulfate (Colic Treatment)

A cathartic that draws water into the bowel lumen, increasing fecal water content and stimulating colonic motility, but can exacerbate dehydration.

Metoclopramide

A prokinetic drug (dopamine antagonist) that stimulates smooth muscle, increasing motility of the stomach and small intestine and enhancing gastric emptying, though it can cause excitation.

Lidocaine (Prokinetic Use)

A fast sodium channel blocker used as a prokinetic, analgesic, and anti-inflammatory in colic cases, but can cause neurologic side effects like excitation or seizures.