Week 6 - Abdominal Pain, Dysphagia/Regurgitation/Vomiting

What are some general clinical signs associated with abdominal pain?

- Decreased appetite

- Abnormal posture (Stretching, arched back)

- Kicking at the abdomen

- Repeatedly lying down and getting up

- Restlessness

- Lethargy

What are some SA specific clinical signs associated with abdominal pain?

- Tender/tense abdomen on palpation (does not improve with repeated palpation as a stress tension might)

- Reluctant to move/stilted gait

- Whine

- Excessive salivation/drooling (naseua)

- Play/prayer pose

What are some ruminant specific clinical signs associated with abdominal pain?

- Grinding teeth (bruxism)

- Grunt/grown

- Abdominal distention

What are some equine specific clinical signs associated with abdominal pain?

- "Colic"

- Pawing

- Sweating

- Quivering upper lip

- Looking at sides/flank watching

- Kicking at the abdomen

What are some GIT related mechanisms of abdominal pain?

- Distention/stretch of intestinal wall (with fluid, gas, ingesta, etc.)

- Mesenteric torsion

- Inflammation

- Ischemia

- Spasm

- Deep mucosal ulceration

What are some non-GIT related mechanisms of abdominal pain?

- Urogenital (urinary obstruction, pyelonephritis)

- Hepatic

- Peritonitis

- Reproductive

- Tumors

- Spleen

Why is it concerning if an animal was tremendously painful and then spontaneously improved?

- Tissues are painful when dying -> if they then acutely improve, may be a poor prognostic indicator that the tissue has died

What are categories of colic in horses?

- Non-obstructive

- Simple obstruction

- Strangulating obstruction

What are some examples of non-obstructive causes of colic in horses?

- Spasmodic/gas colic (Default diagnosis if no other reason for colic)

- Proximal enteritis

- IBD

- Colitis

- Sand (Can be obstructive)

- Peritonitis

- Gastric ulceration

What are some examples of simple obstructive causes of colic in horses?

- Stomach impaction (rare)

- Small intestinal impaction (ileum)

- Ascarid impaction (foals)

- Eosinophilic enteritis (mural bands)

- Large colon impaction (common)

- Large colon displacement (right/left dorsal)

- Enteroliths (alfalfa diet)

- Cecal impaction

- Small colon impaction

If a horse passes an enterolith that is not round in shape, what does this indicate?

- There are other enteroliths

What are some examples of strangulating obstructive causes of colic in horses?

- Strangulating lipoma in small intestine

- Small intestinal volvulus

- Mesenteric rent

- Epiploic foramen entrapment

- Gastrosplenic entrapment

- Intussusception

- Large colon torsion

- Strangulating lipoma of small colon

- Nephrosplenic entrapment

What are some acute diseases of the abdomen in small animals?

- GDV

- Intestinal obstruction (FB)

- Addison's disease

- Mesenteric torsion (rare)

- GI ulceration

- Abdominal adhesions

- Urogenital disease (ureteral obstruction, pyelonephritis, pyometra)

- Septic peritonitis (Ruptured pyometra, acute prostatitis)

- Pancreatitis

- Abdominal neoplasia (peritonitis or GI obstruction)

What are the steps to a diagnostic workup of abdominal pain?

- Thorough history

- Thorough PE

- Equine specific -> Perform rectal exam and NG intubation

- Assess severity (cardiovascular status, GI condition, recurrent signs of pain)

- Observe response to pain medications (while fasted)

- Perform more advanced diagnostics if necessitated

What are some specific history questions to ask in cases of abdominal pain?

- Duration of clinical signs?

- Previous episodes of GI disease/abdominal surgery?

- Recent changes in management/diet?

- Fecal production (last time observed, consistency, frequency)?

- Drinking and appetite?

- Presence of abdominal distention?

- Reproductive status?

- Medications given and response?

- Preventatives?

- Diet?

- Travel history?

What are some specific things to consider when performing a physical exam on a patient with abdominal pain?

- GI auscultation/percussion (LA)

- Equine digital pulses

- SA abdominal palpation

What are some treatment options for abdominal pain?

- Remove feed

- Control pain (PO vs. IV vs. IM vs. transdermal)

- Supportive care (fluid therapy for dehydration, correct electrolyte abnormalities and acid/base status)

- Identify and treat primary disease (surgery if needed)

What are some indications for surgery in a patient with abdominal pain?

- Diagnosis of a strangulating lesion

- Intestinal obstruction that doe snot response to medical therapy

- High level of pain/persistent pain, even when the diagnosis is still unclear (exploratory laparotomy)

When abdominal distention is noted, what should be evaluated?

- Shape

- Location

- Severity

What are some causes of abdominal distention?

- Pregnancy

- Obesity

- Accumulation of fluid (ventral)

- Accumulation of gas (dorsal)

- Accumulation of ingesta

- Organomegaly

- Mass (neoplasia)

Define constipation.

- Infrequent or difficult evacuation of hard, dry feces

What are some causes of constipation?

- Dietary (low in fiber, indigestible material (hair, bones, FBs))

- Dehydration (decreased water intake, increased fluid loss)

- Obstruction (mechanical or functional)

What are some examples of mechanical GIT obstructions?

- Intraluminal: Mass, FB, impaction, displaced intestine

- Extraluminal: Mass, pelvic fracture, perineal hernia

What are some examples of functional GIT obstructions?

- Ileus

- Vagal indigestion (cattle)

- Idiopathic megacolon or dysautonomia

What are some general treatment strategies for constipation?

- Fluid therapy (address dehydration and electrolyte/acid/base derangements either PO or IV)

- Laxatives/cathartics

- Address primary problem (Surgery?)

Define tenesmus.

- Ineffective and repeat straining at defecation (or urination)

What does tenesmus result from?

- Result of disease of large intestine or lower urinary tract

Define dyschezia.

- Difficult and/or painful evacuation of feces

What does dyschezia result from?

- Result of disease of anus and perianal tissue

What are causes of tenesmus?

- Inflammatory condition of lower GIT (IBD vs. Dietary indiscretion vs. Intestinal parasitism vs. colitis)

- Hepatic failure (ruminants and horses)

- Rectal disease (tears, strictures, perirectal mass)

- Reproductive (vaginitis, retained placenta, dystocia)

- Urinary (urolithiasis)

Chronic/sustained tenesmus or dyschezia can result in what?

- Rectal prolapse

Define dysphagia. This results from diseases which can be localized where?

- Difficulty or painful swallowing

- Oral or pharyngeal disease

Define regurgitation. This results from diseases which can be localized where?

- Passive retrograde expulsion of food or fluid from the oral/pharyngeal cavity or esophagus; Does not involve abdominal muscles (no retching)

- Esophageal disease

Define vomiting.

- Forceful ejection of food or fluid through the mouth, from the stomach or proximal duodenum (involves abdominal muscle contraction and "heaves")

What does normal swallowing require?

- Normal tongue and pharyngeal muscle motility

- Normal innervation of tongue, pharynx, larynx, cricopharyngeal muscle and upper esophagus

- Need to be able to sense there is a bolus

How is normal swallowing initiated?

- By voluntary passage of bolus into retropharynx -> Once food in pharynx, an involuntary pharyngeal phase is triggered

What neurologic structures are required for normal swallowing?

- Cranial nerves (VII, IX, X, XII)

- Brain stem

- Swallowing center in the brain (medulla)

What are the three phases of normal swallowing?

1) Oropharyngeal

2) Esophageal

3) Gastroesophageal

What are the three phases of the oropharyngeal phase of swallowing? Indicate if each phase is voluntary or involuntary.

- Oral (Voluntary)

- Pharyngeal (Involuntary)

- Cricopharyngeal (Involuntary)

What is involved in the oral subphase of the oropharyngeal phase of swallowing?

- Uptake of food or liquid and formation of ingesta bolus

What is involved in the pharyngeal subphase of the oropharyngeal phase of swallowing?

- Contractions move the bolus from the tongue to the cricopharyngeal passage. The soft palate is pulled upwards, the vocal cords are approximated, the epiglottis closes, and the larynx is pulled cranially and ventrally to initiate opening of the upper esophageal sphincter.

What is involved in the cricopharyngeal subphase of the oropharyngeal phase of swallowing?

- Relaxation of cricopharyngeal sphincter with passage of the bolus into the esophagus -> Closure of the esophageal sphincter

What is involved in the esophageal phase of swallowing?

- Primary and secondary peristaltic waves move the bolus through the esophagus

Define dysphagia (again).

- Difficult or painful swallowing

What are some general causes of dysphagia?

- Pain during prehension or swallowing process

- Mechanical obstruction of the oral cavity or pharynx

- Neuromuscular dysfunction

What important zoonotic disease must always be considered in patients with dysphagia?

- Rabies

Pharyngeal and cricopharyngeal dysphagia more common accompany __________________ disorders while oral dysphagia is generally more related to the __________________.

- Esophageal motility disorders (esophagus)

- Oral cavity

What are some clinical signs specific to oral dysphagia?

- Can have decreased or absent appetite (Anorexia and salivation may be the only signs in some)

- "Strange" behavior (Turkey poking or gobbling - picking up food and then throwing it back into mouth)

- Dropping of food while eating

- Tilting head back

- Chewing on one side

What are some common causes of oral dysphagia?

- Congenital defects (i.e., palate defects

- Dental, periodontal disease (most common)

- Trauma (Mandibular fractures, TMJ dysfunction)

- Inflammatory disease (lymphoplasmacytic stomatitis)

- Foreign body (sticks, bones, toys)

- Neoplasia

- Disease (Botulism, Masticatory myositis, Rabies, Tick paralysis, etc.)

Describe pharyngeal dysphagia.

- Trouble with the tongue bringing bolus back to pharynx so swallowing starts but is not completed (occurs after initiating of swallowing)

Describe cricopharyngeal dysphagia.

- No relaxation of cricopharyngeus muscle (problem with muscle that forms much of the upper esophageal sphincter)

How are pharyngeal and cricopharyngeal dysphagia diagnosed?

- Fluoroscopy

What are some causes of pharyngeal and cricopharyngeal dysphagia?

- Congenital (cricopharyngeal achalasia)

- FBs

- Neoplasia

- Rabies

- Neurologic disease (more common cause)

What are some examples of neurologic diseases which would lead to pharyngeal or cricopharyngeal dysphagia?

- Diseases of CN

What is cranial nerve VII? What are its functions (briefly)?

- Facial nerve

- Cranial taste sensation to trigger chewing and muscles of facial expression

What is cranial nerve IX? What are its functions (briefly)?

- Glossopharyngeal nerve

- Caudal tongue sensation

What is cranial nerve X? What are its functions (briefly)?

- Vagus nerve

- Major motor function to larynx and pharynx; Important for pharyngeal synchrony

What is cranial nerve XII? What are its functions (briefly)?

- Hypoglossal nerve

- Predominant motor to the tongue

Most commonly, what is the chief complaint of the owner presenting an animal with dysphagia?

- Chief complaint is most often related to secondary effects (i.e., lack of weight gain, strange behavior)

What are some ways to narrow down the list of differential diagnoses for a patient with dysphagia?

- Age (younger animals may be more likely to have congenital defects or FBs, older animals may be more likely to display chronic signs and develop systemic disease)

- Duration of signs (acute signs may be more likely related to a FB, mass, or acute inflammation)

- Presence of other signs (i.e., those suggestive of neurologic disesae)

Describe how an animal with oral dysphagia eats.

- The animal will have difficult before swallowing

- The animal may tilt or throw back head while eating food, may drop food

Describe how an animal with pharyngeal dysphagia eats.

- The animal chews normally (initiated normally) but can't complete the swallowing

- Repeated attempts to swallow, often with flexing/extending of the neck (turkey neck poking)

Describe how an animal with cricopharyngeal dysphagia eats.

- The animal starts to swallow but then coughs or gags

- The bolus enters the cricopharyngeus but it does not relax -> The bolus hits the larynx and initiates a cough

What are some options for a diagnostic workup of dysphagia?

- Complete physical exam (+/- sedated oral exam)

- Neurologic exam (cranial nerves, gait, peripheral nerves)

- Labwork (CBC, serum chemistry, urinarlysis)

- Contrast fluoroscopy with motion study

- Endoscopy

How is dysphagia treated?

- Identify and eliminate the underlying disorder (medical vs. surgical management)

- Feeding tubes may be necessary at times (often used too late -> consider using pre-emptively, especially in cats)

- Treat secondary complications (i.e., aspiration pneumonia)

Define regurgitation.

- Passive expulsion of gastric or esophageal contents

How does timing help anatomically localize the cause of regurgitation?

- Immediately after eating -> Proximal

- Up to several hours after eating -> Distal

What are some clinical signs associated with regurgitation/esophageal disease?

- Regurgitation is the most common clinical sign of esophageal disease

- Appetite is often increased

- Weight loss or poor growth

What does regurgitation result from?

- Results from local mechanical events within the esophagus (compared to vomiting, which is centrally mediated)

Describe the vomitus/bolus which results from regurgitation.

- Undigested feed

- Tubular shape

- Frothy saliva

- Animal may attempt to re-consume the food/vomitus

What are some causes of regurgitation?

- Megaesophagus

- Esophagitis

- Mechanical obstructions (structures, FBs, vascular ring anomalies)

- Endocrine disorders (hypothryoidism vs. hypoadrenocorticism)

- Neuropathies (polyradiculoneuritis, lead poisoning, CDV, brainstem lesion)

- Immune mediated disorders (systemic lupus erythematous and myositis)

- PRAA (may be subclavian artery)

Describe the pathophysiology of PRAAs.

- Common cause of regurgitation in young animals ("poor doer")

- Forms fibrous band encircling the esophagus leading to dilation of esophagus before regurgitation

How is PRAA treated? What is the prognosis?

- Surgery to remove fibrous band

- May have long term esophageal problems

What are some complications of regurgitation diseases?

- Poor growth

- Weight loss

- Appetite increased

- Increased risk of aspiration pneumonia

Why are animals with regurgitation at a greater risk for aspiration pneumonia than those with vomiting?

- Upper airway protective reflexes are not stimulated as effectively as with vomiting because the swallowing center has no role after food is in the esophagus

- With vomiting, the reflex closes vocal folds of the larynx

Vomiting is a "hallmark" sign of ______________ disease.

- Gastric

What does vomiting tell you about a patient?

- That there may be a problem in the stomach or proximal small intestine, but doesn't tell you way

- Can also lead you astray, as other causes include balance issues in the inner ear or other diseases outside the GI tract

What are some causes of vomiting?

- Gastritis

- Pancreatitis

- Hepatitits

- Enteritis

- Nephritis

- Acute renal failure

- Chronic renal failure

True or false: Vomiting is a disease.

- False; It is a clinical sign, not a disease

Where is the vomiting center located? What is it stimulate by?

- Located in the medulla oblongata

- Stimulated by discharge of the chemoreceptor trigger zone (CRTZ)

Describe the role of the chemoreceptor trigger zone (CRTZ) and where it is located.

- Located on floor of fourth ventricle where the BBB is less effective in this area

- Integrates inputs from vestibular center, abdominal organs, and sensors in CTZ itself

What can stimulate the vomiting reflex?

- Direct stimulation by certain blood borne drugs and toxins (i.e., apomorphine, uremic toxins)

- Indirectly through afferent nerves or the CRTZ

- Abdominal viscera stimulation in which the impulse travels along the afferent nerve fibers located in the vagus nerve and sympathetic nerves

- Receptor activation due to inflammation, irritation, distention, or hypertonicity

What are the 3 phases of vomiting?

- Nausea

- Retching

- Vomiting

What are signs of nausea? How long before vomiting does it occur?

- Animal may appear uneasy -> Licking of lips, repeated swallowing, pacing, hiding, whining, yawning, shivering, depression

- Can occur minutes to hours before vomiting

What is the role of saliva in vomiting?

- Saliva neutralizes gastric acid for when vomitus passes through esophagus

What mechanical changes are involved in retching (phase 2 of vomiting)?

- Contraction of abdominal muscles and diaphragm

- Negative pressure in the thorax

- Movement of ingesta from the proximal small intestine and stomach into the esophagus

What mechanical changes are involved in vomiting (phase 3 of vomiting)?

- Forceful ejection of gastric contents

- Positive pressure in thorax

- Apposition of vocal folds and epiglottis to protect airway

Generally, vomiting of a duration less than ____________ is considered acute.

- 7 days

Which is generally more severe, acute or chronic vomiting?

- Acute vomiting

What are some specific causes of acute vomiting?

- Dietary indiscretion

- Gastritis

- Obstruction

- Viral diseases

- Note: Dietary indiscretion and gastritis is usually self-limiting and mild

Acute vomiting is more common in younger or older animals?

- Younger

What frequency/duration generally defines chronic vomiting?

- More than once a day for more than 5 days or twice a week for more than 2 weeks (no hard and fast rule though)

Chronic vomiting is more common in younger or older animals?

- More common in middle-age to older animals because response takes time to develop

What are some complications of vomiting?

- Fluid loss or dehydration

- Electrolyte imbalances (hypokalemia, hypochloremia, hyponatremia)

- Acid/base changes

Does vomiting tend to affect blood glucose levels? Are they exceptions to this rule?

- NO; Unlike in humans, dogs and cats do not become significantly hypoglycemic for days or weeks during fasting dur to endogenous glucose production

- Exceptions to this rule are puppies, toy breeds, and emaciated animals

In regards to dysphagia and regurgitation, answer the following questions.

A. Is it a swallowing disorder?

B. When does it occur?

C. Does the animal drop food?

D. Are there repeated attempts to swallow?

E. Is there coughing or gagging?

F. Is there ptyalism?

A. Both are swallowing disorders

B. Both occur around time of eating

C. Dysphagia may involve dropping food in the oral phase, regurgitation will not

D. Dysphagia may involve repeated attempts to swallow in the pharyngeal phase, regurgitation will not

E. Dysphagia may involve coughing in the cricopharyngeal phase, but regurgitation will not UNLESS cough is secondary to aspiration pneumonia.

F. Ptyalism is occasionally present with dysphagia and absent with regurgitation

In regards to vomiting and regurgitation, answer the following questions.

A. Premonitor nausea?

B. Retching?

C. Ptyalism?

D. White foam?

E. Tubular "casts"?

F. pH?

G. Re-consumption of food?

A. Absent with regurgitation, present with vomiting

B. Absent with regurgitation, present with vomiting

C. Absent with regurgitation, occasionally present with vomiting

D. Common with regurgitation, rare with vomiting

E. Common with regurgitation, rare with vomiting (except in cats)

F. Neutral pH with regurgitation, acid/neutral/alkaline with vomiting

G. Occasionally with regurgitation, rarely with vomiting

Charlie is a doodle of unknown age who was just adopted. Charlie can't seem to keep anything down and is exhibiting strange behavior when he eats. He has a thing BCS, no other obvious abnormalities. You offer food in hospital and he chews normally but must attempt multiple times to swallow. What is your top differential diagnosis?

A. Oral dysphagia

B. Pharyngeal dysphagia

C. Regurgitation

D. Vomiting

B. Pharyngeal dysphagia

Smitty is a 4 YO MC Golden Retriever. He keeps bringing food back up. When asked about the vomitus, the owner recalls it often contains white foam and has a tubular appearance. There are no obvious abnormalities on the physical exam. What is your top differential diagnosis?

A. Oral dysphagia

B. Pharyngeal dysphagia

C. Regurgitation

D. Vomiting

C. Regurgitation