E2: Choke Flashcards
What side of the horse is the esophagus usually on?
Left
T/F: Similar to cats, the cranial two thirds of the esophageal wall is composed of skeltal muscle while the distal third is composed of smooth muscles. The muscles also get thicker as you move aborally.
True
What muscle forms the cranial esophageal sphincter?
Cricopharyngeus
What is the most common cause of primary esophageal obstruction?
Roughage (alfalfa)
What are the earliest signs of esophageal obstruction?
Anxiety
Ptyalorrhea
Dysphagia
Coughing
Gagging or retching
Nasal discharge (bilateral, frothy)
Neck extension
Pawing
Feeling what upon palpation of the jugular furrow suggests esophageal rupture?
Crepitus
Cellulitis
T/F: Gagging and retching can cause esophageal rupture.
True
What landmark do you use for measuring the NG tube length?
13th ICS
T/F: Mineral oil or DSS can be used to resolve an esophageal obstruction
FALSE, never use these (can result in asipration - pneumonia)
What modality is used to definitively evaulate an esophageal obstruction?
Endoscope
Why is acepromazine not the ideal drug choice for reducing esophageal tone and pain in male horses?
Penile prolapse
Which drug or combintion of drugs has the greatest effect on esophageal motlity? What other drugs can be used?
Best: Xylazine and Butorphanol
Oxytocin
Buscopan (antispasmotic)
What is the post-esophageal obstruction treatment prototcol?
Anti-microbials (Potassium penicillin (gr +) + Aminoglycoside (gr-) + Metronidazole (anaerobes))
NSAIDs
Nebulization
Sucralfate (binds to negatively chagred structures, like ulcers)
Omeprazole (gastroprotectant)
Withhold food 24-48 hrs then reassess
What acid-base abnormality often accompanies choke?
Metabolic alkalosis (prolonged salivary loff of Cl and Na)
T/F: Megasophagus following an esophageal obstruction is a progressive, chronic problem.
False, not always can resolve
T/F: Problems with dentition can predispose a horse to choke.
True
That’s why it’s important to check the teeth
What are the 2 types of secondary esophageal obstruction? Give an example of each.
Intramural: tumors (SCC), strictures, diverticula, cysts, vascular ring anomalies
Extramural: mediastinal or cervical mass or abcesses
What secondary clinical signs are seen with choke?
Dehydration
Tachypnea
Aspiration pneumonia
Impaired gas exchange
Bicarb loss and e-lyte imbalance
When placing in esophgeal tube, how should you position youself and in what orientation do you insert the NG tube?
Stand beside, not in front of horse
Push NG tube medially and ventrally (into ventral meatus) in the nasal passage
What must you consider when using drugs such as xylazine or metomidine to reduce esophageal tone and for analgesia?
These drugs cause renal vessel dilation and thus diuresis, whihc is a problem because choke horses tend to be dehydrated and this would execerbate this.
After you resolve a choke, what could you do to figure out whether the obstruction was caused by a stricture, dilation, or diverticulum?
Contrast rads with air or barium
Describe how you would physically disperse the material that is causing the obstriction when treating choke.
NG intubation
Carefully lavage esophagus
External manipulations/massage
Head must be lowered to the ground
What are the options if you cannot resolve the obstruction using an NG tube?
Tilted table under anesthesia
Surgery to massage obstruction without cutting esophagus
Wait a while, NPO + supportive therapy, and try again
Last resort: Esophagostomy
What should be performed immediately after the impaciton is relieved to determine whether any complications are expected? What else should you do before sending the horse home?
When should you re-evaluate your patient after discharging them?
Immediately: Endoscopic exam
Ultrasound exam (for lung damage due to aspiration)
Neuro exam (rule out dysphagia)
Maybe chest rads
Recheck in 2-4 weeks
