Choking

Question 1

Ptyalism/drooling and hypersalivation history

Answer 1

Focussed history – diet, dental
Legume contaminated with Rizoctonia leguminicola?
Oral PBTZ (phenylbutazone) given with Clembuterol?
- Yes? – Hypersalivation

Question 2

Morphological abnormalities - obstructive
Choking horse

Answer 2

• Retropharyngeal lymphadenopathy
• Malformation, injury, oedema (pharynx, larynx, oesophagus)
• Pharyngeal disorders – abscess, cicatrix, inflammation
• Laryngeal disorders – epiglottic cysts, RDPArch
• Palate disorders – DDSP, cleft palate
• Guttural pouch disorders – tympany, empyema
• Oesophageal problems (obstruction and diverticula)

Question 3

Morphological abnormalities - painful
Choking horse

Answer 3

• Teeth – root abscess, broken teeth, abnormal wear
• Mandible, Maxilla – fractures, trauma
• Stomatitis/glossitis
• Temporohyoid OA – pain, may also cause functional
• Temporo-mandibular osteopathy

Question 4

Choking horse other causes not morphological abnormality

Answer 4

Glossitis – foreign body more common – dessicated plant material, metal/wire
Ulcerative stomatitis – phenylbutazone toxicity, Blester beetle poisoning
Vesicular stomatitis – Viral (poxvirus and rhabdovirus serotype
Bacterial – Actinobacillus lignieresii

Question 5

Choking horse - functional abnormalities

Answer 5

• Infectious – rabies, viral encephalitis, verminous encephalitis and EPM, botulism and tetanus, meningitis
• CNS trauma – Cerebral damage/oedema, brainstem haemorrhage
• CNS masses – cholesteroloma
• Toxic – Lead poisoning, yellow star thistle, hepatoencephalopathy
• Other
  Polyneuritis equi
  Grass sickness – dysautonomia
  THOsteoartropathy
  Guttural pouch – mycosis, neoplasia, empyema
  Petrous temporal bone
  Fracture/osteomyelitis

Functional abnormalities – look for muscular aitiology
HYPP – hyperkalemic periodic paralysis – mild to severe muscle spasm and trembling
NMD – nutritional myodegeneration
PSSM – polysaccharide storage myopathy – glycogen build up in muscles
Masseter myositis
Hypocalcaemia tetany/eclampsia
Myotonia
Rectus capitis ventralis rupture
White snake root toxicity
Megaoesophagus

Question 6

Oesophageal obstruction - clinical presentation

Answer 6

• Regurgitation food, water, and saliva
• Ptyalism
• Dysphagia
• Coughing
• Repeated head extensions or retching
• Anxiety

Question 7

Oesophageal obstruction clinical signs

Answer 7

• Distention – left jugular furrow – right side in some horses
• Crepitus – oesophageal rupture

Clinical signs of complications
- Dehydration
- RR/abnormal pattern
- Fever
- Other

Question 8

Investigation - choking horse

Answer 8

Radiography - barium swallow
- rupture, aspiration pneumonia

Question 9

Medical management of choking horse

Answer 9

Spontaneous resolution

Remove all feed and water
IV fluids
NSAIDs/analgesia
Sedation
Oxytocin for proximal obstruction

Assisted resolution
Oesophageal lavage and drainage – sedation, maintain head below the thoracic inlet
Aggressive oesophageal lavage – cuffed nasotracheal and nasogastric – standing or GA
General anaesthesia – minimises aspiration, aids relaxation

Question 10

How to prevent re-obstruction after choking

Answer 10

-Repeat endoscopy to assess mucosal damage
- Fusiform dilation predisposes to reobstruction
- Small quantities soft feed 48 post relief
- Provide electrolytes and fresh water
- Anti-inflammatories
- Broad spectrum antibiotics?

Question 11

Surgical oesophagostomy for choking horse

Answer 11

Longitudinal oesophagostomy
- Standing with tube in place
- Approach dictated by location of lesion
- Laryngeal hemiplegia common complication
Incision 5cm distal to lesion
- Mucosal sutures
Indwelling tube – into stomach – purse string
Pelleted slurry
2nd intention healing

Question 12

Complications of choking horse

Answer 12

Aspiration pneumonia
Oesophageal ulcer - if circumferential stricture
Oesophageal stricture
Megaoesophagus
Diverticula
Oesophageal rupture