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Collapse 193

• Activity, events preceding collapse (e.g., mass or foreign body, laryngeal paralysis, TREATMENT
possible triggers) tracheal collapse, asthma, pneumonia, Treatment Overview
VetBooks.ir PHYSICAL EXAM FINDINGS • Partial seizures: idiopathic epilepsy, brain Correct acute/life-threatening disturbances Diseases and Disorders
pulmonary edema, pleural effusion, lung-
lobe torsion
(severe biochemical or electrolyte abnormalities,
Findings depend on underlying cause. A normal
physical examination is common in animals
disease
abnormalities). Address underlying problem.
presented for historical episodes of collapse. • Spinal cord: trauma, hemorrhage, fibro- severe anemia, hypotension, body temperature
In contrast, animals presented to a veterinarian cartilaginous embolism, intervertebral disc
during collapse often have physical findings that extrusion, neoplasia, meningitis/myelitis, Acute General Treatment
help determine the best diagnostic approach. wobblers Emergency treatment as indicated based on
Findings that may directly assist diagnosis: • Brain/cranial nerves: hemorrhage, infarct, initial physical and laboratory findings: intra-
• Pallor, hypotension, ascites, abdominal mass neoplasia, encephalitis, hydrocephalus, geriat- venous fluids, oxygen supplementation, blood
(e.g., acute hemoabdomen) ric canine vestibular syndrome, intoxications transfusion (anemia), dextrose (hypoglycemia),
• Tachycardia, weak femoral pulses, muffled • Neuromuscular/musculoskeletal: myasthenia calcium (hypocalcemia), dexamethasone
heart sounds (e.g., cardiac tamponade) gravis, polyradiculoneuritis, tick paralysis, (hypoadrenal crisis), anticonvulsants (seizures),
• Tachycardia, bradycardia, irregular pulses botulism, polyarthritis, polyneuropathy, antibiotics (sepsis), diuretics (heart failure),
(e.g., arrhythmia causing syncope) polymyositis antiarrhythmic medications, pericardiocentesis
• Inspiratory or expiratory dyspnea, cough • EIC: suspect based on signalment, normal (cardiac tamponade)
(e.g., primary respiratory disorder) physical examination, and typical clinical
• Neurologic exam abnormalities localizing features of collapse. Differentiate from other Chronic Treatment
disease to the brain, spinal cord, peripheral episodic disorders such as hypoglycemia, Depends on underlying disease process
nerves, or neuromuscular junction hypoadrenocorticism, cardiac arrhythmia,
• Muscle weakness and muscle atrophy epilepsy. PROGNOSIS & OUTCOME
• Fever, muscle pain, joint pain, bone pain, • For greater detail, see Collapse in Section 3
neck pain (p. 1206). Variable, depending on underlying disease
process
Etiology and Pathophysiology Initial Database
Collapse is caused by any condition that dis- • CBC, serum biochemical profile, urinalysis PEARLS & CONSIDERATIONS
rupts the ability of the animal to remain upright • Neurologic exam (p. 1136), orthopedic exam
and walk. The pathophysiologic mechanism is (p. 1143) Comments
specific to each cause (see Differential Diagnosis, • Electrocardiogram (p. 1096), blood pressure • The most common causes of episodic collapse
below) (p. 1206). (p. 1065) with no other historical abnormalities and
• Thoracic radiographs a normal physical examination between
DIAGNOSIS episodes are idiopathic epilepsy, cardiac
Advanced or Confirmatory Testing arrhythmia, pulmonary hypertension, and
Diagnostic Overview As dictated by history, features of collapse, EIC (in Labrador retrievers).
Most animals presented while collapsed have a physical findings, and initial test results: • Hemoabdomen and hypovolemic shock
signalment and historical and physical findings • Echocardiogram (p. 1094); if unremarkable, secondary to mass rupture and cardiac
that will clearly guide the most direct diagnostic consider Holter monitor or event monitor tamponade are common causes of collapse
approach. Animals examined because of one (p. 1120) if episodic collapse that can be suspected based on physical
or more episodes of historical collapse with no • Abdominal ultrasound examination.
physical abnormalities should undergo routine • ACTH stimulation test if hypoadrenocorti- • Detection of hypoglycemia in pets with
screening bloodwork, thoracic radiographs, cism suspected insulinoma may be optimal within 15
and a complete neurologic examination; if no • Sequential blood glucose measurements minutes of eating a meal.
abnormalities are revealed, the patient may be • Pharyngeal, laryngeal, and tracheal endoscopy
hospitalized for observation or the owner can if signs of respiratory obstruction; arterial Technician Tips
be asked to videorecord episodes at home. blood gas if hypoxemia suspected • A good description of collapse episodes is
• Advanced imaging (MRI) if spinal cord or essential for identifying possible causes in
Differential Diagnosis brain disease suspected (p. 1132) animals that are normal between episodes.
• Metabolic/endocrine: anemia, shock, sepsis, • Anticholinesterase response test if myasthenia • Activity preceding collapse and mentation,
anaphylaxis, hypoglycemia, hypokalemia, gravis suspected (p. 668): neostigmine respiratory pattern, posture, muscle tone in
hypocalcemia, hypoadrenocorticism, hypo- (0.01 mg/kg) plus atropine (0.02 mg/kg) each limb during collapse, and behavior after
thyroidism, heat stroke • Electrodiagnostics and muscle/nerve biopsy collapse can be important diagnostic clues.
• Cardiovascular: arrhythmia, congestive if muscle or peripheral nerve disease
heart failure, cardiac tamponade, arterial suspected SUGGESTED READING
thromboembolism, pulmonary hypertension, • Arthrocentesis (p. 1059) if polyarthritis Cosford KM, et al Exercise intolerance in retrievers.
congenital right to left shunt suspected Vet Med 105:64-74, 2010.
• Respiratory: brachycephalic upper airway • DNA testing for EIC and for some congenital
obstruction, pharyngeal or laryngeal muscle diseases AUTHOR: Susan M. Taylor, DVM, DACVIM
EDITOR: Leah A. Cohn, DVM, PhD, DACVIM

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