Differential Diagnosis: Collapse

Following are differential diagnoses for collapsed patients.

Reduced Oxygen Delivery & Shock

• Hypovolemic shock (vomiting, diarrhea, hemorrhage)

• Obstructive shock (gastric dilatation-volvulus, heartworm disease)

• Cardiogenic shock (dilated cardiomyopathy, pericardial effusion)

• Distributive shock (anaphylaxis, sepsis)

Cardiac Disease

• Arrhythmias 

  • Ventricular arrhythmias (boxer, Doberman pinscher)

  • Sick sinus syndrome (miniature schnauzer, West Highland white terrier, dachshund)

  • Second- and third-degree atrioventricular block (older large-breed dogs)

  • Atrial fibrillation (left atrial enlargement, lone atrial fibrillation in giant breeds)

  • Toxins (eg, chocolate, caffeine, methamphetamines)

• Congestive heart failure

• Pericardial effusion

Respiratory Disease & Hypoxemia

• Upper airway obstruction

  • Laryngeal paralysis/geriatric onset laryngeal paralysis polyneuropathy (older dogs, Labrador retriever)

  • Brachycephalic obstructive airway syndrome

  • Foreign body 

• Pulmonary parenchymal disease 

  • Pulmonary hypertension

  • Pneumonia

  • Neoplasia

• Pleural space disease

  • Pleural effusion 

  • Pyothorax 

  • Hemothorax

Endocrine & Metabolic Disease

• Hypoglycemia 

• Insulinoma 

• Hypoadrenocorticism 

• Diabetic ketoacidosis/hyperosmolar hyperglycemic syndrome 

• Hypothyroidism 

• Anemia

Neuromuscular Disorders

• Neuromuscular junction

  • Myasthenia gravis 

  • Botulism

  • Diabetes mellitus (cats more likely than dogs)

• Myopathy

  • Hypokalemic myopathy (Burmese cat)

  • Hypocalcemic myopathy (eg, primary or secondary hyperparathyroidism)

  • Exercise-induced collapse (Labrador retriever, Pembroke Welsh corgi, Boykin spaniel) 

  • Infectious (eg, neosporosis, toxoplasmosis)

• Upper motor neuron

  • Neoplasia

  • Inflammatory (eg, granulomatous meningoencephalitis)

  • Cerebellar disease

• Spinal disease  

  • Degenerative neuropathy

  • Intervertebral disk disease 

  • Fibrocartilaginous embolism 

  • Thromboembolism

  • Diskospondylitis 

  • Atlantoaxial subluxation

Loss of Consciousness

• Cerebral disorders

  • Seizures (primary vs secondary)

  • Inflammation

  • Trauma (eg, concussion)

  • Neoplasia

  • Narcolepsy

  • Encephalopathy (hepatic, uremic)

Orthopedic Disorders 

• Bilateral cruciate disease

• Bilateral elbow disease

• Polyarthropathy (eg, immune-mediated, inflammatory, infectious)

• Polytrauma

Miscellaneous Causes 

• Border collie collapse

• Episodic falling syndrome (Cavalier King Charles spaniel)

*At the time of writing, Dr. Nakamura was affiliated with Coast to Coast Cardiology.