Page 2437 - Cote clinical veterinary advisor dogs and cats 4th

1206 Collapse Coma

Collapse
VetBooks.ir Differential Diagnosis Item Typical Key Feature(s)

Ruptured splenic mass Common cause of collapse in large-breed dogs. Hypotension, pallor, tachycardia—hemorrhagic shock; hemoabdomen,
cavitated splenic mass on ultrasound. Some: concurrent right atrial mass, cardiac tamponade.
Syncope Inadequate cerebral blood flow. Severe bradycardia or tachycardia, pulmonary hypertension, or heart failure. Mucous
membranes pale during collapse but normal when recovered. Collapse is brief (<60 sec). Normal once recovered. Murmur,
arrhythmia, or normal between episodes.
Metabolic causes of collapse Weakness due to anemia, sepsis, hypoglycemia, hypocalcemia, hypokalemia, cortisol deficiency. Weakness typically
persistent but may be exercise-induced initially. Treat cause once discovered; rapid response expected.
Respiratory distress Severe dyspnea, often with cyanosis during collapse. Increased effort during obstructive phase breathing. Inspiratory
dyspnea: pharyngeal/laryngeal disorder (with stridor); pleural space disorder (quiet). Inspiratory/expiratory dyspnea:
pulmonary, collapsing trachea, upper and lower airway. Expiratory dyspnea: small airway disease, asthma.
Pericardial effusion/cardiac tamponade Typically causes weak pulse, muffled heart sounds, tachycardia; abdominal distention also common (from cardiac
tamponade or concurrent abdominal mass rupture).
Partial seizures Can resemble episodes of collapse. Consciousness maintained, ataxia possible, falling/crawling possible. Occasionally
stereotypical movements. Postictal phase possible, including blindness/altered mentation. Paroxysmal, recurrent. Normal
between seizures if due to epilepsy.
Other nervous system disease Structural spinal cord or brain lesion causes localizing neurologic signs. Polyradiculoneuritis, botulism, and tick paralysis
cause profound generalized weakness and loss of reflexes. Myasthenia gravis and muscle diseases cause weakness with
normal proprioception and reflexes. Palpebral reflex may be fatigable in myasthenia gravis.
Bone/joint disease Bone or joint pain or fractures cause reluctance or inability to stand/walk. Pain in multiple joints is common with polyarthritis.
Exercise-induced collapse Inherited in Labrador retrievers, others. Collapse during strenuous exercise, especially in hot environment; primarily affects
hindlimbs, lasts 10-30 minutes; normal between episodes. Genetic test is available; only homozygous dogs collapse.

Reproduced from the third edition in unabridged form.
THIRD EDITION AUTHOR: Susan M. Taylor, DVM, DACVIM

Coma

Cause Salient Characteristic
Intracranial—Acute/Rapidly Progressive
Trauma* History and presence of other traumatic injuries is confirmatory. Most common cause of coma in dogs and cats.
Granuloma Often a diagnosis of exclusion. Rule out other causes. Often multifocal with a history of seizures, although focal forms exist. MRI,
+/− CT scan may be helpful.
Hemorrhage Suspected in patients with hypertension (check blood pressure), hypocoagulable states, and intracranial tumors (particularly
hemangiosarcoma). Coagulation testing (TEG, PT/PTT, BMBT) and MRI often required.
Status epilepticus History and physical examination are confirmatory.
Embolism/ischemic encephalopathy Suspected in patients with predisposing hypercoagulable states (IMHA, hyperadrenocorticism, glomerular disease, heart disease,
etc.). Hypercoagulable TEG tracings in patients with predisposing disease. MRI, +/− CT scan often required for confirmation.
Intracranial—Chronic/Slowly Progressive
Tumor* Often older dogs with a history of seizures, circling, and behavioral changes. MRI, +/− CT scan confirms the diagnosis.
Abscess Possible history of bite wounds, prior infections (parvovirus), or trauma. Rule out other causes. MRI, +/− CT scan required.
Developmental disorders Suspected in young patients with progressive onset and domed skull conformation. Ultrasound (through fontanelle) or MRI
(hydrocephalus, storage diseases) required.
Systemic Infectious
Rabies Vaccination status, geographic exposure risk, history and clinical signs
Feline infectious peritonitis Definitive diagnosis on histopathologic evaluation
Canine distemper History, gastrointestinal signs, often progressive and multifocal. Immunofluorescent antibody testing or anti-CDV antibody titers in
CSF. More common in developing countries.
Fungal CSF culture and cytology, MRI
Parasitic Fecal, CSF cytology, MRI

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