What could be causing an old dog's breathing difficulties, inability to stand unsupported, and left-sided stagger?

Emergency Veterinary Assessment Required Immediately

This old dog is experiencing a life-threatening neurological emergency—most likely vestibular disease or stroke—combined with respiratory compromise that requires immediate veterinary evaluation and stabilization.

Primary Differential Diagnoses

Vestibular Disease (Most Likely)

• Head tilt and left-sided stagger strongly indicate peripheral or central vestibular dysfunction, which is relatively common in older dogs with a prevalence of 0.08% in primary care 1
• The inability to stand unsupported combined with lateralized ataxia is classic for vestibular disease, where 123 of 188 dogs (65%) presented with ataxia in one large study 1
• Idiopathic vestibular disease is the most common cause in older dogs (128 of 188 cases, 68%), with increasing age significantly associated with this diagnosis (OR = 0.866) 1
• Other causes include otitis media/interna (26% of cases), hypothyroidism, or neoplasia 1

Concurrent Respiratory Compromise

• Abnormal breathing ("breathing funny") in an old dog with neurological signs suggests either upper airway obstruction or lower respiratory tract disease 2
• In geriatric large-breed dogs, laryngeal paralysis is extremely common and presents as inspiratory stridor, exercise intolerance, and respiratory distress 3
• Laryngeal paralysis in older dogs is typically part of geriatric onset laryngeal paralysis polyneuropathy (GOLPP), a progressive generalized peripheral neuropathy 3
• The combination of vestibular signs and laryngeal paralysis could both reflect polyneuropathy affecting multiple cranial nerves 3, 1

Immediate Life-Threatening Concerns

Airway Obstruction Assessment

• If the dog has high-pitched inspiratory sounds (stridor), this represents acute upper airway obstruction requiring emergency intervention 4
• Signs of severe obstruction include inability to drink, SpO2 < 90%, or bradycardia—all require immediate veterinary intervention 5
• Apply high-flow oxygen to the face immediately and position the dog with chin lift/jaw thrust to help alleviate respiratory distress 5

Hypoxemia Risk

• Respiratory failure with PaO2 < 50 mmHg despite oxygen therapy or PaCO2 > 50 mmHg indicates need for mechanical ventilation 6
• Dogs with severe respiratory failure that don't respond to conventional oxygen therapy have a guarded prognosis unless the underlying cause is treatable 6

Critical Actions Required Now

Transport and Stabilization

1. Keep the dog calm and minimize stress—avoid sedation without veterinary expertise present as this can worsen airway obstruction 5
2. Transport immediately to emergency veterinary care in a position that allows easiest breathing (often sternal recumbency with head elevated) 7
3. Monitor for worsening respiratory distress during transport: increased respiratory effort, cyanosis (blue gums), or collapse 7

Expected Emergency Interventions

• Supplemental oxygen therapy is the first-line treatment for respiratory distress 7
• Laryngeal examination under light sedation to diagnose laryngeal paralysis (90% sensitivity based on clinical signs alone in appropriate breeds) 3
• MRI of the brain if vestibular disease etiology is unclear or if central vestibular disease is suspected 1
• Blood work including thyroid testing (hypothyroidism found in 7 of 188 vestibular cases) 1

Prognosis Considerations

Vestibular Disease Outcomes

• Incomplete recovery is common: 50 dogs had persistent head tilt, 41 had persistent facial paresis, and 26 experienced recurrence 1
• History of previous vestibular episodes increases likelihood of resolution (OR = 3.533), while cranial nerve enhancement on MRI decreases it (OR = 0.432) 1
• Median survival after idiopathic vestibular disease diagnosis is generally good with supportive care 1

Laryngeal Paralysis Outcomes

• Median survival times of 3-5 years after surgical correction for acquired idiopathic laryngeal paralysis 3
• Prognosis depends on etiology: traumatic cases have good prognosis, while polyneuropathy-induced cases have guarded prognosis 3
• Dogs with diseases requiring surgical treatment (like laryngeal paralysis) have significantly better outcomes than medically treated respiratory patients 2

Critical Pitfalls to Avoid

• Do not delay transport waiting for the dog to "improve"—both vestibular disease and laryngeal paralysis can rapidly deteriorate 7
• Acute onset dyspnea in older dogs is often associated with poor prognosis if not stabilized quickly, especially with non-traumatic causes 2
• Obesity can be an important exacerbating factor in dyspneic dogs and should be addressed long-term 2
• Never attempt blind finger sweeps if foreign body obstruction is suspected, as this can worsen obstruction 4

Bottom line: This represents a true veterinary emergency requiring immediate professional evaluation—the combination of neurological dysfunction and respiratory compromise in a geriatric dog has multiple serious potential causes, all requiring urgent diagnostic workup and treatment.