CONDITION
Pneumonia
Pneumonia involves inflammation and infection of the lungs, arising from bacterial, viral, or aspirated material, and presenting with respiratory distress and general illness.
Why this matters now
Pneumonia can develop at any age but may be more severe in very young, elderly, or immunocompromised animals. The condition often follows respiratory infections, anaesthesia, vomiting episodes, or underlying diseases that compromise normal lung defences.
Early pneumonia may present subtly with mild cough and reduced energy. Without treatment, infection spreads through lung tissue, filling airways with inflammatory fluid and debris. Breathing becomes progressively laboured as functional lung capacity decreases.
Signals & patterns
Early signals
Soft, moist cough
A productive-sounding cough that differs from dry kennel cough or hairball attempts.
Nasal discharge
Mucoid or discoloured discharge from the nose may accompany lung infection.
Reduced activity
Affected animals often become quieter and less interested in usual activities.
Mild fever
Elevated body temperature reflects the body's response to infection.
Decreased appetite
General malaise typically reduces interest in food.
Later signals
Laboured breathing
Increased respiratory effort with visible chest or abdominal movement.
Open-mouth breathing
Particularly concerning in cats, indicating significant respiratory compromise.
Bluish gums
Cyanosis reflects inadequate oxygen levels in severe cases.
Crackling lung sounds
Audible abnormalities when breathing, sometimes heard without a stethoscope.
Click to read about the biological mechanisms
How this is usually investigated
Diagnosis combines physical examination findings with imaging and sometimes sampling of airway secretions to identify the cause and guide treatment.
Chest radiographs
Blood tests
Pulse oximetry
Tracheal wash or bronchoalveolar lavage
Arterial blood gas
Options & trade-offs
Treatment focuses on addressing infection, supporting breathing, and managing underlying causes, with intensity depending on severity.
Antibiotic therapy
Targeted antimicrobial treatment based on likely or confirmed bacteria
Trade-offs: Essential for bacterial pneumonia; course length typically 3-6 weeks; may require culture-guided changes.
Oxygen supplementation
Provides enriched oxygen for animals struggling to breathe
Trade-offs: Life-supporting in severe cases; requires hospitalisation; enables recovery while lungs heal.
Nebulisation and coupage
Moisturising airways and chest physiotherapy to help clear secretions
Trade-offs: Supports airway clearance; can be continued at home; requires patient cooperation.
Fluid therapy
Intravenous fluids to maintain hydration and support circulation
Trade-offs: Important for animals not eating; must be balanced against fluid overload in lungs.
Treatment of underlying cause
Addressing conditions that predisposed to pneumonia
Trade-offs: Essential for preventing recurrence; may include managing regurgitation, laryngeal function, or immune disorders.
Common misconceptions
"Pneumonia only occurs in cold, wet weather"
While environmental factors can contribute, pneumonia develops from infections or aspiration regardless of season.
"A pet with pneumonia will always cough dramatically"
Some animals, particularly cats, may show subtle signs like reduced activity and mild breathing changes rather than obvious coughing.
"Antibiotics work immediately in pneumonia"
While improvement often begins within days, full recovery from pneumonia typically requires weeks of treatment and recovery time.
Owners noticing their pet developing a cough alongside lethargy or breathing changes may benefit from early evaluation. Understanding risk factors like recent vomiting episodes or underlying conditions can help in recognising when respiratory symptoms might reflect something more than a simple cold.
Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS