How is interstitial pneumonia diagnosed?

The vet will primarily use chest auscultation, chest X-ray, or CT imaging, combined with blood tests, respiratory sampling, or immunological tests to identify possible causes. Bronchoalveolar lavage or biopsy may be performed for definitive diagnosis when necessary.

What observations can you make at home to help the vet's assessment?

Recording videos of coughing and breathing, tracking resting respiratory rate, frequency of vomiting, and changes in appetite, as well as noting recovery time after activity, can all help speed up diagnosis and treatment decisions.

If the vet suspects infection, how long before improvement is seen?

If a bacterial infection responds to the chosen medication, clinical signs typically begin to improve within a few days. However, full resolution of the treatment course and imaging changes may take several weeks — follow your vet's instructions for revisits and monitoring.

When is a chest CT scan or biopsy needed?

A CT scan is arranged when X-ray findings are inconclusive or the condition is complex and requires more detailed imaging. If imaging and tests still cannot determine the cause, a biopsy under specialist evaluation may be considered. Ask your vet whether a referral is appropriate.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Interstitial Pneumonia in Dogs & Cats: Symptoms, Imaging & Supportive Care [2025]

Inflammation of the lung interstitium — identifying the underlying cause is key

Take 1 minute to check the symptoms first

Last updated: 2026/01/06

Pethealthmap Editorial Team

Sources: ACVIM, National Taiwan University Veterinary Teaching Hospital

When to See a Vet

Seek emergency care immediately

•Severe respiratory distress and unable to lie down on their own
•Lips or gums are noticeably blue or pale white
•Fainting or brief loss of consciousness with no response

Schedule a clinic visit soon (within 24–72 hours)

•Persistent cough for several days with a noticeable drop in energy
•Faster or labored breathing but still able to eat and move around
•Ongoing vomiting or diarrhea with reduced water intake

01What symptoms indicate something is wrong?

Interstitial pneumonia primarily presents with respiratory symptoms and may be accompanied by digestive or systemic changes. Early recognition of breathing changes and reduced exercise tolerance helps ensure timely veterinary assessment.

Persistent or recurring cough lasting more than a few days without improvement
Rapid or laboured breathing, wheezing, or abdominal breathing effort
Change in lip or gum colour (purple or pale/white)
Vomiting or diarrhoea accompanied by lethargy or signs of dehydration
Decreased appetite, lethargy, or changes in mental alertness

Seek emergency care immediately if you notice the following symptoms:

⚠️ Obvious respiratory distress or laboured breathing (open-mouth breathing or abdominal effort)
⚠️ Clearly purple or pale/white lips or gums (cyanosis)
⚠️ Fainting, brief loss of consciousness, or unresponsiveness

02How can you assess the situation at home? Key observations and criteria for emergency care

Observing and recording changes in breathing, digestion, and behaviour at home provides information that helps your vet quickly assess severity and prioritise examinations.

Record short videos of coughing and breathing on your phone (from the front and side)
Note the number of vomiting episodes, and the colour and smell of vomit
Measure and record resting respiratory rate daily
Observe recovery time and stamina after short-distance activity
Track appetite, water intake, and bowel and bladder habits

03How will the vet diagnose the condition? Common diagnostic tests

Upon arrival, the vet will combine physical examination findings, imaging, and laboratory tests to evaluate for interstitial pneumonia and identify possible underlying causes.

Physical examination

chest auscultation and assessment of breathing pattern and rate

Blood tests

evaluation of infection markers, inflammatory indicators, and organ function

Chest X-ray or CT scan to assess lung changes

Serology or immunological tests to help rule out specific infectious or immune-mediated causes

Respiratory sampling or bacterial culture to identify pathogens and guide treatment

Bronchoalveolar lavage or lung biopsy by a specialist if needed to confirm the diagnosis

04What treatment and care are needed after diagnosis? Medications, dietary adjustments, and care guidelines

Treatment is tailored to the underlying cause and severity of the condition. The primary goals are to control infection, reduce inflammation, and provide supportive care, alongside regular monitoring appointments.

Appropriate anti-infective treatment selected based on test results
Anti-inflammatory medications prescribed by the vet to reduce pulmonary inflammation
Oxygen therapy or hospitalisation for monitoring and respiratory support when needed
Ongoing monitoring of respiratory rate, body weight, and clinical signs
Regular follow-up visits for repeat imaging and blood tests to assess treatment response

05What should you prepare before the vet visit? Key information to help your vet quickly identify the cause

Record videos of coughing and resting breathing (from the front and side)

Note the onset time, the sequence of symptoms, and how they have changed

Keep a specific record of changes in appetite, water intake, and bowel/bladder habits

Test and record recovery time after short-distance activity

Bring a current medication list and any prior chest imaging or test reports

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.

Related Symptoms (You May Also Be Looking For)

Cough

Forceful air expulsion from airways

Cyanosis

Bluish discoloration

Diarrhea

Loose stool

Exercise Intolerance

Reduced exercise capacity

Oliguria

Reduced urine output

Open-Mouth Breathing

Mouth breathing