Lung interstitial disease

Question 1

Interstitial pulmonary fibrosis (IPF) commonly affects…

Answer 1

WHWT and other terriers (SBTs), middle aged to older dogs

Question 2

IPF history

Answer 2

insidious onset, chronic breathlessness which is slowly progressive, coughing can be a feature (typically if they have concurrent airway disease), exercise intolerance, cyanosis?, can cause syncope

Question 3

IPF clinical exam

Answer 3

crackles throughout lung fields, prolonged expiratory phase with expiratory effort

Question 4

IPF diagnosis

Answer 4

Thoracic radiographs (generalised interstitial lung pattern, +/- right sided cardiomegaly, +/- pulmonary hypertension), CT (diffuse increased opacity without loss of appearance of blood vessels), bronchoscopy (BAL samples are either normal or show low cellularity, rules out other inflammatory conditions), lung biopsy (the only method for definitive diagnosis)

Question 5

Why do you get right sided cardiomegaly with IPF?

Answer 5

the right ventricle is trying to push through interstitial tissue that’s fibrous, so it has to have a higher pressure - so get right sided cardiomegaly secondary to pulmonary hypertension

Question 6

Treatment of IPF

Answer 6

symptomatic - avoid collars, harness only, avoid smoke inhalation.
inhaled therapy - bronchodilator, corticosteroids.
oral therapy - bronchodilators (esp if concurrent airway collapse), corticosteroids.
but often bronchodilators don’t do much.
immunosuppression - azathioprine and cyclosporin, effective if active inflammation present but often this is not the case.
management of pulmonary hypertension - phosphodiesterase inhibitors - sildenafil, tadalafil, pimonbendan

Question 7

Prognosis for IPF

Answer 7

guarded as is a progressive disease. reports in dogs suggest ~15.5m median survival times

Question 8

Interstitial pneumonias

Answer 8

severe subacute multifocal to coalescing interstitial pneumonia.
the disease affects the interstitium - to some extent the alveoli and airways are relatively spared.
not common

Question 9

Interstitial pneumonia diagnosis

Answer 9

PM

Question 10

Metastatic disease signs

Answer 10

may be an incidental finding or present with cough/tachypnoea

Question 11

Common metastatic tumours

Answer 11

osteosarcoma, haemangiosarcoma, thyroid carcinoma, melanoma or the mucocutaneous junction

Question 12

Metastatic lung tumour diagnosis

Answer 12

radiographs - both laterals (to allow both lungs to expand and so any soft tissue tumour should become obvious) and DV

Question 13

Metastasis therapy

Answer 13

solitary mets removal increasingly common, may start getting locally delivered chemo

Question 14

Prognosis/survival time with no tx for mets

Answer 14

median survival time 3m