Resp - ILD Flashcards
What are the common causes of interstitial lung disease?
Upper lobe predominant
C - Coal-workers pneumoconiosis
H - Histiocytosis
A - Allergic bronchopulmonary
aspergillosis
A - Ankylosing spondylitis
R - Radiation pneumonitis
T - Tuberculosis
S - Silicosis
S - Sarcoidosis
Lower lobe predominant
C - Idiopathic pulmonary fibrosis
A - Asbestosis
R - Rheumatoid arthritis
D - Drugs (bleomycin, methotrexate,
amiodarone)
S - Scleroderma
How is idiopathic pulmonary fibrosis diagnosed?
Idiopathic pulmonary fibrosis (IPF) is essentially a diagnosis of exclusion, with a largely unknown aetiology. Early diagnosis is essential to try to prevent disease progression. It is the most common form of ILD, and is a devastating progressive condition with no definitive treatment. It is important to differentiate IPF from
other types of ILD because the mortality is significantly worse.
1 Clinical assessment
– Full history including environmental/occupational exposure, presence of
symptoms/signs of systemic disease, drug history
– Restrictive deficit on pulmonary function testing
2 Radiological investigation
– CXR: interstitial shadowing, usuallyworse in the lower lobes (may be normal
early in the disease)
– High-resolution CT: ground glass opacities, reticular shadowing with traction bronchiectasis, honeycomb lung
3 Tissue biopsy may be necessary in cases of diagnostic uncertainty
What treatment options are available for ILD?
The treatment of ILD can be divided into pharmacological and nonpharmacological therapies.
Pharmacological therapies
1 Immunosuppressive therapy (not useful in IPF)
– Corticosteroids
– Cyclophosphamide
– Azathioprine
– Mycophenylate
– Ciclosporin
– Methotrexate
– Biological agents, e.g. infliximab, etanercept, rituximab
2 Antifibrotic agents have been shown to slow the rate of loss of lung function
– Pirfenidone (inhibits transforming growth factor-β (TGF-β) stimulated collagen synthesis) – associated with nausea and photosensitivity
– Nintedanib (tyrosine kinase inhibitor) – associated with diarrhoea
3 Oxygen therapy
– Used to slow down rate of progression of associated pulmonary hypertension (which worsens prognosis), but confers no survival advantage
– The BTS recommends LTOT be considered in patients with ILD and:
i Resting PaO2 ≤7.3 kPa
ii Resting PaO2 ≤8 kPa in the presence of peripheral oedema, polycythaemia or evidence of pulmonary hypertension
– Ambulatory oxygen therapy is primarily indicated to improve outdoor mobility (i.e. those who desaturate on exercise)
– Short-burst oxygen therapy (SBOT) may be used, although there is no evidence supporting its use
Non-pharmacological therapies
1 Pulmonary rehabilitation
– Consists of six-week programme of exercise and education sessions
– Patients benefit most from pulmonary rehabilitation when it is commenced early following diagnosis, although it may be undertaken at other points throughout the course of the disease
– There is evidence that pulmonary rehabilitation improves breathlessness, exercise capacity and health-related quality of life
– Additionally, patients are encouraged to walk or exercise where able to prevent deconditioning (breathless patients may become stuck in a vicious cycle of progressive deterioration – they don’t want to exercise because they feel breathless)
2 Management of comorbidities
– Gastro-oesophageal reflux is heavily implicated in progression of IPF
– Pulmonary arterial hypertension
3 Management of acute exacerbations (see below)
4 Lung transplantation
– Transplant is the only therapy that has been proven to extend life expectancy in patients with ILD
– Mortality ~20% at one year and ~50% at 5 years (similar to mortality rates for patients requiring lung transplant for other indications)
How is an acute exacerbation of ILD managed?
The patient with an exacerbation of ILD should be managed with an ABCDE approach, treating abnormalities as they are found. A cause for the exacerbation should be sought, and close liaison with the respiratory team is essential.
1 Investigations
i Blood tests (FBC, CRP, cultures, ABG)
ii Radiology:
– CXR (may show new infiltrates)
– High-resolution CT (HRCT) if CXR is non-diagnostic (may show new
infiltrates, evidence of infection)
– CT pulmonary angiogram (CTPA) if PE is a possibility
iii Echocardiography (CCF is a frequent cause of acute exacerbations of ILD, and may reveal evidence of RVF due to pulmonary hypertension which can guide therapy and aid prognostication)
iv Bronchoscopy and BAL should be considered to confirm/rule out infection
2 Pharmacological management
i Pulsed methylprednisolone
– Often used in acute exacerbations of IPF
– Single study supporting their use – others have shown a high mortality despite their use
ii Immunosuppression – no strong evidence supporting the use of ciclosporin or cyclophosphamide in acute exacerbations of ILD
3 Non-pharmacological management
i Non-invasive ventilation
– In most cases, the excessive work of breathing associated with acute exacerbations of ILD cannot be managed effectively by NIV for prolonged periods
– Current data does not support use of NIV in these patients unless a rapidly reversible cause is found
ii Invasive ventilation
– Most of the current knowledge regarding practicalities of PPV in patients with ILD has been gleaned from experience of managing patients with ARDS
– However, the pattern of lung damage in ILD is less homogenous than in ARDS, increasing the risk of VILI – high PEEP, recruitment manoeuvres and prone ventilation should be avoided
– Some studies have suggested that these patients should not be intubated unless they are eligible for lung transplantation
iii ECMO can be used as a bridge to transplantation in ILD
iv Lung transplantation
– May be expedited if the patient is already on the transplant waiting list
– May be considered for super-urgent listing if there is an acute deterioration in a patient who has not yet been assessed for transplantation
What specific considerations should be taken into account
if these patients are referred to critical care?
Patients with idiopathic pulmonary fibrosis who deteriorate to the point where they need intensive care have an extremely poor prognosis: the mortality in this group is 60–90%. The cornerstones of management are good supportive care and treatment of the underlying cause. Close collaboration with the respiratory physicians is mandatory, with early discussion as to the appropriateness of escalation of therapy and cardiopulmonary resuscitation.
