Common respiratory causes of respiratory failure in the patient with ILD presenting with breathlessness to the acute take with suggested investigations and management advice
| Diagnosis | Investigations | Management |
|---|---|---|
| Infection / opportunistic infection | Blood tests (WCC and CRP), CXR, sputum and blood culture. Consider blood PCR for CMV, nasal swabs for respiratory viruses, beta-D-glucan antigen test for fungal infection and sputum induction for PJP. Bronchoscopy may be needed later to obtain a wash if appropriate and safe to do. | Broad spectrum intravenous antibiotics. Consider co-trimoxazole to cover PJP where relevant. Discuss with microbiologist. |
| Heart failure +/− pleural effusions | BNP, CXR and echocardiography. CT of the thorax if done might show ground-glass changes, Kerley B lines or bilateral pleural effusions. | Diuretics +/− oxygen, if needed. |
| Acute pulmonary embolus | CTPA preferably with HRCT slices to accurately assess any ILD (do specify on request to radiology). Technique used to acquire CTPA can cause an ‘apparent worsening’ of any ground-glass change. Concurrent HRCT slices allow some adjustment for this phenomenon D-dimer can be used to assess likelihood of PE. It has a high negative predictive value. | Full dose anticoagulation if suspicion is high pending definitive CTPA result. |
| New lung cancer diagnosis +/− pleural effusion | CXR and CT of the thorax/abdomen with contrast. | Diagnostic or symptom management thoracocentesis: chest drain might be required. Onward referral to lung cancer team later. |
| Pneumothorax | CXR. Cystic interstitial lung diseases such as LAM and LCH may present with pneumothorax. Patients in whom emphysema coexists with lung fibrosis are also at higher risk of pneumothorax. | Management of a pneumothorax in a patient with ILD is the same as for other patients. |
| Drug-induced ILD | Carefully assess medication list and dates of starting new relevant drugs. www.pneumotox.com is a good website for information on drugs causing lung disease. Nitrofurantoin, methotrexate and amiodarone are some of the common causes of drug-induced ILD. Pneumonitis from newer cancer agents such as pembrolizumab is also increasingly being recognised. | Stop any possible causative drugs. Discuss with prescribing team when appropriate for further advice regarding ongoing need for alternative treatments. Consider IS if hypoxaemic Guidelines are available to steer management of immunotherapy drug-induced pneumonitis.3 |
| AE-IPF: a diagnosis of exclusion | WCC and CRP will often be raised making exclusion of infection more difficult. CTPA with HRCT slices to confirm/exclude PE and to more accurately assess the ILD. | See main text for full advice. AE-IPF: consider low-dose steroids. AE-non-IPF inflammatory ILD: consider high-dose dual immunosuppression. |
AE = acute exacerbation; BNP = brain natriuretic peptide; CMV = cytomegalovirus; CRP = C-reactive protein; CT = computed tomography; CTPA = computed tomography pulmonary angiography; CXR = chest X-ray; HRCT = high-resolution computed tomography; ILD = interstitial lung diseases; IPF = idiopathic pulmonary fibrosis; IS = immunosuppression; LAM = lymphangioleiomyomatosis; LCH = Langerhans cell histiocytosis; PJP = Pneumocystis jirovecii pneumonia; PE = pulmonary embolism; WCC = white cell count.