11th January 2024

Presentation

Initial symptoms of ILD are often very unspecific, which can present a significant diagnostic challenge. Up to 49% of patients with IPF, for example, are diagnosed more than a year after initial presentation, with up to 23% of these – more than 3 years after.

Breathlessness

The most common presenting complaint is progressive breathlessness, or dyspnoea, on exertion. Timing of progression is diagnostically important, although some ILDs can present both acutely and chronically (see Table 4). Particular care should be taken to differentiate ILDs with indolent presentation from other common causes of dyspnoea, such as chronic obstructive pulmonary disease (COPD) and heart failure.

It is important to check if the breathlessness is continuous or episodic. If episodic with asymptomatic periods in between, ascertain whether there is a clear pattern, e.g. symptoms are worse in the morning/on weekdays/in winter, which could point towards an environmental trigger. On the other hand, episodic breathlessness in the absence of a clear pattern could be suggestive of EGPA, COP or allergic bronchopulmonary aspergillosis (ABPA). Continuous symptoms are more suggestive of fibrotic ILDs such as IPF.

Table 4: diffuse lung disease and time of onset. Adjusted from Oxford Handbook of Respiratory Medicine, 4th ed. 

Other features 

• Another common feature of ILD is persistent, non-productive cough. It is particularly common in conditions affecting airways, such as sarcoidosis, bronchiolitis obliterans, COP, eosinophilic pneumonia and HP. Productive cough is unusual.
• Haemoptysis can occur in vasculitis-related ILD, pulmonary venous hypertension and diffuse alveolar haemorrhage. First episode in a patient with a known ILD may sometimes point towards a malignancy – a well-recognised complication of ILD.
• Chest pain is uncommon; note that acute onset chest pain might point towards an ILD complication such as pneumothorax or pulmonary embolism (PE).
• Extrapulmonary symptoms can occur in connective tissue disorders and vasculitides. In particular, enquire about headaches, changes in vision or photosensitivity, skin rashes, dry mouth and eyes, joint pains or swelling, muscle aches, fatigue, night sweats and fevers. Absence of these symptoms does not rule out a systemic disorder, which may manifest as respiratory symptoms alone at the start. If present, however, they might provide a useful clue. In addition, clear documentation of negative findings at the baseline will help in patient assessment at later stages.
• Lofgren syndrome – specific acute presentation of systemic sarcoidosis, characterised by a triad of fever, erythema nodosum (see below) and bilateral hilar lymphadenopathy on chest X-ray. This is more common in Caucasians. It is usually self-limiting and carries a good prognosis – 80% of cases will resolve spontaneously over 1-2 years.

Image Source: Wikimedia Commons (2010). ENlegs, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:ENlegs.JPG#/media/File:ENlegs.JPG. (Accessed: 3 January 2023).

References

1. Snyder LD, Mosher C, Holtze CH, et al. Time to diagnosis of idiopathic pulmonary fibrosis in the IPF-PRO Registry. BMJ Open Respiratory Research 2020; 7:e000567. doi: 10.1136/bmjresp-2020-000567
2. Oxford Handbook of Respiratory Medicine, 4th ed. Stephen Chapman. Oxford University Press, 2014. ISBN: 9780198837114
3. Talmadge E King, MD. Approach to the adult with interstitial lung disease: Clinical evaluation. UpToDate Inc. http://www.uptodate.com (accessed on 20th of December, 2022)