Clinical: Case study - An unusual cause of breathlessness

After what seemed a routine consultation for a URTI, Dr David Morris found a more surprising cause for a cough.

The initial presentation had appeared undramatic. Brian, a 54-year-old train driver, reported a three-week history of shortness of breath, dry cough and nocturnal wheezing following a minor URTI. He had no associated chest pain or fever.

Examination revealed a mild expiratory wheeze but good air entry throughout his lung fields and a peak expiratory flow reading of 380 litres/min.

Brian had stopped smoking 20 years previously, having smoked 15 cigarettes a day for nearly 20 years. He had no formal diagnosis of COPD and was not taking any regular medication. He had a history of multiple bilateral pneumothoraces that had been treated with pleurodesis 25 years previously.

Brian did not keep pets, and his only recent foreign travel had been to Spain.

Asthmatic response
I felt that Brian had responded in an asthma-like fashion to the insult of a respiratory tract infection, not withstanding the possibility that he might have underlying COPD.

I prescribed doxycycline and prednisolone 30mg daily and asked Brian to make a follow-up appointment to assess response and to consider further investigation, notably spirometry.

In fact, Brian did not return and I thought no more about the episode until he returned to the surgery three months later.

Brian had experienced good symptom relief from the course of antibiotics and oral steroids but over the past month his shortness of breath and dry cough had returned.

More worryingly, he had developed systemic features, reporting fatigue, reduced appetite and weight loss of perhaps 10kg. On examination his temperature was 37.2 degsC, his pulse was 100 beats per minute and regular, his BP was 105/72mmHg, oxygen saturation 98 per cent, no heart murmurs and his chest appeared clear with reasonable air entry and normal expansion. There was no suggestion of calf tenderness or swelling.

Cause for concern
If I had felt the initial presentation to be routine, I was certainly more concerned now. While I had wondered about underlying asthma or COPD, the rapid loss of weight brought other diagnoses into play, including lung carcinoma, interstitial lung disease, TB or systemic illness leading to recurrent chest infection.

I also had nagging doubts about a pneumothorax recurrence even though Brian's initial problems were many years ago.

I arranged an urgent chest X-ray along with blood tests.

Surprising results
The chest X-ray report was surprising and revealing. A 2cm opacity within a cavity at the apex of his left lung was identified, consistent with an aspergilloma. There was an extensive area of shadowing in the right apex with a comment that reactivation of TB should be considered. Brian was referred urgently to a chest physician for further investigation.

Brian underwent fibre optic bronchoscopy and a CT scan of the chest. The latter revealed bilateral fungal balls consistent with aspergillomas at the lung apices. The occurrence of weight loss suggested systemic aspergillosis and a course of voriconazole, a relatively new triazole antifungal treatment, was commenced by the respiratory consultant.

Brian subsequently experienced a single episode of haemoptysis, and his dry cough has remained. He has felt better since completing a month of voriconazole with an improvement in appetite and some weight gain. He is currently maintained on itraconazole and is receiving nutritional supplements.

Discussion
Aspergillus (fumigatus being the most common species) is a ubiquitous fungus found in decaying vegetation and hence reaches highest atmospheric concentrations in late autumn. It thrives in moist, humid environments. Spores are inhaled and colonisation within the lung is always a possibility in patients with chronic lung disease, although this does not necessarily result in symptomatology.

The manifestations of aspergillus lung disease are varied and include an IgE-mediated allergic asthma, which can lead to allergic bronchopulmonary aspergillosis with associated bronchiectasis. An alternative allergic response can cause extrinsic allergic alveolitis that is not IgE mediated or characterised by eosinophils but rather a type III or type IV hypersensitivity reaction. Invasive aspergillosis leads to systemic illness with presentations such as pneumonia, meningitis or abscesses, but this is most likely to arise in the immunocompromised patient.

Colonisation
Aspergillus is an opportunistic organism that can gain a foothold in damaged, scarred lung tissue. Fungal spores can germinate and produce hyphae in cavities arising from previous lung disease to form an aspergilloma. This situation can arise following a previous episode of pneumonia, lung abscess, TB, sarcoidosis or malignancy.

In Brian's case the risk factor for aspergillus colonisation was the history of pneumothoraces and subsequent pleurodesis. The aspergilloma generates a powerful inflammatory response and becomes surrounded by blood vessels derived from the bronchial arteries.

Aspergillomas may be asymptomatic but can present with shortness of breath, cough and not infrequently haemoptysis. Malaise and fever suggest systemic involvement. Investigations that lead to the diagnosis are chest X-ray, CT imaging of the chest, sputum culture and antibodies to aspergillus.

Management
Treatment is unlikely to produce a cure, although itraconazole may control disease and reduce the risk of haemoptysis. Should the latter arise then attempts to reduce the blood supply to the cavity wall of the aspergilloma may be necessary. Options include arterial embolisation or surgical resection. In invasive disease IV antifungal treatment may be necessary.

Dr Morris, a GP in Shrewsbury, Shropshire

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