Adult bronchiolitis and parainfluenza type 2.

Case report A 22-year-old Australian man presented with a 7-day history of dry cough with subsequent severe progressive dyspnoea, bilateral pleuritic chest pain and expectoration of blood-stained sputum, with no response to co-trimoxazole. There was no previous history of chest disease although he had smoked 15 cigarettes daily for several years. On examination he was afebrile, confused, centrally cyanosed and tachypnoeic, with indrawn intercostal spaces on inspiration, widespread bilateral crepitations and sinus tachycardia 120/min with 15 mm systolic paradox. Chest X-ray showed hyperinflation with subcutaneous emphysema in the neck, but no evidence of consolidation. A blood count revealed marked neutrophilia 93% of 25-5 x 106/1. Sputum culture grew parainfluenza type 2 virus but no bacteria. A throat swab and blood cultures produce no growth. Complement fixation titres to Mycoplasma, influenza A and B, respiratory syncytial virus and Legionella pneumophila were insignificant. Serial blood gas analysis showed evidence of marked alveolar hypoventilation with hypoxia (Table 1). Despite treatment with continuous oxygen, physiotherapy and ampicillin, cloxacillin and gentamicin, his condition had deteriorated after 24 hr. A diagnosis of bronchiolitis was then made and additional treatment begun with i.v. aminophylline and hydrocortisone, and nebulized salbutamol inhalation. A rapid fall in Pa,co2 accompanied clinical improvement (Table 1), with progressive recovery over 2 weeks, after which his chest X-ray had returned to normal. Two months later he remained slightly breathless on exertion with FEV, 2-95 litres (predicted normal (p.n.) 4-25±0-5 litres) and FVC 4-7 litres (p.n. 5 05 ±0 58 litres). Following full symptomatic recovery at 3 months he showed evidence of irreversible small airways narrowing with FEV1 3-26 litres, FEV1/FVC 67% (p.n. 78± 7-2%) and maximum expiratory flows at 50% (MEF50) and at 25% (MEF25) vital capacity of 2-6 litres/sec (p.n. 5*1 ±I1 litres/sec) and 0-71 litre/ sec (p.n. 2-0±0-8 litres/sec) without significant change after salbutamol inhalation. DL,CO was 31175 ml/min/mmHg (p.n. 33-45 ml/min/mmHg) with KCO 4-15 ml/min/mmHg. Residual volume was 1-39 litres (p.n. 1 85 litres) with total lung capacity 6-78 litres (p.n. 7-2 litres).