History and admission findings: A 51-year-old man without significant previous illness presented with treatment-resistant arterial hypertension, dyspnoea, increased fatigue and headaches. Except for a florid face and fine tremor the physical examination was unremarkable.
Investigations: The chest x-ray showed pulmonary congestion. Blood gas analysis indicated respiratory alkalosis and hypoxaemia (pO2 65.2 mm Hg, pCO2 33.9 mm Hg, pH 7.46) and polycythaemia (haemoglobin 18.1 g/dl, haematocrit 53.5%). There was no evidence of an underlying cardiopulmonary disease. Sleep apnoea screening with an 8-channel recorder was compatible with the central sleep apnoea syndrome (apnoea/hypopnoea index 38/h).
Treatment and course: In the absence of neurological findings and an underlying medical condition the patient was again questioned. This revealed that in the previous 3 months he had been living and working as a waiter at a height of 3029 m above sea-level, without prior acclimatization. The symptoms and abnormal findings cleared up after a 6-week stay at 800 m.
Conclusion: At a time when people often quickly move between different altitudes, high-altitude sickness should be included in the differential diagnosis of respiratory failure and the central sleep apnoea syndrome.