Smoking more than 10 cannabis joints a day for three days left a computer science student in a perilous situation after he developed acute eosinophilic pneumonia, French doctors say.

The 20-year-old arrived at the southern Île-de-France hospital with acute chest pain, cough and dyspnoea, and no relevant medical history aside from a one pack-year smoking habit.

But he told doctors of a three-day cannabis bender — no alcohol, though — across several social events.

Chest CT revealed acute interstitial pneumopathy, “characterised by regular thickening of septal lines and diffuse ground-glass opacities without air trapping, associated with bilateral moderate pleural effusion”.