There are some things they can't really prepare you for in medical school.

Case in point: when a middle-aged man turns up at the emergency department with tears of blood literally streaming from his eyes and running down his cheeks, like some lost victim of demonic possession in a cult horror movie.

Warning: Graphic image below.

It sounds made up, but this bizarre medical condition is quite real, although it's so incredibly rare that when it does show up in patients, it's inevitably documented for scientific posterity.

Such is the case of the middle-aged man, whose surreal, bloody experience has just been recorded in a new case note published in The New England Journal of Medicine.

The patient, a 52-year-old, presented to the emergency department at a hospital in Italy, weeping tears of blood and – quite understandably – wanting doctors to do something about it.

826 man cries tears blood haemolacria 1(Di Maria et al/NEJM)

The tears of blood had been begun pouring down his cheeks 2 hours earlier, beginning spontaneously and with no evident warning.

After the initial gush, the bloody tears then stopped, before the flood gates opened again just before he turned up at the emergency department.

If there was a positive to be found in this bloody predicament, it was that the tears didn't seem to cause the man any pain, although doctors weren't at first sure what the cause was – since he reported no trauma around his eyes or nose, exhibited normal vision and eye movement, and had never experienced something like this before.

However, further examination revealed he displayed slight conjunctival hyperaemia – an inflammatory excess of blood in the membrane that covers the eyeball – plus evidence of benign tumours called hemangiomas on the inside of both eyelids.

This was what was responsible for the man's rare episode of haemolacria, in which people cry tears composed of varying amounts of blood.

As the photo published in the case note rather graphically shows, the 52-year-old's tears look to have been very bloody, although that's not always the case with milder (read: pinker and more diluted) cases of haemolacria.

The condition can result from infection, inflammation, tumours around the eye, trauma to tissue around the eye, among other reasons.

Luckily for this patient, he was given timolol ophthalmic eye drops – commonly prescribed for treatment of ocular hypertension and glaucoma – to clear up his eyelid hemangiomas, and at a one-year examination reported no further instances of weeping blood.

While the strange condition doesn't turn up very often – and isn't necessarily indicative of serious health dangers – the bloody tide it lets loose can't be an easy thing to go through, especially when you realise it's pouring out of your eye sockets.

As a 15-year-old in Tennessee who had his own unsettling brush with haemolacria put it, "I looked up and saw myself, and I thought I was going to die".

The findings are reported in The New England Journal of Medicine.