Turns out there's a fine line between 'screaming at the top of your lungs' and 'screaming until your lungs collapse'.

A 16-year-old girl in Texas recently landed in the emergency department with a puzzling shortness of breath but no chest pain or other apparent problems. The doctors quickly learned that the night before she'd been yelling at a One Direction concert, leading to a truly bizarre diagnosis.

The patient had no history of lung conditions, not even a cough or a sore throat. Despite the shortness of breath - which prompted her to go to the hospital after it didn't resolve overnight - doctors heard no weird sounds in her breathing and noted "no respiratory distress".

But a physical examination did reveal one unexpected symptom - the doctor could hear a crunchy crackling sound under her skin upon pressing fingers on the front of the girl's neck and chest.

This symptom is called "subcutaneus crepitus", and it's an indication that air has travelled into the tissue right underneath the skin. When you press on it, the air bubbles are popped, causing a crackling sound.

An X-ray confirmed that air had indeed travelled to a bunch of wrong places, and could be found in the narrow space behind the pharynx in the neck, and in the chest cavity.

On top of that, both of her lungs had also very slightly collapsed, which happens when air gets trapped between the chest walls and the lung itself.

As the doctors noted in their case report, these are three separate diagnoses, and when air gets spontaneously (that is, without obvious trauma) trapped in any one of those spaces, that's already deemed to be an uncommon event.

"The combination of all three diagnoses has yet to be described in medical literature," they write in the report.

But it gets even weirder. To find out how the air escaped from the lungs (presumably through a hole or a tear somewhere in the respiratory tract), the team performed a CT scan, only to reveal… nothing.

Because the patient had type 1 diabetes, the doctors hypothesised that there could be a tear in the respiratory tract caused by the deep and laboured breathing people with diabetes can experience if their blood sugar goes too high and sends them into a state called ketoacidosis, when the blood is too acidic.

But blood sugar tests revealed the girl had no acidosis, so the doctors were stumped.

As the lead doctor J. Mack Slaughter Jr. hypothesised in conversation with Live Science, it's possible that there's a very small hole somewhere in the respiratory tract that would only open when enough force was applied (like screaming over your favourite band) but closed up again afterwards. We'll probably never know.

Thankfully, despite how dramatic all this sounds, none of this turned out to be a life-threatening problem.

Mild lung collapses, such as the one this girl experienced, usually don't require much treatment other than observation at the hospital and giving the body extra oxygen to help the lungs recover. So that's what the doctors did, and the girl was soon fine to go home.

"After an uneventful period of observation with an unchanged repeat chest x-ray study, the patient was discharged the following day with no further visits for this problem," the team noted in the report.

What makes this case useful to medicine is the truly unusual way in how air ended up trapped in the girl's neck. According to the doctors, there's only one other case when this happened spontaneously, and that time it was during singing.

Meanwhile, spontaneous and mild lung collapses have been known to happen due to things like diving, weight lifting, and military flying, but after this case the team suggests that "forceful screaming during pop concerts should be added to that list."

The case study was published in The Journal of Emergency Medicine.