When a 39-year-old man ended up at an urgent care center with abdominal pain, a physician assistant noticed his skin was very yellow and sent him to the ED, where doctors tried to discover what was causing the man's change in skin color, Lisa Sanders writes for the  New York Times Magazine.

Intense abdominal pain

The man ended up at  CityMD Urgent Care in Ronkonkoma, New York, because of his intense abdominal pain. The man said he had experienced the pain before. Once or twice a year he'd eat something that didn't agree with him and he would feel bloated with pressure — often so bad that he'd make himself throw up to relieve it. This pain typically lasted a day, sometimes two, and once it started, he couldn't eat anything.

But while he was at urgent care, a physician assistant noticed the man looked very yellow and sent him to Stony Brook University Hospital's ED. By the time he was called into the treatment area, the man was covered in sweat and could barely stand.

Doctors took his blood and gave him a CT scan and an ultrasound, discovering he had stones in his gallbladder. One of those stones was stuck in the narrow tube that carries bile from the gallbladder to the small intestine, which was likely the source of the pain.

While the stone would likely pass on its own, the doctors said they'd remove his gallbladder, and when the patient asked if the gallbladder stones were causing his yellow skin, the doctors said it was possible.

Why the yellow skin?

The next day, the patient was feeling better, meaning the gallstone likely got loose and moved on, Sanders writes.

A group of doctors came to visit the patient and one of them started talking about jaundice, a yellowing of the skin and eyes. The color comes from a buildup of bilirubin, a product of broken-down red blood cells.

There are some diseases that can increase bilirubin levels, and it's possible the stuck gallstone blocked the flow of bilirubin to the patient's gastrointestinal tract. However, that wouldn't necessarily cause jaundice like the patient had — it may cause the whites of his eyes to yellow, but this patient’s entire body was visibly yellow.

The patient asked the doctors if they thought he was hemolyzing, a term describing the destruction of red blood cells.

Peter Braverman, one of the doctors on the team, noted to his three trainees that the patient's blood-cell count showed he had anemia, which is rarely found in men. In addition, the blood cells he did have were very small, something that is typically only found in patients with severe iron deficiencies or some anomaly in the shape of their blood cells.

Over the next several days, the patient's skin turned back to normal, and his gallbladder was removed. He was visited by the hematology team who found that the shape of the patient's blood cells wasn't caused by a lack of iron, so they started looking for an inherited abnormality that could cause his red blood cells to be destroyed at a higher rate than normal.

Several weeks later, the patient saw the hematology team again and was told he had hereditary spherocytosis. This is a disease that causes red blood cells to look like tiny spheres rather than biconcave disks, making them much easier to damage as they flow through blood vessels and other pathways.

The patient said no one in his family had the disease, and the hematologist suggested he may be the first to have the mutation. Either way, Sanders writes, the patient was "glad to finally have an explanation for his episodes of abdominal pain. And really glad to know that now that he didn't have a gallbladder, he wouldn't have another." (Sanders, New York Times Magazine, 5/16)