Patients with Rare Blood Disease Benefit from Increased Awareness
Research and Innovations Paraxysmal Nocturnal Hemoglobinuria (PNH) used be considered a deadly disease, but now with effective treatment, patients with PNH can expect to live a long healthy life.
Imagine being presented with a set of symptoms that seem completely unrelated. Then add to the mix a condition that’s so rare, it affects just one person out of every million. That’s what doctors like Dr. Richard Wells, a Hematologist and Research Scientist at the Sunnybrook Research Institute in Toronto face when looking for answers to why some patients experience a combination of symptoms like stomach pain, trouble swallowing, and dark, reddish urine. Through blood tests, doctors are able to see that paroxysmal nocturnal hemoglobinuria (PNH), a disease of the blood-forming cells in the bone marrow, is responsible for the symptoms. PNH causes red blood cells to be destroyed faster than the body can replace them, resulting in anemia and acute fatigue.
Solving a medical puzzle with mixed symptoms
Anyone can get PNH. It doesn’t discriminate based on age, race, ethnicity, or gender though the average age at diagnosis is in the 30s. Everyone, from children to seniors, can be affected by the disease which is caused by a defective gene called PIG A. In Canada, there are 30 new cases diagnosed annually.
“People with PNH get a weird set of symptoms that seem unconnected,” says Dr. Wells. “When complement (part of the immune system) destroys red blood cells, the contents of those cells, including hemoglobin, are released into the liquid part of the blood. This allows hemoglobin, which normally carries oxygen, to mop up nitric oxide, another gas that’s very important in regulating blood vessels.” This leads to an array of problems — including anemia, severe headaches, fever, blood clots, and shortness of breath.
Two decades ago, PNH was barely on doctor’s radars, but awareness has steadily increased. “PNH is actually easy to diagnose once it’s suspected,” Dr. Wells explains. “The problem is that PNH is so rare that it’s not considered as a possibility right away, because there are other, more common conditions that could also explain the symptoms.”
Drug therapies help prevent life-threatening symptoms
Once PNH is suspected, doctors test the blood for high levels of lactate dehydrogenase, a red blood cell enzyme that is released when those cells are destroyed, and also perform a reticulocyte count in order to examine the rate at which the bone marrow is making new red blood cells. The definitive diagnosis comes from high sensitivity flow cytometry, a test that counts certain types of blood cells. Patients may also require a bone marrow biopsy.
“Prompt diagnosis is crucial because untreated PNH can cause complications — like blood clots — that are life-threatening,” says Dr. Wells. “This risk is very quickly and radically reduced when effective treatment begins.”
The good news is that PNH patients can live full lives. “In the old days, before we had an effective treatment, PNH was a deadly disease,” says Dr. Wells. “The average life expectancy after diagnosis was only 10 years. Nowadays, with proper treatment, it’s pretty much the same for PNH patients as it is for a healthy person.”