Why It’s Important to Recognize Signs of Rare Blood Disease
The road to a PNH diagnosis can take up to five years. That’s why awareness is critical for both patients and physicians.
Paroxysmal nocturnal hemoglobinuria (PNH) is an ultra-rare and acquired blood disease caused by a mutation in some of the bone marrow stem cells. “The subsequent blood cells produced lose their protection against a part of our immune system called complement,” says Dr. Christopher Patriquin, a hematologist and Clinician Investigator at the University Health Network and Assistant Professor of Medicine at the University of Toronto. This can lead to the destruction of the red blood cells, as well as damage, and activation of the platelets and white blood cells, which puts the patient at increased risk of thrombosis (blood clots). “Some patients with PNH may also have bone marrow failure, such as aplastic anemia, where blood cell production is significantly reduced,” says Dr. Patriquin.
The median age for PNH diagnosis is between the ages of 35 and 40 — people in the prime of their career and family responsibilities. “It’s devastating because when your red blood cells are being destroyed, you’re not really able to function properly,” says Cindy Anthony, Executive Director of the Aplastic Anemia and Myelodysplasia Association of Canada, a patient support organization.
The importance of recognizing signs and symptoms
“Undiagnosed, symptomatic PNH has a 35 percent five-year mortality rate with up to two thirds of deaths being due to thrombosis,” says Dr. Loree Larratt, Professor Emeritus in Clinical Hematology at the University of Alberta. These severe blood clots can form virtually anywhere throughout the body, including the brain, heart, lungs, and kidneys. “Beyond the risk of thrombosis, untreated patients with PNH may develop many other complications from the continual breakdown of their red blood cells, such as fatigue, shortness of breath, abdominal pain, difficulty swallowing, and kidney damage,” adds Dr. Patriquin.
Diagnosis is made by a test of the patient’s blood called flow cytometry. But the challenge is recognizing that patients may have PNH to begin with and need to be tested. “It’s important to recognize that the patient may present with some very common symptoms such as fatigue, anemia, or thrombosis, for which there are often other clinical explanations,” says Dr. Patriquin.
Symptoms that may warrant testing include unexplained low blood counts, some types of bone marrow failure, thrombosis that may be unprovoked or presenting in an atypical location, red-coloured urine (called hemoglobinuria), and hemolytic anemia that is not otherwise explained.
Hope for living well with PNH
While there’s no cure for PNH other than a bone marrow transplant, which is usually reserved for severe cases of bone marrow failure, it’s possible for people with PNH to live full and active lives. “Not all patients initially require therapy, but they should still be seen by a physician with expertise in PNH,” says Dr. Larratt.
The core treatment strategy for PNH is to protect red blood cells from damage and destruction. Since 2009, a complement inhibitor has been approved in Canada, which is administered by intravenous infusion every other week. The medication effectively stops the hemolysis, thus improving the quality of life and increasing survival by reducing the risk for thrombosis for many PNH patients. “These new treatments have been a game-changer for sure,” says Anthony.
Things are expected to get even better. “How we manage PNH 10 years from now will likely be quite different from how things are done today, with hopefully more options for our patients that continue to control the disease while also improving quality of life and reducing the treatment burden,” says Dr. Patriquin. “That’s why it’s imperative that there is continued support in Canada for research into PNH and its treatment.”
It’s important to recognize that the patient may present with some very common symptoms such as fatigue, anemia, or thrombosis for which there are often other clinical explanations.