Medical Mystery | What caused a college student’s shortness of breath and abdominal pain?
A college student gets over the flu, but two weeks later feels winded after climbing stairs and complains of abdominal pain. What caused it?
An 18-year-old student went to her campus health clinic complaining of a fever, runny nose, sore throat, muscle pain, headache, cough, and fatigue. Diagnosis: Flu.
Her flu symptoms gradually improved, but two weeks later she noticed that just climbing stairs made her feel winded. Days later, she developed lower abdominal pain and returned to student health. Blood work indicated there was something wrong, and the doctor sent her to the emergency department.
She appeared anxious and pale, on top of her abdominal discomfort. She had no fever and a normal blood oxygen level. On physical examination, her lungs sounded normal.
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The lab tests from student health showed pancytopenia, meaning that her white blood cells, red blood cells, and platelets all were dangerously low. The lack of white blood cells put her at risk for severe infections. The low red blood cell count indicated anemia, which explained her shortness of breath on exertion. The low platelet count increased her risk of bleeding.
Viruses can cause pancytopenia, and she did test positive for the virus influenza A at her initial visit to student health. She tested negative for other common viruses.
The patient was deemed critically ill and admitted to the hospital. A hematologist examined a drop of the patient’s blood under the microscope, and the red blood cells, white blood cells, and platelets all appeared normal, but there just weren’t enough of them.
Blood cells are made in the bone marrow, so the next step was a bone marrow biopsy, taken from her pelvis under local anesthesia. Although her platelet count was low, the patient didn’t bleed excessively.
The biopsy showed that she had a higher-than-normal number of young immature cells. This meant that she was producing blood cells, but they were being destroyed in the blood stream after leaving the bone marrow. The good news was that no cancer cells were identified.
But the question remained: What was causing her body to destroy blood cells?
Solution
The patient’s bone marrow cells were sent for flow cytometry, a special test that looks at proteins on the surface of cells. Her results showed that she was missing two important proteins (CD55 and CD59) that protect red blood cells, white blood cells, and platelets from attack by the body’s own immune system. The absence of these proteins allows the immune system to destroy blood cells in a disease known as paroxysmal nocturnal hemoglobinuria (PNH).
PNH results from a genetic mutation that manifests after birth. Over time, the cells that are missing the two proteins replace normal bone marrow cells. Events like stress, trauma, or infections activate the immune system, destroying blood cells. In the patient’s case, the culprit was most likely Influenza A.
The patient’s abdominal pain was caused by PNH as well. Normally, the body uses a chemical found in the blood known as nitric oxide to relax muscles in the intestine. When blood cells break down in PNH, the body uses its nitric oxide to get rid of the destroyed blood cells, leading to intestinal cramping.
In the hospital, the patient required red blood cell and platelet transfusions. To prevent the cell destruction seen in PNH, her hematologist started her on a long-term treatment, an infused medication called ravulizumab.
PNH is a chronic disease, but she was so determined to face it, she switched from prelaw to premed so she can become a hematologist.
Paul Rosenberger is a pediatric resident and Rima Himelstein is an adolescent medicine specialist at Nemours Children’s Hospital, Delaware.