Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired, life-threatening hematopoietic stem cell disorder characterized by the triad of hemolytic anemia, thrombosis, and impaired bone marrow function. PNH arises due to an acquired mutation in the synthesis of the glycosylphosphatidylinositol (GPI) anchor protein, which leads to a deficiency of complement regulatory proteins and unregulated complement-mediated hemolysis.1 With a reported incidence of 1 to 10 cases per million and a 3-5% risk of developing leukemia, new therapeutic advances have emerged to decrease the 10-year mortality associated with PNH.2,3 Here, we discuss the presentation of a 59-year-old male with PNH, strategies to diagnose this rare condition, and therapeutic challenges regarding anticoagulation in these patients.

Case Presentation:

The patient is a 59-year-old Russian-speaking male with a past medical history significant for diabetes and hypertension who presented to the Emergency Department (ED) with two days of fever, headache, and altered mental status. The headache was described as a constant, 7/10 bilateral posterior headache that radiated anteriorly and improved with over-the-counter acetaminophen. His family described his altered mental status as confusion regarding recent events and short-term memory loss. The patient denied photophobia or neck stiffness. He denied changes in vision, unilateral weakness, loss of sensation, or any other focal neurological deficits. He had no recent travel or sick contacts. He is a former cigarette smoker (40 pack-year history) and social drinker with no history of illicit drug use.

On admission, the patient was noted to be febrile to 103.1° F, tachycardic to 121 beats per minute, tachypneic to 22 breaths per minute, and normotensive at 121/70. On physical exam, he was awake, alert, and oriented to person, place, and time but not to situation or recent events. He was noted to have scleral icterus and hepatomegaly. The remainder of the physical exam was unremarkable. Labs on admission were notable for anemia (Hemoglobin 7.7, baseline of 9.4), thrombocytopenia (Platelet count of 108, baseline of 152), transaminitis (AST 84, ALT 53), hyperbilirubinemia (Total Bilirubin 1.9, Direct Bilirubin 0.7), and coagulopathy (PT 30.9, PTT 43, INR 3.8). The patient’s renal function was within normal limits. A CT scan of his head on initial presentation was unremarkable.