Researchers reported on a patient with untreated aplastic anemia who presented with classical paroxysmal nocturnal hemoglobinuria (PNH). The case study was published in Cureus.

A 29-year-old man presented with a weeklong history of generalized weakness and intermittent nausea. He was previously diagnosed with aplastic anemia via bone marrow biopsy. The only relevant medical history was intermittent, nocturnal, and gross hematuria in the past year. 

He was observed to be pale and laboratory findings revealed low leukocyte, erythrocyte, platelet, hemoglobin, and haptoglobin levels. He was also discovered to have elevated levels of reticulocytes, serum creatinine (in the absence of chronic kidney disease), bilirubin, creatinine kinase, and lactate dehydrogenase. 

A peripheral blood smear revealed schistocytes and spherocytes. A bone marrow biopsy and aspirate revealed hypercellular bone marrow, with cellularity estimated to be around 90%. Under 20x magnification, scientists were able to observe numerous erythroid precursors that demonstrated a leftward shift in maturation. 

An ADAMTS-13 and direct Coombs test were both negative, and an abdominal ultrasound scan was unremarkable.

Read more about PNH etiology 

The myeloid:erythroid ratio was approximately 1:10. Blasts were estimated to be less than 5%; no dysplastic features were observed in any of the 3 cell lineages. Iron stores were identified to be low to low-normal. Flow cytometry revealed that 9.85% of cells were deficient in CD59. 

The patient’s physicians suspected that he had PNH due to the strong pathophysiological correlation between the condition and aplastic anemia. He was started on cyclosporine and later eculizumab therapy, which eventually resulted in improvements in his weakness and nocturnal hematuria. 

Eculizumab is the standard therapy offered to patients with classical PNH. It protects erythrocytes lacking CD55 and CD59 from complement-mediated hemolysis. 

“Ultimately, it is imperative that comorbid hematologic disease be screened for and diagnosed early on to prevent the acute complications of a chronic condition,” the authors of the report concluded. 


Rayas J, Hassan M, Hock RA, et al. Attack of the clones: a patient with untreated aplastic anemia presenting with classical paroxysmal nocturnal hemoglobinuria. Cureus. Published online January 23, 2023. doi:10.7759/cureus.34093