Paroxysmal nocturnal hemoglobinuria



Paroxysmal nocturnal hemoglobinuria


Coagulation disorders


Vitamin K deficiency

Leukemoid reaction

Leukemoid reaction


Paroxysmal nocturnal hemoglobinuria


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USMLE® Step 1 questions

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High Yield Notes

13 pages


Paroxysmal nocturnal hemoglobinuria

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USMLE® Step 1 style questions USMLE

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A 33-year-old man comes to the primary care office because of fatigue, shortness of breath, pallor, and increased respiratory infections for the past six months. Temperature is 37.3°C (99.1°F), pulse is 86/min, respirations are 20/min, and blood pressure is 108/68 mmHg. Physical examination shows scleral icterus. Laboratory tests are obtained, and the results are shown below.
Acidified serum lysis test is positive. Which of the following is a potential complication of this patient’s disease?

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Eculizumab p. 120

for paroxysmal nocturnal hemoglobinuria p. 417

Pancytopenia p. 429

paroxysmal nocturnal hemoglobinuria p. 417

Paroxysmal nocturnal hemoglobinuria p. 417

in anemia taxonomy p. 425

CD53 deficiency p. 105

eculizumab for p. 120

flow cytometry diagnosis p. 52

intravascular hemolysis in p. 429

presentation p. 718

Venous thrombosis p. 417

paroxysmal nocturnal hemoglobinuria p. 417


Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening condition characterized by the destruction of red blood cells by the complement portion of the immune system.

This destructive process is a result of a defect in the formation of surface proteins on the red blood cell, which normally functions to inhibit such immune reactions. Common symptoms of PNH are fatigue due to anemia, abdominal pain, and thrombosis, which is the major cause of death. There can also be jaundice from the accumulation of bilirubin, and characteristic dark-colored urine.

The management of PNH involves drugs like eculizumab, a monoclonal antibody that blocks the activity of the complement system, anticoagulation therapy in case of thrombosis, blood transfusion, and supportive management as needed.


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