Hematology and Immunology Flashcards

A patient with disseminated intravascular coagulation (DIC) would be expected to have which laboratory profile?

Answer: Low platelets, high D-dimer, prolonged PT/PTT, low fibrinogen

DIC consumes platelets and clotting factors and generates fibrin degradation products, producing thrombocytopenia, elevated D-dimer, prolonged PT/PTT, and low fibrinogen.

Which transfusion reaction is most life-threatening and typically results from ABO incompatibility?

Answer: Acute hemolytic reaction

Acute hemolytic transfusion reactions from ABO incompatibility cause intravascular hemolysis, shock, and renal failure and require immediate cessation of the transfusion.

A patient receiving heparin develops a platelet count drop of more than 50% on day 6. What condition should be suspected?

Answer: Heparin-induced thrombocytopenia (HIT)

HIT is an immune-mediated reaction occurring 5-10 days after heparin exposure, causing thrombocytopenia and a paradoxical thrombosis risk.

Which finding best indicates a neutropenic patient is at highest infection risk?

Answer: Absolute neutrophil count below 500/mm3

An ANC below 500/mm3 defines severe neutropenia and markedly increases the risk of serious infection.

What is the priority intervention for a neutropenic patient who develops a fever of 38.5C?

Answer: Obtain cultures and start broad-spectrum antibiotics promptly

Neutropenic fever is an emergency requiring blood cultures and empiric broad-spectrum antibiotics within an hour to prevent sepsis.

Which clotting factor pathway does the PTT (partial thromboplastin time) primarily evaluate?

Answer: Intrinsic pathway

PTT measures the intrinsic and common pathways and is used to monitor heparin therapy.

A patient with sickle cell disease in vaso-occlusive crisis requires which priority interventions?

Answer: Oxygen, hydration, and pain management

Vaso-occlusive crisis is managed with oxygenation, aggressive hydration, and adequate analgesia to relieve sickling and ischemic pain.