Platelet count and function studies are performed on a patient ...

[lunatika]

Platelet count and function studies are performed on a patient with a history of easy bruising, and the following results are obtained:
 
  Test Result
  Platelet count 295  109/L
  Bleeding time Prolonged
  Platelet aggregation with epinephrine Primary but no secondary wave
  Platelet aggregation with low-dose adenosine
  diphosphate (ADP) Primary but no secondary wave
 
  Platelet aggregation with ristocetin Normal
 
  What is the most likely diagnosis for this patient?
 
  a. Bernard-Soulier disease
  b. Dense granule deficiency
  c. Glanzmann thrombasthenia
  d. Gray platelet syndrome

Question 2

All of the following are common conditions or situations that interfere with platelet function except:
 
  a. Liver disease
  b. Uremia
  c. Allergic purpura
  d. Cardiopulmonary bypass surgery

[JYan]

Answer to Question 1

ANS: B
The platelet count on this patient is normal; however, the bleeding time is abnormal, which suggests platelet dysfunction. Of the disorders listed, only dense granule deficiency has the platelet aggregation results that are listed. Patients with Bernard-Soulier disease have normal aggregation studies with every agonist except ristocetin, which is abnormal. The reverse is true for Glanzmann thrombasthenia: they have normal aggregation with ristocetin but have no primary wave, as well as no secondary wave with other agonists. Patients with gray platelet syndrome have a moderate thrombocytopenia, prolonged bleeding time, and large platelets that appear gray on a Wright-stained blood film because of the absence of a-granules. Platelet aggregation studies are unremarkable.

Answer to Question 2

ANS: C
Allergic purpura does not interfere with platelet function. All of the other listed conditions or situations can affect platelet function.

[lunatika]

Correct answers!

[JYan]

Great! Please up vote