Question

1) a 4 year old were seen in the pediatrician's office for vomiting and coughing for the past 2 days. He showed extensive bruising on his extremities and was lethargic and dehydrated. A viral illness had been spreading through the daycare center he attends.

WBC= 25 x 10^9/L

RBC= 3.4 x 10^12/L

Hct= 34%

Plt= 50 x 10^9/L

What is the mechanism of platelet destruction in this patient?

A: improper mixing of sample

B: Missing vWF

C: Immune destruction of platelets

D: antibody coating of platelets leading to sequestration

2) A 6 your old girl presented to the pediatric dentist with a severe toothache. After examination it was determined that the tooth had a cavity. Because it was a baby tooth it was decided to extract the tooth. The tooth extraction was accompanied by a prolonged episode of severe bleeding. The patient mentioned that she "bruised easy like my sister."

Plt: 100 x 10^9/L

Blood smear revealed large platelets

What is the pathophysiology of this disorder?

A: Absence of vWF

B: Absence of GPlb/IX

C: Absence GOllb/lla

D: Absence of platelets

Answer 1

1)Antibody coating of platelets leading to sequesteration.The main mechanism might be due to the dehydration which causes Thrombocytopenia,which is basically abnormal low level of platelets.This condition is seen in most of the patients infected with virus like dengue fever.In this case the virus use the platelets as a host for its reproduction which finally burst to release the small viral particles.

2)option b.Absence of GPIb/IX.It is a membrane receptor in megakaryocytes which is exclusively seen in the surface of platelets.It mediate the first critical step in platelete adhesion.Without it platelets cannot get attached on the wound.