Dentosphere : World of Dentistry

Decreased osmotic fragility is seen in:

# Which of the following have decreased osmotic fragility?

a. Hereditary spherocytosis

b. Hereditary elliptocytosis

c. Hereditary xerocytosis

d. Hereditary stomatocytosis/hydrocytosis

The correct answer is C. Hereditary xerocytosis.

Osmotic fragility has been typically increased in Hereditary spherocytosis and hereditary elliptocytosis. There are 2 types of hereditary stomatocytosis: hereditary xerocytosis (complex permeability defect d/t increased membrane lipids) and hereditary stomatocytosis – hydrocytosis (d/t deficiency of band 7.2b or stomatin). Both have autosomal dominant inheritance. Osmotic fragility is decreased in xerocytosis and increased in hydrocytosis. Xerocytosis may result in recurrent fetal loss, hydrops fetalis, neonatal hepatitis and familial pseudohyperkalemia.

CLICK HERE FOR MORE MCQs

Major risk factor for venous thrombosis:

Which of the following is a major risk factor for venous thrombosis?

a. Smoking

b. High cholesterol

c. Hypertension

d. Diabetes mellitus

e. Cancer

The correct answer is E. Cancer.

Venous thrombosis, including deep vein thrombosis and pulmonary embolism, occurs at an annual incidence of about 1 per 1000 adults. Rates increase sharply after around age 45 years, and are slightly higher in men than women in older age. Major risk factors for thrombosis, other than age, include exogenous factors such as surgery, hospitalization, immobility, trauma, pregnancy and the puerperium and hormone use, and endogenous factors such as cancer, obesity, and inherited and acquired disorders of hypercoagulation.

Ref: Cushman M. Epidemiology and risk factors for venous thrombosis. Semin Hematol. 2007;44(2):62-69. doi:10.1053/j.seminhematol.2007.02.004

CLICK HERE FOR MORE MCQs

Commonest inherited cause of thrombosis

# Commonest inherited cause of thrombosis in Caucasians is:

a. Protein S deficiency

b. Factor V leiden mutation

c. Anti thrombin III deficiency

d. Protein C deficiency

The correct answer is B. Factor V Leiden mutation.

Factor V Leiden (G1691A or arg 506 glu substitution) and prothrombin (G 20210 A) are rare in African and orientals but they have prevalence in whites, highest prevalence of heterozygotes (11–14%) is reported in Sweden and Arabs.

CLICK HERE FOR MORE MCQs