124 Hereditary Fibrinogen Abnormalities

Question 1

Normal fibrinogen levels range from

Answer 1

150 to 350 mg/dL

1.5 to 4 g/L

Fibrinogen is an abundant protein, synthesized in the liver

Normal half-life of 3 to 5 days

Question 2

In afibrinogenemia, the fibrinogen concentration is less than

Answer 2

Less than 20 mg/dL

In hypofibrinogenemia, the level is less than normal.

Question 3

Affect the quantity of fibrinogen in circulation (afibrinogenemia and hypofibrinogenemia)

Answer 3

Type I fibrinogen disorders

Question 4

Affect the quality of circulating fibrinogen (dysfibrinogenemia and hypodysfibrinogenemia)

Answer 4

Type II fibrinogen disorders

Question 5

A rare disorder of hepatic biosynthesis of fibrinogen, inherited as an autosomal
recessive trait, with low levels of fibrinogen typically found in both parents.

Answer 5

Congenital afibrinogenemia

Umbilical cord bleeding may occur after birth. Later, bleeding may be from mucosal surfaces, into muscles, or into joints.

Spontaneous abortions are frequent.

Death is most often a result of intracranial hemorrhage.

Question 6

Appears to be caused by abnormal intracellular hepatic storage of fibrinogen

Answer 6

Hereditary hypofibrinogenemia

Question 7

Fibrinogen concentrate should be given to increase the plasma concentrations by at least

Answer 7

150 mg/dL

Question 8

One gram of fibrinogen concentrate raises the plasma fibrinogen level by ______ in adults.

Answer 8

20 mg/dL

Question 9

Cryoprecipitate typically contains _______ mg of fibrinogen per unit.

Answer 9

300 mg of fibrinogen per unit

Approximately 50% to 70% of the administered fibrinogen circulates after transfusion, and the biologic half-life of fibrinogen is 3 to 5 days.

Question 10

The recommended initial dose of cryoprecipitate

Answer 10

1 unit of cryoprecipitate (300 mg of fibrinogen) per 5 kg of body weight

Patients should receive one-third of the initial loading dose daily as long as is necessary to sustain the fibrinogen level.

Question 11

The production of structurally abnormal fibrinogen molecules with altered functional properties.

Inherited as an autosomal dominant trait.
Most patients are heterozygous but some are homozygous.

AR mga Type 1

Answer 11

Inherited dysfibrinogenemia

Question 12

Refers to patients with low levels of circulating abnormal fibrinogen

Answer 12

Hypodysfibrinogenemia

Question 13

Fibrinogen abnormalities usually affect one or more phases of fibrin formation:

Answer 13

• Impaired fibrinopeptide release
• Defective fibrin polymerization
• Defective cross-linking by factor XIIIa

Question 14

An autosomal dominant trait in which there is progressive extracellular deposition of “amyloid” protein in the kidneys due, in some instances, to deposition of fragments of a structurally abnormal fibrinogen

Answer 14

Hereditary renal amyloidosis

Question 15

Acquired dysfibrinogenemia

Answer 15

• Liver diseases (e.g. cirrhosis, chronic active liver disease, hepatoma, liver failure) are the main causes
• Paraproteinemia (e.g. monoclonal gammopathy)

Question 16

Almost half of pregnancies in hypofibrinogenemic women resulted in ____________ , and about one-third had a complication, including 20% with vaginal bleeding and 5% with placental abruption

Answer 16

Miscarriage