ultrasound diagnosis of fatal anomalies

SKELETAL ANOMALIES
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2
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Type II: is characterized even at the prenatal
stage by severe findings and has a fatal prognosis,
with death resulting at the early neonatal
stage.
Type III: shows a slow progression and leads to
severe handicap; it is diagnosed in the early
adult stage.
Type IV: is a mild form with a very high tendency
to fractures. Sclera are normal.
Incidence: One in 30 000–70 000 births.
Sex ratio: M:F=1:1.
Etiology: Inheritance is most frequently autosomal-dominant;
recessive forms are also
known. Type II is due to a new mutation, rarely
inherited. The disorder is caused by a defect in
the synthesis of type I collagen. Prenatal detection
using molecular-genetic diagnosis is
possible.
Teratogens: Not known.
Associated malformation: Cataracts.
Fig. 8.15 Osteogenesis imperfecta. Loss of continuity
of the humerus due to fractures at
32 + 4 weeks.
Ultrasound findings: Types I and IV: isolated fractures
of the slightly shortened long bones. Callus
formation in the fracture region. Bowing and
bending of the long bones. Type II is diagnosed if
detection is possible in the prenatal stage. Earliest
prenatal diagnosis at 14 weeks. Generalized
significant undermineralization, with multiple
deformities of the ribs. The skull is compressible
and devoid of echo. The bones of the extremities
are shortened with multiple fractures.
Clinical management: Further ultrasound
screening, including fetal echocardiography. If a
cardiac anomaly is detected, then the diagnosis
has to be questioned. Possible radiographic examination.
Hydramnios may develop. In the
nonfatal forms, delivery by cesarean section
should be considered, in order to avoid fractures
and intracranial bleeding due to soft skull bones.
Procedure after birth: The fatal type II disorder
is suspected in the presence of multiple fractures
and blue coloring of the sclera. In this case, “minimal
handling” is indicated; due to the fragility
of the bones and risk of fractures, the newborn
should be handled extremely carefully.
Prognosis: This depends on the type of disorder.
Death is the usual outcome in type II, due to respiratory
failure. In the nonfatal forms, the infants
survive with considerable disability, 30% of
cases requiring a wheelchair if the fractures
occur before the child has learned to walk. Healing
of the fractures is complicated with pseudoarthrosis
in 20% of cases.
Self-Help Organization
Title: Osteogenesis Imperfecta Foundation
Description: Support and resources for families
dealing with osteogenesis imperfecta.
Provides information for medical professionals.
Supports research. Literature, bimonthly
newsletter. Telephone support network.
Scope: National
Number of groups: 21 affiliated groups
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