Chapter 27,limbs.pptx

Chapter 27 Normal and Abnormal Fetal Limbs Tina Welch,MA,RT, ( R ),RDMS,RVT,RCS  Describe the normal sonographic appearance of the fetal skeletal system. Summarize measurement techniques of the fetal long bones. Evaluate limbs for abnormal size and appearance. Identify fetal skeletal abn...

Chapter 27 Normal and Abnormal Fetal Limbs Tina Welch,MA,RT, ( R ),RDMS,RVT,RCS  Describe the normal sonographic appearance of the fetal skeletal system. Summarize measurement techniques of the fetal long bones. Evaluate limbs for abnormal size and appearance. Identify fetal skeletal abnormalities and their associated findings. Discuss differential diagnoses for pathology visualized. Identify the Doppler spatial peak-temporal average maximum as recommended by the U.S. Food and Drug Administration. Summarize the normal fetal spectral Doppler waveform appearance in the umbilical artery and vein, middle cerebral artery. Explain fetal and maternal factors influencing Doppler waveforms.  Micromelia-abnormal short limb (mild and bowed) Mesomelia-abnormal short middle portion (radius,ulna,tibia,fibula) Rhizomelia-shortening proximal portion(femur and humerus) Acromelia -shortening distal portion (hands,feet) Syndactly-soft tissue or fusion of digits ( associated with triploidy if third and fourth digits Talipes equnovarus-inverted plantar flexed foot seen in same plane as tibia,fibula  Management Family history Advanced paternal age Serial images-growth if long bones measure below 2 standard deviations for gestational age  Assess AFV Limb length( determine which portion is shortened) Bone mineralization-can compress skull-demineralization Decreased shadowing-demineralization Bone appearance Fractures Bowing Skull shape –cloverleaf shape(due to premature synostosis,craniosynostosis,frontal bossing Thorax size and rib length-lethal dysplasia associated with pulmonary hypoplasia Ratio:Fl/AC less than 0.16 or TC/AC less than 0.79 indicates hyperplastic thorax  Some skeletal dysplasias incompatible with life Lethal forms characteristically extremely severe in prenatal appearance, as with severe micromelia ;often occompanied with pulmonary hypoplasia Nonlethal skeletal dysplasias tend to manifest in milder form  Skeletal dysplasia Abnormal development of cartilaginous and osseous tissues Bones appear Short Thin Deformed Fail to form  Most Common Achondrogenesis Thantophoric dysplasia Camptomelic dysplasia Osteogenesis imperfecta Achondroplasia Talipes Femur most common Lethal skeletal dysplasia Achondrogenesis -micromelia Osteogenesis imperfect type II -micromelia Asphyxiating thoracic dysplasia- mesomelia Thantophoric dysplasia - Captomelic dysplasia – micromelia mesomelia,rhizomelia Short rib polydactyly Ellis-Van Creveld syndrome - syndrome -micromelia rhizomelia Homoqygous achondroplasia- Thrombocytopenia-absent **************** radius syndrome rhizomelia******** autosomal dominant Vacterl associate Hypophosphatasia ---- micromelia Talipes  1.Assess limb shortening. All long bones should be measured. Skeletal dysplasia suspected when limb lengths fall more than two standard deviations below mean 2.Assess bone contour. Thickness, abnormal bowing or curvature, fractures, and ribbonlike appearance should be noted. 3.Estimate degree of ossification. Decreased attenuation of bones with decreased shadowing suggests hypomineralization. Special attention should be focused toward assessment of cranium, spine, ribs, and long bones. 4.Evaluate thoracic circumference and shape. Long, narrow chest or bell-shaped chest may be indicative of specific dysplasias. 5.Survey for coexistent hand and foot anomalies, such as talipes and polydactyly. 6.Evaluate face and profile for facial clefts, frontal bossing, micrognathia, hypertelorism, other facial anomalies that may be associated with skeletal dysplasias. Survey for other associated anomalies, such as hydrocephaly, heart defects, and nonimmune hydrops Non-lethal Achondroplasia- Achondroplasia- herterozygous homozygous Normal intelligence Lethal Rhizomelia Narrow thorax Macrocephaly Trident hands (short proximal and middle phalanges) Depressed nasal bridge Frontal bossing Mild ventriculomegaly may be identified Thanatophoric Dwarfism Anomalies- Lethal most common Most common lethal skeletal dysplasia Curved or bowed long bones Hypomineralization Macrocephaly Frontal bossing Narrow thorax Proximal bone short Type 1-most common extreme rhizomelia Protuberant abdomen Frontal bossing (bulging forehead) Hypertelorism (widely spaced eyes) Flat vertebral bodies (platyspondyly) Other sonographic findings:  Severe polyhydramnios  Hydrocephalus  Nonimmune hydrops  Achondroplasia Anomalies-non lethal Frontal bossing Narrow thorax Macrocephaly hydrocephaly  Achondrogenesis Anomalies-lethal Hypomineralization Narrow thorax Bone fractures Severe micromelia Decreased or absent ossification of spine Macrocephaly Short trunk Short thorax and short ribs Micrognathia Polyhydramnios Hydrops possibly identified Short Rib-Polydactyly Syndrome Anomalies-3 types Narrow thorax Other sonographic findings Hypomineralization  Anomalies of central nervous system Polycactyly/syndactyly  Anomalies of cardiovascular system Gastrointestinal/genital/  Anomalies of genitourinary urogenital malformations tract Cleft lip/palate midline facial cleft micromelia  Lethal Type I, or Saldino-Noonan syndrome Type II, or Majewski syndrome Type III, or Naumoff syndrome  Asphyxiating Thoracic Dysplasia Anomalies Narrow thorax Polydactyly Pelvic/renal anomalies Also know as Jeune’s syndrome Rhizomelia Autosomal recessive Lethal due to pulmonary hypoplasia  Ellis-van Creveld Syndrome Anomalies Polycactyly Short limbs Narrow thorax Heart malformations -ASD Dysplastic nails/teeth Abnormal upper lip Frequent in Amish community  Osteogenesis Imperfecta Anomalies Curved or bowed long bones Hypomineralization-especially skull Bone fractures Bell-shaped thorax micromelia Four classifications, types I to IV polyhydramnios Types I and IV mildest forms; unlikely that diagnosis made in utero Type II considered most severe form; lethal outcome –inherited autosomal recessive  Camptomelic Dysplasia Anomalies Curved or bowed long Hypomineralization bones Macrocephaly Pyelectasis Bell-shaped thorax Hypoplastic scapulae Micrognathia Cleft palate Hydrocephalus Talipes Hydrocephalus Polyhydramnios hypertelorism  Congenital Hypophosphatasia Anomalies Hypomineralization Curved or bowed long bones Short bones Small thorax micromelia Diagnosis confirmed with alkaline phosphatase assay, achieved through:  Fetal blood sampling  Chorionic villus sampling  DNA analysis Anomalies Associated with Dysostosis Abnormal ossification Craniofacial dysostosis-widening of cranial fontanelles(associated with absent clavicles,Hypoplastic middle,distal phlanges,spinal abn. Associated with craniosynostosis Syndactyly- fusion of digits Apert syndrome Detected in 3rd trhimester, bilater syndactyly,other abnormalities cardiac,GU,cerebral(corpus callosum most common) Clubfoot / Talipes-male predom  Rocker-bottom foot characterized by prominent heel and convex sole Is associated with multiple syndromes and chromosomal anomalies, especially trisomy 18 27 Amniotic band sequence Also known as synechiae Attached from one uterine wall to other. Caudal Regression Syndrome/Sirenomelia Includes range of malformations of caudal end of neural tube Sirenomelia is anomaly in which there is fusion of lower extremities Can be ssociated with monoqygotic twinning,single umbilical artery and cocaine use Sacral agenesis talipes Sirenomelia Sonographic Findings Variable fusion of lower extremities Bilateral renal agenesis Oligohydramnios Single umbilical artery 30 VACTERL Association-3 features must be identified VACTERL association is group of anomalies that may occur together  Vertebral defects  Anal atresia  Cardiac anomalies  Tracheoesophageal fistula  Renal anomalies  Limb dysplasia 31 Locate mid cord or at placental CI. > 3 abnormal < 3 normal indications IUGR abnormal biophysical profile abnormal AFI multiples  Normal pregnancy MCA S/D ratio decrease with advanced gestational age Indications Fetal anemia IUGR Hydrops Isoimuniztion IUGR & hypoxic stress Drop in MCA S/D ratio Decreased in resistance Brain sparing effect Let’s Review!! BPD landmarks AC landmarks FL Ratios If FL/AC or HC/AC ratio is high then AC should not be used for age estimation