A newborn boy is being evaluated in the nursery. The patient was born at 39 weeks gestation via cesarean delivery to a 30-year-old primigravida. Head circumference, weight, and length are at the 75th to 90th percentiles. The anterior fontanelle is open and soft. The neck is supple. Cardiopulmonary examination is unremarkable, and the abdomen is soft. The back appears unremarkable. Hip examination shows no hip clicks. Both feet are plantar flexed and adducted with the soles pointing medially. There is resistance to range of motion assessment in both feet. Muscle tone is normal and newborn reflexes are intact. The abnormal findings on this patient's physical examination most likely represent which of the following types of congenital anomalies?

Question

A newborn boy is being evaluated in the nursery.  The patient was born at 39 weeks gestation via cesarean delivery to a 30-year-old primigravida.  Head circumference, weight, and length are at the 75th to 90th percentiles.  The anterior fontanelle is open and soft.  The neck is supple.  Cardiopulmonary examination is unremarkable, and the abdomen is soft.  The back appears unremarkable.  Hip examination shows no hip clicks.  Both feet are plantar flexed and adducted with the soles pointing medially.  There is resistance to range of motion assessment in both feet.  Muscle tone is normal and newborn reflexes are intact.  The abnormal findings on this patient's physical examination most likely represent which of the following types of congenital anomalies?

Quizplus · Accepted Answer

11ec160b_374d_3299_9249_9d2ae972eef1_MD0001_00 This newborn has talipes equinovarus (ie, clubfoot), a congenital anomaly in which one or both feet are rigidly flexed downward and inward. Talipes equinovarus is a deformation anomaly, or a structural abnormality caused by extrinsic forces on the developing fetus. Normal growth and positioning of the foot are restricted due to poor in utero mobility (eg, multiple gestation, breech positioning). Subsequent underdevelopment of the talus bone causes subluxation of the surrounding joints and shortening of the adjacent calf muscles and tendons. The result is hyperplantar flexion with adduction and medial deviation of the foot. Soft tissue contractures and bony misalignment lead to a rigid deformity that resists range-of-motion testing. Clubfoot is a clinical diagnosis, and treatment involves manipulation and stretching with serial casting. (Choice B) Disruption refers to destruction of a structure that was previously developing normally. For example, amniotic bands are fibrous tissues that encircle and constrict fetal limbs, disrupting previously normal development. Constriction rings, hypoplasia, or amputation of the distal extremity is seen on examination. (Choice C) Dysplasia is the proliferation of abnormal cells, which can lead to the abnormal formation of an organ, such as the acetabulum in patients with developmental dysplasia of the hip (DDH). Restrictive, extrinsic forces can also contribute to DDH, but examination would reveal a hip clunk on examination due to femoral head dislocation. (Choice D) A congenital malformation is due to an intrinsic defect (eg, genetic, teratogenic) that prevents the proper development of a structure. For example, spina bifida, a malformation of the spine and spinal cord, is caused by failure of neural tube closure. Although clubfoot can be associated with spina bifida, an outpouching (eg, meningocele, myelomeningocele) or hair tuft (eg, spina bifida occulta) would be expected on the lower back. (Choice E) A sequence refers to a group of anomalies seen together that represent a cascade effect from a single defect. For instance, Potter sequence is characterized by flat facies, pulmonary hypoplasia, and limb deformities (eg, clubfoot) that result from oligohydramnios due to a urinary tract anomaly. This patient has isolated feet deformities with an otherwise normal examination. Educational objective: A deformation anomaly is caused by extrinsic forces on a developing fetus. Talipes equinovarus (ie, clubfoot), in which the foot is rigidly flexed downward and inward, is a deformation anomaly involving an underdeveloped talus bone.

A Newborn Boy Is Being Evaluated in the Nursery