14-month-old: Non-weight bearing

Case History

Mrs. M was at a new-patient visit with her FP. She was planning a pregnancy within the next 6 months. Her 14-month old daughter P was on her lap when the FP entered the room. After asking Mrs. M’s permission, the FP lifted P and spoke to her for a moment, and then gently placed her on a mat on the floor so that he could examine Mrs. M. The provider noted that P went into a sitting position and did not bear weight on her legs. The provider asked Mrs. M whether P regularly avoided weight on her legs, and Mrs. M responded that P was not pulling to stand or walking. She told the provider that she was not worried about her daughter’s motor skills because the rest of her development was ahead of the norm.

Clinical Pearl: Children can make developmental progress, even with progressive weakness. Developmental progress does not exclude the possibility of an underlying neuromuscular condition.

The family recently moved to a new state, and Mrs. M felt that the move may have played a role in delaying her daughter’s walking, as she had been held more than usual in preparation for and after the move.

The FP completed the examination on Mrs. M, and at the end of the appointment asked Mrs. M to schedule a visit later that week for P. During P’s examination the provider noted normal cognitive development and generalized weakness. P had a history of poor feeding and delayed but consistent motor development. Mrs. M reported that there was no family history of weakness, low tone or muscle disorders. The FP drew blood for a CK and made a referral to pediatric neurology. The CK result was normal. However, the child’s delay was still worrisome and warranted a referral to neurology. The provider also referred P to early intervention and for PT.

Clinical Pearl: Children with some neuromuscular disorders have a normal CK. Normal or near normal CK should not be reassuring if a child is weak or losing milestones.

The neurologist diagnosed P with SMA II within 1 month of the referral. This allowed Mrs. M to take advantage of prenatal diagnosis in her subsequent pregnancy; for P to benefit from therapies targeted to her diagnosis; and for Mrs. and Mr. M to benefit from connecting with support and advocacy organizations.

Clinical Pearl: Early diagnosis and treatment of SMA is essential to maximizing a child’s health outcomes, reduces family distress related to the diagnostic process, and provides the opportunity for accurate and timely genetic counseling. Prognosis is improved with early treatment. If you suspect SMA do not delay; refer immediately to a specialist for genetic testing.