This is a nine month-old boy who presents for a well baby check-up. Mother reports that the baby has had a decrease in his feeding over the past few weeks and that he appears weaker and is sleepy. He can no longer sit without support. There has been no recent history of infection.

PMH: The child was born at 39 weeks gestation and was the product of an unremarkable pregnancy, labor and delivery.

Medications: None

Allergies: NKDA

Family History: The mother has no other children. There is no known family history of neurologic or neuromuscular disease.

Social History: Mother is 18 years of age and she is living with her new boyfriend. The biological father is not involved with the child’s care.

Physical:
BP 80/65   HR 105    T 37.1°C  RR 20
General: Weight and length are at the 25th percentiles, while the head circumference is at the 95th percentile.
Mental Status: The boy has an alert expression but appears withdrawn. He becomes irritable with stimulation and has a high-pitched cry.
HEENT: PERRL, EOMI, no nystagmus. Funduscopic examination reveals a hemorrhage in the left retina. Facial sensation and strength are normal. Palate and tongue are at midline. The anterior fontanelle is open and firm, and the sagittal and coronal sutures are palpable.
Motor (Power/Tone/Bulk): Truncal, neck and extremity tone are all reduced. The boy moves all four limbs with appropriate strength, but he has an overall reduction in spontaneous movements.
Sensory: Withdraws extremities to noxious stimuli.
Reflexes: 3/4 at biceps, brachioradialis and knees; 4/4 at ankles with 2-3 beats of clonus. Plantar simulation results in equivocal responses of the great toe.
Coordination: The boy cannot sit without support. He does not attempt to reach for toys.
Gait: The boy cannot bear weight on his legs.
Abnormal Movements: None
Other Organs: The general physical examination is unremarkable. Specifically, there are no neurocutaneous lesions, no organomegaly, and there are no dysmorphic features.