The problem is not all in her head

The Case

It's another busy day in the emergency department. Your next patient is a 4-year-old girl with a 5-day history of unsteady gait, tremors, and loss of balance. According to her mother, the girl was in her usual state of health until the onset of her weakness 5 days ago. Her mother noticed that she was frequently tripping and falling, approximately 3 or 4 times a day, before coming to the hospital. She became particularly concerned when her daughter progressed to the inability to walk independently and then complete refusal to stand 2 days ago.

Your patient has also had weakness of the upper extremities and has been frequently dropping things. The mother has noted her daughter's emotional lability and excessive clinging behavior. She was seen at an outside facility where she was admitted for a day and discharged before coming to you. She has had no vomiting, weight loss, or fever. Other pertinent negatives include absence of lethargy or seizures; change in urine and bowel habits; bleeding; and fatigue. She did have watery diarrhea 2 weeks ago that lasted 3 days and had subsided on its own.

A few significant findings

On physical exam, your patient appears to be well developed and well nourished and in no apparent distress. Her weight is at the 50th percentile for age, her height is at the 90th percentile, and her head circumference is at the 50th percentile. She has a temperature of 37.7°C, heart rate of 125 beats per minute, respiratory rate of 26 breaths per minute, and blood pressure of 109/66 mm Hg.

She clings to her mother when approached. She has marked postural instability, is unable to stand without support, and has an unsteady gait even with support. Tone, power, and deep tendon reflexes are diminished but present in all extremities. Muscle bulk is normal with no wasting or hypertrophy, and no muscle tenderness is appreciated. Cranial nerve examination is normal. There is no bowel or bladder incontinence, and the rectal tone is normal. Meningeal signs are negative. She has no murmur and heart sounds are normal, though better heard on the right. The remainder of her physical exam is unremarkable.