Arnold Chiari I Malformation with Tip-Toe Gait: A Case Report
A 12-year-old male patient presented to our institute complaining of tip-toe gait for the previous ten years (). The patient was born via normal vaginal delivery with a weight of 3.2 kg and a gestational age of 36 weeks. The developmental course had been normal. The boy underwent surgery to correct a ventricular septal defect at four years of age, and his sister suffered from an atrial septal defect. His mother reported that the boy's maternal grandfather also had a tip-toe gait. The patient had not previously experienced abnormal motor or sensory deficits, pain or discomfort, nor did he have any problems walking or running. Neither he nor any of his family members have undergone ankle evaluation.\nOn physical examination, the motor and sensory abilities of both the upper and lower limbs were normal. No pathologic reflexes were observed, and the passive dorsiflexion and plantarflexion of both ankles were 0° and 50°, respectively. These results indicate reduced ranges of motion (ROM) of ankle dorsiflexion.\nOther than those of the ankles, the ROM of all joints were within the normal limits. No muscular atrophy was observed in the upper or lower limbs, and no valgus or varus deformities were observed in either ankle. And neurologic examination about cerebellar function was performed and showed normal findings. The biceps, triceps and knee jerk responses were normal, exhibiting the double-positive reaction; however, both ankle jerks were slightly hypertonic as triple-positive reactions. The patient's heels did not contact the floor during walking.\nAt admission, the blood test and ankle radiologic X-ray results were normal, and the electrodiagnostic study including nerve conduction test, electromyography and somatosensory-evoked potential studies were all normal. Therefore we thought the cause of his tip-toe gait was less likely to peripheral nerve or orthopedic problems. So tests for determining upper motor neuron disease and magnetic resonance images (MRI) of the brain and whole spinal cord were conducted. The MRI of the whole spinal cord was normal; however, a brain MRI revealed that the cerebellar tonsil was about 7mm lower than normal. This finding suggested the diagnosis of ACM I (). To differentiate from hereditary spastic paraplegia (SPG), SPG3A and SPG4 gene studies were performed with normal results.\nThe only symptoms demonstrated by the patient were tip-toe gait, hyperreflexic ankle tone and limitation of ankle dorsiflexion. Surgery was therefore not recommended, and the patient was observed and followed-up with the Neuro-surgery Department. He also underwent applied physical therapy for his ankles, resulting in improvements.