Background: To study the clinical and radiological features of symptomatic Chiari I malformations. Materials and methods: This study was a retrospective study conducted in Government medical college, Thrissur, which is a tertiary care government medical college in Kerala, India. The patients admitted with diagnosis of symptomatic Chiari I malformations during the period of 2015 to 2019 were selected for the study. Results: The mean age was 23.3 years. Females were 66.7% and males were 33.3%. Mean duration of symptoms (onset of first symptom to the time of presentation) was 16.75 months. Occurrence of symptoms include - sensory symptoms 14(58.3%), walking difficulty 10(41.7%), headache 8(33.3%), neck pain 6(25%), vertigo 5(20.8%), weakness of limbs 4(16.7%), spine deformity 2(8.3%), seizures 2(8.3%) diplopia 1(4.2%) , hoarseness of voice 1(4.2%), swallowing difficulty 1(4.2%) and signs (table3&figur3) include gait disturbance 12(50%), hyperreflexia 8(33.3%), nystagmus 4(16.7%), hypertension 4(16.7%), cape sensory loss 4(16.7%), hand atrophy 3(12.5%), scoliosis 2(8.3%). Mean tonsillar descend from the level of foramen magnum was 11.5 mms. Syringomyelia was present in 14(58.3%) cases. Discussion: Patients with Chiari I malformation usually do not become symptomatic until adulthood hence it is also known as adult Chiari malformation. In our study, mean age is 23.5 years. The anomaly is more common among females and our study also females are affected more(66.7%).The most common presenting symptom is usually occipital and upper cervical pain(60% to 70%), often induced by sneezing or coughing according to most of the studies.5,6,7 Sensory symptoms 14(58.3%) are the commonst symptoms in our study. Magnetic resonance imaging is the imaging modality of choice and it is helpful in differentiating intramedullary spinal cord tumours from syrinx.13,14,15,16 The radiological definition of Chiari I malformation has been reported as tonsillar herniation of at least 3 mm17 or at least 5 mm18 below the foramen magnum. We considered tonsillar herniation 5mm as the cut off for the diagnosis of Chiari I malformation. Mean tonsillar descend from the level of foramen magnum was 11.5 mm as per our study. Syringomyelia was present in 58.3% of cases in our study. Conclusions: Chiari I Malformations are more common in adults and incidence is slightly higher in females. Various symptoms include sensory symptoms,walking difficulty, headache , neck pain, vertigo, weakness of limbs, spine deformity, seizures, diplopia, hoarseness of voice, swallowing difficulty and signs include include gait disturbance, hyperreflexia, nystagmus, hypertension, cape sensory loss, hand atrophy, scoliosis in their order of frequency occurrence. Syringomyelia is commonly associated with Chiari I Malformations.
