II. Definition: Chiari I Malformation
- Cerebellar Tonsils fall >5 mm below foramen magnum
III. Pathophysiology
- Congenital disorder
IV. Epidemiology
- Chiari I symptom onset 30-40 years of age
V. Symptoms (Chiari I is often asymptomatic)
- Headaches provoked by straining
- Neck Pain
- Lower Cranial Nerve disorders
- Vertigo
- Vertical Nystagmus (down-beating Nystagmus)
- Ataxia
- Urinary Frequency
- Lower extremity spasticity
- Dissociated Anesthesia
VI. Differential Diagnosis: Chiari I
- Multiple Sclerosis
- Bony compression at craniocervical junction
- Syringohydromyelia
- Syringobulbia
VIII. Management: Chiari I
- Decompression of bone at craniocervical junction
IX. References
- Behrman (2000) Nelson Pediatrics, Saunders, p. 1810
- Goetz (1999) Clinical Neurology, Saunders, p. 530
- Goldman (2000) Cecil Medicine, Saunders, p. 2076