Childhood presentation: Chiari I malformation most commonly occurs in children. 40% of cases occur in children younger than 5 years of age, 25% occur in children 5–10 years of age, and 30% occur in children 11-15 years of age (10).
60–70% have pain: Pain is the most common presenting symptom (60–70%) (14, 28, 32). Usually occipital or upper cervical headache occurs, which is exacerbated by Valsalva maneuvers.
Other symptoms variable: Other symptoms vary greatly and may include motor (40– 74%) and sensory (50%) changes in the extremities, clumsiness (15%), and dysphagia (10%) (14, 15, 28).
Chiari II malformation
Dysfunction of CNs 9 and 10: Symptoms of Chiari II malformation commonly include dysfunction of CNs 9 and 10, which may lead to dysphagia and respiratory distress.
Up to 20% of patients present with respiratory emergency: Chiari II malformation may present as a neurosurgical emergency in up to 20% of affected patients. A child with Chiari II malformation and any respiratory abnormality needs close attention. Symptoms usually occur in infants and toddlers beginning at 2 or 3 months of age and up to 2 years (39). It is unusual for newborns to be symptomatic.
Myelopathy: Older children usually present with a spinal cord syndrome and/or syringomyelia, similar to patients with Chiari I malformation (29, 30, 40)
Chiari III malformation
Brainstem symptoms: Any number of brainstem syndromes along with developmental delay may be the presenting symptoms.
Severely compromised: Children with Chiari III malformation often are severely compromised neurologically at birth, and their prognosis is poor with any therapy.
Must be distinguished from cervical myelomeningocele: It is important to distinguish Chiari III malformation from upper cervical myelomeningocele, which has a very favorable prognosis with surgical correction (30) and often yields an intact neurological examination.
Chiari IV malformation
May be asymptomatic: Patients may have surprisingly few symptoms or may be asymptomatic (10).
Patterns of evolution
Chiari I – pain on Valsalva: The most common presenting symptom of Chiari I malformation is pain induced by Valsalva maneuvers such as coughing, laughing, or sneezing. Other common initial symptoms include weakness or numbness, hyperreflexia, loss of temperature sensation, and unsteadiness, as well as cape-like sensory loss, ataxia, and lower cranial nerve dysfunction. Many patients have some type of ophthalmological disturbance at diagnosis such as blurry vision, nystagmus, extraocular muscle palsies, diplopia, and/or otological complaints such as tinnitus, fluctuating hearing loss, vertigo, and nausea (49).
Chiari II – stridor and oropharyngeal dysfunction: Patients with Chiari II malformation present with stridor, vocal cord paralysis, and oropharyngeal dysfunction, usually in the first 2 years of life. The rate of permanent complications and death (previously a common problem) has been dramatically reduced by aggressive management of shunt function.
Time for evolution
Usually slow: Signs and symptoms evolve progressively over the course of years for most patients with Chiari I malformation. It is believed that diagnosis occurs, on average, approximately 5 years after onset of symptoms. Most patients with Chiari II malformation become symptomatic in the first 2 years of life, although rarely in the immediate neonatal period.
Evaluation at Presentation
Careful history and physical examination: A detailed neurological history and careful examination are imperative, with the purpose of determining whether the symptoms are referable to the Chiari malformation and how fast they are progressing.
Intervention at Presentation
Airway protection and hemodynamic support: Patients who present with emergent symptoms mostly related to lower cranial nerve dysfunction, such as apnea, dysphagia, and aspiration events need to be stabilized and require immediate critical care interventions for airway protection and hemodynamic support.
Preparation for definitive intervention, nonemergent
Neuraxis imaging: The entire spine and brain must be imaged to rule out hydrocephalus, syringomyelia, craniocervical instability, or other congenital problems.
Preparation for definitive intervention, emergent
Chiari I – emergency rare: Emergency surgery for Chiari I malformation is rarely necessary.
Chiari II – shunt evaluation: Symptoms of Chiari II malformation should immediately trigger an investigation of shunt function.
Routine admission orders
VS: Continuous monitoring is needed if concern exists about hydrocephalus.