Unusual Presentations of the Chiari I Malformation

Abstract

Chiari type I malformations (CM I) most commonly present with exertional occipital headaches and neck pain. In infants, these headaches may simply present as irritability. Cerebellar tonsil herniation can also cause compression of the medulla and lower cranial nerves leading to neurologic symptoms as well. Syringomyelia, commonly associated with CM I, also can result in neurologic sequelae. This spectrum of symptoms includes extremity weakness, sensory deficits, and abnormal reflexes. Lower cranial nerves can also be affected resulting in vocal cord paralysis, tongue weakness, aspiration, hoarseness, nystagmus, palatal weakness, and sleep apnea. Although the vast majority of patients with CM I present with the symptoms listed above, there have been reports in the literature of more unusual presentations. This chapter will review the less common and more unusual presentations of CM I, including syncope, hearing loss, cranial nerve neuralgias, respiratory failure, endocrinologic dysfunction, hiccups, esotropia, peripheral nerve syndromes, and acute sensory or motor deficits.