Headache and diplopia after rapid maxillary expansion: a clue to underdiagnosed pseudotumor cerebri syndrome?

Rapid maxillary expansion (RME) is an orthodontic procedure that separates the two maxillary bones at the mid palatine suture level. RME is commonly used in the pediatric age group to reduce and/or eliminate a transverse maxillary deficiency. At our institution we followed up an 11-year-old adolescent who was diagnosed with a class III malocclusion and was treated by RME with the combined use of expansion appliances (i.e., Hyrax) in addition to maxillary protraction devices (i.e., Delaire facemask). Three months after the start of treatment, he complained of headache and double vision, and was admitted to our hospital. A funduscopic examination revealed papilledema. Magnetic resonance imaging of the brain showed intraocular protrusion of the optic nerve head and enlarged perioptic subarachnoid space. Cerebrospinal fluid opening pressure during lumbar puncture was elevated (+370 mm H2O), confirming the diagnosis of the pseudotumor cerebri syndrome (PTCS). Removal of the maxillary expander and facemask led to the complete resolution of clinical symptoms in 1 week. The association of RME and PTCSrelated manifestations was first reported by Timms in 1986, but, to the best of our knowledge, further cases have been not described in the medical literature. This overlooks PTCS as a potential RME-associated complication. We suggest that clinicians should carefully consider PTCS in all pediatric patients that complain of headache and/or visual disturbances during a treatment by RME. We also speculate on the possible changes of the cerebral venous circulation during RME, potentially leading to an impaired venous drainage that may cause increased intracranial pressure and PTCS.