A 58-year-old otherwise healthy woman had a 2-year history of vertigo while straining at stool. Symptoms comprised a violent whirling sensation, as if threatening to "throw her to the ground," which lasted a few minutes. This had become so prominent in the 3 months preceding her referral that she was forced to use a laxative daily. No headaches, nausea, or vomiting was present. Findings from physical and neurological examinations revealed no abnormalities. Papilledema and cerebellar signs were not observed. Routine laboratory tests revealed no unusual results. Neuro-otological and neurophysiological investigations, including auditory-evoked brainstem response, failed to yield conclusive results. However, magnetic resonance imaging revealed a nonenhancing cystic mass iso-intense with cerebrospinal fluid, present in the quadrigeminal cistern extending to the left posterior thalamic region. The lesion severely compressed the tectal plate and cerebellar vermis, causing aqueductal stenosis and tonsilar ptosis (Figure 1).
Kurita H, Nitta Y, Nakamura M, Shiokawa Y. Defecation-Induced Vertigo. Arch Neurol. 2004;61(7):1137-1138. doi:10.1001/archneur.61.7.1137