Fourth nerve (IVn.) Trochlear palsies emergency

Most trochlear palsies are not emergent. Most trochlear palsies are due to stroke, trauma, and rarely neoplasm or aneurysm. Rarer causes are GCA and increased ICP that occassionally need to be addressed. 0.02 % of low pressure headaches after lumbar puncture have an associated IV nerve palsy (Continuum August 2009).