Pituitary tumors most commonly involve the oculomotor nerve; 14% to 30% of pituitary tumors lead to TNP.13 Pituitary apoplexy secondary to infarction or hemorrhage is often associated with visual field defects and TNP.13
An underlying aneurysm manifests in a minority (10% to 15%) of patients presenting with TNP.3
Imaging is key to getting at the cause of TNP
The evaluation of patients presenting with acute TNP should be focused first on detecting an aneurysmal compressive lesion.3 CTA is the imaging modality of choice.
Once an aneurysm has been ruled out, the work-up should include a lumbar puncture and an erythrocyte sedimentation rate. Older patients should be assessed for conditions such as hypertension or diabetes that put them at risk for microvascular disease.3 If microvascular TNP is unlikely, MRI with MR angiography is recommended to exclude other potential etiologies of TNP.3 If the patient is younger than 50 years of age, consider potential infectious and inflammatory etiologies (eg, giant cell arteritis).3
Treatment options are varied
The treatment of patients with TNP is specific to the disease state. For those patients with vascular risk factors and a presumptive diagnosis of microvascular TNP, it is reasonable to observe the patient for 2 to 3 months.3 Antiplatelet therapy is usually initiated. Patching 1 eye is useful in alleviating diplopia, particularly in the short term. In most cases, deficits related to TNP resolve over weeks to months. Deficits that persist beyond 6 months may require surgical intervention.
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