Non-Aneurysmal: Definition & Clinical Context

Non-aneurysmal means not related to an aneurysm—a localized, pathological dilation or bulging of a blood vessel caused by weakening of the vessel wall.

Usage in Medical Terminology

• Non-aneurysmal subarachnoid hemorrhage (SAH): SAH without identifiable aneurysm on angiography (~10-15% of SAH). Causes: perimesencephalic (benign), arteriovenous malformation, venous anomaly, tumor, anticoagulation, trauma, RCVS, pituitary apoplexy, idiopathic.
• Non-aneurysmal vascular lesion: Dissection, fistula, malformation, pseudoaneurysm (false aneurysm—contained rupture, not true dilation).
• Non-aneurysmal widening: Ectasia (diffuse dilation <50% normal diameter) vs. aneurysm (focal >50%).

Clinical Importance

• Distinguishing aneurysmal vs. non-aneurysmal SAH changes management: non-aneurysmal perimesencephalic SAH has excellent prognosis, no coiling/clipping needed, low rebleed risk.
• Guides surveillance: Aneurysms require monitoring/repair; non-aneurysmal etiologies may not.
• Informs family screening: Familial aneurysm syndromes (ADPKD, connective tissue disorders) vs. sporadic non-aneurysmal causes.

Precise terminology directs appropriate workup, treatment, and counseling.