Case 4: MCA aneurysm ("angio-negative")

posted June 3, 1996

Resident: Ian Angel, MD
Attending Staff: Deepak Awasthi, MD

This 56 year old Hispanic woman presented to the emergency room with a complaint of a severe headache (persistent) which started the evening prior to admission. This was accompanied by a stiff neck and one bout of vomiting on the morning of admission. Patient's past medical history is significant for essential hypertension.

PHYSICAL EXAMINATION: Vital signs: T: 98; Pulse:60; BP: 190/100; RR: 20 (regular). Patient is awake and alert. She is in moderate distress from the headache. Patient complains of photophobia. Neck is stiff, meningeal signs are present. No focal neurological deficits. Pupils equal, round and reactive. General examination is within normal limits (no murmurs).

DIAGNOSTIC STUDIES: Cranial CT scan without contrast was performed in the ER- see below:

Selected axial views of the non-contrasted cranial CT scan above show that majority of the subarachnoid blood is in the left Sylvian cisten.

With the suspicion of a left middle cerebral artery aneurysm rupture, the patient was taken to the angiographic suite for a 4-vessel cerebral angiogram- see below:

Shown above is an AP projection of the left internal carotid artery (ICA) injection. The angiogram was read as negative. A magnified view of the left ICA injection is shown below:

The marker points to what was felt to be an abnormality at an early branch from the left M1 segment of the middle cerebral artery.
Of note: NO other abnormalities were noted in the anterior or posterior circulations. There was no evidence of vasospasm on the angiogram.

What do you think about the angiographic abnormality- is it the source of the SAH? How would you proceed at this time- explore or wait and re-angio? If wait, how long will you wait?

Please comment: dawast@lsuhsc.edu

STEPS TAKEN AT LSU: Given the suspicious lesion on the left M1 segment of the MCA, the relative focality of the SAH, and the fact that the patient was grade I (Hunt and Hess)- we elected to explore on day 3 after SAH. Intraoperative findings were that of a "microaneurysm" arising from the junction of a fronto-orbital branch from the M1 segment of the left MCA- see below:

Marker is pointing at the aneurysm.

Of note: there was significant amount of blood clot around this aneurysm. In addition, the MCA bifurcation was normal.

POSTOPERATIVE COURSE: Patient did well postoperatively. She remained awake and alert with no focal neurological deficits. Postoperative dopplers did reveal moderate vasospasm- not manifest clinically. A repeat cerebral angiogram (4-vessel) two weeks postoperative revealed no aneurysm, vasospasm or abnormality. Patient was discharged home in good condition.

References

1. Tatter SB, Crowell RM, Oglivy CS: Aneurysmal and microaneurysmal "angiogram-negative" subarachnoid hemorrhage. Neurosurgery 37:48-55, 1995.
2. Osoda K, Fujita S, Kawaguchi T, Shose Y, Hamano S: Saccular aneurysms of the proximal (M1) segment of the middle cerebral artery. Neurosurgery 36:441-446, 1995.

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