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Headache and Syncope

Hx: A 34 yo female presents with headache and syncope. She is accompanied by family  who give most of the hx. The patient has a hx of daily migraines for which she takes excedrin. Last night she had onset of a severe frontal HA, no radiation, timing unknown. She took a dose of excedrin. This morning she awoke with a headache that was worse, severe, frontal, non-radiating, 10/10 then was witnessed to have a syncopal episode. No shaking or muscle stiffness. Loss of consciousness was very brief but the patient was slow to answer questions immediately afterward. Family called EMS.

The paramedics note the patient had an abnormal rhythm but a normal pulse and was hemodynamically stable in route. They started an IV and gave a dose of zofran for vomiting.

PMHx: Migraine

SocHx: Has a twin, smokescigarettes regularly, occasional alcohol, no drugs.


  • General: in distress, shielding her eyes, awake
  • Vitals: 150/90, 85, sat 100% RA, temp 98, RR 16
  • Head: Atraumatic, normocephalic
  • ENT: TM’s clear, pupils 3mmand reactive, very photophobic, clear pharynx
  • Neck: Able to flex and extend but with some posterior neck pain on flexion
  • Resp: clear to auscultation bilaterally
  • Cardiovascular: regular rate and rhythm, pulses normal all extremities
  • Abdomen: Soft, non-tender, non-distended
  • Extremities: Warm,
  • Neuro: CN II-XII normal, moving all extremities purposefully, normal sensation and strength

Differential Diagnosis:

  • SAH / ICH
  • CVA
  • Migraine
  • Carotid Dissection
  • IC mass
  • Drug withdrawal
  • Dehydration
  • Dysrhythmia
  • AMI
  • Aortic Dissection
  • Occult pregnancy


  • EMS rhythm strips were reviewed and showed an intermittent regular wide complex rhythm consistent with a ventricular origin but with the absence of tachycardia. By the time a field 12 lead was performed, her rhythm has already begun to change.
Rhythm strip #1.jpg
EMS Rhythm Strip #1
Rhythm strip #2.jpg
EMS Rhythm Strip #2
Rhythm strip #3.jpg
EMS Rhythm Strip #3
EMS 12 lead
  • Laboratory studies were normal including complete blood count, complete metabolic profile, and cardiac enzymes (troponin).
  • Urinalysis and pregnancy test were also negative.
  • ECG demonstrated a sinus rhythm with rate of 90 and a normal QRS
Hospital 12 Lead.jpg
Hospital ECG
  • CT head without contrast demonstrated an acute sub-arachnoid hemorrhage with blood in the 4th ventricle
Head CT 1.jpg
Red Arrows Show Sub-Arachnoid Hemorrhage and Blood In 4th Ventricle
  • A follow up CT angiography of the head and neck demonstrated a  fenestrated basilar artery with two aneurysms at the bifurcation, as well as congenitally absent right internal carotid artery.
Head CT 5.jpg
5 contrast filled structures are seen where only a basilar artery should be seen (red arrow)
Head CT Coronal 1.jpg
A circular base (fenestration) of the basilar artery can be seen.
Head CT Coronal 3.jpg
Circular base (fenestration) of the basilar artery seen.
Head CT Angio.jpg
Imaging demonstrates the fenestrated basilar artery with a small aneurysm seen at the bifurcation.


Hospital Course:

  • The patient is taken to the neuro angiography suite where 3 aneurysms are identified: 7mm x4.5mm aneurysm at the anterior vertebro-basilar junction, 1.5mm aneurysm at the posterior vertebro-basilar junction, and a 4mm incidental left cavernous aneurysm.
  • The largest aneurysm is coiled with plans for repeat angiography and intervention in a staged fashion.

Diagnosis: Acute Subarachnoid Hemorrhage due to intracranial aneurysm; Congenital fenestrated basilar artery.


This patient presented with multiple interesting findings.:

  1. She was found to have a sub-arachnoid hemorrhage due to an intracranial aneurysm arising from a fenestrated basilar artery. Although rare, basilar artery fenestration represents the most common intra-cranial arterial fenestration. Some studies have suggested that this fenestration carries an increased risk of aneurysm formation (quoted as 7% or more) however, there is debate regarding the accuracy of this rate. The populations studied were primarily those with known aneurysms or hemorrhage. Other studies conducted on a more general population of asymptomatic patients have not been able to find an increased association with aneurysms.
  2. This patient’s presentation of a sudden onset headache, worse than her prior migraines, and associated with syncope and neck pain summarizes the classic teaching for acute sub-arachnoid hemorrhage.  Though there may be characteristics in common with her migraines, such as photophobia or phonophobia, the severity and sudden onset represent a clear departure from benign pathology.
  3. This patient also presented to EMS with an abnormal rhythm post syncope which cold have easily led the evaluation away from the area of actual pathology. Intra-cranial hemorrhage has been shown to create PACs, PVCs, ventricular tachycardia, and ventricular fibrillation. There are two mechanisms postulated: autonomic neural stimulation from the hypothalamus or elevated levels of circulating catecholamines. Stimulation from the hypothalamus may lead to ECG changes without true coronary ischemia,  and elevated catecholamine levels can result in QT-interval prolongation and true myocardial damage. These ECG changes can mislead the provider and cause unnecessary cardiac testing and consultations which can detract from the immediate neurosurgical emergency. In the correct clinical setting, dysrhythmia should be expected at onset of the sub arachnoid hemorrhage and may occur up to 48 hours after the initial presentation. Cardiac monitoring is important however, treatment is typically directed at the intra-cranial hemorrhage instead of the dysrhythmia.

For further reading:

A great neurosurgery blog with angiographic images !

More on aneurysms and fenestrated vessels

More on CT angiography vs MRA

More on abnormal cardiac rhythms resulting from SAH

More on fenestrations and aneurysm risk

Article on Basilar Fenestrations

More on aneurysms and vertebro-basilar fenestrations

More on endovascular treatment of basilar aneurysms

More on basilar artery fenestration and duplication



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