Subarachnoid Hemorrhage
EDiNR, EDiPNR, EDER
Chief of Neuroradiology Section,Ege University Medical Faculty, Dept of Radiology
Izmir, TURKEYMacdonald RL. Delayed neurological deterioration after subarachnoid haemorrhage. Nat Rev Neurol. 2013;10:44–58
What is SAH?
• Bleeding in subarachnoid
space(Between arachnoid & pia mater which
is normally filled with CSF)
• A neurologic emergency
SAH:
Traumatic SAH occurs 35-40% of TBIs
The incidence of Aneurysmal SAH 7-10/100.000
Mortality and morbidity very high
1/3 recovery, 1/3 with complications, 1/3 fatal
What are the causes of SAH?1. Trauma
Most common cause
2. SpontaneousRuptured Aneurysm (80-85%)Unknown (7%)AVMArterial dissectionVasculitis, Amyloid angiopathyCerebral venous thrombosisTm, PRESDrug abuseetc….
Risk factors for SAH:
Peak between 50-60 years of age
Female > Male
Hypertension
Smoking, excessive alchohol intake
Family history
Drug abuse
Sickle cell disease
etc
SAH: Clinical featuresHeadache
* thunderclap or worst* reaching maximal intensity in 1 min.* Sudden onset more important than severity of HA
Nausea & vomiting
Seizure
Loss of consciousness
Neck stiffness / meningismus
Neurological deficits
CNIII, CNVI palsies
SAH: Diagnosis
Non-contrast CT
The primary choice.
Sensitivity depends on the interval betweensymptom onset and image acquisition.
100% in first 6 hours97% between 6-72 hours50% after 5 days
Because the blood density decreases by timeAcute stage 4 days later
Acute stage 8 days later
SAH: Diagnosis
SAH may be associated with:
Cerebral hematoma
Intraventricular hemorrhage
Subdural hematoma
SAH: Diagnosis
Lumbar Puncture (LP)
Recommended only if NCCT negative
Should be performed after 12 hours of symptomsto detect Xanthochromia (after red blood cell lysis)
Can be false negative / false positive (traumatic LP)
(!! Only 1% true positive with negative NCCT)
SAH: DiagnosisCTA
When NCCT positive
In the same session
Precise relationship with anatomic structures
Thrombus, calcification
Sensitivity 95-97%
DSA
Gold standard
Doubt on CTA
Better for small aneurysms
Treatment planning
Diagnosis of AVM, AVF
Should be repeated if initial DSA negative
54 y, M. Acute severe HA
SAH: DiagnosisMRI
SE, FSE, GRE, FLAIR, SWI, MRA
Sensitivity increases in the subacute phase.
<4 days: sensitivity 95%. 4-14 days: sensitivity 100%
FLAIR, SWI should be the choice
MRA 3T higher sensitivity
Rule out other causes
(Venous thrombosis, PRES, Tm, Amyloid angiopathy….)Aneurysm, SAH; MRI, MRA
Pseudo-SAH appearance on:1. FLAIRMeningitisLeptomeningeal carcinomatosisSupplemental 100% oxygenCSF pulsationMotion artifactGd leakage into CSF
2. CTMeningitisVenous sinus thrombosisLarge subdural hematomaBrain edema
SWI
53y F. Acute onset headache
SWI
Reversible cerebral vasoconstriction syndrome (RCVS)
SAH: LocationDiffuse
Perimesencephalic
Convexal
SAH: Location
Ant choroidal aneursymPartially thrombosed
DSA
Acute HA;
SAH, hematoma
MCA aneurysm
Acom aneurysmIntraventricular hemorrhage
SAH: Perimesencephalic-
Better prognosis. CTA / DSA should be performed
5% Aneurysm, AVF, Tm
SAH: ComplicationsSAH is not a monophasic disease !!
(biphasic / triphasic…. disease)
Knowledge of physiopathology is important
To understand the complications
SAH: what happens after bleeding?
Leakage of the blood to SA space leads to:
ICP CBF Activates injury cascade
Acute global ischemia, early brain injury, Anaerobic glycolysis
BBB breakdown, impaired autoregulation, cerebral edema…
Is blood a poison when out of the vessels?
Macdonald, R. L. (2013) Delayed neurological deterioration after subarachnoid haemorrhageNat. Rev. Neurol. doi:10.1038/nrneurol.2013.246
SAH: what happens after bleeding? SAH: ComplicationsAcute (day 0-3)
Rebleeding
Acute hydrocephalus
Cerebral edema
Non-neurological complications
Subacute (day 3-30)Vasospasm
Chronic (day >30)Chronic hydrocephalus
SAH: Complications
Possible complications predict the outcome.
Prediction of the complications can be done by CT.
Fisher Scale / Modified Fisher Scale
Grade CT findings
0 No SAH, No IVH
1 Focal/diffuse thin SAH, No IVH
2 Focal/diffuse thin SAH, IVH present
3 Focal/diffuse thick* SAH, No IVH
4 Focal/diffuse thick* SAH, IVH present
*Thick: completely filling at least one cistern or fissure
Complication rate increases by grade
SAH: ComplicationsAcute (day 0-3)
Rebleeding
Acute hydrocephalus
Cerebral edema
Non-neurological complications
Subacute (day 3-30)Vasospasm
Chronic (day >30)Chronic hydrocephalus
Rebleeding:Most serious complication
Occurs in first 3 days
Emergency treatment crucial
Poor prognosis
Fisher grade 3 4
SAH: ComplicationsAcute (day 0-3)
Rebleeding
Acute hydrocephalus
Cerebral edema
Non-neurological complications
Subacute (day 3-30)Vasospasm
Chronic (day >30)Chronic hydrocephalus
SAH: ComplicationsAcute (day 0-3)
Rebleeding
Acute hydrocephalus
Cerebral edema
Non-neurological complications
Subacute (day 3-30)Vasospasm
Chronic (day >30)Chronic hydrocephalus
Cerebral edema:
SAH
Decompressive craniectomy
Rebleeding
SAH: ComplicationsAcute (day 0-3)
Rebleeding
Acute hydrocephalus
Cerebral edema
Non-neurological complications
Subacute (day 3-30)Vasospasm
Chronic (day >30)Chronic hydrocephalus
SAH: Non-neurological complications
ECG abnormalities
Myocardial distress
Acute respiratory syndromes (Edema, ARDS)
Na & K abnormalities
Due to sympathetic nervous system activation
SAH: ComplicationsAcute (day 0-3)
Rebleeding
Acute hydrocephalus
Cerebral edema
Non-neurological complications
Subacute (day 3-30)Vasospasm
Chronic (day >30)Chronic hydrocephalus
SAH: Vasospasm !Most common (and dangerous)
Occurs between day 3-15
The risk depends on Fisher Grade !!
Degradation of blood products in CSF lead to
release of vasoactive mediators
Vasoconstruction
Leading to decreased CBF
27 y, M. Acute HA; 27 y, M. Acute HA; 3 days later
Vasospasm
Pcom aneurysm
ICA + Basilar artery
27 y, M. Acute HA; 8 days later
27 y, M. Acute HA; 13 days later 27 y, M. Acute HA; 15 days later
27 y, M. Acute HA; 1 7 days later SAH:
SAH:
SAH is di-tri phasic disease
Imaging findings are important for management
Follow-up imaging has a crucial role
Each change in clinical condition should be verified by imaging modalities
We must be aware of imaging findings to choose optimal imaging modality !!
THANKS FOR YOUR ATTENTION