7 Nonaneurysmal Subarachnoid Hemorrhage
Abstract
In 1985, van Gijn et al1 were the first to report the existence of a variant of subarachnoid hemorrhage (SAH) characterized by negative angiography and focal bleeding in the prepontine cistern, referred to as nonaneurysmal perimesencephalic subarachnoid hemorrhage (PMSAH). Early prospective series revealed that patients with PMSAH had superior clinical outcomes when compared with aneurysmal or classic bleeding patterns on computed tomography (CT) that were also angiographically unremarkable, including reduced rebleeding and neurologic deficits.2,3 These findings prompted the need for developing a diagnostic paradigm for angiographically occult patients with SAH, especially in those patients with classic SAH patterns on CT with no evidence of aneurysm rupture.
Keywords: subarachnoid hemorrhage, angiographically negative hemorrhage, perimesencephalic hemorrhage, nonaneurysmal hemorrhage, catheter-based angiography
7.1 Goals
1. Evaluate the natural history of patients with nonaneurysmal subarachnoid hemorrhages (SAHs).
2. Explore the basis for the evaluation and management of patients with nonaneurysmal SAHs.
3. Understand the results of repeated testing for nonaneurysmal SAHs.
7.2 Case Example
7.2.1 History of Present Illness
A 65-year-old female with a history of coronary artery disease status postbypass graft, hypertension, hyperlipidemia, and diabetes mellitus presented to the emergency department with sudden onset 10/10 bitemporal and occipital headache with altered mental status, confusion, nausea, vomiting, photophobia, and weakness. Her blood pressure was 229/89 on admission, and she was started on a nicardipine drip and intravenous labetalol. She was well oriented and responsive but appeared distressed. Noncontrast computed tomography (CT) head demonstrated spontaneous SAH of unknown origin, and the patient was transferred to the Neurological Interventional Care Unit.
Past medical history: Angina pectoris; coronary artery disease status post bypass graft; diabetes mellitus; high cholesterol; hypertension; migraine headache.
Past surgical history: Cardiac catheterization (x2); cardiac ablation of ventricular tachycardia and premature ventricular contraction; coronary artery bypass graft; vascular surgery.
Allergies: Phenergan; Levaquin (rash); Penicillins (rash); Per-cocet (anxiety).
Medications: Acetaminophen; ascorbic acid, calcium carbonate-vitamin D; clobetasol; desoximetasone; fexofenadine; fish oil; furosemide; detemir; lispro; levothyroxine; lisinopril; multivitamin; nitroglycerin; nystatin-hydrocortisone-zinc oxide; rosuvas-tatin; tramadol.
Family history: Mother—diabetes; father—stroke age 62, lung cancer age 72; brother—myocardial infarction age 60, history of drug abuse; brother—myocardial infarction age unknown, history of drug abuse.
Social history: Married; works as a bookkeeper; former smoker 20 pack-years, quit date January 1,1970; rare alcohol consumption.
Physical examination: Pulse 89, temperature 36.2 °C, respiratory rate 12, Sp02 98%, blood pressure 229/89.
Glasgow Coma Scale (GCS) of 15, Hunt and Hess grade 1. Cranial nerves were intact, no pronator drift, 5/5 strength, and sensation intact to light touch in all extremities. Imaging studies: See ▶ Fig. 7.1.
7.2.2 Treatment Plan
Given the continued need for monitoring and the appearance of early hydrocephalus on the CT scan, a right frontal ventriculostomy catheter was placed, and the patient was transferred to the Neurosurgical Intensive Care Unit. A six-vessel diagnostic cerebral angiogram the following morning was negative for any source of the diffuse SAH.
Fig. 7.1 CT head demonstrating subarachnoid hemorrhage with the greatest burden in the prepontine cisterns (Fisher grade 4). There is also a moderate burden of subarachnoid hemorrhage in the suprasellar cistern and also along the right tentorial leaflet extending to the posterior fossa. Small intraventricular hemorrhage layering in the posterior occipital horns is also present. There are enlarged temporal horns demonstrating early hydrocephalus.
7.2.3 Hospital Course
The patient was admitted to the Neurointensive Care Unit. The patient received serial transcranial Doppler studies and repeat angiography was performed 1 week later, which did not show clear pathology explaining the SAH. The external ventricular drain (EVD) was discontinued during the course of her hospitalization, and the patient was discharged to an acute rehabilitation facility. A follow-up computed tomography angiography (CTA) head performed after 6 weeks was negative for any significant vascular pathology.
7.3 Case Summary
1. What is the time course for the treatment of nonaneurysmal SAH?
Care for nonaneurysmal SAH (NASAH) is generally the same as aneurysmal SAH (ASAH), in that both are treated as an acute emergency. Neurologic decompensation occurs in up to 35% of patients within 24 hours of symptom onset.4 In addition, patients presenting in a hypertensive state often require blood pressure control.
The amount of subarachnoid blood present, neurologic status on admission, and volume and blood pressure status are predictors of delayed cerebral ischemia (DCI).5 Nimodipine is administered to minimize the complications secondary to cerebral vasospasm. While it is the standard of care for patients with ASAH, there are no formal studies showing benefit of nimodipine in perimesencephalic subarachnoid hemorrhage (PMSAH) or NASAH.
Some studies suggest that the reduced incidence of vasospasm in this cohort argues against nimodipine use.6 Triple H therapy is another method used to address vasospasm. Triple H therapy represents induced hypertension, hypervolemia, and hemodilution therapy. Cardiac complications, such as transient left ventricular dysfunction (TLVD) in SAH, are also contributing factors to DCI.7 While vasospasm is the most critical side effect of SAH to address, hyponatremia, deep venous thrombosis (DVT), hyperglycemia, anemia, and fever are other medical complications that may arise.
2. How do different hemorrhage patterns impact treatment and patient outcomes?

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