Subarachnoid Hemorrhage: Clinical Findings
Sudden bleeding into space surrounding the brain (for pathogenesis, see Subarachnoid Hemorrhage: Pathogenesis)
Authors: Jason An, M. Patrick Pankow Reviewers: Owen Stechishin, Dave Nicholl, Haotian Wang, Hannah Mathew, Ran (Marissa) Zhang, Yan Yu*, Cory Toth* * MD at time of publication
Bleed into subarachnoid space
Subarachnoid Hemorrhage (SAH)
Posterior hypothalamus ischemia (↓ Blood flow and oxygen)
Red blood cell lysis from energy depletion or complement activation
Release of spasmogens (spasm inducing agents)
Cerebral vasospasm (narrowing of arteries from persistent contraction) ↓ blood flow
Cerebral ischemia
Release catecholamines (hormones from the adrenal gland; e.g., epinephrine, norepinephrine)
↑ Intracellular calcium
Release of antidiuretic hormone
Antidiuretic hormone acts on the distal convoluted tubule and collecting duct in kidney to reabsorb water
Dilution of serum sodium
Hyponatremia (low blood sodium levels)
Release of epileptogenic (potential seizure causing agents) into cerebral circulation
Seizure
Products from blood breakdown in cerebral spinal fluid
Irritation of meninges (membranes surrounding the brain)
Aseptic meningitis (non-infectious inflammation)
Meningismus
(neck pain + rigidity)
Cerebral infarction (death of tissue)
Obstructs cerebral spinal fluid flow and absorption at subarachnoid granulations
Hydrocephalus (fluid build up in ventricles)
↓ Level of consciousness
Reduced cerebral blood flow
Dilation of cranial vessels to ↑ blood flow
Rapid ↑ internal carotid artery intracranial pressure
Refer to Increased Intracranial Pressure: Clinical Findings slide
Internal carotid artery
Pituitary ischemia
Hypopituitarism
[underactive pituitary gland, failing to produce 1+ pituitary hormone(s)]
Refer to hypopituitarism slides
Myocardial disruption
Left ventricle dysfunction
↑ Pressure in left heart
Blood forced backwards into pulmonary veins
↑ Pulmonary blood pressure
Fluid from blood vessels leaks into lungs
Dysrhythmias (disturbance in rate/rhythm of heart) causing ↓ cardiac output
Syncope
(loss of consciousness due to ↓ blood flow to the brain)
Pulmonary edema
(excess accumulation of fluid in lung)
Cerebral hypoperfusion
Sudden ↑in blood volume
Vessels and meninges suddenly stretch
Thunderclap Headache (worst headache of patient’s life)
Shortness of breath
Reactive cerebral hyperemia (excess blood in vessels supplying the brain)
Artery specific findings:
Rapid ↑ internal carotid artery intracranial pressure
Middle cerebral artery
Posterior communicating artery
Compression of outer CN3 Compression of inner CN3
Anterior communicating artery
Nonreactive pupil
Gaze palsy
(eye deviates down and out)
Diplopia
(double vision)
Ptosis
(drooping of upper eyelid)
Frontal lobe ischemia
Avolition
(complete lack of motivation)
Ischemia of motor strip pertaining to the legs
Bilateral leg weakness
Motor strip ischemia
Hemiparesis
(weakness/ inability to move one side of the body)
Ischemia of parietal association areas (brain regions integral for motor control of the eyes, the extremities and spatial cognition)
Aphasia
(impaired ability to speak and/or understand language)/ neglect
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published July 1, 2014, updated August 10, 2022 on www.thecalgaryguide.com