Stroke Causes and Symptoms

## Stroke: Causes and Clinical Presentation ### Definition and Pathophysiology Stroke is defined as the acute onset of a non-convulsive neurologic deficit caused by a disturbance of cerebral circulation, with symptoms developing abruptly over seconds to minutes [5][7]. The underlying mechanism is either **ischemia** (loss of blood flow to focal neural tissue) or **hemorrhage** (rupture of a vessel with bleeding) [5]. Regardless of cause, brain cells suffer ischemia and hypoxia; brain cells are exquisitely vulnerable, with irreversible cell death occurring after approximately 5 minutes without oxygen [2]. ### Causes of Stroke #### Ischemic Stroke (80–90% of all strokes) [3][5] | Mechanism | Examples | |-----------|----------| | **Cardioembolism** | Atrial fibrillation, myocardial infarction, infective endocarditis, valvular lesions [3][9] | | **Large-artery atherosclerosis** | Carotid bifurcation disease, atherosclerosis of neck and intracranial arteries [3][9] | | **Small-vessel disease** | Lacunar infarction [3][9] | | **Cryptogenic** | ~30% of ischemic strokes have no clear cause identified [3] | #### Hemorrhagic Stroke (10–20% of all strokes) [3][5] - **Hypertension** — the predominant cause [3][9] - **Vascular malformations** — aneurysm, arteriovenous malformation, cavernous malformation, fistula [3][9] - **Cerebral amyloid angiopathy** [3] - **Other** — trauma, anticoagulant therapy, blood dyscrasias, brain tumor [9] #### Uncommon Causes (Young Adults and Atypical Presentations) Retrieved evidence from a cohort of 1,322 young adults with ischemic stroke identified several rare etiologies, including: acute systemic infection preceding stroke, neurological infections (neurosarcoidosis, neuroborreliosis, neurolues), MELAS, Takayasu arteritis, intracranial dissection, and hypotension [6]. Additional uncommon causes span vascular (arterial dissection, fibromuscular dysplasia, Moyamoya disease, CADASIL), hematologic (sickle cell disease, antiphospholipid syndrome, thrombotic thrombocytopenic purpura), inflammatory (primary CNS vasculitis, systemic vasculitides), drug-related (cocaine, amphetamines, oral contraceptives), infectious (endocarditis, meningitis, HIV), malignant, and metabolic categories (Fabry disease, homocystinuria, MELAS) [7][8]. ### Risk Factors **Modifiable** [3][9][10]: - Hypertension - Diabetes mellitus - Hyperlipidemia/dyslipidemia - Atrial fibrillation and other heart disease (heart failure, infective endocarditis) - Tobacco/nicotine use (smoking, vaping, chewing) - Prior stroke or TIA **Non-modifiable** [3][9][10]: - Age - Male sex - Ethnicity/race - Socioeconomic status - Family history/genetic predisposition ### Clinical Symptoms The presentation is variable and depends on the affected vascular territory [9]. #### Core Warning Signs (Stroke 911 Mnemonic) [2] - **Facial asymmetry** — one side of the face droops when smiling - **Arm weakness** — one arm drifts downward when both are raised - **Speech disturbance** — slurred or confused speech #### Additional Signs [2][10] - Sudden dizziness or severe headache - Numbness or weakness, especially unilateral - Blurred or double vision, or gaze deviation - Unsteady gait or poor coordination - Altered consciousness or seizures #### Anterior Circulation (Carotid Territory) [9] - Contralateral hemiplegia and cortical sensory loss - Aphasia with left hemispheric involvement #### Posterior Circulation (Vertebrobasilar) [9] - Vertigo, nausea, vomiting, dizziness - Dysarthria, ataxia - Unilateral or bilateral cranial nerve and brainstem signs #### Additional Clinical Features [7] - Headache occurs in approximately 25% of ischemic stroke patients but is more common in intracerebral or subarachnoid hemorrhage - Nausea and vomiting, particularly with brainstem/cerebellar involvement - Decreased level of consciousness is unusual in the first hours unless the brainstem reticular activating system is affected - Acute hypertension (>70% of cases), often normalizing spontaneously over subsequent days ### Key Clinical Takeaway Public awareness data indicate that while recognition of common motor and speech symptoms is high (>70%), recognition of **sudden memory loss** as a stroke symptom is notably lower — representing a gap in understanding cognitive manifestations of stroke [1]. Clinicians should maintain a low threshold for considering cognitive symptoms in the differential of acute neurologic presentations. --- *This content is AI-generated based on retrieved literature and is intended for clinical reference only. Please verify against primary sources and apply individual patient judgment.*