A 61-year-old man is brought to the emergency room with slurred speech. According to the patient's wife, they were watching a movie together when he developed a minor headache. He soon developed difficulty speaking in complete sentences, at which point she decided to take him to the emergency room. His past medical history is notable for hypertension and hyperlipidemia. He takes aspirin, lisinopril, rosuvastatin. The patient is a retired lawyer. He has a 25-pack-year smoking history and drinks 4-5 beers per day. His father died of a myocardial infarction, and his mother died of breast cancer. His temperature is 98.6°F (37°C), blood pressure is 143/81 mmHg, pulse is 88/min, and respirations are 21/min. On exam, he can understand everything that is being said to him and is able to repeat statements without difficulty. However, when asked to speak freely, he hesitates with every word and takes 30 seconds to finish a short sentence. This patient most likely has an infarct in which of the following vascular distributions?

Superior division of the middle cerebral artery

Proximal middle cerebral artery

Inferior division of the middle cerebral artery

Middle cerebral artery and posterior cerebral artery watershed area

Anterior cerebral artery and middle cerebral artery watershed area

A 76-year-old woman with hypertension and coronary artery disease is brought to the emergency department after the sudden onset of right-sided weakness. Her pulse is 83/min and blood pressure is 156/90 mm Hg. Neurological examination shows right-sided facial drooping and complete paralysis of the right upper and lower extremities. Tongue position is normal and she is able to swallow liquids without difficulty. Knee and ankle deep tendon reflexes are exaggerated on the right. Sensation to vibration, position, and light touch is normal bilaterally. She is oriented to person, place, and time, and is able to speak normally. Occlusion of which of the following vessels is the most likely cause of this patient's current symptoms?

Contralateral lenticulostriate artery

Ipsilateral anterior cerebral artery

Contralateral middle cerebral artery

Ipsilateral posterior inferior cerebellar artery

A 62-year-old woman comes to the physician for decreased vision and worsening headaches since this morning. She has hypertension and hypercholesterolemia. Pulse is 119/min and irregular. Current medications include ramipril and atorvastatin. Ocular and funduscopic examination shows no abnormalities. The findings of visual field testing are shown. Which of the following is the most likely cause of this patient's symptoms?

Occlusion of the posterior cerebral artery

Occlusion of anterior cerebral artery

Occlusion of the anterior inferior cerebellar artery

Impaired perfusion of the retina

A 67-year old woman is brought to the emergency department after she lost consciousness while at home. Her daughter was with her at the time and recalls that her mother was complaining of a diffuse headache and nausea about 2 hours before the incident. The daughter says that her mother has not had any recent falls and was found sitting in a chair when she lost consciousness. She has hypertension. Current medications include amlodipine, a daily multivitamin, and acetaminophen. She has smoked 1/2 pack of cigarettes daily for the past 45 years. Her pulse is 92/min, respirations are 10/min, and blood pressure is 158/100 mm Hg. She is disoriented and unable to follow commands. Examination shows nuchal rigidity. She has flexor posturing to painful stimuli. Fundoscopic examination is notable for bilateral vitreous hemorrhages. Laboratory studies are within normal limits. An emergent non-contrast CT scan of the head is obtained and shows a diffuse hemorrhage at the base of the brain that is largest over the left hemisphere. Which of the following is the most likely cause of this patient's symptoms?

Intracranial arterial dissection

Spinal arteriovenous malformation

Intracranial arteriovenous malformation

A 68-year-old woman is brought to the emergency department after being found unresponsive in her bedroom in a nursing home facility. Her past medical history is relevant for hypertension, diagnosed 5 years ago, for which she has been prescribed a calcium channel blocker and a thiazide diuretic. Upon admission, she is found with a blood pressure of 200/116 mm Hg, a heart rate of 70/min, a respiratory rate of 15 /min, and a temperature of 36.5°C (97.7°F). Her cardiopulmonary auscultation is unremarkable, except for the identification of a 4th heart sound. Neurological examination reveals the patient is stuporous, with eye-opening response reacting only to pain, no verbal response, and flexion withdrawal to pain. Both pupils are symmetric, with the sluggish pupillary response to light. A noncontrast CT of the head is performed and is shown in the image. Which of the following is the most likely etiology of this patient’s condition?

Charcot-Bouchard aneurysm rupture

Arteriovenous malformation rupture

A 72-year-old man comes to the physician because of a 6-month history of intermittent dull abdominal pain that radiates to the back. He has smoked one pack of cigarettes daily for 50 years. His blood pressure is 145/80 mm Hg. Abdominal examination shows generalized tenderness and a pulsatile mass in the periumbilical region on deep palpation. Further evaluation of the affected blood vessel is most likely to show which of the following?

Fragmentation of elastic tissue in the tunica media

Obliterative inflammation of the vasa vasorum

Formation of giant cells in the tunica media

Necrotizing inflammation of the entire vessel wall

Accumulation of foam cells in the tunica intima

Cerebrovascular diseases — USMLE Lesson

Ischemic Stroke - The Brain's Plumbing Problem

Brain injury from ↓ blood flow, creating a core infarct surrounded by a salvageable ischemic penumbra. Time is brain; intervention aims to save the penumbra.

Ischemic Penumbra and Infarct Core with Treatment Outcomes

Etiologies:
- Thrombotic: Atherosclerotic plaque rupture in cerebral arteries.
- Embolic: Clot from heart (AFib) or large arteries travels to the brain.
- Systemic Hypoperfusion: "Watershed" infarcts from shock/hypotension.

⭐ Histological "red neurons" (eosinophilic cytoplasm, pyknotic nuclei) are the first microscopic sign, visible at 12-24 hours post-infarct.

Vascular Territories - Stroke's GPS

Axial view of cerebral artery territories

Anterior Cerebral Artery (ACA)
- Supplies: Medial surface of the brain (1° motor/sensory cortex for leg-foot).
- Deficits: Contralateral paralysis and sensory loss in the lower limb.
Middle Cerebral Artery (MCA)
- Supplies: Lateral convexity of the brain, including speech areas.
- Deficits: Contralateral face/arm paralysis & sensory loss, aphasia (dominant hemisphere), or hemineglect (non-dominant).
⭐ The MCA is the most frequently affected vessel in ischemic stroke.
Posterior Cerebral Artery (PCA)
- Supplies: Occipital lobe.
- Deficits: Contralateral homonymous hemianopia with macular sparing.
Lenticulostriate Arteries
- Branches of MCA supplying deep structures (basal ganglia, internal capsule).
- Occlusion causes pure motor or pure sensory lacunar strokes.

Hemorrhagic Stroke - When Pipes Burst

Pathophysiology: Bleeding into brain parenchyma (intracerebral) or subarachnoid space.
Intracerebral Hemorrhage (ICH):
- Causes: Chronic hypertension (basal ganglia), cerebral amyloid angiopathy (lobar, elderly), AVMs, tumors.
- Mechanism: Rupture of Charcot-Bouchard microaneurysms.
Subarachnoid Hemorrhage (SAH):
- Presentation: Sudden "worst headache of my life," nuchal rigidity.
- Causes: Ruptured saccular (berry) aneurysm (85%), trauma, AVM.
- Diagnosis: Non-contrast CT. Lumbar puncture shows xanthochromia.

⭐ Berry aneurysms are common at Circle of Willis branch points (esp. AComA) and are associated with ADPKD and Ehlers-Danlos syndrome.

Aneurysms & Malformations - Ticking Time Bombs

Saccular (Berry) Aneurysm: Most common cause of non-traumatic subarachnoid hemorrhage (SAH). Thin-walled outpouching, lacks media layer. Associated with ADPKD, Ehlers-Danlos syndrome.
- Location: Anterior Communicating Artery (ACoA).
Charcot-Bouchard Microaneurysm: Affects small vessels (<300 μm) from chronic hypertension; may rupture, causing intracerebral hemorrhage (e.g., basal ganglia).
Arteriovenous Malformation (AVM): Congenital tangle of arteries & veins.

⭐ Ruptured saccular aneurysm → SAH → classic complaint of "worst headache of my life."

Circle of Willis with berry aneurysm sites

High‑Yield Points - ⚡ Biggest Takeaways

Ischemic strokes (~85%) are most common, typically from atherosclerosis or cardioembolism (e.g., atrial fibrillation).

The Middle Cerebral Artery (MCA) is the most frequently involved vessel in ischemic stroke.

Hypertension is the main risk factor for deep intraparenchymal hemorrhages (Charcot-Bouchard microaneurysms) and lacunar infarcts.

Subarachnoid hemorrhage classically presents as a "thunderclap headache" from a ruptured berry aneurysm.

Watershed infarcts affect border zones between arterial territories, often due to severe systemic hypotension.

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