A 72-year-old woman comes to the physician for follow-up care. One year ago, she was diagnosed with a 3.8-cm infrarenal aortic aneurysm found incidentally on abdominal ultrasound. She has no complaints. She has hypertension, type 2 diabetes mellitus, and COPD. Current medications include hydrochlorothiazide, lisinopril, glyburide, and an albuterol inhaler. She has smoked a pack of cigarettes daily for 45 years. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 12/min, and blood pressure is 145/85 mm Hg. Examination shows a faint abdominal bruit on auscultation. Ultrasonography of the abdomen shows a 4.9-cm saccular dilation of the infrarenal aorta. Which of the following is the most appropriate next step in management?

Elective endovascular aneurysm repair

Adjustment of cardiovascular risk factors and follow-up ultrasound in 12 months

Adjustment of cardiovascular risk factors and follow-up ultrasound in 6 months

Adjustment of cardiovascular risk factors and follow-up CT in 6 months

A 48-year-old woman is brought to the emergency department because of a 1-hour history of sudden-onset headache associated with nausea and vomiting. The patient reports she was sitting at her desk when the headache began. The headache is global and radiates to her neck. She has hypertension. She has smoked one pack of cigarettes daily for the last 10 years. She drinks alcohol occasionally. Her father had a stroke at the age 58 years. Current medications include hydrochlorothiazide. She is in severe distress. She is alert and oriented to person, place, and time. Her temperature is 38.2°C (100.8°F), pulse is 89/min, respirations are 19/min, and blood pressure is 150/90 mm Hg. Cardiopulmonary examination shows no abnormalities. Cranial nerves II–XII are intact. She has no focal motor or sensory deficits. She flexes her hips and knees when her neck is flexed while lying in a supine position. A CT scan of the head is shown. Which of the following is the most appropriate intervention?

Administer intravenous alteplase

Administer intravenous vancomycin and ceftriaxone

Perform decompressive craniectomy

A 54-year-old man comes to the physician because of a painful mass in his left thigh for 3 days. He underwent a left lower limb angiography for femoral artery stenosis and had a stent placed 2 weeks ago. He has peripheral artery disease, coronary artery disease, hypercholesterolemia and type 2 diabetes mellitus. He has smoked one pack of cigarettes daily for 34 years. Current medications include enalapril, aspirin, simvastatin, metformin, and sitagliptin. His temperature is 36.7°C (98°F), pulse is 88/min, and blood pressure is 116/72 mm Hg. Examination shows a 3-cm (1.2-in) tender, pulsatile mass in the left groin. The skin over the area of the mass shows no erythema and is cool to the touch. A loud bruit is heard on auscultation over this area. The remainder of the examination shows no abnormalities. Results of a complete blood count and serum electrolyte concentrations show no abnormalities. Duplex ultrasonography shows an echolucent sac connected to the common femoral artery, with pulsatile and turbulent blood flow between the artery and the sac. Which of the following is the most appropriate next best step in management?

Ultrasound-guided thrombin injection

A 48-year-old woman undergoes awake craniotomy for resection of a left frontal glioma near Broca's area. Intraoperatively, cortical mapping identifies eloquent tissue, but the tumor extends into functionally critical regions. The surgeon achieves 70% resection when the patient develops expressive aphasia during mapping. Frozen section shows low-grade astrocytoma. The family previously expressed desire for maximal resection. Evaluate the intraoperative decision-making.

Stop resection to preserve language function

Use awake testing to define exact limits of safe resection

Obtain family consultation intraoperatively about acceptable deficits

Convert to asleep anesthesia and use anatomic landmarks for resection

Continue resection since low-grade tumors justify aggressive surgery

Arteriovenous malformation treatment — USMLE Lesson

🧠 Tangled Vessels 101

An Arteriovenous Malformation (AVM) is a congenital tangle of vessels where arteries connect directly to veins, bypassing the capillary bed. This creates a high-flow, high-pressure central nidus, prone to rupture and cause intracranial hemorrhage (ICH).

Cerebral AVM angiogram with nidus and draining vein

Spetzler-Martin Grading Scale (predicts surgical risk):

Size of Nidus:
- <3 cm: 1 pt
- 3-6 cm: 2 pts
- 6 cm: 3 pts
Eloquence of Brain Area:
- Non-eloquent: 0 pts
- Eloquent: 1 pt
Venous Drainage Pattern:
- Superficial only: 0 pts
- Deep: 1 pt

⭐ The annual hemorrhage risk for an unruptured AVM is 2-4%. Risk is higher if previously ruptured or associated with an aneurysm.

💣 Diagnosis - Finding the Ticking Bomb

Clinical Presentation:
- Intracranial Hemorrhage (ICH): Most common (~50%), often a sudden, severe "worst headache of life."
- Seizures: New-onset, particularly in a young adult.
- Focal Neurological Deficits (FNDs): Weakness, sensory loss, aphasia.
- Headaches: Chronic, often pulsatile or migraine-like.
Imaging Pathway:
- Acute: Non-contrast CT to rapidly detect hemorrhage.
- Non-invasive: CT Angiography (CTA) or MR Angiography (MRA) to visualize the vascular tangle.
- Gold Standard: Digital Subtraction Angiography (DSA) provides definitive diagnosis and is essential for treatment planning.

DSA of cerebral AVM showing nidus and draining veins

⭐ AVM is the most common cause of spontaneous intracerebral hemorrhage in children and young adults.

🧠 Management - Untangling the Knot

Goal: Obliterate the nidus to prevent hemorrhage while preserving function. Decision balances treatment risk vs. natural history, guided by the Spetzler-Martin (SM) Grade (Size, Venous Drainage, Eloquence). Multimodality therapy is common.

Modality	Mechanism	Best For	Pros	Cons
Microsurgery	Direct excision of nidus	Small, superficial, non-eloquent AVMs (SM Grade I-II)	Immediate & high rate of cure	Invasive; risk of intra-op bleed, neuro deficit
Embolization	Endovascular glue/coils to block feeding arteries	Adjunct to surgery/SRS; palliative for high-grade AVMs	Minimally invasive; reduces nidus size/flow	Rarely curative alone; risk of stroke, vessel perforation
SRS	Focused radiation induces thrombosis	Small (<3 cm), deep, eloquent AVMs	Non-invasive	Delayed effect (1-3 yrs); hemorrhage risk during latency; radiation necrosis

Treatment Algorithm:

AVM treatment modalities by patient and AVM type

⚠️ Complications - When Things Go Wrong

Untreated AVMs:
- Re-hemorrhage (highest risk in 1st year)
- Seizures, hydrocephalus, vasospasm
Treatment-Related:
- Microsurgery: Infection, new neurological deficits
- Embolization: Embolic stroke, vessel perforation
- SRS: Radiation necrosis (delayed), hemorrhage before obliteration

⭐ Normal Perfusion Pressure Breakthrough (NPPB): Post-resection, chronically hypo-perfused brain tissue is suddenly exposed to normal arterial pressure. Loss of autoregulation leads to vasogenic edema, hemorrhage, and seizures.

⚡ Biggest Takeaways

The primary goal of AVM treatment is preventing hemorrhage, the most feared complication, especially in young adults.

Microsurgical resection is the gold standard for accessible AVMs, providing an immediate and definitive cure.

Stereotactic radiosurgery (SRS) is ideal for small (<3 cm), deep, or eloquent-area AVMs; obliteration takes 1-3 years.

Endovascular embolization is typically an adjunctive therapy to reduce AVM size and blood flow before surgery or SRS.

Treatment choice is guided by the Spetzler-Martin grade.

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