Examkin

Soru

Zorluk: OrtaPhysical Examination Findings

A 68-year-old man presents to the primary care clinic for evaluation of recurrent dizziness and left arm fatigue. He states that he frequently experiences lightheadedness and blurred vision when doing yard work, particularly when using a manual hedge trimmer for extended periods. His past medical history includes hypertension, type 2 diabetes mellitus, and hyperlipidemia. Current medications include lisinopril, metformin, and atorvastatin. Vital signs show a heart rate of 78/min. On physical examination, blood pressure is 158/88 mm Hg in the right arm and 112/70 mm Hg in the left arm. A distinct systolic bruit is auscultated over the left supraclavicular fossa. The left radial pulse is diminished in amplitude compared to the right. Neurologic examination is unremarkable when the patient is at rest. Which of the following is the most likely diagnosis?

  1. Subclavian steal syndromeCevap
  2. B
    Aortic dissection
  3. C
    Thoracic outlet syndrome
  4. D
    Carotid artery stenosis
  5. E
    Takayasu arteritis

Cevap

Subclavian steal syndrome
Subclavian steal syndrome occurs due to severe atherosclerotic stenosis or occlusion of the proximal subclavian artery, located before the origin of the vertebral artery. During arm exercise, local vasodilation lowers the vascular resistance in the arm. To meet this demand, blood flows up the contralateral vertebral artery, into the basilar artery, and flows retrograde (backward) down the ipsilateral vertebral artery to supply the exercising arm. This 'steals' blood from the vertebrobasilar circulation, causing symptoms of brainstem ischemia (dizziness, blurred vision, ataxia). The physical examination classically reveals a significant blood pressure discrepancy between the arms (typically >15 mm Hg), a diminished pulse on the affected side, and a supraclavicular bruit over the stenotic vessel.

Adım Adım Çözüm

1
Analyze the patient's vital signs and distinct physical examination findings.
There is a significant >40 mm Hg systolic blood pressure discrepancy between the arms (158 vs 112) along with a diminished left radial pulse and a left supraclavicular bruit.
These specific physical findings strongly indicate a hemodynamically significant stenosis in the left subclavian artery.
2
Correlate the physical findings with the patient's exertional symptoms.
The patient experiences dizziness and blurred vision (vertebrobasilar symptoms) simultaneously with left arm fatigue during vigorous arm exertion (yard work).
Identifying the relationship between arm exertion and brainstem symptoms points to a hemodynamic 'steal' phenomenon rather than isolated local ischemia.
3
Synthesize the underlying mechanism to establish the diagnosis.
Stenosis of the proximal left subclavian artery lowers distal vascular resistance during arm exercise, causing retrograde flow down the left vertebral artery to supply the arm, stealing blood from the posterior cerebral circulation.
This pathophysiology perfectly explains both the physical examination findings and the clinical presentation, definitively identifying subclavian steal syndrome.

Anahtar Kavram

Identifying subclavian steal syndrome through the integration of classic physical examination findings (upper extremity blood pressure discrepancy, supraclavicular bruit) and exertional vertebrobasilar insufficiency.
Bu soruyu puanla

Konular

Physical Examination Findings

Bu konudan daha fazla soru