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Common Congenital Heart Lesions - page 52 / 126





52 / 126

52 of 126

    • ii.

      “renovascular hypertension” : renal artery stenosis

        • o

          Can be stenosis of one or both of the renal arteries

          • o

            Can be caused by atherosclerosis

              • Atherosclerotic lesions arise from plaque formation in the renal artery or abdominal aorta near the renal artery.

              • Atherosclerotic lesions are most common in older men.

          • o

            Can be caused by fibromuscular dysplasia

              • Fibromuscular dysplasia = lesions of fibrous material or muscle proliferation within the arterial media.

              • This type is more common in young women.

          • o

            Elevated BP in renal artery is caused by reduced blood flow, so the kidney responds by secreting more renin.

          • o

            Diagnosis: ABDOMINAL BRUIT, UNEXPLAINED HYPOKALEMIA (excessive excretion of K)

          • o

            Treatment: catheter interventions, surgical reconstruction. ACE inhibitors are useful in unilateral stenosis

  • 3)

    Mechanical Causes: Coarctation of the Aorta

      • Definition: narrowing of the aorta, usually near the subclavian artery

      • Can cause reduced blood flow to the kidneys, resulting in increased renin and VASOCONSTRICTION

      • Additionally, the narrowing can stiffen the aortic arch and prevent the baroreceptors from doing a good job

      • Clinical clues

          • o

            Inadequate flow to the legs or left arm

            • o

              Absent femoral pulse

            • o

              Midsystolic murmur—best heard on the back between the scapula

            • o

              Chest x-ray will show indentation of the aorta

            • o

              Notched appearance of the ribs (enlargement of the intercostal arteries)

      • Treatment:

            • o

              Angioplasty or surgery to correct the stenosis

            • o

              HTN may not disappear completelyÆdesensitization of baroreceptors

  • 4)

    Endocrine Causes: 3 kinds

    • Pheochromocytoma

      • o

        Catecholamine secreting tumors of neuroendocrine cells

        • o

          Tumor is often in the adrenal medulla

        • o

          Release lots of NE and EPI which causes vasoconstriction and tachycardia

        • o


          • Autonomic attacks: severe headaches, profuse sweating, palpitations, tachycardia.

          • Most patients have elevated BP even between attacks

        • o


          • Plasma catecholamine levels

          • Urine catecholamine metabolite levels (VMA)

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