A 45-year-old man on long-term atenolol for hypertension abruptly discontinues the medication without consulting his physician. Within 48 hours, he presents with BP 210/130 mmHg, HR 118/min, RR 22/min, diaphoresis, palpitations, and substernal chest pain. Troponin is negative. He denies prior angina or coronary disease. Physical examination reveals no peripheral edema or jugular venous distension. Which mechanism best explains this acute hypertensive crisis with tachycardia?
- A)Beta-adrenergic receptor upregulation with unopposed catecholamine sensitivityGABARITO
- B)Withdrawal of direct vasodilatory properties inherent to atenolol
- C)Acute myocardial infarction from sudden increase in myocardial oxygen demand
- D)Activation of the renin-angiotensin-aldosterone system by sympathetic withdrawal
- E)Rebound hyperthyroidism increasing metabolic rate
Explicação
Chronic beta blocker use causes compensatory upregulation of beta-adrenergic receptors. Abrupt discontinuation removes the blocking effect while receptors remain upregulated, creating a hyperadrenergic state with excessive catecholamine sensitivity. This "rebo... Ver explicação completa e trilha adaptativa →