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Zorluk: OrtaBreast and Endocrine Surgery

A 3838-year-old man presents to the clinic complaining of episodic headaches, excessive sweating, and a feeling of a rapid heart rate. His blood pressure in the clinic is 172/105 mmHg172/105 \text{ mmHg}. He reports that these "spells" have been occurring once or twice a week for the past 33 months. Physical examination is otherwise unremarkable. Laboratory evaluation reveals a serum potassium of 4.2 mEq/L4.2 \text{ mEq/L} and fasting blood glucose of 115 mg/dL115 \text{ mg/dL}. A 2424-hour urine collection shows fractionated metanephrines that are 44 times the upper limit of normal. Contrast-enhanced CT of the abdomen reveals a 4.5 cm4.5 \text{ cm} well-circumscribed, lipid-poor mass in the right adrenal gland. The patient is scheduled to undergo a laparoscopic right adrenalectomy in 33 weeks. Which of the following is the most appropriate preoperative pharmacological sequence to prevent perioperative complications?

  1. Initiation of phenoxybenzamine now, with addition of propranolol 33 days prior to surgeryCevap
  2. B
    Initiation of propranolol now, with addition of phenoxybenzamine 33 days prior to surgery
  3. C
    Initiation of spironolactone now, with addition of oral potassium chloride
  4. D
    Administration of ketoconazole now, with hydrocortisone on the day of surgery
  5. E
    Immediate scheduling of surgery with intraoperative esmolol and nitroprusside drip available

Cevap

Initiation of phenoxybenzamine now, with addition of propranolol 3 days prior to surgery
The correct answer requires the initiation of phenoxybenzamine followed by propranolol. This patient has a classic presentation of a pheochromocytoma, a catecholamine-secreting tumor of the adrenal medulla. The diagnosis is confirmed by elevated 2424-hour urine fractionated metanephrines and an adrenal mass on CT. Surgical resection (adrenalectomy) is the definitive treatment. However, manipulating the tumor during surgery can cause a massive release of catecholamines, leading to a life-threatening hypertensive crisis. Therefore, adequate preoperative pharmacological preparation is essential. The standard of care requires initiating an alpha-adrenergic antagonist (such as phenoxybenzamine or doxazosin) 1010 to 1414 days prior to surgery to control blood pressure and allow for plasma volume expansion. Once adequate alpha-blockade is achieved, a non-cardioselective beta-adrenergic antagonist (such as propranolol) is added 22 to 33 days preoperatively to control tachycardia.

Adım Adım Çözüm

1
Analyze the clinical presentation and diagnostic findings.
The patient has episodic hypertension, tachycardia, headaches, elevated urine metanephrines, and a 4.5 cm4.5 \text{ cm} adrenal mass, confirming the diagnosis of a pheochromocytoma.
Establishing the correct diagnosis is essential to determine the specific perioperative requirements for this unique endocrine tumor.
2
Identify the standard surgical treatment and associated risks.
Laparoscopic adrenalectomy is indicated. The primary risk is a massive release of catecholamines during tumor manipulation, causing a severe hypertensive crisis.
Understanding the surgical risks dictates the necessity of pharmacological blockade prior to the operation.
3
Determine the correct pharmacological sequence to mitigate this risk.
An alpha-blocker (phenoxybenzamine) must be started first for 1010-1414 days to control blood pressure and expand plasma volume. Only after adequate alpha-blockade should a beta-blocker (propranolol) be added to control tachycardia.
Giving a beta-blocker before an alpha-blocker causes unopposed alpha-adrenergic stimulation, which can precipitate a fatal hypertensive crisis.

Anahtar Kavram

In the preoperative management of pheochromocytoma, alpha-adrenergic blockade must always precede beta-adrenergic blockade to prevent unopposed alpha-receptor stimulation and hypertensive crisis.

Alternatif Yöntem

If patients cannot tolerate alpha-blockers due to severe side effects (such as profound orthostatic hypotension), calcium channel blockers (e.g., amlodipine, nifedipine, or nicardipine) can be used for preoperative blood pressure control. Metyrosine, an inhibitor of catecholamine synthesis (tyrosine hydroxylase), can also be added in refractory cases.
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