An 18-year-old male with a history of headaches presents to the emergency department with complaints of severe headache. His vitals are:
CT scan of the brain showed diffuse cerebral edema but no acute intracranial bleed. ECG demonstrates sinus tachycardia but is otherwise normal. Despite multiple administrations of antihypertensives, his blood pressure is still 194/110, and he is admitted for hypertensive crisis. Workup demonstrates mild hypokalemia. Hormonal studies were significant for elevated plasma renin and aldosterone levels, but normal renin/aldosterone ratio. Plasma metanephrines, thyroid-stimulating hormone, T3, T4, and free T4 are normal. Imaging shows a juxtaglomerular mass on the right kidney and no evidence of renal artery stenosis.
Which of the following regarding his diagnosis is correct?A. Patients often present with concurrent metabolic acidosis
Correct Answer: D
The patient presents with hypertensive crisis, hypokalemia, high plasma aldosterone, and high plasma renin, but normal renin/aldosterone ratio which suggests secondary hyperaldosteronism from excess renin. Normal plasma metanephrines rules out pheochromocytoma or paraganglioma. The presence of a juxtaglomerular mass further suggests that this patient’s symptoms are likely due to a juxtaglomerular cell tumor secreting renin, or reninoma.
Renin is normally secreted from the juxtaglomerular kidney cells in response to: (1) a decrease in renal perfusion pressure detected via stretch receptors in the vascular walls of the juxtaglomerular cells and (2) signaling from the macula densa when sodium delivery to the distal tubule decreases. It hydrolyzes angiotensinogen into angiotensin I, which is further cleaved in the lungs by endothelial-bound angiotensin-converting enzyme (ACE) into angiotensin II, a potent vasoconstrictor peptide. Angiotensin II also acts on the adrenal glands to release aldosterone, which stimulates the epithelial cells in the distal tubule and collecting ducts of the kidney to increase reabsorption of sodium and water and excretion of potassium and hydrogen ions. This results in an increase in intravascular volume, hypertension, hypokalemia, and metabolic alkalosis.
While abdominal ultrasonography is noninvasive and easily performed, it may miss small lesions. Contrast-enhanced computed tomography or magnetic resonance imaging is recommended as the diagnostic modality of choice. Medical management consists of antihypertensives, particularly ACE inhibitors, angiotensin receptor blockers (ARBs), and aldosterone antagonists. Definitive treatment is by surgical resection with most patients becoming and remaining normotensive.