A 28-year old woman comes to the physician complaining about right flank pain. She is afebrile and her blood pressure is 150/98 mm Hg. She has a history of hypertension treated with an angiotensin-converting-enzyme inhibitor in the past two years. She also complains about frequent headaches which most of the time have been relieved with over-the-counter medications. She also complains about intermittent vision problems that resolve spontaneously after a few seconds. Her recent laboratory studies from a routine check-up have revealed 1.1 mg/dl Creatinine level,95 mg/dl LDL and 53 mg/dl HDL. An abdominal X-ray is ordered and is unremarkable. The remaining physical examination is unrevealing. She is not smoking and denies using illicit drugs, although she reveals that she used to smoke marijuana in college. She drinks one glass of wine every weekend. Her father has a history of stroke at age 63 and her mother has a history of migraines. She has a 3-year monogamous relationship and uses condoms consistently.
The correct answer is: E. History of tinnitus
This young female patient with a history of hypertension, recurrent headaches, vision problems and flank pain most likely has fibromuscular dysplasia (FMD). FMD is a non-inflammatory and non-atherosclerotic condition that causes narrowing of the medium and small size arteries of the body.1,2 The disease is more common in women of childbearing age.1,3 Although its etiology is not well established, it has been accepted that hormonal, mechanical and genetic factors might contribute to the pathogenesis of the disease.1 Among the arteries affected, renal and carotid artery involvement is predominant.1-3
FMD can be asymptomatic but should be suspected in any young patient with onset of hypertension before age 40 years, recent increase in blood pressure, and refractory hypertension despite the use of multiple antihypertensive drugs.1 In cases of bilateral renal artery involvement, the use of antihypertensive drugs affecting the renin-angiotensin-aldosterone system (RAAS) should be used with caution, due to the high risk for rapid deterioration of renal function.2 This young woman complains of frequent headaches and vision problems (i.e. amaurosis fugax) due to cerebrovascular involvement. Other complications include ischemic stroke, intracranial aneurysm formation, or even intracerebral and subarachnoid hemorrhage.2 Involvement of vertebral arteries can lead to symptoms such as tinnitus, lightheadedness and dizziness.1
Visceral arteries can also be affected leading to abdominal pain, while renal artery involvement can lead to flank pain due to ischemia of the affected kidney with subsequent increase in plasma renin1 (Answer D). This will lead to secondary hyperaldosteronism and subsequent increase of sodium reabsorption from the tubular cells. Consequently, urine sodium will be reduced (Answer C).
Physical exam may reveal bruits due to turbulent flow along stenotic arteries (e.g. abdominal bruit). Laboratory evaluation may be unremarkable or reveal renal involvement (high creatinine and blood urea nitrogen (BUN) levels and other signs of secondary hyperaldosteronism: hypokalemia, metabolic alkalosis).
Initial diagnostic imaging consists of Doppler ultrasonography, followed by computed tomography (CT) angiography or magnetic resonance angiography (MRA), which can provide more details of the affected vessels.1,2 Catheter based angiography can be ordered if noninvasive diagnostic modalities are unrevealing and clinical suspicion is high. Although it is an invasive test, catheter-based angiography remains the diagnostic gold standard of FMD.1,2 Other imaging modalities can be used according to presenting symptoms (e.g. brain CT and magnetic resonance imaging (MRI) in case of stroke presentation).
Leukocyte esterase (Answer A) is an enzyme of white blood cells and when it is found in urine, it indicates a urinary tract infection or inflammation. Although the patient's flank pain could be a sign of pyelonephritis, she is afebrile, and she has no urinary problems (indicating cystitis) or risk factors for an ascending urinary tract infection.
Gallbladder stones (Answer B) cause abdominal discomfort after meals and can lead to cholecystitis. The location of pain and the presence of hypertension in this young woman make this diagnosis unlikely. In addition, FMD has no association with gallbladder stones.
FMD is a non-atherosclerotic disease affecting young women. However, this woman has no risk factors contributing to diffuse atherosclerosis (e.g. homocystinuria, chronic inflammatory rheumatologic conditions) (Answer F).
High yield fact: FMD should be suspected in a young woman with sudden onset of hypertension, resistant hypertension or deterioration of renal function after an angiotensin-converting-enzyme inhibitor or angiotensin receptor blocker. Rarely, it can lead to hypertensive crisis. The initial symptoms, emerging from underlying vascular pathology, might be flank pain, tinnitus, recurrent headaches, blurred vision or problems with speech.
References
- Olin JW, Gornik HL, Bacharach JM, et al. Fibromuscular dysplasia: state of the science and critical unanswered questions: a scientific statement from the American Heart Association. Circulation 2014;129:1048-78.
- O'Connor SC, Gornik HL. Recent developments in the understanding and management of fibromuscular dysplasia. J Am Heart Assoc 2014;3:e001259.
- Takahashi K, Unno T. Fibromuscular dysplasia: another paradigm shift in renovascular hypertension? Intern Med 2018;57:2605-06.
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