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Zorluk: OrtaFormulating a Differential Diagnosis

A 27-year-old woman presents to the outpatient clinic for a routine health maintenance examination. She has felt well overall but mentions experiencing occasional, dull, throbbing headaches over the past few months. She has no significant past medical history. Her only medication is a combined oral contraceptive pill, which she has taken for three years. She does not use tobacco, alcohol, or illicit drugs. Her family history is notable for a father with type 2 diabetes mellitus; there is no family history of early-onset cardiovascular disease.

Vital signs show a blood pressure of 172/105 mm Hg in the right arm and 168/104 mm Hg in the left arm. Her pulse is 76/min, and respiratory rate is 14/min. Her body mass index is 21 kg/m². On physical examination, the lungs are clear to auscultation, and the heart has a regular rate and rhythm without murmurs. Auscultation of the abdomen reveals a soft, high-pitched, continuous bruit in the right periumbilical region. There is no peripheral edema.

Laboratory studies are notable for:
- Sodium: 141 mEq/L
- Potassium: 3.1 mEq/L
- Chloride: 102 mEq/L
- Bicarbonate: 29 mEq/L
- Blood urea nitrogen: 12 mg/dL
- Creatinine: 0.8 mg/dL

Which of the following is the most likely diagnosis?

  1. Fibromuscular dysplasiaCevap
  2. B
    Atherosclerotic renal artery stenosis
  3. C
    Primary hyperaldosteronism
  4. D
    Oral contraceptive-induced hypertension
  5. E
    Pheochromocytoma

Cevap

The most likely diagnosis is fibromuscular dysplasia.
The correct diagnosis is fibromuscular dysplasia (FMD). This patient presents with severe hypertension, hypokalemia, and a right-sided abdominal bruit. In a young female lacking cardiovascular risk factors, this classic triad strongly suggests renovascular hypertension secondary to FMD. FMD is a nonatherosclerotic, noninflammatory vascular disease that most commonly affects the renal and internal carotid arteries in young to middle-aged women. Decreased perfusion to the affected kidney stimulates the juxtaglomerular cells to release renin. This activates the renin-angiotensin-aldosterone system, leading to secondary hyperaldosteronism, which subsequently manifests as hypertension, hypokalemia, and metabolic alkalosis. The continuous abdominal bruit is a direct physical sign of turbulent flow through the stenosed renal artery.

Adım Adım Çözüm

1
Analyze the patient's demographic and vital signs.
The patient is a healthy 27-year-old woman presenting with severe, asymptomatic hypertension (>170/100 mm Hg).
Severe hypertension in a young adult without a significant family history strongly warrants investigation for secondary causes.
2
Correlate physical examination and laboratory findings.
The physical examination reveals an abdominal bruit, and laboratory studies show hypokalemia with metabolic alkalosis.
An abdominal bruit indicates turbulent blood flow, suggesting vascular stenosis. The hypokalemia and metabolic alkalosis reflect secondary hyperaldosteronism, driven by increased renin release due to decreased renal perfusion.
3
Differentiate between the causes of renovascular hypertension.
Given the patient's young age and absence of atherosclerotic risk factors, the non-inflammatory condition fibromuscular dysplasia is the most probable cause.
Atherosclerotic renal artery stenosis is much more common overall but almost exclusively affects older patients with established cardiovascular risk factors.

Anahtar Kavram

Secondary hypertension due to fibromuscular dysplasia should be suspected in young women presenting with severe hypertension, an abdominal bruit, and hypokalemia driven by secondary hyperaldosteronism.
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Formulating a Differential Diagnosis

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