A DEXA Scan is used in the diagnosis of:

Appeared in: GMCH - 2016

Explanation

Dual-Energy X-ray Absorptiometry (DEXA) is the primary clinical tool for diagnosing osteoporosis.
It works by measuring bone mineral density (BMD), which is a direct indicator of bone strength and fracture risk.
According to World Health Organization (WHO) criteria, a T-score of -2.5 or lower, as measured by a DEXA scan, confirms a diagnosis of osteoporosis.

Option A: Breast cancer is a malignancy of the breast tissue. Its diagnosis relies on imaging like mammography and ultrasound, followed by a tissue biopsy. A DEXA scan measures bone density and is not used to evaluate breast tissue.
Option C: Coronary artery disease involves the narrowing or blockage of the heart's blood vessels. It is diagnosed using tests that assess cardiac function and blood flow, such as an ECG, stress test, or coronary angiography. A DEXA scan has no role in diagnosing heart conditions.
Option D: A pulmonary embolism is a blood clot in the arteries of the lungs. The definitive diagnostic test is a CT pulmonary angiography (CTPA), which visualizes the pulmonary arteries. A DEXA scan is irrelevant for this acute vascular condition.

Clinical Relevance

Nursing practice connection: Use the key finding related to Diagnostic application of DEXA scan to guide bedside assessment, documentation, and the next nursing action.
Nurses are crucial in identifying and educating at-risk populations (e.g., postmenopausal women, elderly, those on long-term steroids) about the need for DEXA screening to facilitate early diagnosis of osteoporosis.
Early detection via DEXA allows for timely interventions, such as medication (e.g., bisphosphonates) and lifestyle changes (e.g., calcium/vitamin D intake, weight-bearing exercise), to prevent debilitating fractures.
What if? If a patient over 50 experiences a fragility fracture (a fracture from a fall from standing height or less), they are considered to have clinical osteoporosis and require treatment, even if their DEXA T-score is in the osteopenia range (between -1.0 and -2.5).

How to Approach the Question

Identify the core subject of the question: the clinical use of a 'DEXA Scan'.
Recall or deduce the function of a DEXA scan. The name 'Dual-Energy X-ray Absorptiometry' hints at measuring density ('absorptiometry') of bone.
Evaluate each option against this function. Osteoporosis is a disease defined by low bone density.
Systematically eliminate the other options by recalling their respective primary diagnostic tools: Mammogram for breast cancer, ECG/angiography for heart disease, and CT scan for pulmonary embolism.
This process of elimination confirms that DEXA is specifically used for osteoporosis, making it the correct answer.

Concept Tested & Keywords

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E6 Gynecology Williams p. 73-96

E6 Medicine Harrison 22e Part 2 pp. 1201-1203, 1954-1956

Practise the full GMCH - 2016

Attempt every question from this paper in a timed mock, then review the full solution for each one.