Osteoporosis
Osteoporosis is low bone strength that raises fragility fracture risk, diagnosed by a hip or spine T-score of -2.5 or less or by a fragility fracture itself. First-line treatment is an oral bisphosphonate, alendronate or risedronate, alongside adequate calcium and vitamin D intake.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Definition: Osteoporosis is a skeletal disorder of low bone mass and disrupted microarchitecture that reduces bone strength and raises fracture risk with minimal trauma.
- Epidemiology
Postmenopausal predominance: osteoporosis is most prevalent in postmenopausal women, reflecting accelerated bone loss after the fall in estrogen at menopause.
- Risk factors
Nonmodifiable factors: older age, female sex, race and ethnicity, a first-degree relative with low BMD, and genetic bone disorders (osteogenesis imperfecta, Ehlers-Danlos syndrome, hypophosphatasia) raise risk.
- Pathophysiology
Bone remodeling imbalance: osteoporosis results when osteoclastic bone resorption exceeds osteoblastic bone formation, so more bone is removed each remodeling cycle than is replaced.
- Clinical features
Diagnostic core feature: most patients are asymptomatic until a fragility fracture occurs, so the disease is defined by its consequence rather than by symptoms preceding it.
- Differential diagnosis
Osteomalacia: very low 25-hydroxyvitamin D (below 10 ng/mL), low or low-normal calcium and phosphorus, and elevated alkaline phosphatase distinguish osteomalacia, which, unlike osteoporosis, does not cause permanent loss of bone structure.
- Diagnosis
Diagnostic basis: in postmenopausal women and men older than 50 years, osteoporosis is diagnosed by a femoral neck, total hip, or lumbar spine (two or more evaluable vertebrae) T-score of -2.5 or…
- Management
First, ensure adequate mineral and vitamin intake in every patient: calcium intake of 1000-1200 mg/day, ideally from dietary sources, with a calcium supplement only if diet is insufficient vitamin D2…
- Complications
Hip fracture: the most morbid osteoporotic fracture, with substantial 1-year mortality and frequent loss of independent living.
- Prognosis
Fracture reduction with treatment: first-line bisphosphonates reduce spine, hip, and nonvertebral fracture risk in patients who meet treatment criteria and remain adherent.
- Prevention
Screening thresholds: average-risk women should have BMD testing starting at age 65 years; men and women aged 50-69 years with risk factors should be screened earlier.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Vertebral compression fracture
A vertebral compression fracture is a collapse of the anterior or middle vertebral body, most often from osteoporotic fragility with minimal or no trauma, presenting as acute focal spinal tenderness or, in up to two-thirds of cases, as an asymptomatic finding on imaging. Diagnosis is by spine radiograph confirming the fracture, which alone establishes a clinical diagnosis of osteoporosis, and first-line management is analgesia (acetaminophen 650 mg PO every 6 hours) with antiresorptive or anabolic pharmacotherapy to prevent further fracture.
- Primary hyperparathyroidism
Primary hyperparathyroidism is autonomous PTH oversecretion, most often from a solitary parathyroid adenoma, producing hypercalcemia with an elevated or inappropriately normal PTH and low or low-normal phosphorus. Most patients are asymptomatic and identified on routine labs; parathyroidectomy is curative and is first-line for symptomatic disease or when specific biochemical, skeletal, or renal criteria are met, while observation with annual monitoring suffices for mild, asymptomatic disease.
- Vitamin D deficiency rickets
Vitamin D deficiency rickets is defective mineralization of the growing cartilaginous growth plate from inadequate vitamin D, most often in a breastfed infant without supplementation, presenting with bowing of the legs, a rachitic rosary, and delayed motor development around 15 months of age. Diagnosis rests on a low 25-hydroxyvitamin D with elevated parathyroid hormone and characteristic metaphyseal cupping and fraying on long-bone radiographs, and first-line treatment is ergocalciferol 2,000 IU PO once daily for 6 weeks with calcium supplementation.
- Hypercalcemia
Hypercalcemia is an elevated serum calcium concentration, most often caused by primary hyperparathyroidism in ambulatory patients or malignancy in hospitalized patients. Mild disease requires only treatment of the underlying cause, while severe or symptomatic hypercalcemia is treated with aggressive IV isotonic fluids, followed by an IV bisphosphonate or denosumab for sustained control and subcutaneous calcitonin as a rapid but short-lived bridge.