Secondary Osteoporosis

Osteoporosis does not show any clinical manifestations until a fracture occurs, which most commonly occur in the spine, hips, and forearm. Other clinical manifestations include height loss, thoracic kyphosis, and backache with varying degrees of severity.  However, many vertebral compression fractures are asymptomatic. A careful history and physical exam are important when treating or screening patients with/for secondary causes of osteoporosis.

Evaluation of secondary osteoporosis may include:

• Complete blood count (CBC)
• Complete metabolic panel (CMP)
• Serum testosterone
• Estradiol
• LH and prolactin
• Serum ferritin
• Calcium
• Phosphate
• Albumin
• Alkaline phosphatase
• 25-hydroxyvitamin D
• Twenty-four-hour urine calcium
• Serum  and urine protein electrophoresis
• Parathyroid hormone
• Thyroid-stimulating hormone (TSH)
• Tissue transglutaminase antibodies
• Dexamethasone suppression test or a 24-hour urinary free cortisol
• Bone resorption and formation markers
• X-rays (lumbar and thoracic spine) to look for vertebral fractures.

The diagnosis of osteoporosis can be made by dual-energy x-ray absorptiometry (DXA), if the T-score less than or equal to -2.5 or if the individual has had low-trauma fractures.[11][1][12]

The effective treatment of secondary osteoporosis should, first and foremost, address any underlying reversible causes. This would include vitamin D replacement in deficient individuals, testosterone replacement in hypogonadal men, lowering the dose of corticosteroids, if possible, in steroid-induced osteoporosis, and correction of metabolic disorders or malabsorption if possible. FDA-approved indications for the treatment of glucocorticoid-induced osteoporosis are oral bisphosphonates, intravenous bisphosphonates, and teriparatide.[13][14][15]

Weight-bearing exercise is helpful in stimulating the bone formation. There is an association between reduced physical activity and bone fracture in elderly men along with the positive influence of exercise in women who had osteoporosis. In addition, smoking cessation and avoidance of alcohol intake should be encouraged.

Once reversible causes are addressed, if pharmacologic therapy is needed, bisphosphonates such as alendronate, zoledronic acid, ibandronate and risedronate are often used in patients with adequate renal function (GFR greater than 30ml/min to -35 ml/min). Before starting bisphosphonates, vitamin D should be replaced, and, during treatment, adequate intake of calcium and vitamin D intake is important.

Teriparatide is a recombinant human parathyroid hormone which is given as a 20 micrograms daily subcutaneous injection. Teriparatide is not the first line drug line drug used in the treatment of secondary osteoporosis, but it is used in glucocorticoid-induced osteoporosis in patients who have severe osteoporosis, those who are unable to tolerate or have contraindications to bisphosphonates, or those who have failed other modalities of treatment.

Denosumab is a human monoclonal antibody, and it is given as 60 mg subcutaneous injection for the treatment of osteoporosis secondary to malignancies, especially prostate cancer or other malignancies with metastasis to the bone.

Differential diagnosis of secondary osteoporosis includes osteomalacia, renal osteodystrophy, lymphoma, mastocytosis, sickle cell anemia, multiple myeloma, Paget disease, osteonecrosis, infection, homocystinuria, scurvy, homocysteinemia, and metastatic bone disease.

Patients with secondary osteoporosis have a mild increase in overall morbidity due to the vertebral and hip fractures and its complications, such as pulmonary embolism, deep vein thrombosis, and pneumonia. Compression fractures may also lead to reduced quality of life, chronic neurogenic pain, impaired ventilation, and deformities of the spine.

Increased awareness in avoiding the risk factors of secondary osteoporosis and increased vigilance in the workup for the causes of secondary osteoporosis and its treatment are essential to improve bone health in all patients.

Today an interprofessional approach is being recommended to establish measures to prevent fractures in patients with osteoporosis. The an interprofessional team should include physicians, nurses, physical and occupation therapists, social workers and other allied healthcare workers like the pharmacist. Evidence shows that an interprofessional approach can help improve post-fracture osteoporosis by early identification of patients, documenting their disease state, and making appropriate referrals. Such an approach has been shown to be cost-effective in avoiding the cost of secondary fractures. In addition, patient referral to the endocrinologist, nurse, geriatrician or rheumatologist can increase the number of patients who get treated with medications and thus, improve outcomes. Unfortunately, there are still a significant number of patients who do not get such treatment because they are lost to follow up. Today, prior to the discharge of a patient with a fracture, the nurse should ensure that the patient has the appropriate referrals, resources, and a dedicated social worker to follow up with. [16][17][18](Level III)

Outcomes

There continue to be significant deficiencies in the healthcare system with respect to communication and follow up of patients with fractures. Although there is a clear focus on preventing fractures and falls, this has not translated into better care for patients with osteoporosis. Thus, today many healthcare institutions have created a dedicated fracture liaison nurse to ensure that no patient with a fracture is missed. Without dedicated personnel, secondary prevention of osteoporosis still remains a major challenge in the US. [19][20](Level III)