Secondary osteoporosis is a metabolic bone disease with reduced bone mass, destruction of bone microarchitecture, increased bone fragility and ease of fracture due to disease or medication. There are many causes of secondary osteoporosis, clinically endocrine metabolic diseases, connective tissue diseases, kidney diseases, gastrointestinal diseases and drugs are the most common causes.
I. Common causes
Endocrine metabolic diseases: hyperparathyroidism, Cushing’s syndrome, hypogonadism, hyperthyroidism, pituitary lactinoma, diabetes mellitus (mainly type 1 diabetes), hypopituitarism, etc.
2, connective tissue diseases: systemic lupus erythematosus, rheumatoid arthritis, dry syndrome, dermatomyositis, mixed connective tissue disease, etc.
3, a variety of chronic kidney diseases leading to renal osteodystrophy.
4, gastrointestinal diseases and nutritional diseases: malabsorption syndrome, after major gastrointestinal resection, chronic pancreatic diseases, chronic liver disorders, protein-calorie malnutrition, long-term intravenous nutrition support treatment, etc.
5.Hematological system diseases: leukemia, lymphoma, multiple myeloma, Gaucher disease and myelodysplastic syndrome, etc.
6, neuromuscular system diseases: various causes of hemiplegia, paraplegia, motor dysfunction, myotonic dystrophy, stiff person syndrome and myotonic syndrome, etc.
7, long-term braking or space travel.
8.After organ transplantation.
9.Drugs: glucocorticoids, immunosuppressants, heparin, anticonvulsants, anticancer drugs, aluminum-containing antacids, thyroid hormone, GnRH-a or dialysis solution, etc.
II. Clinical manifestations
1. Symptoms vary depending on the degree of osteoporosis and the nature of the primary disease. Most of the symptoms are insidious and non-diagnostic specific, often masked by the performance of the primary disease, and many patients are found to have complications of osteoporosis only when they undergo X-ray examination. Some patients complain of low back pain, weakness, limb twitching or difficulty in moving. In severe cases, there can be obvious skeletal pain, and minor injuries are prone to spine, rib, hip or long bone fractures, and rib fractures are more common in secondary osteoporosis than in primary osteoporosis.
The main signs are similar to those of primary osteoporosis, including height shortening and, in severe cases, kyphosis, hunchback or thoracic deformity.
3. Multiple clinical manifestations of the primary disease.
III. Diagnostic points
There is no clinical method to directly measure bone strength, so the following diagnostic indicators are often used clinically: low bone density and/or fragility fracture. For secondary osteoporosis, it is also necessary to have a clear cause of osteoporosis.
1.Brittle fracture: It is the ultimate consequence of the decrease in bone strength, so having had a brittle fracture caused by a definite disease or drug can diagnose secondary osteoporosis.
2.Bone mineral density measurement: see the primary osteoporosis treatment guide for details.
3.Bone mineral density measurement method: see the primary osteoporosis treatment guide for details. More attention should be paid to Z-value when analyzing the results
4.Diagnostic criteria: refer to the diagnostic criteria recommended by the World Health Organization (WHO). For details, please refer to the primary osteoporosis diagnosis and treatment guidelines.
5.X-ray plain film: It is less sensitive and accurate for diagnosing osteoporosis, so it is not very helpful for the early diagnosis of osteoporosis. However, it is of great value in detecting the presence of fracture and differentiating it from bone tumor and joint lesions.
6.Bone conversion biochemical index measurement: there is no biochemical index that can be used as the diagnostic standard of osteoporosis. It is mainly used for bone conversion typing, judging the rate of bone loss, monitoring the condition and evaluating the efficacy of drugs. Commonly used biochemical indicators of bone transformation are shown in the primary osteoporosis treatment guidelines.
7. Tests related to the primary cause of osteoporosis: such as liver and kidney function, autoimmune index, thyroid function, parathyroid function, gonadal function, tumor-related tests, etc.
IV. Treatment principles and programs
1. Treatment of primary disease: actively searching for the cause of osteoporosis is important for the effective treatment of secondary osteoporosis. Once the cause is clear, the primary disease should be treated in a timely manner.
2. General measures: Pay attention to a balanced diet rich in calcium, low in salt and moderate in protein. Without prejudice to the treatment of the primary disease, appropriate outdoor activities to increase sunlight exposure, increase the body’s coordination ability, prevent falls, avoid alcohol and tobacco, and cautiously use other drugs that may affect bone health.
3. Basic medication: including appropriate supplementation of calcium, vitamin D or its active metabolites, etc. Refer to the guidelines for the treatment of primary osteoporosis. Special attention should be paid to the fact that calcium and vitamin D preparations should be contraindicated in patients with hypercalcemia, such as tumors or hyperparathyroidism. If the patient has kidney stones and high urinary calcium excretion, calcium and vitamin D preparations should be used with caution.
4.Medication: Give effective bone resorption inhibitors (such as bisphosphonates and calcitriol) if necessary. Drug usage and precautions are described in the primary osteoporosis treatment guidelines. Whether bone formation promoters (such as parathyroid hormone amino-terminal fragments) are suitable for secondary osteoporosis is subject to future experience.
V. Treatment of several specific types of secondary osteoporosis
1.Sex hormone deficiency osteoporosis: actively treat the primary disease. For young female patients, appropriate amount of estrogen or estrogen and progestin should be supplemented, and male patients should be supplemented with androgens. If necessary, use other types of anti-osteoporosis drugs.
2.Glucocorticoid osteoporosis: Physiological doses of glucocorticoids can also cause bone loss, and the decrease in bone mass is most obvious in 6-12 months of medication. Certain diseases require long-term application of glucocorticoids, and if the condition allows, the lowest effective dose should be used. Supplementation with calcium, vitamin D preparations and bisphosphonate anti-osteoporosis drugs, as appropriate, can help prevent the occurrence of glucocorticoid osteoporosis. For patients with significant bone pain, calcitonin analogs can be added.
3.Braking (disuse) osteoporosis: general treatment and drug treatment are the same as primary osteoporosis, but special attention should be paid to functional exercise and rehabilitation of the braking site.
4.Osteoporosis caused by long-term parenteral nutrition support: general treatment and drug therapy are the same as primary osteoporosis. As this disease is easy to combine rickets (or osteochondrosis), in addition to the use of aluminum-free nutritional support solution, to actively supplement vitamin D preparations.
5, diabetic osteoporosis: the main thing is to strictly control hyperglycemia, while applying anti-osteoporosis drug treatment.
6, post-organ transplantation osteoporosis: the same as primary osteoporosis.
7, hemodialysis osteoporosis: the prevention and treatment method is the same as primary osteoporosis. Avoid using aluminum-containing dialysis solution and low-phosphorus dialysis solution.