Which type of osteoporosis occurs without a known secondary cause?

• A. Secondary osteoporosis
• B. Type 1 primary osteoporosis
• C. Type 2 primary osteoporosis
• D. Idiopathic osteoporosis

Answer: (D)

The type of osteoporosis that occurs without a known secondary cause is idiopathic osteoporosis. This condition is characterized by a decrease in bone density and an increase in fracture risk arising without any identifiable reason, such as hormonal imbalances, medical conditions, or medications that are typically associated with other forms of osteoporosis.

This term specifically refers to cases where the underlying factors contributing to the bone density loss are unclear after thorough investigation. Idiopathic osteoporosis can affect both men and women and typically presents in younger adults, distinguishing it from more common types that are often linked to aging, menopause, or chronic illnesses.

In contrast, primary osteoporosis, which includes both Type 1 and Type 2, is typically related to aging and hormonal changes rather than being classified as 'idiopathic'. Type 1 primary osteoporosis is generally associated with post-menopausal women, while Type 2 occurs typically in older adults and is related to age-related bone loss. Secondary osteoporosis, on the other hand, arises from specific identifiable causes like prolonged steroid use or conditions such as hyperthyroidism or malabsorption syndromes.

Understanding idiopathic osteoporosis helps clinicians recognize and manage cases where conventional risk factors do not apply, guiding them to take a more individualized approach to diagnosis and treatment.