Osteoporosis: Clinical sciences

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Introduction0:00–1:10

Osteoporosis is a metabolic bone disease characterized by low bone density, decreased bone mass, and increased risk of fracture.
Osteoporosis can be either primary or secondary. Primary osteoporosis is more common in postmenopausal patients, and it refers to bone loss that occurs with aging due to low levels of sex hormones, namely estrogen.
Low estrogen levels cause increased osteoclastic activity, and since osteoclasts break down bone, this means increased bone resorption and, as a consequence, low bone density.
Secondary osteoporosis, on the other hand, occurs because of an underlying cause, typically a medical condition, like rheumatoid arthritis, or a side effect of medications like glucocorticoids, especially when used for long periods of time.
Osteoporosis is typically diagnosed using a dual-energy X-ray absorptiometry or DXA scan, and sometimes a FRAX score.Now, most patients with osteoporosis are asymptomatic, so perform a focused history and physical exam.

Focussed H&P1:10–2:11

When obtaining history, important risk factors include being postmenopausal, fracture history without major trauma, low BMI less than 20 kg/m2, osteopenia on imaging, a family history of osteoporosis or parental hip fracture, a history of smoking or excessive alcohol use, as well as medical conditions like rheumatoid arthritis, or the use of medications like long-term glucocorticoids.
Finally, regardless of risk factors, you should screen all biological females over 65, biological males over 70, and individuals who are 5 years postmenopause for osteoporosis.
Additionally, physical exam findings might reveal skeletal deformities, such as kyphosis or loss of height. Ok, now, if you suspect osteoporosis based on the patient’s risk factors and physical exam, the next step is ordering a DXA scan, which tests a patient’s bone mineral density.

DXA scan & FRAX score2:11–5:34

A DXA scan is typically performed at the hip and lumbar spine level. In patients with either known or suspected hyperparathyroidism a DXA scan of the distal third of the radius can be considered, as in these patients, bone loss tends to occur faster in the radius.
Alright, now lets look at the possible results of our DXA scan. DXA scan results are typically reported as a T-score, which is a standard deviation measure of a patient’s bone density compared to a reference population.
Ok, now, a T-score greater than or equal to -1.0 is normal. In other words, there’s no osteoporosis and you can consider alternate diagnosis.On the other hand, if the T-score is between -1.0 and -2.5, then the patient may have either osteopenia or osteoporosis, so you should use the Fracture Risk Assessment Tool to calculate a FRAX score.
The FRAX score estimates a person's 10-year risk of either a hip fracture, or a major osteoporotic fracture based on their age, sex, weight, height, and history of personal or parental fracture.
It also takes into account smoking status, alcohol use, glucocorticoid use, history of rheumatoid arthritis, and bone mineral density at the femoral neck.
If the FRAX score shows that the patient’s 10-year risk is less than 3% for hip fracture, and less than 20% for major fracture, then your patient has osteopenia.
If this is the case, you should encourage lifestyle modifications, such as increased dietary calcium intake, alongside vitamin D supplementation.
Next, counsel your patient on smoking cessation, limiting alcohol intake, as well as weight-bearing, balance, and resistance exercises.
If the patient is at increased risk of falling, you should refer them to a physical therapist. However, if the FRAX score reveals a 10-year risk equal to or greater than 3% for hip fracture, and equal to or greater than 20% for major fracture, you can diagnose osteoporosis.
Now, let’s go one step back and check the DXA scan one more time. If the T-score is -2.5 or lower, you can directly make the diagnosis of osteoporosis.Here’s a clinical pearl to keep in mind!
A fragility fracture is a break that occurs after a low-energy trauma, such as a fall from standing. The most common sites include the femoral neck, lumbar vertebrae, and the radius.
Any patient with a fragility fracture has osteoporosis, no matter what their DXA scan or FRAX score shows, and might also need evaluation for underlying malignancy to rule out a pathologic fracture.Now that you’ve diagnosed your patient with osteoporosis, you should assess for secondary causes of osteoporosis.

Assess for secondary causes5:34–6:26

Vitamin D deficiency and chronic kidney disease can both cause osteoporosis. Next, review the patient’s medication list and look for any that can cause bone loss, such as long-term glucocorticoids, androgen deprivation therapy, and antiepileptic medications.
Additionally, assess for endocrine disorders that cause osteoporosis, like hyperparathyroidism, hyper, or hypothyroidism, hypercortisolism, as well as premature ovarian failure.
Finally, evaluate for malnutrition or malabsorption conditions like celiac disease, inflammatory bowel disease, or a history of gastric bypass.Ok, now, if you’ve ruled out secondary causes of osteoporosis.

No secondary cause identified6:26–8:04

In this case, you can diagnose primary osteoporosis, so management involves the same lifestyle modifications, as well as pharmacologic therapy.
Now, the mainstay of pharmacologic therapy in osteoporosis are bisphosphonates, so let's look at these drugs in greater detail.
A key point to make when prescribing these medications is to tell your patients to avoid lying down for 30 to 60 minutes after taking the medication.
This is because bisphosphonates can often cause or worsen esophageal disorders. Another thing to keep in mind is that because they can cause esophagitis, they shouldn’t be prescribed to patients with esophageal disorders.
Also, these medications should be used with caution in patients with chronic kidney disease, as they can worsen renal function.
Some rare but serious side effects of bisphosphonates also include osteonecrosis of the jaw, and atypical femoral stress fractures.
To minimize this risk, stop treatment after 3 to 5 years to give your patient a temporary treatment break, which is also known as a “drug holiday”.
Additional pharmacologic therapy options for osteoporosis include a RANKL inhibitor called denosumab, as well as parathyroid hormone-related analogs like teriparatide.
Lastly, you can offer estrogen-related therapy to postmenopausal patients, but only if they can’t tolerate these other medications, given its increased risk for deep vein thrombosis.Ok, so now that you’ve started your patient on pharmacologic therapy, assess their response to therapy after 1 year using DXA scan.

Assess response to therapy8:04–8:34

If the DXA scan shows stable or improving bone mineral density, and there are no new fractures, continue current management.
However, if the DXA scan reveals continued bone loss, or there are new fractures, you should reassess for secondary causes of osteoporosis and consider alternative medication.
Alright, now let’s go all the way back to our initial assessment for secondary causes of osteoporosis. Some important causes to look for include vitamin D deficiency, chronic kidney disease, certain medications, endocrine disorders, and malnutrition or malabsorption.

Secondary cause identified8:34–9:17

If you do identify a secondary cause of osteoporosis, you can diagnose secondary osteoporosis. Management includes treating the secondary cause, and encouraging the same lifestyle modifications.
Lastly, if the patient continues to have bone loss despite this management, you should consider adding pharmacologic therapy.Alright, as a quick recap… If you suspect osteoporosis based on history and physical exam, order a DXA scan.

Review9:17–10:39

A T-score of -1.0 or greater is normal. If the T-score is between -1.0 and -2.5, calculate a FRAX score.
If it doesn’t show a high risk of fracture, diagnose osteopenia and encourage lifestyle modifications; but if the FRAX score reveals a high risk of fracture, or the T-score is -2.5 or lower, diagnose osteoporosis.Then evaluate for secondary causes.
If there are none, it’s primary osteoporosis, so start pharmacologic therapy. After one year, repeat the DXA scan.
If bone density remains stable or improves, and there are no new fractures, continue treatment. However, if there’s continued bone loss or new fractures, reassess for secondary causes and consider switching to an alternative medication.
Lastly, if there’s an underlying cause, diagnose secondary osteoporosis. Management includes treating the secondary cause, lifestyle modifications, and sometimes pharmacologic therapy.
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