This lesson will discuss a condition known as Paget’s disease of bone. We’ll talk about its risk factors, why it occurs, how a doctor may diagnose it, as well as how it may be treated.
Odd Pathological Interactions
Sometimes, the weirdest associations and things occur in nature. Some ants actually farm by using other insects, such as aphids. Birds will willingly go into a crocodile’s mouth to get some food as the crocodile willingly lets them without causing them harm. And a louse can enter a fish and take on the role of the fish’s tongue.
It’s all weird but true.These natural oddities extend to humans and our interactions with things like pathogens. This lesson will point out one such odd interaction and how it may influence a condition that affects our bones.
What Is Paget’s Disease of Bone?
There’s a condition called Paget’s disease of bone. This is a disease characterized by large and improperly shaped bones that lead to pain, fractures, and arthritis.
This condition is more likely to affect older men of Northern European descent, although this doesn’t preclude women or both sexes of other heritage from being affected.We suspect that some viruses may actually cause this condition to occur, but cannot explain why. That’s right! Different types of viruses have been implicated in this condition even though they don’t directly affect the bones of the people they infect.
Why Does Paget’s Disease of Bone Occur?
Besides viral issues, you can clearly tell that genetic issues have to play a role in this disease, since I mentioned that men of Northern European ancestry are more likely to develop it.Whether it’s genetic, viral, or otherwise, this disease affects the way your bones are remodeled. There are two cells involved in the remodeling of bone, called osteoclasts and osteoblasts. The osteoclasts and osteoblasts can be likened to home remodelers.
The osteoclasts are the guys that come in first and tear everything down that needs to be torn down, while the osteoblasts come in and build everything anew to stabilize the house and make it look pretty.A similar process occurs in your bones, where osteoclasts break down the bone and osteoblasts build it back up again.In Paget’s disease of bone, this building and rebuilding is very disorganized and out of sync compared to healthy people. You can liken the two home remodelers coming in and, instead of first tearing things down then cleaning things up before remodeling everything to make it look better, the remodelers instead tear everything down in excessive fashion and try to build everything back up far too quickly. This leads to a haphazard collection of semi-finished rooms with tears and holes in the walls intermixed with beautiful floors and semi-finished ceilings.
This disorganized formation of bone in people with this disease may result in the formation of bones that are larger than before, but not as dense, leading to a higher risk of fracture. You can liken it to our remodelers building a larger house but not using enough two by fours in between the drywall to hold the larger house up. It’s bound to crack under its own weight!
Clinical Signs, Symptoms, and Diagnostics
Curiously, most of the bones that are affected in this condition include the skull, spine, pelvis, and legs, and we’re not sure why. This is critical to know because another condition, known as osteoporosis, also leads to weakened bones that are more prone to fracture, but osteoporosis can affect all the bones in the body.
People affected with this condition feel quite a bit of pain, especially if it affects their skull or spinal cord. Arthritis, or inflammation of the joints, may develop in addition to the bowing of the legs, and increased risk for fracture.Besides using all of the signs I mentioned to diagnose this disease properly, a doctor may also run some blood tests. These blood tests may show higher-than-normal levels of an enzyme called alkaline phosphatase. Those of you who may have recently been learning about the liver may think I’m crazy, as this is a very commonly looked for enzyme in people with a liver condition. However, there are different subtypes of alkaline phosphatase, and one of them is released when the bone is affected by a serious condition, such as this disease or another, such as bone cancer.
Blood tests in this malady will also reveal normal levels of calcium and phosphate in the blood. While you may think that normal levels of something aren’t as important to know as decreased or increased levels of something, physicians don’t think like this. Even normal levels are indicative of something. In this case, it’s important to note because another bone disease, called osteomalacia, will actually have decreased levels of these compounds instead. This little distinguishing feature is just another tool a doctor will use to better rule out one condition and narrow down the list of possibilities.
Besides blood work, bone scans and x-rays may reveal features that point to Paget’s disease of bone, such as misshapen bones, overly large bones, excessive bone resorption, fractures, and so forth.
Treatment of Paget’s Disease of Bone
Once a doctor finally diagnoses Paget’s disease of bone, they can begin to give the proper treatment for its effects.One class of drug that may be given to treat this condition is known as bisphosphonates. These drugs will localize to the bone and will begin to interfere with the destructive effects on the bone that this condition entails.In cases where fractures may have occurred as a result of Paget’s disease of bone, surgery may be performed to fix the problem. Surgery may also be indicated in cases where severe arthritis causes the erosion of joint cartilage, necessitating the replacement of a joint.
In summary, Paget’s disease of bone is a disease characterized by large and improperly shaped bones that lead to pain, fractures, and arthritis.It occurs as a result of an improper balance between the activity of two cells involved in the remodeling of bone, called osteoclasts and osteoblasts.This improper activity causes a person to have misshapen bones, increased risk of fracture, and arthritis, among other things.Diagnosis is made by running blood tests, bone scans, and x-rays.Once diagnosed, a physician may use medicine, such as bisphosphonates, and, if necessary, surgery, to correct the problem.
When this lesson is over, you should be able to:
- Explain what Paget’s disease is
- Identify and explain osteoclasts and osteoblasts
- Understand how the disease is diagnosed and treated