by AK Team
Osteoporosis is an orthopaedics disease that occurs when the bone either loses too much bone or is able to make too less bone. In simple words osteoporosis means porous bone.
Osteoporosis causes the bones to become weak and brittle. The bones become so weak and brittle that a slight pressure like coughing or bending over may cause a fracture.
It may occur when the production of new bones is not as much as the loss of old bones.
Medications, treatment, healthy diet and weight bearing exercises can help prevent osteoporosis and may provide strength to the bones that are already weak.
PATHOPHYISIOLOGY OF OSTEOPOROSIS
- Osteocytes are the most abundant cell type in bone and are non – participating bystanders of bone metabolism.
- New insights into osteocyte physiology from the last two decades support a pivotal role of this cell type in bone and mineral homeostasis.
- Along with being important regulators of calcium and phosphate homeostasis, their central role as initiators of bone remodelling by communicating with osteoblast and osteoclast formation.
- This crosslink is facilitated by a complex network of dendritic processes, which spans the whole bone matrix.
- It connects osteocytes with the bone surface and the vasculature.
- Thereby, osteocytes directly or by the release of effector proteins influence osteoclast and osteoblast activity on the surface of a basic multicellular unit.
- Osteoporosis is a classic example of multifactorial disease with a complex interplay of genetic, intrinsic, exogenous, and lifestyle factors contributing to an individual’s risk of the disease.
- Traditional pathophysiologic models frequently emphasized endocrine mechanisms.
- However, it has become clear in the last years that pathophysiological mechanisms contributing to the onset of osteoporosis go far beyond this.
TYPES OF OSTEOPOROSIS
There are basically two types of categories of osteoporosis that have been identified :
- Primary osteoporosis :
Primary osteoporosis is the most common form of osteoporosis and it includes postmenopausal osteoporosis (type I), and senile osteoporosis (type II)
- Secondary osteoporosis :
Secondary osteoporosis is characterized by having a clearly definable etiologic mechanism.
Type I is associated with a loss of estrogen and androgen resulting in increased bone production in total, with bone resorption exceeding bone formation, and a predominant loss of trabecular bone compared with cortical bone.
Type II represents the gradual age related bone loss found in both sexes caused by systemic senescence, is induced by the loss of stem – cell precursors, with a predominant loss of cortical bone.
STAGES OF OSTEOPOROSIS
There are basically four stages of osteoporosis :
Stage 1 :
- Between the age of 30 to 35 in general, the rate of bone deposition slows down to be almost equal to the rate of breakdown.
- This state of equilibrium may be considered the first stage of declining bone mineral density, a process that can be referred to as leaching.
Stages 2 :
- Between the age of 25 and 35 the rate of bone breakdown will eventually outweigh the rate of bone deposition.
- Bone loss begins to occur at an approximate rate of 0.25% a year and is variable depending on many genetic and environmental factors.
- This may be considered the second stage towards osteoporosis.
- It is important to understand that this is a perfectly normal part of the aging process.
Stage 3 :
- From the age of 44 to 54 the breakdown of bone occurs at a faster pace in women due to the effects of menopause and associated reduction in the hormone oestrogen which is maintaining the health of all body tissues including bone, muscle, ligament and tendon.
- Linked with this third stage, is an increase in fragility fractures, where stress on a bone , previously considered normal in younger years, may now be enough to cause a fracture.
Stage 4 :
- Without any intervention, it can proceed to stage four.
- In this stage the effects of significant bone loss become visible.
- Softening of bones and accumulated fragility fractures especially in the spine, results in deformity.
- Associated with the deformity is pain and more difficulty managing normal activities of daily living such as – getting into and out of a car, chair or bed, climbing stairs, hanging out washing and reaching overhead, etc.
SYMPTOMS OF OSTEOPOROSIS
There are specifically no symptoms of osteoporosis in the early stages. But as the disease proceeds, the symptoms begin to appear. Some common symptoms are listed below.
- A stooped posture
- Bone breaks much easily than expected
- Loss of height over time
- Lower back pain, caused by a fractured or collapsed vertebra.
- Shortness of breath (smaller lung capacity due to compressed disks)
CAUSES OF OSTEOPOROSIS
The exact cause of osteoporosis is not yet discovered, still there is theory of what how it is caused.
- The bones are made of living, growing tissue.
- The inside of this healthy bone looks like a sponge. This area is known as the trabecular bone.
- An outer shell of the dense bone wraps around the spongy part of the bone. This hard shell is called cortical bone.
- In case of osteoporosis, the holes in the sponge grow larger and more numerous, which leads to weakening of the inside of the bone.
- Bones support the body and protect vital organs and also provide a structure to the body.
- Bones also store calcium and other minerals.
- After the age of 35, bone breakdown occurs faster than bone build up, which causes gradual loss of bone mass.
- If one has osteoporosis, he or she lose bone mass at a much greater rate.
- In females, after menopause, the rate of bone breakdown occurs even more quickly.
For the diagnosis of osteoporosis , the bone density of the patient has to be measured. This can be measured by a machine that uses low levels of X-rays to determine the proportion of mineral in the patient’s bones. During this painless diagnostic test, the patient has to lie on a padded table as a scanner passes over his body. In most of the cases, only few bones are checked and these are usually the hip bone and the spine bone.
The treatment of osteoporosis is done based on an estimation of the patient’s risk of breaking bone in the next 10 years using information such as the bone density test.
Some of the medications that are used for treating osteoporosis are listed below:
- Alendronate ( binosto, Fosamax)
- Risedronate (Actonel, atelvia)
- Ibandronate (boniva)
- Zoledronic acid (reclast, zometa)
Monoclonal antibody medications
Hormone related therapy
Bone building medications
- Teriparatide (forteo)
- Abaloparatide (tymlos)
- Romosozumab (evenity)