Osteoporosis in patients with chronic kidney disease.

Basic relation between bone and kidney health.

Bone health is intertwined with renal health as vitamin D is processed in the kidneys. Activation of calcitriol occurs in the proximal convoluted tubules of the nephrons. Deterioration of kidney health status adversely affects the bones. Bones when undergoing deterioration they tend to become hypodense. This in turn results in a lower mass of the bone and the destruction of its internal trabecular structure. This condition is grossly termed as osteoporosis. The kidney is the major responsible organ that carries out the function of maintaining electrolyte balance and the buffering actions of the body. Electrolyte imbalance also leads to poor bone nourishment resulting in its wear and tear.

What are the causes of osteoporosis in chronic kidney disease patients?

1. Electrolyte imbalance in the body leads to reduced calcium and potassium deposition in the bones. This leads to the weakening of the same. Reduction in the bone density occurs as mineral content in the bone is reduced with a reduction in glomerular filtration rate or kidney functioning.
2. Reduced metabolism of vitamin D and improper generation of an activated product of calcitriol paves the way for osteoporosis. Lower micro and macro mineral levels in the bones become one of the leading factors for disrupted bony structure.
3. High levels of parathormone are noted which in turn stimulates the antagonist hormone which is calcitonin. But calcitonin when released is not sufficient to neutralize the parathyroid hormone, bone calcium reduces thereby increasing blood calcium. Calcitonin functions by depositing the calcium from the blood into the bone and parathyroid hormone deposits calcium from the bone into the blood. Therefore, when para thyroid hormone increases, and is not neutralized well, bone mineral density is reduced leading to osteoporosis. As homeostasis is hampered in CKD patients, neutralizing of parathyroid hormone is affected in most of the patients.
4. The geriatric population faces osteoporosis due to CKD to a greater extent.
5. Steroids and other medical managements show adverse effects or secondary effects in the form of osteoporosis.
6. Patients on dialysis can undergo osteoporotic changes quite quickly for the same reasons stated above.
7. Low levels of physical activity and exercise reduces bone metabolism and leads to weak skeletal structures.
8. CKD associated with thyroid issues, vascular disorders, and other associated conditions have greater chances of developing osteoporosis.

Symptoms of osteoporosis in CKD patients.

1. Recurrent fractures with very less impact injury.
2. Bow legs and knock knees.
3. Reduction in height of the vertebral column.
4. Pain in the joints.
5. Crepitus in the joints, especially the knee joint.
6. Weakness with minimal activity.
7. Forward bend posture with forward head and rounded shoulders.
8. Slouched sitting.
9. Pain in the upper and lower back.
10. Common in females.
11. Associated stomach issues or dental issues.
12. Appetite and sleep disturbances may be associated.

How to avoid osteoporosis in CKD patients?

Reducing the bone destruction and improving the bone formation makes the bone stronger and less porous. This can be achieved by maintaining proper diet, exercise, supplementary intake, and modifications in the activities of daily living. Some of the measures are mentioned below,

1. Diet: in CKD, not all the mineral-rich foods can be consumed, hence vitamin K rich foods along with calcium rich foods should be given in controlled quantities. Milk, spinach, etc. is recommended in strict proportions.
2. Exercises: weak bones don’t contribute to the excuse of not exercising. Exercising is the best possible way to avoid and control osteoporosis as well. Specific exercise program is mandatory which one can get from a qualified physiotherapist.
3. Supplementary intake: vitamin D tablets, calcitriol, and calcium supplements are usually recommended. This has to be in coordination with sunlight exposure at the proper time and adequate durations as well.
4. Modifications in the activities of daily living: reducing the work load by limited bending, limited overhead activities, heavy weightlifting, long standing, etc. using of modified toilets is one of the major modifications required.
5. Others: maintain proper body mass index, wear proper footwear by avoiding heels, and avoid junk food, alcohol, and cigarette smoking.

Why is osteoporosis a topic of concern?

1. If left untreated osteoporosis can lead to serious disabilities in the form of fractures, and weakness to a severe extent.
2. It may lead to dependency. Inability to ambulate independently, inability to participate in social events.
3. It may lead to severe pain and irritability.
4. It can lead to osteoarthritis, cartilage abnormalities, and other joint complications.
5. Dependency in bowel and bladder voiding due to dependency in ambulation can further worsen the existing condition.

Summary:

Osteoporosis is a secondary complication of chronic kidney disease, in which bones lose their density and become porous. This increases their chance of getting damaged and broken. CKD treatment and dietary modifications are the factors that can lead to this condition. It is commonly seen in old age, hormonal imbalance, steroid usage, electrolyte imbalance, etc. 

Osteoporosis leads to severe issues concerning activities like walking, climbing, washing, bathing, bending, lifting, shifting, etc. also, this activity restriction leads to dependency and further emotional complications.

Brittle bones, deformed joints, and pain in the extremities can be the early signs. X-ray shows porous bones and loose trabecular structures of the long bones like the femur. It can very much be avoided by dietary modifications, proper and specific exercise like quadriceps and hamstrings strengthening in a clinical setting along with ergonomic modifications. Supplementations and other lifestyle modifications are equally important.

Osteoporosis in CKD can be a point of concern and at the same time, it is avoidable and controllable with adherence to the medical line of treatment, pharmacological treatment, and physiotherapy line of management. A holistic approach towards osteoporosis not only helps to control it but also improves the quality of life of the patient and the caregivers as well.