Osteomalacia is common in celiac disease. Osteomalacia can occur at any age. It children, it is called rickets. It is a metabolic bone disorder that involves slow loss of minerals from bone tissue throughout the skeleton, stemming from inadequate absorption of vitamin D. As minerals are dissolved from bone tissue to provide for essential functions elsewhere in the body, bones gradually lose their hardness.
Consequently, pronounced softening of the bones characterizes osteomalacia. Soft bones become deformed, especially bones of the arms, legs, spine, thorax and pelvis. The softer bones have a normal amount of collagen, a strong fibrous protein in the bone matrix (osteoid) that gives bone its structure and tensile capacity, but there is not sufficient calcium and phosphate minerals available to properly mineralize or be deposited in the osteoid to give it necessary hardness.
Bone is living, dynamic tissue. Up to age 18 years, bone is modeled or continually formed to grow bones bigger. After growth stops in adulthood, bone is continuously being remodeled or remade and repaired to keep it strong. Older areas of bone are resorbed (dissolved) and then filled in with new bone tissue on a regular basis.
What causes osteomalacia?
In celiac disease, malabsorption of vitamin D causes the lack of sufficient vitamin D necessary to adequately absorb and use calcium and phosphorus minerals in the body. In addition, fat malabsorption underlies in large part the malabsorption of all three nutrients: vitamin D, calcium and phosphorus. Certain other necessary nutrients needed in small amounts for bone health may also be malabsorbed. These other nutrients include magnesium, vitamin K and selenium.
What are the symptoms of osteomalacia?
- First, lack of energy and rheumatic aches or pains in the lower back and thighs develop.
- Then weakness of the thighs develops that progressively involves the arms and ribs. It becomes more difficult to climb stairs or get up from a squatting position because of thigh weakness. In arm weakness, objects feel heavier than they should to lift or carry. Breathing is more shallow when weak chest muscles do not fully expand the ribs, which is the mechanism that expands the lungs to pull in air.
- Bone tenderness develops, especially in the hips.
- Bones become misshapen from weight of the body and/or the pulling of muscles that attach to them, producing strain on the joints of the hips, knees, lower legs, ankles, and feet. The pelvis flattens front to back and widens side to side. Either bowlegs or knock-knees may result from significant angling of the knees in or out, causing pain and difficulty in walking.
In bowlegs, long bones of the legs above and below the knee bow outward, the knees angle out causing the space between knees to widen and the ankles and feet to roll out. Walking becomes duck-like or waddling.
In knock-knees, the knees angle inward causing the distance between them to decrease. Knees may eventually overlap, hitting each other in walking. The ankles are spaced apart with the feet rolling inward on the arch, creating an awkward walk or gait. From the side, legs may appear saber-shaped as the knee is forced backward.
High impact exercise such as jogging or aerobics puts the person with either bowlegs or knock-knees at high risk for injuries.
- Bones in the tips of fingers can become eroded due to resorption, making them thin and small.
- Bone fractures may develop, especially of the wrist and pelvis.
- Osteoarthritis of the knee will develop if osteomalacia is not treated.
How is osteomalacia diagnosed?
People with vitamin D deficiency need medical treatment to restore bone health. Your doctor will order medical tests that may include:
- Blood work shows low vitamin D, calcium and phosphate levels and usually elevated bone alkaline phosphatase (an enzyme) and parathyroid stimulating hormone (PTH) levels typical in celiac disease.
- Bone X-rays show bone deformities such as bowing and translucent pseudofractures called Looser’s zones that are diagnostic of osteomalacia.
- Bone biopsy of bone tissue shows demineralizaton at a microscopic level.
- Dexascan is a non-invasive procedure that scans bone of the lumbar spine, hip and wrist to measure bone density.
A doctor will prescribe the correct dosage of vitamin D based on bloodwork to restore normal levels and follow-up to monitor response. Blood monitoring of calcium and phosphorus is also important to evaluate the need for supplements while bone is healing. Too much is just as bad as too little.
Because many processed foods are fortified with vitamin D, it necessary to read food labels for added vitamin D in order to tell the doctor how much vitamin D is in the fortified products you regularly consume. This way he can factor that amount into the dosage he wants to prescribe.
Pain and weakness usually disappear within 1 to 2 months. Repeat x-rays show improvement in bones within a few weeks while complete healing takes 6 months.
A study investigating bone metabolism in celiac patients demonstrated that static and dynamic microscopic examination of cells of iliac crest bone biopsy are useful tools to evaluate bone metabolism in CD, especially if hyperparathyroidism or mineralization defect are suspected. Hyperparathyroidism, caused by inadequate calcium, may be a problem in patients before introducing a gluten-free diet. Mineralization defect and osteomalacic changes are common later on, irrespective of whether patients are in remission or not. Changes may not respond to a gluten-free diet alone but may require supplementation.
What should I do?
1. Check yourself for bone changes. We cannot “see” bone softening. And because muscle, fat and other soft tissue surrounding bone make it hard to notice bowing in early stages of osteomalacia, the way to check for bone changes is to look at the knee joints. They should be over the center of your feet.
- Stand in front of a full-length mirror with feet spaced so they are in line with your hip joints. The knees normally are centered over the feet and the kneecaps face forward.
- In bowlegs, a line straight down from the kneecap falls outside the feet and knee-caps turn out.
- In knock-knees, a line straight down from the kneecap falls inside the feet and knee-caps turn in.
- If you have knee problems, plan to see an orthopedic doctor to learn what treatment is necessary and what exercises are appropriate for you. High impact exercises should be avoided. Cycling or swimming are low impact forms of exercise, as are pilates and yoga.
3. Learn more about vitamin D deficiency through this newsletter, books and online resources.
4. Spend time in the sunshine. Worried about skin cancer? Sun damage to the skin that may lead to cancer is caused by burning the skin. This doesn’t happen in the 10 minutes it takes to get enough vitamin D. So enjoy your break outside when the sun shines. When you walk the children to school, let everyone get sun on their skin. Put the kids outside to play.
5. Use an untraviolet lamp indoors if getting out in the sunshine is not an option.
6. Keep a strict gluten-free diet. It is essential to heal the intestinal lining to prevent vitamin D deficiency through fat malabsorption.
7. Include natural food sources, such as fatty fish and eggs, and fortified food sources, such as milk, rice milk, soy milk, orange juice and cereal products in your diet. The egg has been shown to be an ideal food. The old assumption that the natural cholesterol in an egg would be harmful has been proven false by well-designed studies that show the opposite effect. Natural lecithin in egg is a powerful reducer of bad cholesterol in humans.
8. To prevent stress fractures and falls, learn and use proper body mechanics.
- Sleep on a firm mattress to keep your body in alignment while sleeping
- Use assistive devices to prevent losing balance by overreaching for high things or trying to pick up low things.
Damage from osteomalacia is progressive and the deformity is irreversible, making early treatment imperative to allow bones to heal and stop or prevent deformities from developing.
- Recognizing Celiac Disease by Cleo Libonati.
- http://courses.washington.edu/bonephys/ophome.html by Dr. Susan Oh is a website with excellent detailed explanation of bone tissue with graphics.
Author Information: Cleo Libonati, RN, BSN
Cleo Libonati is president/CEO and co-Founder of Gluten Free Works, Inc. She is the author of Recognizing Celiac Disease. She can be reached by E-mail.