Avascular necrosis describes the death of bone tissue that occurs when the blood supply to an area of bone is cut off. It causes severe damage to the bone and is also known as ischemic bone necrosis, aseptic necrosis, bone infarction and osteonecrosis.…
What is bursitis?
Bursitis is swelling and irritation of the bursa. Bursa are small, fluid-filled sacs that help reduce the friction when tendons or ligaments rub against other structures such as bones, muscles and skin, reducing any wear and tear. The cells within the bursa secrete synovial fluid, a protein-rich fluid that helps reduce friction, absorb shock and provides nutrition to surrounding tissues.
Injury or disease can cause inflammation of the bursa, which is known as bursitis, and can cause pain, redness, swelling and limited movement.
Bursitis can be caused by a wide range of factors, including:
Risk factors for bursitis include:
- Rheumatoid arthritis, gout, pseudogout and diabetes;
- Age - as you get older, tendons lose strength and flexibility, leaving you more susceptible to injury;
- Manual jobs or hobbies with repetitive stress or pressure to the affected area;
- Trauma to the skin overlying the bursa. This can introduce organisms into the area and increase the risk of an infection, and;
- Obesity - being obese or overweight places extra strain on joints.
Numerous bursa are located throughout the body, although bursitis tends to be more common in the shoulder, knee, elbow and hip joints.
There are numerous different bursa around the knee that can become inflamed. The most common types are:
- Prepatellar bursitis - also known as housemaid's knee, is caused by inflammation of the bursa that lies underneath the kneecap (patella). It is most commonly due to kneeling for prolonged periods, or trauma to the front of the knee;
- Anserine bursitis - the anserine bursa is located on the lower part of the inside of the knee, just at the top of the shinbone (tibia). It is more common in women, especially those who are obese, middle-aged or have arthritis, and;
- Infrapatellar bursitis - affects the bursa that lies below the kneecap (patella) and is commonly caused by a jumping injury.
A common bursa in the shoulder is the subacromial bursa. Subacromial bursitis can cause a dull ache in the upper arm, especially when moving your arm above the shoulder or when lying on the affected side at night.
This affects the bursa at the tip of the elbow, or olecranon. The elbow can become very swollen and painful to move. This is usually caused by pressure or overuse, such as leaning or resting on the elbow.
There are two common types of hip bursitis:
- Trochanteric bursitis - the bursa is located around the top of the bony head of the thighbone. Often felt after an injury, repetitive activity, lying on the side or after a long walk, the pain is usually felt in the uppermost lateral side of the thigh. Sometimes the pain may radiate down toward the outer knee, causing you to wake up at night;
- Iliopsoas bursitis - the bursa is located on the inner, front aspect of the hip joint. It typically causes pain within the groin region.
Pelvic bursitis occurs when the bursa between the hamstring muscle and the pelvic bone become inflamed. The bursa lie beneath the buttock muscles and pain is usually felt in the lower buttock. These bursa are often irritated by energetic activities, such as running or kicking, but also by sitting for long periods of time.
There are two main types of bursitis found here:
- Posterior Achilles tendon bursitis - occurs when the bursa located between the skin and the Achilles tendon becomes irritated. The Achilles is a large tendon that attaches the calf muscle to the heel. Wearing high heels and shoes that exert pressure on the back of the heel can cause this, and;
- Anterior Achilles tendon bursitis - also known as retromalleolar bursitis, it occurs when the bursa located in front of the Achilles tendon attachment become irritated. This bursitis is often seen with the formation of a bony bump.
Both types of bursitis can be caused by poor footwear choices.
Signs and symptoms
The signs and symptoms experienced will vary, depending on the nature and location of the condition.
- Pain, swelling and redness when using the affected joint;
- Constant pain that becomes worse during the night, and;
- Stiffness, aching and decreased range of movement.
If the bursitis is caused by an infection, a fever may occur as well as a general feeling of being unwell.
Methods for diagnosis
Your doctor may be able to diagnose bursitis from your medical history and examination of the affected joint. Bursa close to the surface of the skin are easier to examine, but deeper-placed bursa may require imaging scans to allow assessment.
Commonly used imaging scans include ultrasound and magnetic resonance imaging (MRI).
Your doctor may also send a sample of the synovial fluid to a pathology laboratory to check for infection, gout or pseudogout. This fluid is taken from the affected bursa using a fine needle (medically known as fine needle aspiration).
Types of treatment
It often helps to give the affected joint time to heal by reducing its use for a few days. Icing the affected bursa, for short periods of time, can help to reduce the swelling and pain. Alternatively, a heat pack may provide some relief.
- Pain-relief medications, such as acetaminophen and ibuprofen, may relieve pain and are often suggested for the first few days of recovery;
- Corticosteroids, such as prednisolone, may be prescribed for a few days in cases of severe inflammation, and;
- Antibiotics are needed for septic bursitis.
- Injection directly into the bursa - if there is severe swelling and pain, an injection of local anesthetic combined with corticosteroid may be offered. In most cases, this works quickly to reduce the symptoms, but is not useful in cases of septic bursitis. These injections can only be offered a few times per year, to avoid side effects such as muscle wasting or localized skin discoloration;
- Aspiration (using a needle to draw out fluid) is sometimes offered, especially if there is very severe swelling or an infection. Removing the excess fluid will relieve pressure and pain in most cases, and;
- Stretching exercises for the muscles and tendons.
Surgery is only considered as a last resort for most cases of bursitis. However, it is often used to treat septic bursitis that is not responding to antibiotic treatment. Your surgeon may remove the affected bursa, or make a small cut to drain it.
The outlook for bursitis depends on the cause. If you have rheumatoid arthritis or other underlying medical conditions, then the prognosis depends on the treatment of the underlying condition. If you have bursitis due to overuse of or pressure on a joint, changes in lifestyle habits may improve the condition. Your doctor may recommend muscle-strengthening exercises to help avoid bursitis. With age, joints lose their strength and extra care is required to prevent their damage.
Development of bursitis cannot be prevented in all cases, but you can lessen the chances of a flare-up by following these measures:
- Be careful how you perform repetitive activities. As you age, you are more likely to experience bursitis, so taking care of the joints is important;
- Protect the joints - wear protective pads on knees, braces on elbows and good-quality shoes for running or hiking;
- Learn exercises that encourage flexibility and strength, to avoid future injury, and;
- Maintain a healthy weight to reduce the strain on the affected joints.