Calcium crystal diseases
What are calcium crystal diseases?
Calcium crystal diseases are acute joint diseases and occur when crystals form deposits in the joint and surrounding tissues.
There are two different types of calcium crystals: calcium pyrophosphate (CPP) crystals deposit within the joints themselves and cause a condition known as acute CPP crystal arthritis or “pseudogout”; and apatite crystals usually deposit in the tendons, sometimes inside the joints, and cause a condition called acute calcific tendinitis.
Acute CPP crystal arthritis or pseudogout, is often mistaken for gout due to the similarity of symptoms, but the two conditions involve different types of crystals that form in the joints. Gout involves urate crystals, rather than calcium pyrophosphate crystals which are diamond in shape and will intensely irritate the joints. These commonly occur in one joint, like the wrist, knee, shoulder, and sometimes the ankle, and will involve short-lived attacks.
Acute calcific tendinitis, otherwise known as acute periarthritis, commonly affects the supraspinatus tendon which helps move the shoulder. It can also be found in tendons in the hip, hand and other parts of the body. It is caused by the shedding of crystals in a tendon where there is already calcific tendinitis.
How are the conditions diagnosed?
doctor will usually conduct a series of clinical tests, including examination of the joint fluid for crystals and infection, blood tests to look for the extent of the inflammation, calcium level, and kidney function, and x-rays to assess the calcification in the joint or tendon. Occasionally, other joint imaging tests may be done, including CT scan, MRI or ultrasound.
What are the symptoms?
Pseudogout can be mistaken for gout as the symptoms are very similar.
Like gout, pseudogout attacks can recur on occasion in the same joint or in different joints. Unlike gout, attacks are not linked to certain foods in the diet.
Patients usually experience sudden pain and stiffness in the affected joint, in particular the knee, swelling and tenderness, inflamed skin over the joint, and a raised temperature. These symptoms will persist for at least a few days and up to two weeks, before eventually recovering. Due to severity of the pain, patients may also struggle to sleep, becoming very tired, and generally feel unwell.
Acute calcific tendinitis usually presents with painful swelling, redness, and tenderness around the joint, usually the shoulder. The patient is likely to see these symptoms settle after 2 to 4 weeks. If the crystal deposits are particularly large, it can cause the tendon to bulge.
What are the causes?
Attacks of pseudogout and acute calcific tendinitis usually occur spontaneously and for no obvious reason. However, sometimes there will be an underlying cause of the attack, such as an injury to the knee or shoulder which may shake the crystals loose and trigger an attack later on.
Conditions such as flu or a chest infection can initiate crystal shedding, which will lead to an acute attack. Certain metabolic diseases can also interfere with the body’s calcium or polyphosphate levels.
Some research has suggested there may be genetic factors involved, in which abnormality of a particular gene may lead to the overproduction of pyrophosphate, provoking repeat attacks, sometimes at a particularly young age (20s to 30s). Underlying health conditions, including diabetes and kidney disease, can also be risk factors for developing a calcium crystal disease.
Who gets calcium crystal diseases?
Acute calcific tendinitis usually affects the shoulders of young or middle-aged adults. Acute CPP crystal arthritis can be present in all ages but tends to be a condition affecting people over the age of 40. It is rare for someone under the age of 60 to develop the condition.
People with other rheumatic conditions, such as osteoarthritis, in which a joint has been affected previously are prone to an attack of acute CPP crystal arthritis.
Underlying health problems, such as diabetes, high blood pressure, kidney disease and hyperlipidaemia can put people at risk. People with bone marrow disorders, like leukaemia, lymphoma, and any condition associated with high cell turnovers, are also at risk.
What treatments are available?
These conditions tend to settle with time and without any treatment required. However, due to the severity of the pain and discomfort of the attacks, treatment aimed at relieving the patient of the pain, inflammation and duration of the attack is likely to be prescribed by the doctor.
The main two forms of medication for acute attacks are anti-inflammatory drugs, such as ibuprofen and paracetamol, and colchicine. The doctor may also use a needle and syringe to release fluid out of the joint.
If an acute attack does not improve through these medications, the doctor might prescribe steroid treatment, either through an intravenous injection into the joints or oral medication. Sometimes simply applying an ice pack to the affected area can reduce the pain, heat and swelling. Patients may also want to consider seeing a physiotherapist to help assist in strengthening the affected muscles and joints.
What are the benefits of treatment?
As these conditions will settle with time, the main benefits of treatment are to manage the pain and quicken the recovery process. The earlier the patient receives the treatment, the more effective it will be to reduce the frequency of attacks, and avoid any long-term joint damage and other health implications associated with the conditions.
Are there any side effects of the treatment?
Anti-inflammatory drugs have side effects like all drugs, but the doctor will monitor the patient closely to avoid these and may prescribe a low dosage for a short period of time.
Side effects can include digestion problems, such as stomach upsets and indigestion. There is also the increased risk of heart attack, especially if the patient has any underlying health conditions, such as diabetes, high cholesterol, or high blood pressure.
Are there any self-help measures the patient can do in addition to receiving treatment?
A healthy lifestyle should be maintained, not just for general wellbeing but because it will also help ease acute attacks. It is very important that patients ensure their affected joints and muscles are moving and kept active following an attack. Regular, but limited, amounts of exercise will help strengthen the muscles and joints, and quicken the recovery process.
Diet is not directly related to calcium crystal diseases, as crystal deposition is not affected by the diet. However, patients should maintain a health balanced diet for general wellbeing, lose weight if they are obese or overweight, avoid excessive quantities of alcohol, and ensure they drink plenty of water to keep hydrated. Patients are also encouraged to use an ice pack for the affected area to reducing the swelling and pain, alongside any treatment given by the doctor.
What is the outlook like for patients?
As these conditions are effectively cured with time, the right treatment, and self-help, the outlook for a patient is very good. Joint pain and swelling are likely to go away promptly. And whilst it is common for attacks to flare up and return, it is usually possible for these to be controlled with repeated treatment.
However, the crystal deposits associated with pseudogout can cause long-term joint damage, which can mimic the signs and symptoms of osteoarthritis or rheumatoid arthritis. Therefore, the earlier patients receive treatment, the better their long-term outlook will be.