What is calciphylaxis?

Calciphylaxis is a rare yet serious condition most commonly seen in people having dialysis (estimated to effect less than 1% of dialysis patients per year).

Calciphylaxis happens when small blood vessels in and around the skin become blocked by a build-up of phosphate and calcium. This causes painful skin ulcers which can lead to serious infections.

The cause in uncertain. But it occurs more often in people who are not having enough dialysis and/or have long-term problems with renal bone disease, as shown by high calcium and phosphate levels in the blood

Different types

Calciphylaxis has two types:

Uraemic (you-reem-ick; meaning related to advanced CKD). This type is the more common of the two. This typically happens in people who have end-stage renal failure (ESRF), i.e. are on dialysis (or occasionally with a kidney transplant)
Non-uraemic. This type is rarer and happens in people who have mild CKD, who have a recent injury to one or both kidneys – or who do not have kidney problems at all.

Calciphylaxis is also more common in women, who are twice as likely to develop the condition as men.

Other risk factors include: diabetes mellitus, obesity, warfarin use, calcium and vitamin D supplementation, and hypercoagulable disease states (protein C/S deficiency).

Clinical features

In most cases, calciphylaxis happens because calcium deposits form in and block the blood vessels that supply your skin and the tissue just underneath it. They can form internally in the eyes, lungs, brain, muscles, and intestines in rare cases.

When it affects surface tissue like skin, calciphylaxis is extremely painful. It also causes the affected area to become an open wound, similar to a bedsore. It may go black as the skin and tissue around the wound dies, and the damage from the dead tissue spreads outward. These wounds are slow to heal and can lead to major complications.

Calciphylaxis

If a wound gets infected and that infection spreads through your body, it can cause an overreaction of your immune system called sepsis. This condition is the most dangerous complication of calciphylaxis.

How is calciphylaxis treated?

Because there is not a great deal of research on calciphylaxis available, there is also limited guidance on the best ways to treat it. Currently, the disease is not curable, but it can go into remission if treatment is successful.

In general, doctors will focus on the following:

Wound care

Preventing infection and helping wounds to heal are both priorities. This can include several advanced types of care, such as:

Hyperbaric oxygen therapy. This involves placing you in an airtight chamber with a 100% oxygen atmosphere (instead of the normal oxygen concentration of about 20%). The pressure in the chamber will also be slightly higher than normal. This can be very effective at encouraging wounds to heal
Debridement. This is the surgical removal of dead or dying tissue from a wound, helping prevent infection and encouraging the wound to heal
Skin and tissue grafting. In cases with greater tissue loss, skin grafts from elsewhere on the body may help with wound repair and healing
Antibiotics. These can help stop infections from bacteria.

Pain management

Calciphylaxis is an extremely painful condition, making it harder for you to rest and let your body heal. Opiate pain medication may be needed.

Treatment of renal bone disease

Ensuring the right levels and balance of minerals (especially calcium and phosphate) in your blood is important in this condition. You may need changes to your phosphate binding drugs and vitamin D, if you are on them.

This also includes making sure parathyroid hormone levels are not too low or too high. In some cases, it may involve surgery to remove one or both of the parathyroid glands.

Dialysis

A higher dose of dialysis is usually needed. Some patients on CAPD or APD will need to transfer to haemodialysis, so they can have a higher dialysis dose.

Sodium thiosulfate

This medication, given in an IV, may help remove calcium built up in blood vessels or other tissues.

Combination of treatments

This usually required. In other words, to make it better, you will need increased treatment for renal bone disease, more dialysis and surgical procedures.

Outlook for calciphylaxis

Calciphylaxis has a poor prognosis with 1-year mortality rates between 45% and 80%, and the response to therapy is also poor. Patients with ulcerated lesions are particularly prone to infection, which is the leading cause of death.

Summary

We have described what is calciphylaxis. It is a very serious, but fortunately rare, complication of CKD – that usually occurs in patients on dialysis.

Other resource

This is a review article: Westphal, 2022.

Last Reviewed on 4 April 2024