Calciphylaxis: A Comprehensive Guide To Diagnosis And Treatment

What is calciphylaxis?

Calciphylaxis, also known as calcific uraemic arteriolopathy (CUA), is a rare and serious condition characterized by calcification of small blood vessels in the skin and subcutaneous fat, leading to ischemia, necrosis, and painful ulcers. It predominantly affects patients with end-stage kidney disease (ESKD), particularly those on dialysis, though cases occur in non-uremic patients. The calcification causes vascular occlusion through medial calcification, intimal fibrosis, and thrombosis, resulting in tissue death and high morbidity.

This condition is life-threatening, with mortality rates exceeding 50% within one year, often due to sepsis from infected wounds. Incidence in dialysis populations ranges from 1-4%, higher in women and obese patients.

Who gets calciphylaxis?

Calciphylaxis primarily occurs in individuals with chronic kidney disease (CKD), especially ESKD on hemodialysis. Risk factors include:

• Dialysis duration >2 years
• Female sex
• Obesity (BMI >30)
• Diabetes mellitus
• Hypoalbuminemia (<3.5 g/dL)
• Hyperparathyroidism (PTH >300 pg/mL)
• Warfarin use
• Corticosteroid therapy
• Liver disease

Non-uremic calciphylaxis affects 1-20% of cases, linked to primary hyperparathyroidism, malignancy, or connective tissue diseases. Systemic inflammation and protein C/S deficiencies contribute in CKD patients.

Clinical features

Symptoms begin with painful, livedo-like reticulated erythematous or violaceous mottling on adipose-rich areas like abdomen, thighs, and buttocks. Lesions progress to indurated nodules, plaques, or ulcers with black eschar and surrounding erythema. Pain is disproportionate and severe, often requiring opioids.

Proximal lesions (trunk) indicate worse prognosis than distal (acral). Extracutaneous involvement includes myonecrosis, visceral ischemia (intestines, lungs), and penile necrosis. Systemic symptoms: fatigue, weakness from pain, infection, or treatment side effects.

Skin findings

• Early: Livedo racemosa, tender subcutaneous nodules
• Intermediate: Violaceous plaques, palpable purpura
• Late: Necrotic ulcers with eschar, secondary infection

Ulcers are slow-healing, prone to polymicrobial infection, risking sepsis.

Pathophysiology

Multifactorial: vascular smooth muscle cells transdifferentiate into osteogenic cells, depositing calcium-phosphate in arteriolar media. Endogenous inhibitors fail: low fetuin-A, matrix Gla protein, pyrophosphate. Inflammation upregulates IL-6/TIMP-1, promoting thrombosis.

Endothelial dysfunction causes intimal hyperplasia; hypercoagulability from protein C/S deficiency and platelet activation leads to microthrombi. Ischemia ensues in dermis/subcutis, causing fat necrosis and panniculitis.

Diagnosis

Clinical suspicion in at-risk patients with painful necrotic lesions. No specific test; diagnosis combines history, exam, labs, and biopsy.

Differential diagnosis

Investigations

• Labs: Calcium-phosphate product, PTH, albumin, CRP, ferritin
• Imaging: X-ray (vascular calc), DEXA (low bone density predicts)
• Biopsy: Gold standard – medial calcification, microthrombi, fat necrosis. Deep punch (6mm).

Biopsy risks infection worsening; defer if high suspicion.

Treatment

Multidisciplinary: nephrology, dermatology, wound care, pain management. No RCTs; based on registries, case series.

Wound care

• Debridement (autolytic, sharp if non-infected)
• NPWT for granulating wounds
• Topical antibacterials; avoid silver if calcified

Sodium thiosulfate (STS)

First-line: IV 25g 3x/week post-HD; oral 2-4g/day adjunct. Antioxidant, calcium chelator; response in 40-70%.

Phosphate control

• Low-phosphate diet, binders (sevelamer preferred over calcium-based)
• Dialysis intensification

Parathyroidectomy

For severe hyperparathyroidism; improves survival in responders.

Anticoagulation

• Citrate anticoagulation HD
• Prostacyclin analogs (limited evidence)

Pain management

• Opioids (fentanyl preferred), ketamine infusions
• Gabapentinoids, lidocaine patches

Emerging

• Rheopheresis: reduces cytokines/thrombi; 63% remission in severe cases
• IL-6 inhibitors (clazakizumab): targets inflammation
• Pyrophosphate analogs: restore inhibitors

Complications

Sepsis (most common cause of death), organ failure, chronic pain/debility. Non-healing wounds lead to amputations in distal cases.

Prevention

Avoid triggers: minimize warfarin, calcium/phosphate overload, obesity. Aggressive CKD-MBD control: target Ca 8.4-9.5 mg/dL, P 3.5-5.5 mg/dL, PTH 150-300 pg/mL.

Prognosis

Poor: 1-year mortality 56-80%, higher with proximal lesions, multiorgan involvement. Survival better with early STS, wound care; remission possible but relapses common.

Frequently Asked Questions

What causes calciphylaxis?

Calcium deposition in small vessels due to CKD-related mineral imbalance, inflammation, and thrombosis.

Is calciphylaxis curable?

No cure; chronic but manageable with multimodal therapy; remission possible.

How is it diagnosed?

Clinical + biopsy showing vascular calcification/thrombosis.

What is the best treatment?

Sodium thiosulfate, wound care, dialysis optimization; individualized.

Can it be prevented?

Yes, via CKD mineral bone disorder control and avoiding risk factors.

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medha deb

 

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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