Uremic pruritus

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Classification according to ICD-10
L29 Pruritus
N18 Chronic renal failure
ICD-10 online (WHO version 2019)

The uremic pruritus ( pruritus uraemicus ) is a chronic itching which all at 50-90% dialysis patients occurs and significant impairment of sleep can lead and work. Uraemic pruritus occurs more frequently in hemodialysis patients than in peritoneal dialysis patients, is more common in men and with higher urea levels .

General skin changes in chronic kidney failure

Almost 100% of all dialysis patients suffer from at least one skin disease . Many patients with chronic kidney failure are also affected by skin diseases. These can lead to a considerable impairment of the quality of life and under certain circumstances to serious illnesses.

Changes in skin color range from paleness due to anemia (anemia) to increased pigmentation ( hyperpigmentation ). The nails can also be discolored. A reduction in the sebum and sweat glands leads to dry skin ( xerosis cutis , syn. Xeroderma). The aging of the skin is often accelerated. The fine-tissue examination of tissue samples shows a thickening of the basement membrane of the skin vessels, an activation of the endothelial cells and signs of chronic inflammation.

Pathogenesis

The cause is not clear. Direct consequences of kidney disease such as dry skin (xerosis cutis), anemia, increased parathyroid hormone (secondary hyperparathyroidism ), and increased serum levels of aluminum and magnesium can lead to itching. The itching can also be the result of concomitant diseases such as diabetes mellitus , hepatitis , hypothyroidism or drug intolerance .

With chronic kidney failure, the number of mast cells in the skin is increased. These release histamine , which stimulates nerve endings, which the central nervous system perceives as itching. However, there is no relationship between the number of mast cells and the intensity of the subjective itching.

The neuropeptide substance P is increased in chronic renal insufficiency. Substance P stimulates opioid receptors . This stimulation can be felt as itching.

Neuropathic changes, chronic inflammation, and dysfunction of endogenous opioid receptors also appear to play a role. In uremic pruritus in particular, an increased activity of the μ-opioid receptors and a reduced activity of the peripheral κ-opioid receptors were found. By activating the κ-opioid receptors, the afferent activity of peripheral sensory nerves can be inhibited, thus reducing the transmission of pain.

diagnosis

The itching usually occurs during dialysis, but can also occur between dialysis treatments. A prerequisite for diagnosis is regular occurrence or at least three episodes within two weeks that last for several minutes. The physical examination shows scratches (excoriations) . It is usually not necessary to take a skin sample.

Differential diagnosis

A variety of other skin diseases occur in chronic kidney failure:

Diseases that can lead to chronic kidney failure and skin changes are

therapy

A definitive cure is only possible with a kidney transplant . Relief can be achieved by increasing the effectiveness of the dialysis treatment ( Kt / V ).

Topical treatment

The topical treatment consists of cleansing with mild soaps , skin creams containing urea with a high moisture content and, if necessary, medicinal preparations containing capsaicin .

Physical therapy

Phototherapy with UV-B radiation leads to relief. The mechanism of action and tumor risk with long-term use have not yet been clarified. Because of the increased risk of developing skin cancer after a kidney transplant , ultraviolet radiation should be used with caution and sparingly in dialysis patients who have been registered for kidney transplantation.

There is no strong evidence of a soothing effect from acupuncture .

Operative therapy

In patients with overactive parathyroid glands (secondary renal hyperparathyroidism), removal of the parathyroid corpuscles can lead to an improvement if this renal secondary disease cannot be controlled with medication.

Systemic treatment

A variety of drugs have been used for systemic treatment with varying degrees of success.

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Individual evidence

  1. David JR Steele: Difelikefalin for the Treatment of Uremic Pruritus New England Journal of Medicine 2020, Volume 382, ​​Issue 3, January 16, 2020, pages 289-290, DOI: 10.1056 / NEJMe1916598
  2. Kun Hyung Kim, Myeong Soo Lee, Sun-Mi Choi: Acupuncture for treating uremic pruritus in patients with end-stage renal disease: a systematic review . In: Journal of Pain and Symptom Management . tape 40 , no. 1 , 2010, ISSN  1873-6513 , p. 117-125 , PMID 21796811 .
  3. Steven Fishbane, Aamir Jamal, Catherine Munera, Warren Wen, Frédérique Menzaghi: A Phase 3 Trial of Difelikefalin in Hemodialysis Patients with Pruritus New England Journal of Medicine 2020, Volume 382, ​​Issue 3 January 16, 2020, pages 222-232, DOI: 10.1056 / NEJMoa1912770