What is Uremic Pruritus Evaluation and Treatment ?
Uremic pruritus, also known as chronic kidney disease (CKD)-associated pruritus (CKD-aP), is a common and bothersome symptom experienced by patients with kidney disease. It is particularly prevalent among those with end-stage renal disease (ESRD), which is the last stage of chronic kidney disease. Uremic pruritus is primarily associated with itching that is not linked to any skin disease. It is important to rule out other conditions that could cause itching such as eczema, liver disease, and thyroid diseases before a uremic pruritus diagnosis is confirmed.
About more than 40% of patients undergoing hemodialysis, a treatment for kidney failure, often experience chronic itching. Sadly, the exact cause of CKD-aP remains unclear. Ingredients released by the body like histamine, parathyroid hormone (PTH), magnesium, and calcium have been linked to its occurrence. Researchers are also studying abnormalities related to opioid-receptors and slight inflammation, as possible causes of CKD-aP. However, more research is needed in this area.
Itching can be very challenging to manage due to limited treatment options. Doctors usually recommend a step-by-step approach for treatment, starting with skin moisturizers, a medication called gabapentin, and light therapy. If these treatments aren’t effective, newer options may be considered, such as drugs that work on certain types of opioid receptors. In severe cases, a kidney transplant may be the preferred option, since a successful kidney transplant can relieve patients from CKD-aP.
What Causes Uremic Pruritus Evaluation and Treatment ?
The exact cause of itching in people with severe kidney disease, also known as uremic pruritus, is not fully understood. The process leading to itchy skin involves different compounds like histamine, prostaglandins, cytokines, neuropeptides, and proteases. These compounds turn on nerve cells to send itch messages to your brain through nerve cells located in your spinal cord. It has been suggested that toxins related to kidney disease, including certain elements like aluminum, calcium, phosphate, and a hormone produced in the parathyroid glands, might play a role in causing itchiness. However, a study conducted between 2012 and 2015 found no link between itchiness and the levels of calcium or phosphorus in the blood.
Other elements like increased blood urea, a molecule called β2-microglobulin, magnesium, and vitamin A could also contribute to itchiness. Some research indicates that lower levels of a protein called albumin and higher count of white blood cells can be significantly linked with moderate to severe itchiness. Conditions like anemia, low levels of a hormone called erythropoietin, high levels of a protein called ferritin, and low levels of transferrin have also been considered as possible risk factors for itching in kidney disease.
The possible underlying mechanisms for itchiness in kidney disease might involve skin alterations, inflammation, malfunctions in pain-sensing receptors, and abnormalities in opioid receptors, which are involved in managing pain and mood. While many people with kidney disease experience dry skin, not everyone with severely dry skin will experience itchiness. Issues with the function of sensory nerve cells and interconnected nerve cells might also contribute to itchiness. Additionally, mild skin inflammation could play a part, as one study found higher levels of a protein called C-reactive protein in patients with severe kidney disease undergoing hemodialysis who had itchiness.
The role of the opioid pathway in itch sensation is increasingly recognized. A theory suggests that an imbalance between two types of opioid receptors might cause itchiness. Other potential triggers of itchiness might include kidney-related toxins, dry skin, overall body inflammation, and common co-existing conditions such as diabetes, viral hepatitis, and hormonal disorders.
Risk Factors and Frequency for Uremic Pruritus Evaluation and Treatment
Pruritus, or itching, is a common issue among patients with advanced kidney disease. This is often referred to as uremic pruritus. It affects somewhere between 18% and 98% of patients, with the overall prevalence around 55%. It’s important to note that uremic pruritus doesn’t favor a particular gender, although some studies do report a slightly higher occurrence in males. It’s also less common in children. Uremic pruritus can occur in patients undergoing both hemodialysis and peritoneal dialysis.
Substantial research has been done to understand the prevalence of uremic pruritus across different countries. A significant study known as DOPPS surveyed patients from countries such as France, Canada, Australia, Germany, Italy, Japan, the UK, Sweden, New Zealand, and the USA. In this study, 42% of patients reported experiencing moderate to extreme itching. Other studies conducted in 11 countries between 1973 and 2012 found an average prevalence of itching in patients with end-stage renal disease (ESRD) to be around 35%. Combining this data with other DOPPS studies provides an estimate that around 41% of patients experience this issue. Of note, a recent study, DOPPS-III, found that 44% of patients in Japan experienced moderate-to-extreme uremic pruritus between 1996 and 2008.
Signs and Symptoms of Uremic Pruritus Evaluation and Treatment
People with Chronic Kidney Disease (CKD) may experience a condition called pruritus, or severe itching. This itching can range from mild and occasional to persistent and annoying. It can occur all over the body or just in specific areas like the face, back, or arm where a shunt, a device to access the bloodstream for dialysis, is located. Different patients have different experiences; some may find the itching worsens during and after dialysis, while others get itchy before their dialysis sessions.
Unfortunately, this itching often happens every day or nearly every day, with the discomfort peaking at night. It can occur on large, discontinuous, bilateral, and symmetric areas of the skin, most commonly on the back and arms, though any area can be affected. The itching may stay in the same place or move around, and different things can trigger it, like heat, stress, dialysis, cold, physical activity, or showering. For most patients, this itching can last from months to years.
However, because the symptoms can vary greatly, it can be challenging to identify the source of itching. If normal treatments don’t work, other possible causes besides CKD should be explored, especially if the symptoms are not symmetric, or if there are ulcerating or blister-like lesions that suggest other systemic diseases. The itching might also be a side effect of a new or long-standing medication. The skin may look normal or it might show signs of chronic itching, such as scratching scars and linear crusts. Other symptoms could include skin infection, bumps, or a condition called prurigo nodularis, which causes hard, itchy lumps to form on the skin.
Testing for Uremic Pruritus Evaluation and Treatment
Uremic pruritus, also known as chronic kidney disease-related itching, is often determined through a process of elimination. Because itching is common in people with chronic kidney disease, doctors often attribute the symptom to uremic pruritus. However, before settling on this diagnosis, it’s important to rule out other causes of itching. These could include reactions to medication, liver disease, thyroid disease, or skin conditions.
If you are suffering from itching, your doctor may want to gauge how severe it is. This helps track whether any treatments are working. This can be evaluated using different tools like ‘intensity scales’ to measure how intense the itching is, ‘scratch lesion’ assessments to see how much you’ve been scratching, and ‘quality of life’ measures to see how the itching is impacting your daily life.
It’s also critical to assess how the itching is affecting your sleep. Your doctor has a range of tools at their disposal to evaluate this. These include:
1. Visual analog scale: This is a simple graph where you mark a point that best describes the severity of your itching. On this scale, 0 means no itching, and 10 represents the worst itching you can imagine.
2. Numeric rating scale: Similar to the visual analog scale, but you’re asked to pick a number to represent the severity of your itching. For example, 0 means no itching, 1-3 is mild itching, 4-6 is moderate, 7-8 is severe, and 9 or above represents very severe itching.
3. 5-D itch scale: This one is a bit more comprehensive. It assesses five aspects of your itching — how long it lasts (duration), how severe it is (degree), where it’s located on your body (distribution), whether it’s getting better or worse (direction), and how much it’s impacting your daily activities like work, school, or housework (disability).
Remember, itching is subjective and can be hard to measure. While your doctor can count how many scratch marks you have, this doesn’t always give an accurate picture of how severe the symptom is. That’s why it’s often assessed through self-reported measures. By having you describe how severe your itching is and how much it’s affecting your daily life, your doctor can get an idea of its intensity and monitor if and how it changes over time.
Treatment Options for Uremic Pruritus Evaluation and Treatment
Managing the uncomfortable itch, known as uremic pruritus, associated with kidney disease isn’t straightforward and there’s no universal agreement among doctors on how to best treat it. Here are some strategies they might use:
Balancing Your Calcium and Phosphate Levels
Doctors might recommend that patients with kidney disease try to keep their calcium and phosphate levels in balance. But a study called DOPPS raised some doubts about whether this does any good in relieving itching from uremic pruritus. Not to mention, there’s no clear guidance on what the ‘right’ levels of calcium and phosphate should be in the blood.
Improving Dialysis Treatments
One idea is that better and more frequent dialysis treatments might help by removing more itch-causing substances from the blood. There’s no agreement yet on the perfect frequency or intensity of dialysis for itching, so doctors usually just try to hit the targets that have been linked with the best overall health outcomes.
Skin Care and Topical Treatments
Careful skin care is crucial. This might involve moisturizers or emollient creams (plain or medicated), and certain drugs like tacrolimus, a cream that suppresses immune responses that can cause itching. However, doctors might be cautious about using tacrolimus with certain patients because it can increase skin cancer risk.
Antihistamine Pills
These are drugs that are often taken to relieve common allergies and their effectiveness in this context isn’t entirely clear. Sedative antihistamines might help more than non-sedative ones, but safety concerns with older adults might limit their use.
Gabapentin and Pregabalin Pills
These are drugs typically used to treat nerve pain and both have been shown to help with itching in kidney disease as well.
Mast Cell Stabilizers
Some drugs like hydroxyzine, cromolyn sodium, and nicotinamide also relieve itching possibly by stabilizing certain immune cells.
Phototherapy
This is a light therapy treatment that may help by changing the way the immune system responds to inflammation.
Medications Acting on Opioid Receptors
These are drugs known as difelikefalin, nalfurafine, and nalbuphine that may lessen itching by their actions on opioid receptors in the body.
What else can Uremic Pruritus Evaluation and Treatment be?
When patients with chronic kidney disease (CKD) experience itching, doctors need to look at other possible causes not related to their kidney condition that could be causing the itchiness. Here are some alternative causes they might consider:
- Liver disease
- Thyroid disease
- Skin disorders
- Adverse reactions to medications
- Infestations caused by lice, scabies, or bed bugs
- Conditions involving elevated levels of calcium in the blood
- Hodgkin lymphoma (a type of cancer)
- Cutaneous T-cell lymphoma (a type of skin cancer)
- Polycythemia vera (a type of blood disorder)
- Post-herpetic neuralgia (nerve pain after shingles)
- Human Immunodeficiency Virus (HIV)
What to expect with Uremic Pruritus Evaluation and Treatment
Some research has found that patients with severe CKD-aP, a condition where your kidneys are damaged, tend to have a worse outlook, though the reason for this is still unclear. One study found that severe itching, a symptom in these patients, was linked to increased deaths. This held true even when other factors such as diabetes, age, and certain blood proteins (β2-microglobulin, albumin) were considered. Additionally, intense itching due to uremic pruritus – a condition caused by long-term kidney disease – not only affects a person’s quality of life but also leads to poor outcomes, particularly in patients undergoing regular blood-cleansing treatment, known as chronic hemodialysis.
Possible Complications When Diagnosed with Uremic Pruritus Evaluation and Treatment
Uremic pruritus, a condition typically associated with kidney disease, can lead to several negative outcomes:
- Struggling to follow treatment plans
- Difficulty sleeping properly
- Feeling depressed
- A reduced quality of life
- Marks appearing on the skin
- Thoughts of suicide
Preventing Uremic Pruritus Evaluation and Treatment
Uremic pruritus, which is a fancy term for intense itching caused by kidney disease, can seriously affect a patient’s health. But often patients themselves don’t tell their doctors or nurses about this symptom. Why does this happen? Some patients may not know that the itching is actually linked to their kidney disease. Others might feel that they have more severe issues to discuss with their health professionals.
However, educating patients about this and encouraging them to share it with their healthcare team is crucial. The reason is the significant effect this itching can have on both their physical health and mental well-being. It’s important to remember that your healthcare team is there to help, so don’t hesitate to bring up all symptoms, no matter how small they may seem.
