Uremic Frost - Causes, Clinical features, Diagnosis, and Treatment

Introduction:

Uremic frost is a striking skin disease seen in patients with severe kidney disease. Uremic frost is a manifestation of advanced chronic kidney disease seen these days due to the early initiation of renal transplant therapies. Familiarity with this condition can be a life-saving signal to initiate urgent dialysis. Uremic frost generally occurs at blood urea nitrogen levels of approximately 200 mg/dL, although it may arise with less severe uremia. Recently confirmed urea transporters in the skin may play a role in developing uremic frost. Alternatively, damages the cutaneous microvasculature and pilosebaceous units.

As seen in chronic kidney disease, it could account for the high levels of urea deposited outside the skin. The treatment of uremic frost is aimed mainly at correcting the underlying cause of uremia and the other life-threatening conditions associated with renal failure. Uremia is a buildup of toxins in the blood. Uremia can occur when the kidney is damaged. The toxins, or the bodily waste, that the kidneys usually send out in one's urine end up circulating. These toxins are also known as creatinine and urea. Uremia is one of the severe conditions and, if untreated, can be life-threatening. Uremia is a significant symptom of renal failure. It is also a sign of the last stages of long-time kidney disease.

What Is Uremic Frost?

Uremic frost is a white crystalline material found on the skin. When blood urea nitrogen levels rise, urea in the sweat also rises. Conversely, when sweat with significantly higher urea levels evaporates, the urea crystallizes and is deposited on the skin as uremic frost.

What Are the Causes of Uremic Frost?

Kidney disease can result from some conditions that range from primary kidney disorders, such as:

• Focal segmental glomerulosclerosis.

• Polycystic type of kidney disease to systemic disorders can lead to renal damage.

• IgA (immunoglobulin A) nephropathy.

• Membranoproliferative glomerulonephritis.

Systemic disorders can include:

• Diabetes mellitus.

• Lupus.

• Multiple myeloma.

• Amyloidosis.

• Goodpasture disease.

• Thrombotic thrombocytopenic purpura.

• Hemolytic uremic syndrome.

The leading cause of the end-stage renal disease (ESRD) in the United States is diabetes.

Additional causes are listed in the order in order of decreasing incidence:

• Hypertension.

• Glomerulonephritis.

• Interstitial disease.

• Cystitis.

• Neoplasms.

Acute kidney injury, if that involves a sudden increase in levels of urea or creatinine, results in uremia.

What Are the Clinical Features of Uremic Frost?

Uremia occurs once the creatinine clearance decreases below 10 mL/min. Unless kidney failure develops acutely, some patients may become symptomatic at higher clearance rates. Patients presenting with uremia typically complain of:

• Nausea.

• Vomiting.

• Anorexia.

• Weight loss.

• Muscle cramps.

• Changes in mental status.

• Pruritus.

The metabolic disturbances associated with the condition explain uremia's clinical presentation. For example, fatigue resulting from anemia is considered one of the significant components of uremic syndrome. Conversely, patients with a history of diabetes may show improved glycemic index as kidney function worsens.

• Hypertension.

• Atherosclerosis.

• Valvular stenosis.

• Insufficiency.

• Chronic heart failure.

• Angina.

It may develop due to platelet abnormalities and present with vomiting or nausea. Uremic frost, ammonia, or urine-like odor of the breaths may also occur in uremic patients.

What Is the Diagnosis of Uremic Frost?

A history of end-stage renal disease and uremic frost shows white, brittle, crystalline characteristics that can verify that the crystals are all composed of urea or nitrogenous waste substances. Scrapings of the crystal frosts can be diluted in normal saline, which can be tested for elevated urea nitrogen levels comparable to blood levels. Diagnosis of renal failure is based on abnormalities in the glomerular filtration rate or creatinine clearance. It is essential to determine whether a patient presents with uremic symptoms and is experiencing acute renal failure or chronic renal failure, which occurs as acute kidney injury is reversible. The laboratory studies to evaluate for abnormalities in the following conditions are:

• Hemoglobin.

• Calcium.

• Phosphate.

• Parathyroid hormone.

• Albumin.

• Potassium.

• Parathyroid hormone.

• Albumin

• Potassium.

• Bicarbonate and urinalysis (with microscopic examination) will help point toward any potential abnormalities.

To verify the crystals were composed of urea or nitrogenous waste, scrapings of the frost were taken and diluted in normal saline; frost tested this for urea levels comparable with serum urea levels. Evaporation of sweat with high urea concentration causes urea to crystallize and deposit on the skin. Therefore, this frost contains a white or yellowish color coating of urea crystals due to the deposition of urea crystals on the skin surface of patients with severe uremia.

A 24-hour urine collection may provide insight into both glomerular filtration rate and creatinine clearance, but this method needs to be revised and more accurate. Alternatively, a nuclear medicine radioisotope clearance assay may measure GFR (glomerular filtration rate). However, this test is time-consuming and expensive relative to the Cockcroft- Gault formula. Therefore, per the national kidney foundation, patients with chronic kidney disease are usually staged based on the estimated form GFR (creatinine clearance) as calculated by the diet modification in the renal disease formula.

• Stage 1 - Normal GFR ranges from 90 mL/min or greater.

• Stage 2 - Mild reduced GFR ranges from 60 mL/min to 90 mL/min.

• Stage 3 - Moderate reduced GFR from 30 mL/min to 59 mL/min).

• Stage 4 - Severely reduced GFR from 15 mL/min to 29 mL/min.

• Stage 5 - End-stage renal disease (ESRD) (GFR less than 15 mL/min or patient on dialysis).

What Is the Treatment for Uremic Frost?

The treatment of uremic frost is aimed mainly at correcting the underlying cause and other life-threatening conditions associated with symptomatic uremia (nausea, vomiting, hyperkalemia, metabolic acidosis) that is not treatable. A patient presenting with a uremic emergency requires emergency dialysis, which the patient should initiate gently to avoid dialysis disequilibrium syndrome, a neurologic symptom secondary to cerebral edema that occurs on or shortly after the initiation of the dialysis. The best renal replacement therapy is seen as renal transplantation. However, practitioners may consider long-term hemodialysis and peritoneal dialysis. Generally, the prognosis for a patient with uremia is poor unless they are treated with renal replacement therapy.

Conclusion:

Patients with uremia are also at high risk for adverse cardiac events and stroke compared to the general population. However, when the cause of the uremia is reversible, the prognosis is better than in patients with an irreversible cause.