Renal failure, especially if mild, is often asymptomatic. Here are the warning signs.

What is it

It is a condition in which the kidneys are not able to ensure a correct elimination of metabolic waste substances, with consequent alteration of the composition of the body’s fluids, especially the blood.

In particular, there is on the one hand a loss of blood electrolytes (such as sodium and potassium) and, on the other, an accumulation of nitrogenous substances.

The latter are produced by the demolition of proteins (normally eliminated with urine in the form of urea and uric acid) and creatinine, the product that is obtained when the muscles consume creatine for energy.

Renal failure can be acute, that is, such as to set up within a few hours or a few days, or chronic, linked to another underlying disease.

Chronic insufficiency is divided into stages based on the level of residual renal function, assessed on the basis of creatinine clearance. The progression or not of chronic renal failure is linked to the success in controlling the pathology that causes it.

Discover the kidney health quiz and test your knowledge.


Acute renal failure is caused by a sudden blockage of kidney function due to severe infections, adverse drug reactions, surgical interventions.

Chronic renal failure is the consequence of diseases that, over time, damage the kidneys. The main ones are diabetes (diabetic nephropathy), arterial hypertension, glomerulonephritis (primitive, from autoimmune diseases such as systemic lupus erythematosus, vasculitis, infections).

Most common symptoms

If kidney function is reduced slightly, the disease is asymptomatic and can only be detected by laboratory tests.

Even with more significant renal failure the symptoms may be vague: asthenia, fatigue, pallor and possible episodes of nocturnal loss of urine (nocturia) or slight mental confusion. You may also experience an increase in blood pressure.

In the most serious insufficiencies there may also be anorexianausea, vomiting, widespread itching, increased urine, while in the terminal phase there is a decrease (oliguria) or even the disappearance (anuria) of urine.

Fluid retention associated with oliguria can manifest as dyspnea and swelling in the hands, ankles, eyes.

Acute insufficiency is characterized by reduced urine output (oliguria).


Complications of this pathology can be different. Let’s see them in detail in the following table.

Hypertension It can be a cause but also a consequence of the disease
Anaemia Due to the loss of the kidney’s ability to produce the hormone (erythropoietin) that stimulates the growth of red blood cells
Osteomalacia Metabolic disorders related to renal failure cause insufficient synthesis of the bone matrix (osteomalacia), with skeletal problems
Congestive High blood pressure, salt and fluid buildup, and anemia can lead to an overload of the heart


If diabetes or hypertension is at the origin, blood sugar control or hypertension significantly reduces the risk of progression of renal failure.

It is essential to stick to a diet low in protein (low-protein) and phosphorus. Particular attention should be paid to caloric intake, because many patients risk malnutrition, also due to the lack of appetite that affects many patients.

Since the patient is often also diabetic or hypercholesterolemic, the assistance of a dietician is often appropriate.

In many cases, a limitation of the intake of sodium (salt) and potassium is also advisable.

If therapies fail to stop the progression of the disease, chronic dialysis or transplantation may eventually be necessary.

In acute renal failure, therapy is represented by the elimination of the cause that caused it, the restoration of diuresis, the correction of electrolyte imbalances, such as acidosis or excess potassium, possibly also proceeding with dialysis.

When to consult your doctor

Since the disease has a subtle onset, it is advisable to periodically perform normal routine laboratory tests. In the presence of unexplained swelling, widespread itching, episodes of nocturia and mental confusion, it is good to seek medical attention immediately.

Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.

The blog covers a wide range of topics related to health and wellness, with articles organized into several categories.

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