WEEKLY TOP 7 – Top 7 clinical signs of kidney failure

These days medical students are just flooded with a huge amount of information – different description of diseases, fresher and fresher publications – all available online. It is really difficult to pick the clinically relevant data, especially when you do not have those years of practice behind your back. In our blog series You will find short and straightforward lists of clinical signs and symptoms which are the most typical and pathognomonic in certain diseases.

One of the most troubling characteristics of kidney failure (or at least worsening kidney functions) is its progressivity and that this progress goes on asymptomatically for a long period of time. The patient can lose up to 90% of their kidney functions before experiencing any symptoms. However, there are still signs which can give you the idea that the patient’s kidneys are in a bad shape.

1. Decreased urine output

Why? Damaged cells of the glomeruli and tubules do not excrete correctly, which leads to a decrease in GFR.

2. Swollen feet, hands and ankles, periorbital edema

Why? Decreased production of urine causes the build-up of extra fluid in the body, which manifests in edema.

3. Brown, red or purple urine / Foamy or bubbly urine

Why? Again, the cells of glomeruli and tubules are damaged, as well as their barrier function. Red blood cells and protein start to “leak”into the urine: causing discoloration and foaming at the same time.

4. Elevated urine albumin

Why? Normal urinary protein excretion is < 150 mg/24 hour, daily albumin excretion is < 30 mg. Larger amount of protein present in the urine is a sign of renal cell damage.

5. Paleness, feeling cold - when others don’t, fatigue, decreased mental alertness, forgetfulness, decrease in RBC count, hemoglobin and hematocrit

Why? Erythropoietin produced by the peritubular cells of the kidney is responsible for the stimulation of red blood cell production in the bone marrow. When the erythropoietin level drops down, anemia appears (later augmented by hematuria) and consequent hypoxemia causes various neurological symptoms, listed above.

WHO definition of anemia

Children (6 months – 6 years) Children (6 – 14 years) Adults
Hb < 11 g/dL Hb < 12 g/dL Hb < 12.5 g/dL

6. Loss of appetite, nausea, vomiting, itching, bad taste in the mouth, bad breath

Why? The loss of the detoxification function of kidneys leads to uraemia. The waste products accummulate in the skin, the mucosa causing itchiness and bad tastes. They also excite the chemoreceptor trigger zone in the brain causing nausea, vomiting.

7. Elevated serum creatinine and blood urea nitrogen (BUN)

Why? These are the two main waste products “produced” by the muscles and the liver and their elevated values indicate the presence of uremia. In fact, the international classification of kidney failure is based on the rate of serum creatinine rise (RIFLE-criteria).


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