Nephroptosis: What It Is, Types, and How Kidney Ptosis Manifests

Nephroptosis is abnormal mobility of the kidney. The organ shifts from its usual position, sometimes quite noticeably. Below is what such a diagnosis means, who it affects, and how it is confirmed.

What nephroptosis is and why it occurs

Nephroptosis (from the Greek "nephros" — kidney, and "ptosis" — falling, descent) is a kidney disease in which the kidney is abnormally mobile. In everyday speech, people use the terms "kidney ptosis," "dropped kidney," "mobile kidney," and "floating kidney" — all referring to the same condition.

The kidney, about the size of a fist, lies in the lumbar region below the ribs. Normally it is held in place by surrounding tissues; in nephroptosis it shifts and becomes abnormally mobile, sometimes rotating around its axis. The right kidney shifts more often than the left: of 91 cases described by Ebstein, right-sided displacement occurred 65 times, left-sided 14, and in the rest both were displaced.

The main causes are relaxation of the abdominal wall after repeated pregnancies and a decrease in perirenal fat tissue due to rapid weight loss. There is nothing to be embarrassed about here: this is about the mechanics of holding the organ in place, not about a person's behavior. Women are affected noticeably more often: for every 100 women there are 1 to 18 men. Most often this is between the ages of 30 and 60, although cases have been described in girls aged 6–10 and in a nine-year-old boy.

When to see a doctor

The reason to see a doctor is pain in the hypochondrium or in the iliac region, especially if it weakens or disappears when lying on the back. A second reason is a dense formation that can be felt on the side under the ribs.

In most people, kidney ptosis causes no symptoms, so the diagnosis is often an incidental finding on examination. If the pain recurs and is accompanied by chills, nausea, or vomiting, the visit should not be delayed.

Right-sided, left-sided, and bilateral nephroptosis

Displacement may be on one side or both; the right kidney shifts more often than the left.

Floating kidney: what is seen on examination

"Floating kidney" is another name for nephroptosis that comes from old medical texts. It describes the essence: the kidney is not fixed and moves easily.

On examination this is visible even without equipment. In the standing position, under the free edge of the ribs on the side, an elongated elastic formation with a smooth surface can be felt, tender on pressure. In the lying position it usually disappears. Percussion over the lumbar region helps distinguish the kidney from the intestine: over the kidney the sound is dull, over the intestine it is tympanic.

Symptoms and how nephroptosis is detected

In most patients the disease runs without clinical manifestations. The first, and sometimes the only, symptom is pain in the hypochondria or in the iliac region. Its distinguishing feature is that when lying on the back the pain weakens or disappears entirely.

• pain in the hypochondrium or in the iliac region;
• weakening or disappearance of pain in the supine position;
• a feeling of heaviness in the lower back on one side;
• neuralgic pain along the sciatic and femoral nerves;
• a dense formation under the ribs on the side, tender on pressure.

Nephroptosis is detected on examination: the mobile formation is easier to feel in the standing position, and in the lying position it usually disappears. How percussion helps distinguish the kidney from the intestine is described in the section on floating kidney. If kidney disease is suspected, the doctor may order blood and urine tests. Nephroptosis is differentiated from tumors of the gallbladder, a mobile spleen, fecal masses, perityphlitis, local inflammation of the peritoneum, tumors of the adrenal glands, and ovarian cysts.

Possible complications and warning signs

The displaced kidney itself often changes: hydronephrosis, kidney stones, diffuse inflammation of the kidneys, suppuration, and cancer occur.

Strangulation is a separate matter. The displaced organ enlarges, and even a light touch causes sharp pain. Strangulation is explained by rotation of the kidney around its axis and compression of the ureter — this leads to acute hydronephrosis. The attack may end after several days with copious discharge of urine containing pus and mucus.

Kidney ptosis by itself is not a reason to call an ambulance. 103/112 — if during strangulation there is sharp pain on touching the kidney, chills, fever, nausea, vomiting, or signs of collapse.

In severe cases, surgical fixation of the kidney — nephropexy — is discussed; in recent years laparoscopic methods have been used for it.

This article is for reference: it explains what happens to the kidney and does not replace a doctor's consultation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer