Generality
Kidney diseases are the morbid conditions that alter the anatomy and function of the kidneys, two fundamental organs for human health.
Among the main and most widespread kidney diseases, it is certainly worth mentioning: kidney stones, pyelonephritis, glomerulonephritis, nephrotic syndrome, diabetic nephropathy, polycystic kidney disease, hydronephrosis, kidney failure and kidney cancer.
Since many kidney diseases cause the same symptoms and signs, their correct identification requires the use of different diagnostic tests.
Brief anatomical and functional recall of the kidneys
In number of two, the kidneys are the organs which, together with the urinary tract, constitute the so-called urinary tract or excretory apparatus, whose task is to produce and eliminate urine.
Representing the main structures of the aforementioned apparatus, the kidneys reside in the abdominal cavity - to be precise on the sides of the last thoracic vertebrae and the first lumbar vertebrae - they are symmetrical and possess a shape very similar to that of a bean.
Figure (of a kidney and enlargement of a nephron): a human kidney with its main components (renal pelvis, renal cortex, renal medulla, etc.).
The magnification on the right shows the nephron, which is the functional unit of the kidneys, ie the smallest structure capable of performing all the functions of the organ. Among the various elements of a nephron, the proximal and distal tubules, the glomerulus, Bowman's capsule, Henle's loop and the collecting duct deserve special mention.
FUNCTION OF THE KIDNEYS
The kidneys hold various functions; among these, the most important are:
- Filter the waste substances, the harmful ones and the foreign ones, present in the blood, and convert them into urine;
- Adjust the hydro-saline balance of blood;
- Adjust the acid-base balance of blood.
As readers will have noticed, kidney functions are closely related to blood; the latter comes from the kidneys from the renal artery and returns to the venous system through the renal vein, which then flows into the so-called vena cava .
What are kidney diseases?
Kidney diseases are the diseases that affect the kidneys, altering their functions more or less deeply.
Given the fundamental importance of the kidneys for human beings and their good health, kidney diseases represent medical conditions of considerable clinical importance, especially when the functions of the affected organs are severely impaired.
Causes
The list of possible causes of kidney disease is particularly long and includes: bacterial or viral infectious agents, parasites, systemic autoimmune diseases, hereditary genome alterations, tumors, an incorrect diet (eg: poor fluid intake, salt abuse from cooking etc.), diabetes mellitus, heart diseases, liver failure, severe dehydration, some drugs, hypertension, toxic / noxious substances (cocaine, alcohol or heavy metals) etc.
Symptoms
Very many kidney diseases, even when they depend on extremely different causes, produce similar symptoms and signs.
A list of symptoms and signs that typically share numerous kidney diseases is shown in the table below.
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Diagnosis
The tests that allow the diagnosis of kidney diseases include:
- The physical examination;
- The medical history;
- Urinalysis (or urinalysis);
- Blood tests;
- Abdominal ultrasound;
- Nuclear magnetic resonance of the abdomen;
- Abdominal CT;
- Intravenous pyelography;
- Renal arteriography;
- Renal biopsy.
Examples
Renal diseases are numerous; among these, the most famous and widespread in the world are:
- Kidney stones;
- Pyelonephritis;
- Glomerulonephritis;
- Nephrotic syndrome;
- Diabetic nephropathy;
- The polycystic kidney;
- The hydronephrosis;
- Renal failure, which is divided into the acute form and the chronic form;
- Kidney cancer.
Kidney stones
Kidney stones are small aggregates of hard consistency, similar to pebbles, which form in the kidneys or along the urinary tract, due to the anomalous precipitation of mineral salts typically contained in urine.
Often linked to an incongruous diet (eg: too much salt and / or poor water intake), and to a certain genetic predisposition, kidney stones can be both symptomatic and asymptomatic.
In medicine, kidney stones are also known as nephrolithiasis .
pyelonephritis
Pyelonephritis is the inflammation of the so-called renal pelvis or renal pelvis.
Existing both in acute and in chronic form, pyelonephritis is typically due to some bacteria; among these bacteria, the most important are Escherichia coli, Klebsiella, Proteus and Enterococcus .
Severe pyelonephritis can compromise the function of the kidneys to the point of even causing the death of the affected individual.
glomerulonephritis
Glomerulonephritis is the inflammation of the renal glomeruli.
Generally due to systemic autoimmune diseases, glomerulonephritis is responsible for a marked and pathological reduction of the filtering capacities of the renal glomeruli involved.
Nephrotic syndrome
The nephrotic syndrome is the medical condition that results from a serious damage to the nephron glomeruli and that has three typical consequences: proteinuria, reduction of proteins in the blood and the appearance of edema in several points of the body (face, ankle, feet and abdomen) ).
Diabetic nephropathy
Representing one of the long-term complications of diabetes mellitus, diabetic nephropathy is a renal disease, which involves damage to the vast network of capillaries that make up the renal glomeruli.
When severe, a disease such as diabetic nephropathy can degenerate into a nephrotic syndrome and / or glomerulosclerosis, which in turn can lead to renal failure.
Polycystic kidney
The polycystic kidney is a genetic, hereditary disease that is characterized by the replacement of normal renal tissue (renal parenchyma) with a series of cysts. In other words, patients with polycystic kidney have one or both kidneys covered with cysts, instead of the renal parenchyma.
Clearly, in the polystyrene kidney, the presence of cysts, combined with the absence of normal renal tissue, seriously affects the functions of the affected kidney or kidneys.
hydronephrosis
Physicians call hydronephrosis the particular pathology of the kidneys in which the renal pelvis and the renal calyxes undergo abnormal dilatation and swelling, due to the unusual accumulation of urine within them.
A cause of hydronephrosis is generally an impediment to the normal flow of urine within the urinary tract; this impediment may depend on a blockage inside the urinary tract (eg: kidney stones) or on an external compression of the urinary tract (eg prostate cancer, in men, or pregnancy, in women).
Kidney failure
Kidney failure is the medical term that indicates a serious inability on the part of the kidneys to properly perform its functions.
People suffering from kidney failure need immediate and appropriate care; otherwise, in fact, they are destined to die within a short time.
There are two forms of renal failure: acute renal failure (or renal block ) and chronic renal failure . To distinguish these two forms of renal failure are:
- The speed with which the kidneys lose their functional capacity. In acute renal failure, functional loss is sudden and sudden; in chronic renal failure, however, functional loss is gradual (can occur in months or years) and progressive;
- The curability. While acute renal failure is potentially reversible, chronic renal failure is incurable;
- The causes. Acute renal failure is due to causes other than chronic renal failure.
Table . Summary of causes of acute renal failure and chronic renal failure.
| Causes of acute renal failure | |
Conditions that slow or block direct blood flow to the kidneys. |
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Conditions or events that cause direct damage to the kidneys. |
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Conditions that block the flow of urine into the organs and structures of the excretory system. |
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Causes of chronic renal failure | |
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Kidney tumor
Kidney cancer is the result of a benign or malignant neoplastic process that begins in a kidney cell.
Risk factors for kidney cancer include obesity, cigarette smoking, some inherited genetic diseases (eg, tuberous sclerosis, Von Hippel-Lindau syndrome), exposure to some chemical pollutants (eg, asbestos, cadmium or benzene) and some serious kidney diseases (chronic renal failure).
