What are the common kidney diseases?

Patient's question:

Common kidney diseases in children

Doctor's answer:

The kidneys are an important organ in the human body. Their main functions include filtering blood, reabsorption, and excretion, helping to maintain the electrolyte and acid-base balance in the blood. They also have the function of concentrating urine to maintain water balance. The kidneys can secrete various bioactive substances, such as prostaglandins, which can regulate renal blood flow and the reabsorption of water and salt by the renal tubules. Under stress, prostaglandins can increase blood flow.
In addition to prostaglandins, the kidneys also secrete other active substances such as renin, erythropoietin, and kinin-releasing enzyme. Broadly speaking, kidney disease refers to diseases of the entire urinary system, while narrowly defined, it refers to diseases of the kidneys themselves. If the kidneys are affected by disease, it disrupts the aforementioned kidney functions, compromising the stability of the internal environment. Severe kidney dysfunction can lead to uremia, directly threatening the life of the patient. To understand kidney diseases, it is essential to first understand the anatomical structure of the urinary system, which includes:
(1) Kidneys—located on both sides of the spine in the waist area, primarily responsible for producing urine.
(2) Ureters—connect the kidneys to the bladder, serving as the channel through which urine flows from the kidneys to the bladder.
(3) Bladder—stores urine.
(4) Urethra—one end connects to the bladder, while the other opens to the outside of the body, expelling urine.
Kidney diseases can be categorized as surgical or medical conditions. The former are often congenital developmental abnormalities, such as polycystic kidney disease, bladder exstrophy, and urethral fissure. Other surgical conditions include urinary tract stones and phimosis, which generally require surgical treatment.
Common medical conditions include:
(1) Nephritis—divided into acute and chronic nephritis. Acute nephritis is the most common kidney disease in children, with typical symptoms including edema, oliguria or anuria, hematuria, and hypertension. It often follows a history of respiratory infection or streptococcal infection.
(2) Nephrotic syndrome—characterized by edema, significant proteinuria in urine tests, foamy urine, high cholesterol levels in blood tests, low total protein, and an inverted albumin-to-globulin ratio.
(3) Urinary tract infection—mainly frequent urination, urgency, and dysuria. During acute phases, fever may occur, and urine tests may show a large number of white blood cells. Prompt treatment is necessary to prevent chronic inflammation and recurrent infections.