What are kidneys?
Kidneys are bean-shaped urinary organs and are about 12 cm in length. They are located in the space behind the abdomen on the left and right sides of the spine. The article discusses types of kidney disease and their symptoms.
What is the function of the Kidney?
They perform the function of the extraction of waste material from the blood. All the blood present in the body passes through the kidney several times a day for filtration. The blood enters through renal arteries and exits through renal veins both of which are blood vessels. The filtered waste is ultimately converted to urine which then passes from the kidney through the ureter to the urinary bladder for excretion.
Kidneys are also responsible for maintaining electrolytes and fluid balance in the body. Kidneys absorb sodium, bicarbonate, solute-free water, and amino acids and excrete hydrogen, potassium, ammonium, and uric acid.
What are nephrons?
The kidney contains millions of nephrons which are structural and functional units of a kidney. Nephrons are responsible for most of the kidney functions but kidneys also perform some functions where nephrons are not involved such as the conversion of vitamin D to calcitriol and hormones such as erythropoietin and renin.
Types of kidney disease and their symptoms
Kidney stones are also known as nephrolithiasis. This is one of the most common problems related to kidneys. Almost 80% of kidney stones are formed of calcium oxalate or phosphate and the rest 20% is made up of uric acid and cystine.
Symptoms: small kidney stones mostly do not cause any problems as they can easily pass from the kidney through the ureter to the urinary bladder but stones greater than 6mm in size may get stuck in the ureter blocking the path for urine which can cause severe pain.
Pyelonephritis is mostly caused by gram-negative bacteria. In most cases, Escherichia coli is the main cause of pyelonephritis, other pyelonephritis causing bacteria include Proteus, Enterobacter, and Klebsiella. Pyelonephritis is a result of urinary tract infections that move from the bladder to the kidneys where the infection causes inflammation in the kidney.
Types of Pyelonephritis
Pyelonephritis is mainly of two types: complicated and uncomplicated, complicated pyelonephritis includes patients with diabetes, pregnancy, kidney transplants, patients with abnormal urinary structure, acute or chronic kidney failure, and patients with a weakened immune system. Uncomplicated pyelonephritis can occur in a normal human being, not having diabetes, pregnancy, kidney-related problems, or abnormal urinary structure. This condition occurs mostly due to gram-negative bacteria.
Why Pyelonephritis is more common in women?
Pyelonephritis is more common in women than in men because of the shorter urethra which makes the spread of infection easy, the shorter distance of the anus to the urethral opening, and hormonal imbalance. Kidney stones and urine obstruction can cause bacteria to multiply as they are not completely flushed out of the system which leads to infection. Vesicoureteral reflux is a condition more common in young children and infants where urine starts flowing back into the kidney which can cause acute pyelonephritis.
Common symptoms are fever, nausea, vomiting, burning sensation while urinating, and constant and urgent need to urinate.
It is a term that is used to refer to kidney diseases that are related to inflammation of either the glomeruli or the small blood vessels inside the kidney. The presence of glomerulonephritis is associated with hematuria, proteinuria, nephrotic syndrome, nephrotic syndrome, or acute or chronic kidney disease.
Classification of Glomerulonephritis
These are broadly grouped into proliferative and non-proliferative. The inflammation of the glomerulus can result in both nephrotic and nephritic syndrome.
Nephrotic syndrome: This syndrome is characterized by edema (swelling caused by fluid build-up), proteinuria (increased level of protein in urine), low level of protein in the blood, and increased fat in the blood. Other symptoms include fatigue, weight gain, and foamy urine.
Nephritic syndrome: Nephritic means inflammation of the kidney and glomeruli, tubules, or interstitial tissue surrounding glomeruli and tubules. Inflammation and thinning of the glomerulus and the presence of small pores in podocytes indicate glomerulonephritis. The nephrotic syndrome is characterized by proteinuria but does not include hematuria ( presence of blood in the urine). The nephritic syndrome involves both proteinuria and hematuria.
Minimal change disease
As the name suggests, this disease does not show any major change in the glomerulus but under the light microscope, the fusion of the foot process of the podocytes called pedicles can be seen. This disease can be characterized by nephrotic syndrome and corticosteroids are used to control this disease. Minimal change disease does not progress to chronic kidney disease.
Focal segmental glomerulosclerosis (FSGS)
It is characterized by sclerosis of glomeruli. This condition is associated with HIV, heroin abuse, or Alport syndrome. Corticosteroids are used for treatment but this disease gradually weakens kidney function and may ultimately lead to kidney failure.
Membranous glomerulonephritis (MGN)
It is the second most common cause of nephrotic syndrome with focal segmental glomerulosclerosis being the most common and progressing slowly in the kidney.
Most cases of MGN are associated with antibodies to an M-type phospholipase A2 receptor. Several cases are associated with an autoantigen called thrombospondin type 1 domain-containing 7A (THSD7A). some studies also suggest the cationic bovine serum albumin and neprilysin as the cause of MGN.
Thin basement membrane disease (TBMD)
TBMD is also known as benign familial hematuria as it is one of the most common causes of hematuria along with IgA nephropathy. It involves the thinning of the basement membrane of the glomeruli in the kidney. The patients can expect a normal kidney function throughout their lives while suffering from TBMD as this disease has a benign prognosis.
In this disease, fibronectin-1 protein gets deposited in the glomeruli which impair the filtration ability of the glomeruli.
It is characterized by an increased number of cells in the glomerulus. These forms are present in the body with nephrotic syndrome, hematuria, hypertension, and low urine output.
This disease is also known as Berger’s disease and it is present with hematuria and low-level proteinuria. It is characterized by immunoglobulin A (IgA) antibody deposit in the space between glomeruli capillaries that causes inflammation of the glomeruli. The kidney functions normally with the non-aggressive form of IgA but the aggressive form can cause kidney damage and also affects major organs of the body such as the skin, liver, and heart.
It is caused by bacterial infection from the bacteria streptococcus pyogenes. The symptoms are restlessness, fever, nausea, and nephritic syndrome with hematuria and high blood pressure.
Membranoproliferative glomerulonephritis (MPGN)
It is also known as mesangiocapillary glomerulonephritis. MPGN is characterized by a spike in the number of cells in glomeruli and changes in the glomerulus basement membrane. MPGN gives rise to hypocomplementemia which means decreased levels of the complement system. There are three types of MPGN:
- Type 1: It is the most common type of MPGN that is caused by immune complexes deposition in the kidney.
- Type 2: It is also known as “dense deposit disease”, and it is caused by the deposition of complement C3 in the glomeruli that does not allow space for immunoglobulin in the glomeruli.
- Type 3: subepithelial and subendothelial cells start depositing in the glomeruli. These deposits start damaging the cells in their surrounding.
Rapidly progressive glomerulonephritis(RPGN):
It is also known as crescentic glomerulonephritis. There is a very fast and growing decline in kidney function and this disease is present with nephritic syndrome. There are three types of rapidly progressive glomerulonephritis:
- Type 1: It is known as Goodpasture syndrome. Immunoglobulin G antibodies get deposited in the basement membrane of the glomerular causing an inflammation reaction in the kidney. It also affects the lungs and can cause blood in the cough.
- Type 2: It is characterized by the deposition of immune complexes in the glomeruli. The immune complex disease that involves glomeruli can progress to RPGN.
- Type 3: This disease is also known as pauci-immune RPGN. It does not involve the deposition of immune complexes or antibodies rather the cause of this type of RPGN is the activation of neutrophils in response to Anti-Neutrophilic Cytoplasmic Autoantibody(ANCA).
Polycystic kidney disease
It involves the development of multiple fluid-filled non-cancerous sacs in the kidney. These sacs or cysts can grow large over time and interfere with kidney function. People with polycystic kidney disease suffer from back pain, high blood pressure, and a swollen abdomen.
Acute renal failure
It involves the sudden loss of kidney function. The kidney loses its ability to filter the waste product due to which body fluid can rise to very high levels causing edema, decreased urine output, nausea, and shortness of breath. It can also lead to multiple organ failures if not treated.
Chronic Renal failure
It involves damage to the kidneys over a long period. It can cause permanent damage to the kidney gradually. There can be various reasons for chronic kidney failure such as high blood pressure, diabetes, kidney stones, glomerulonephritis, and infection in the kidney. Dialysis and kidney transplant are the known treatment if the kidney loses its function completely.
End-stage renal disease (ESRD)
ESRD is the last stage of chronic kidney failure, where the kidney stops working completely and fails to filter waste out of the blood. ESRD is life-threatening and requires immediate treatment.
It is a type of nephropathy where damage is caused to the renal papilla which is a duct where renal pyramids empty urine. Damage to the renal papilla causes death to the cells of the renal papilla or the area surrounding it, these dead cells can obstruct the kidney and damage it. Symptoms include tissue pieces in urine, back pain, cloudy urine, and painful and frequent urination.
The high levels of glucose in diabetic patients can damage the kidney. This can lead to proteinuria or microalbuminuria.
This disease involves damage to the kidney due to chronic high blood pressure. Chronic high blood pressure results in tissue hardening and blood vessels narrowing. A lesser amount of blood and oxygen reaches different organs which damage small blood vessels, glomeruli, and kidney tissues.
There is a growth of tumors in the kidney that may show symptoms such as nack pain, blood in the urine, lumps in the abdomen, fever, fatigue, and weight loss. The three significant types of kidney cancer are renal cell cancer (RCC), Transitional cell cancer (TCC), and Wilms tumor. RCC and TCC are mostly caused due to smoking, high blood pressure, pain medications, obesity, and certain chemicals. Wilms tumor is caused due to family history or genetic disorder.
It involves inflammation of the renal interstitium which is responsible for electrolyte and fluid exchange. The inflammation can cause damage to renal cells and lead to permanent damage to the kidney.
Nephrogenic diabetes insipidus
It is caused when the kidney fails to respond properly to the anti-diuretic hormone which leads to dilute urine as the kidney fails to reabsorb filtered water. It is hereditary mostly but certain medications and kidney problems can also cause this disease.
This disease is very common in adults. Renal cysts are harmless, fluid-filled sacs. Large cysts can be removed through surgery without any future complications. Polycystic kidney disease can cause kidney damage and high blood pressure.