Introduction
Each kidney is made up of around one million filter units called nephrons. Each nephron contains a glomerulus and a filter called a tubule. Nephrons work through a two-step process:
glomeruli filter the blood, and renal tubules return necessary substances to the blood and remove waste products. As blood flows through each nephron, it enters a collection of small blood vessels called glomeruli. The walls of the glomerulus are thin, and they allow smaller molecules, waste products, and fluids (mainly water) to enter the renal tubules. Molecules of larger size, such as proteins and blood cells, remain in blood vessels. Blood vessels run along tubules. As the filtered fluid travels down the tubules, the blood vessels reabsorb almost all the water along with the minerals and nutrients the body needs. The tubules help remove excess acid from the blood. Fluid and debris left in the tubules become urine.
What Is Glomerulotubular Balance?
Glomerular tubule balance (GTB) is defined as the ability of each segment of the proximal tubule to reabsorb a certain proportion of the supplied glomerular filtrate and solutes.
Glomerulotubular balance helps prevent overloading of the distal tubular segment when the glomerular filtration rate increases. Glomerulotubular balance functions as a second line of defense to buffer the effects of spontaneous changes in glomerular filtration rate on urine output. The glomerulotubular balance prevents large changes in the fluid flow in the distal tubules.
What Is the Process of Glomerulotubular Balance?
Sodium chloride homeostasis is critical for complex organisms with closed blood systems. The kidney regulates the excretion of this salt by regulating the relationship between glomeruli and renal tubules. Tubules respond to glomeruli in glomerular tubule equilibrium, whereas glomeruli respond to tubules through tubuloglomerular feedback. These relationships are dynamic, and a lot still needs to be researched on this process. Glomerulotubular imbalance affects the kidney's filtering unit, the glomerulus. Instead of circulating proteins and red blood cells in the blood, damaged glomeruli release some of these products into the urine. One of many roles of proteins in the blood, such as albumin, is to carry excess water from the body into the bloodstream so that it can be filtered by the kidneys and out of the body as urine. When there isn't enough protein in the bloodstream, excess water stays in the body, causing swelling in areas such as the face, hands, feet, abdomen, and ankles. Glomuerulotubular imbalance may have the following outcomes:
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A Lack of Sodium Balance in the Body - Sodium is an electrolyte and helps regulate the amount of water in and around cells. Sodium depletion leads to mental distress, confusion, shivering, and unconsciousness.
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Hypertension - Extremely high sodium levels in the body cause elevated blood pressure.
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Protein Imbalance in the Body - When there isn't enough protein in the bloodstream, excess water stays in the body, causing swelling in areas such as the face, hands, feet, abdomen, and ankles.
What Causes Glomerulotubular Imbalance?
The causes of glomerulotubular imbalance are listed below:
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Glomerulonephritis is inflammation (swelling) of the glomeruli.
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Glomerulosclerosis, scarring/hardening of the glomerulus.
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Infections or drugs, or chemicals that are harmful to the kidneys.
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A disease that affects the whole body, including the kidneys.
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Autoimmune diseases.
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A disease that causes swelling or scarring of the nephron or glomerulus.
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Cause of unknown origin.
What Are the Symptoms of Glomerulotubular Imbalance?
Signs of glomerulotubular imbalance include one or more of the following:
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Foamy urine (a sign of protein in the urine, also called proteinuria).
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Urine that is pink or light brown (blood in the urine also called hematuria).
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Swelling around the face/eyes (especially in the morning), hands, feet, and ankles (especially at the end of the day). This swelling is called edema (fluid buildup).
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High blood pressure (hypertension).
How Is Glomerulotubular Disease Diagnosed?
After taking a thorough physical and medical history, the doctor will order several tests, including:
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Urinalysis - To check for high protein, red blood cells, and white blood cells (which indicate infection or inflammation).
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Blood Test - To check for low levels of protein, creatinine (kidney function), and urea nitrogen (waste products). A calculation called the glomerular filtration rate (GFR) is performed to determine if the kidneys are properly filtering.
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Additional Blood Tests - To test for infections and autoimmune diseases.
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Imaging Tests - Such as ultrasonography, are done to check for abnormalities in the shape and size of the kidneys.
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Kidney Biopsy - The doctor uses a needle to remove a small piece of kidney tissue to examine it under a microscope.
When to Seek Help for Glomerulotubular Imbalance?
Seek immediate medical appointment if any signs or symptoms of glomerulotubular disease or any of the following symptoms are noticed:
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Fever.
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Nausea.
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Lethargy.
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Malaise.
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Blood while urinating.
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Reduced urine output.
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Vomiting.
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Seizures.
How Is Glomerulotubular Imbalance Treated?
Glomerulotubular disease is treated in the following ways:
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Immunosuppressants - These medications are given in case of an autoimmune disease.
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Plasmapheresis - A procedure that removes antibodies that attack the body.
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Angiotensin-Converting Enzyme Inhibitors - This medication may be used to relax the blood vessels and decrease the blood volume.
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Medications To Regulate Blood Pressure - Antihypertensive drugs are given to relieve elevated blood pressure.
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Antibiotics - This medication is given to relieve any infection that may be the cause.
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Dialysis - This process is done to remove excessive waste from the blood.
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Kidney Transplant - The kidney is transplanted from a donor to save life.
How to Prevent Glomerulotubular Imbalance?
People can make lifestyle changes to stay healthy and reduce the risk of getting diseases like glomerulotubular imbalance. These changes include
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Maintain a healthy weight.
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Keep daily salt intake low. Do not add extra salt to the food.
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Keep blood pressure under control. The ideal blood pressure level is 120/80 mmHg.
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Control blood sugar in case of diabetes.
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Take all prescribed medicines and follow the treatment goals discussed with the doctor.
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Avoid smoking.
Conclusion:
Glomerulotubular balance refers to the constant reabsorption of a proportion of the nephron's filtered water and solutes over a specific range of glomerular filtration rates (GFR). In other words, a spontaneous increase in GFR results in a proportional increase in the rate of reabsorption of water and solutes in the tubules, maintaining the same proportion of filtered solutes and water reabsorbed. Many different diseases and conditions can damage the renal glomeruli and can affect the glomerulotubular balance. It is important to contact medical services as soon as possible in case any of the symptoms of a renal imbalance are noticed. Sometimes glomerulotubular imbalance does not show any symptoms it is best to get regular medical health checkups done to ensure kidneys are functioning at optimal levels.
