Having Blood in Urine: What You Need to Know About Glomerulonephritis?

Your kidneys filter close to 150 litres of blood every single day. That work happens inside nearly two million tiny structures called glomeruli, spread across both kidneys, each one small enough to be invisible to the naked eye but together doing the job of keeping your blood clean. When something goes wrong with these filters, the effects show up in places you’d never expect to look for a kidney problem in the colour of your urine, in puffiness around your eyes in the morning, in blood pressure readings that suddenly won’t come down.

That condition is called glomerulonephritis, and it’s far more common than most people realise. It can appear quietly, with no symptoms at all until a routine urine test flags something, or it can hit suddenly after a bout of strep throat and leave you with cola-coloured urine within a week or two. This guide walks through what glomerulonephritis actually is, why it happens, how doctors catch it, and what treatment and prevention look like so that if you or someone in your family is dealing with it, you know what questions to ask and when it’s time to see a specialist.

What Is Glomerulonephritis?

Every kidney holds around a million microscopic filtering units, and each one starts with a cluster of blood vessels called a glomerulus. Blood flows through these clusters under pressure, and the glomerulus acts like a very fine sieve  it lets waste products, excess salt, and extra water pass through into urine, while holding back the blood cells and proteins your body needs to keep circulating. Glomerulonephritis is what happens when this sieve gets damaged, usually because the immune system, which is supposed to attack invaders like bacteria and viruses, mistakenly turns on the glomeruli themselves.

Once that damage sets in, the filter stops doing its job properly in two opposite ways at once. It starts leaking things it shouldn’t blood cells and protein slip through into the urine — while also failing to clear out waste and fluid the way it normally would. That combination is what produces the mix of symptoms doctors look for: blood or protein showing up in urine tests, and puffiness or swelling building up in the body because fluid isn’t being removed efficiently.

Doctors describe glomerulonephritis in two ways depending on how it behaves over time, and separately, in terms of what’s causing it.

Based on how quickly it develops:

• Acute glomerulonephritis comes on fast, often within one to three weeks of an infection like strep throat, and can improve significantly with the right treatment some cases resolve almost completely on their own.
• Chronic glomerulonephritis develops slowly, sometimes silently, over months or years, and tends to cause more lasting damage because it isn’t caught early.

Based on what’s driving it:

• Primary glomerulonephritis starts in the kidney itself, without any other underlying disease responsible for it.
• Secondary glomerulonephritis develops as a consequence of another condition in the body — lupus and diabetes are two of the most common examples, where the kidney damage is really a downstream effect of a disease happening elsewhere.

IgA nephropathy, in which an antibody called IgA settles inside the glomeruli and slowly damages them, is considered the most common form of glomerulonephritis found worldwide, and it often runs a chronic, gradually progressive course.

Nephrotic vs Nephritic: Why Your Symptoms Can Look So Different

One thing that confuses a lot of patients is that glomerulonephritis doesn’t always look the same from person to person, even though the underlying damage is similar. That’s because glomerular damage tends to produce one of two symptom patterns, called nephrotic syndrome and nephritic syndrome, and understanding the difference actually explains why the symptoms happen in the first place.

In nephrotic syndrome, the glomeruli become leaky enough that large amounts of protein pass into the urine, which is why the urine often looks frothy or foamy. Here’s the part that explains the swelling: protein in the bloodstream normally works like a sponge, pulling fluid inward and keeping it inside blood vessels through something called osmotic pressure.

When too much protein leaks out through damaged glomeruli, that pulling force weakens, and fluid starts seeping out of blood vessels into the surrounding tissue instead of staying where it belongs. That’s what causes the puffiness around the eyes first thing in the morning, and swelling that can spread to the ankles, calves, and eventually the abdomen in more severe cases.

In nephritic syndrome, the damage is more about the glomeruli leaking blood, along with a smaller amount of protein, and the kidneys filtering less fluid overall. This is why nephritic syndrome tends to show up as blood in the urine, reduced urine output, and high blood pressure, since the kidneys’ declining ability to filter fluid causes blood volume and pressure to creep upward.

Some people experience a mix of both patterns, and the type of glomerulonephritis seen under a microscope during a biopsy doesn’t always predict which pattern of symptoms a person will actually have.

Symptoms of Glomerulonephritis

A significant number of people with glomerulonephritis, especially the chronic form, don’t notice anything wrong for a long time. The condition can sit quietly and only get picked up when a routine blood or urine test turns up an abnormality. When symptoms do appear, they tend to include:

• Pink, red, brown, or cola-coloured urine, caused by blood leaking through damaged glomeruli into the urine
• Foamy or bubbly urine, a sign that excess protein is passing through where it shouldn’t
• Swelling (oedema) in the face, especially around the eyes in the morning, as well as in the legs, ankles, or abdomen
• High blood pressure, since the kidneys play a direct role in regulating blood pressure, and damage to them throws that regulation off
• Passing less urine than usual, or urinating more frequently at night as kidney function shifts
• Fatigue and shortness of breath, which can develop as waste products build up in the blood or as fluid accumulates around the lungs
• Nausea, vomiting, and poor appetite, particularly in children, as toxins that would normally be filtered out start to accumulate
• Muscle cramps, often linked to shifts in the body’s salt and mineral balance as kidney function changes
• Joint or abdominal pain, which may point toward an underlying autoimmune condition driving the kidney damage rather than the kidney disease acting alone
• Unexplained weight loss, depending on the underlying cause

If glomerulonephritis triggered by an infection is left unchecked and progresses toward kidney failure, additional warning signs can appear, including dry and itchy skin, disturbed sleep, and worsening fatigue — signals that waste products are building up to a level the body can no longer manage on its own.

Causes and Risk Factors

Most cases of glomerulonephritis trace back to the immune system attacking the kidneys, either directly or as a side effect of fighting something else. Understanding what triggers that immune response helps explain why certain infections, diseases, and even medications show up again and again as risk factors.

Infections are one of the most well-documented triggers. A streptococcal infection the same bacteria responsible for strep throat or certain skin infections is the classic example, and symptoms typically develop one to three weeks after the infection as the immune system’s antibody response, originally built to fight the bacteria, ends up depositing in the glomeruli and inflaming them.

This pattern, known as post-streptococcal glomerulonephritis, is seen most often in children between five and fifteen years old, though it can occur at any age. Hepatitis B, hepatitis C, and HIV have also been linked to glomerular damage, since these viruses can trigger immune complexes that settle in the kidney’s filtering units.

Autoimmune diseases are another major category. In conditions like lupus, the immune system that’s supposed to protect the body instead starts attacking its own tissue, including the kidneys.

Goodpasture syndrome works similarly but specifically targets both the lungs and kidneys at once. IgA nephropathy, mentioned earlier, falls into this category too antibody deposits build up gradually in the glomeruli and slowly damage them over years.

Blood vessel disorders such as granulomatosis with polyangiitis and polyarteritis cause inflammation in small and medium blood vessels throughout the body, and since glomeruli are essentially clusters of tiny blood vessels, they’re often caught up in this inflammation too.

Long-standing conditions like high blood pressure and diabetes contribute in a slower, more mechanical way persistently elevated blood pressure puts continuous stress on the delicate blood vessels inside the glomeruli, while high blood sugar in diabetes gradually thickens and damages the filtering membrane, a process that eventually shows up as diabetic kidney disease.

Certain medications, particularly long-term or high-dose use of NSAIDs (common painkillers), have also been associated with kidney inflammation, and in some cases, doctors are never able to pin down an exact trigger at all.

Risk factors that raise the odds of developing glomerulonephritis include:

• A personal or family history of kidney disease, since some forms, such as Alport syndrome, are inherited
• Existing autoimmune conditions
• Chronic high blood pressure or poorly controlled diabetes
• Exposure to certain toxins or long-term medication use

How Glomerulonephritis Is Diagnosed

Because glomerulonephritis can develop silently, diagnosis usually starts with a combination of simple tests before moving to more detailed investigations if something abnormal turns up.

Urine tests are typically the first step. A dipstick test can quickly flag the presence of blood or protein in urine, and in some cases, doctors ask for a 24-hour urine collection to measure exactly how much protein is being lost — a more precise way of gauging how severe the leak is.

Blood tests come next, and they tell doctors how well the kidneys are actually functioning. Serum creatinine is a waste product normally cleared by the kidneys, so rising creatinine levels signal that filtration isn’t working as it should.

This value is also used to calculate the estimated glomerular filtration rate, or eGFR, which gives a more complete picture of kidney function than creatinine alone. Blood urea nitrogen, complete blood count, and antibody tests (to check for conditions like lupus or a recent streptococcal infection) round out the picture.

Imaging tests, usually an ultrasound, help doctors check the size and structure of the kidneys and rule out blockages or other structural problems that could be causing similar symptoms.

Kidney biopsy is the test that gives the most definitive answer. A small sample of kidney tissue is removed using a fine needle, guided by ultrasound and done under local anaesthetic, and examined under a microscope.

This is how doctors identify the exact type of glomerulonephritis findings like IgA deposits, membranous changes, or focal segmental scarring each point to a different underlying process, which in turn shapes how aggressively the condition needs to be treated and what the long-term outlook looks like.

Treatment of Glomerulonephritis

There’s no single treatment plan for glomerulonephritis because the right approach depends entirely on what’s driving it, how severe the damage is, and whether it’s acute or chronic. In mild cases picked up early, doctors sometimes recommend nothing more than close monitoring with regular blood and urine tests. In more active or severe cases, treatment usually combines several approaches at once.

Medications form the core of most treatment plans:

• Steroids and immunosuppressive drugs calm down an overactive immune response, which is especially useful when an autoimmune condition is behind the kidney damage.
• ACE inhibitors, a class of blood pressure medication, do double duty here they lower blood pressure and also reduce the amount of protein leaking into the urine, which helps protect the kidneys from further strain.
• Diuretics help the body clear excess fluid, easing the swelling that builds up when protein loss disrupts the body’s fluid balance.
• Cholesterol-lowering medicines are sometimes added, since nephrotic syndrome can also raise blood cholesterol levels.

Treating the underlying cause matters just as much as managing the kidney symptoms directly. If an infection triggered the glomerulonephritis, treating that infection is part of the plan. If lupus or another autoimmune disease is the root cause, controlling that condition often improves the kidney picture too.

Diet and fluid adjustments are commonly advised, usually involving lower salt intake and sometimes restricted fluid or protein consumption, tailored by a dietician based on how the kidneys are functioning.

Plasmapheresis (plasma exchange) is reserved for more severe or specific cases. It works similarly to dialysis but focuses on removing harmful antibodies circulating in the plasma the antibodies responsible for attacking the kidneys in the first place are filtered out and the plasma is replaced, which can reduce ongoing damage in certain autoimmune-driven forms of the disease.

Dialysis and kidney transplant become necessary when kidney function has declined severely enough that the kidneys can no longer clear waste and fluid on their own. Dialysis takes over that filtering role artificially, while a transplant replaces the damaged kidney altogether in cases that progress to end-stage kidney disease.

Complications of Glomerulonephritis

Left undiagnosed or poorly managed, glomerulonephritis can progressively affect how well the kidneys work, and the complications that follow tend to build on each other.

• Acute kidney failure can occur when kidney function drops suddenly in severe, fast-moving cases.
• Chronic kidney disease develops when glomerular damage persists over three months or longer, gradually reducing how efficiently the kidneys filter blood.
• End-stage kidney disease is the most advanced stage, where the kidneys can no longer function well enough to keep a person alive without dialysis or a transplant.
• High blood pressure both results from and worsens kidney damage — since the kidneys help regulate blood pressure, damaged glomeruli disrupt that control, and the resulting high blood pressure then puts even more strain on the kidneys, creating a cycle that’s hard to break without treatment.
• Fluid retention and swelling happen when the kidneys can’t clear excess fluid, and worsen further when protein loss lowers the blood’s ability to hold fluid inside blood vessels.
• Increased cardiovascular risk, since uncontrolled high blood pressure and kidney dysfunction together raise the risk of heart disease and stroke over time.

Prevention and Long-Term Management

Not every case of glomerulonephritis can be prevented, particularly when genetics or an unpredictable autoimmune trigger are involved. But several steps genuinely reduce the risk of developing it or slow its progression once it’s diagnosed.

• Treat infections properly and promptly  because post-streptococcal glomerulonephritis develops after untreated or partially treated strep infections, finishing a full course of prescribed antibiotics for throat and skin infections matters more than it might seem.
• Keep blood pressure under control, since consistently high blood pressure is both a cause and a consequence of kidney damage, making it a key lever for prevention.
• Manage diabetes carefully, as good blood sugar control slows the gradual thickening and damage that diabetes causes to the glomeruli over time.
• Follow a kidney-friendly diet when advised, which usually means lower sodium, and sometimes adjusted protein and potassium intake based on lab results and a dietician’s guidance.
• Avoid unnecessary long-term use of NSAIDs and other medications linked to kidney inflammation, and never self-medicate for prolonged pain without medical advice.
• Practise good hygiene and safe sex, since certain infections tied to glomerulonephritis, including hepatitis B, hepatitis C, and HIV, are preventable through these basic measures.
• Stay up to date on vaccinations, including flu and pneumococcal vaccines, since glomerulonephritis and its treatments (particularly immunosuppressive medication) can make the body more vulnerable to infections.
• Avoid smoking, which adds cardiovascular strain on top of existing kidney stress.
• Get regular checkups if you’re at higher risk — anyone with a family history of kidney disease, autoimmune conditions, or long-standing diabetes or hypertension benefits from periodic urine and blood tests, since early detection makes a real difference in outcomes.

When to See a Doctor

Glomerulonephritis is easiest to treat effectively when it’s caught early, so it’s worth taking these signs seriously rather than waiting them out:

• Blood in the urine or urine that looks pink, red, brown, or cola-coloured
• Persistent foamy or bubbly urine
• Unexplained swelling in the face, legs, feet, or abdomen, especially puffiness around the eyes in the morning
• A noticeable drop in how much urine you’re passing, or urinating much more frequently at night
• Blood pressure readings that stay high despite lifestyle changes
• Shortness of breath or unexplained fatigue that doesn’t improve with rest
• Persistent joint or abdominal pain alongside any of the symptoms above

If you’re noticing any combination of these, it’s best not to wait for symptoms to worsen. You can book an online consultation with a nephrologist through HealthPil to get your symptoms evaluated and figure out whether further testing is needed early evaluation is often what separates a fully reversible case from one that leads to lasting kidney damage.

How HealthPil Can Help:

HealthPil connects you with nephrologists who can diagnose and treat glomerulonephritis effectively. Schedule a consultation today!

Summary

Glomerulonephritis is inflammation or damage to the glomeruli, the tiny filtering units inside your kidneys, and it can show up suddenly after an infection or build slowly and silently over years. The symptoms blood in urine, foamy urine, swelling, high blood pressure all trace back to the same root problem: damaged filters that leak what they should hold onto and retain what they should release.

Diagnosis relies on urine and blood tests, imaging, and sometimes a kidney biopsy to pin down the exact type and cause. Treatment ranges from simple monitoring to medications, plasma exchange, dialysis, or transplant, depending on severity. The single biggest factor in a good outcome is catching it early, so persistent changes in your urine, unexplained swelling, or stubborn high blood pressure are always worth getting checked rather than waiting out.