nephritis on one side

Overview

Nephritis is a condition where one or both of your kidneys become swollen and irritated (inflamed). When it happens on only one side, it means the inflammation is in just one kidney. This can affect how well that kidney filters waste and extra fluid from your blood.

Nephritis is not extremely common, but it does happen. Unilateral nephritis, especially from a kidney infection (pyelonephritis), is seen more often in women than men.

Nephritis on one side can affect people of any age, but it is more common in women (for infections) and in people with conditions like diabetes or a weak immune system. It can also occur in children and older adults.

Symptoms

Common symptoms

• Pain in the side or lower back (usually on the affected side)
• Fever and chills
• Frequent or painful urination
• Blood in the urine (pink, red, or cola-colored)
• Feeling very tired or generally unwell

Symptoms in children

• High fever that comes on quickly
• Vomiting or not wanting to eat
• Fussiness or irritability
• Pain in the belly or side

Symptoms in older adults

• Confusion or changes in mental state
• Loss of appetite
• Low-grade fever (may not have a high fever)
• Increased weakness or fatigue

Causes

Main causes

• A bacterial infection that starts in the bladder and travels up to one kidney (called pyelonephritis)
• Autoimmune diseases (like lupus) that cause the immune system to attack kidney tissue
• Medications that can irritate the kidney, such as some pain relievers or antibiotics
• A blocked urine flow (like a kidney stone) that leads to infection in one kidney

Risk factors

• Being female – the urethra is shorter, making bladder infections more common
• Having a weakened immune system (from illness or medicines)
• Using a urinary catheter for a long time
• Having kidney stones or an enlarged prostate that blocks urine flow
• Diabetes, especially if blood sugar is not well controlled

When to see a doctor

See a doctor urgently if:

• If you have fever with pain in your side or back
• If you see blood in your urine
• If you feel very sick or cannot keep fluids down

Book a routine appointment if:

• If you have mild side pain that comes and goes
• If you have frequent bladder infections
• If you have risk factors (like diabetes) and notice any new urinary symptoms

Diagnosis

Your doctor will ask about your symptoms, examine your back and belly, and order tests to check your urine and blood. They may use imaging to look at your kidneys.

Tests that may be done

• Urine test (urinalysis) – checks for infection, blood, or inflammation
• Blood test – measures kidney function (creatinine, blood urea nitrogen)
• Ultrasound – uses sound waves to see the size and shape of your kidneys
• CT scan (sometimes with contrast) – provides detailed images if needed

What to expect at your appointment

The tests are usually quick and painless. For a urine test, you will need to provide a clean sample. Ultrasound does not hurt. Your doctor will explain what they find and what it means for you.

Treatment

Treatment for nephritis on one side depends on the cause. If it is an infection, antibiotics are used. If it is an autoimmune condition, medicines that calm the immune system may be given. The goal is to reduce inflammation and protect the function of your kidney.

Self-care at home

• Drink plenty of water (unless your doctor tells you to limit fluids)
• Get plenty of rest to help your body fight infection or inflammation
• Use a warm compress on the painful side to ease discomfort
• Take pain relievers like paracetamol (acetaminophen) as directed – avoid non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen unless your doctor says it is safe, as they can stress the kidneys

Medical treatments

Doctors may prescribe antibiotics if a bacterial infection is found. For autoimmune nephritis, they might use medicines that suppress the immune system, such as corticosteroids or other disease-modifying drugs. Treatment is tailored to you – your doctor will explain the options.

When is surgery considered?

Surgery is rarely needed for unilateral nephritis. It might be considered if there is a large abscess (a pocket of pus) that does not drain with medicine, or if a kidney stone is causing repeated infections and cannot be treated otherwise.

Living with this condition

Most people with unilateral nephritis recover fully with treatment. If the inflammation was severe, you may need to see a kidney specialist (nephrologist) to monitor your kidney function over time. You might need to avoid certain over-the-counter pain medicines.

Lifestyle tips

• Stay well hydrated – water helps flush out infections
• Urinate when you feel the urge – don't hold it in
• Practice good hygiene, especially after using the toilet, to prevent infections
• Quit smoking – smoking can worsen kidney disease

Diet and exercise

A balanced diet with plenty of fruits, vegetables, and whole grains is helpful. If your kidney function is reduced, your doctor may suggest limiting salt, potassium, or protein. Gentle exercise like walking can support overall health, but avoid heavy lifting if you have pain.

Mental health and emotional wellbeing

Dealing with a kidney problem can feel stressful or worrying. It is normal to feel anxious. Talk to your doctor or a counselor if you feel overwhelmed. Connecting with others who have similar experiences may help.

Prevention

Some causes of unilateral nephritis cannot be prevented (like autoimmune conditions), but you can lower your risk of infection-caused nephritis. Staying hydrated, urinating after sex, and managing conditions like diabetes can help.

Vaccines

Getting the flu vaccine each year and other recommended vaccines (like the pneumonia vaccine) can reduce your risk of infections that might spread to your kidneys.

Screening programmes

If you have risk factors like diabetes or a history of kidney stones, your doctor may check your urine regularly to catch problems early.

Complications

If left untreated

• The inflammation can cause permanent damage to the affected kidney, reducing its function
• An untreated kidney infection can spread to the bloodstream (sepsis), which is life-threatening
• Scarring of the kidney may increase the risk of high blood pressure or chronic kidney disease later

Long-term outlook

With prompt and proper treatment, most people with unilateral nephritis recover fully without lasting kidney damage. Even if there is some scarring, your other kidney can often compensate. Your healthcare team will help you monitor and protect your kidney health.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.