nephritis with fever

Overview

Nephritis (say nef-RYE-tis) is inflammation of the kidneys. When you have a fever along with it, it often means an infection is causing the inflammation. The kidneys are two bean-shaped organs that filter waste from your blood and make urine. Inflammation can damage them if not treated.

Nephritis is not extremely common, but it is a serious condition that doctors see regularly. The type with fever is most often seen in children after a strep throat infection, but it can affect anyone.

It can affect people of all ages. Children after certain infections, people with autoimmune diseases like lupus, and older adults with other health problems are at higher risk.

Symptoms

Common symptoms

• Fever (temperature above 38°C / 100.4°F)
• Pain in the side or lower back (flank pain)
• Blood in the urine (pink, red, or cola-colored)
• Swelling in the face, hands, feet, or belly (edema)
• Feeling very tired or weak
• Nausea or vomiting

Symptoms in children

• High fever
• Irritability or fussiness
• Poor appetite or refusal to eat
• Dark or bloody urine
• Swelling around the eyes or in the feet

Symptoms in older adults

• Fever (may be lower than in younger people)
• Confusion or feeling 'off'
• Loss of appetite
• Lower back pain
• Less urine output than usual

Causes

Main causes

• Bacterial infection — often from a strep throat or a skin infection that spreads to the kidneys
• Autoimmune diseases — where the body's immune system attacks the kidneys (e.g., lupus nephritis)
• Medications that cause an allergic reaction in the kidneys (rare)
• Viral infections (less common)

Risk factors

• Recent infection with group A streptococcus bacteria (strep throat, impetigo)
• Having an autoimmune condition like lupus or vasculitis
• Family history of kidney disease
• Being very young or very old
• Weakened immune system (e.g., from HIV, chemotherapy)

When to see a doctor

See a doctor urgently if:

• If you have fever along with blood in your urine
• If you have fever and swelling in your face or limbs
• If you have severe back pain with fever
• If you have signs of high blood pressure (severe headache, blurred vision, chest pain)

Book a routine appointment if:

• If you have mild fever and lower back discomfort that lasts more than 2 days
• If you notice your urine is darker than usual
• If you feel unusually tired or have mild swelling in the morning

Diagnosis

Your doctor will ask about your symptoms and do a physical exam. They will check your temperature and blood pressure and press on your lower back for tenderness. Based on that, they may order tests to look at your urine and blood.

Tests that may be done

• Urine test (urinalysis) — checks for blood, protein, and signs of infection
• Blood test — measures kidney function (creatinine, BUN) and checks for infection markers
• Ultrasound of the kidneys — takes pictures to look for swelling, blockages, or abscesses
• Sometimes a kidney biopsy (taking a tiny sample of kidney tissue) if the cause is unclear

What to expect at your appointment

If your doctor thinks you have nephritis with fever, they may start treatment right away while waiting for test results. For bacterial infections, that usually means antibiotics. You may need to stay in the hospital if the infection is severe or if you are very unwell. Otherwise, you can often be treated at home with follow-up visits.

Treatment

Treatment targets the cause of the inflammation and helps your kidneys recover. For bacterial nephritis, antibiotics are the main treatment. For immune-related nephritis, medicines that calm the immune system are used. Managing fever, pain, and blood pressure is also important.

Self-care at home

• Get plenty of rest to help your body fight the infection
• Drink fluids as advised by your doctor (avoid too much or too little)
• Take paracetamol (acetaminophen) for fever and pain if your doctor says it's safe — do not take ibuprofen or other NSAIDs unless your doctor says it's okay, as they can affect the kidneys
• Monitor your temperature and urine color. Note any changes.

Medical treatments

Doctors will prescribe antibiotics for bacterial infections. The type and length of treatment depend on the bacteria found. For autoimmune-related nephritis, medications that reduce inflammation (like corticosteroids) or that suppress the immune system may be used. You may need medicines to control high blood pressure, such as ACE inhibitors or ARBs (these are types of blood pressure medications that also protect the kidneys). If kidney function drops very low, dialysis (a machine that filters the blood) may be needed temporarily until the kidneys recover.

When is surgery considered?

Surgery is rarely needed. It may be required if an abscess (a pocket of pus) forms in the kidney and does not drain with antibiotics, or if there is a blockage that needs to be removed.

Living with this condition

If you have had nephritis with fever, recovery may take a few weeks. You will need to take all your medicines as prescribed, attend follow-up appointments, and watch for signs that the infection is returning. Most people feel better steadily.

Lifestyle tips

• Wash your hands often to avoid infections
• Keep any wounds or skin infections clean and covered
• Avoid taking over-the-counter pain relievers like ibuprofen or naproxen without consulting your doctor
• Get regular check-ups for blood pressure and kidney function if you have had severe or repeat episodes

Diet and exercise

Your doctor may recommend a diet low in salt to control blood pressure and reduce swelling. For most people, a balanced diet with plenty of fruits and vegetables is good. Light exercise like walking can help you regain strength once the fever is gone, but avoid strenuous activity until fully recovered.

Mental health and emotional wellbeing

Dealing with a kidney infection can be stressful and scary. It's normal to feel anxious about your health. Talk to your doctor or a counselor if you feel overwhelmed. Many people recover fully and go back to their normal lives.

Prevention

You cannot always prevent nephritis, but you can lower your risk by treating infections quickly and completely. For example, finish all antibiotics for a strep throat. Manage chronic conditions like lupus with your doctor's help.

Vaccines

Staying up to date with vaccines, especially for flu and pneumonia, helps reduce infections that can lead to kidney problems.

Screening programmes

If you have a high risk (like lupus or a family history of kidney disease), your doctor may do regular urine and blood tests to check your kidneys.

Complications

If left untreated

• Permanent kidney damage (chronic kidney disease)
• High blood pressure that is hard to control
• Kidney abscess (pus collection)
• Sepsis (life-threatening infection spreading in the blood)
• Kidney failure requiring dialysis or transplant

Long-term outlook

With prompt treatment, most people with nephritis and fever recover completely. The kidneys often heal well, especially if the cause was a one-time infection. For chronic causes like lupus, long-term treatment can control the disease. Even if some kidney damage occurs, people can live well with careful management. Your doctor will help you stay on track.

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