What is nephritic syndrome?
Nephritic syndrome is the name given to a collection of different signs and symptoms that occur as a result of inflammation in the kidneys. This inflammation causes the kidneys to work less effectively. It also causes protein and red blood cells to leak from the bloodstream into the urine.
There are many conditions that may cause nephritic syndrome, and it can occur in people of all ages. Common causes are infections, immune system disorders and inflammation of the blood vessels. The main symptoms are passing less urine than normal, leading to a fluid buildup in the body, and having blood in the urine. People with nephritic syndrome also often develop high blood pressure.
Treatment depends on the underlying cause, but usually involves managing the high blood pressure and reducing the inflammation in the kidneys. Although many people recover well from nephritic syndrome, some people may go on to develop renal failure. The risk of renal failure depends on the severity of the syndrome and its underlying cause.
Nephritic syndrome is not a disease but a syndrome. A syndrome is a group of symptoms that often and predictably occur together, and which develop as a result of another condition. Syndromes are not necessarily specific to any disease or disorder. Nephritic syndrome has many potential triggers, therefore, successfully treating it involves identifying the underlying cause.
Nephritic syndrome has both acute and chronic forms. Acute, or rapidly-progressing, nephritic syndrome usually comes on suddenly and, because of acute and painful symptoms, seldom goes undetected. Chronic nephritic syndrome typically progresses slowly and often goes undetected for some time. 
Chronic inflammation of the kidneys can cause scarring, which may negatively impact kidney function and lead to high blood pressure and, eventually, if left undiagnosed and untreated, to a need for dialysis (renal replacement therapy, when a dialysis machine replaces the kidneys’ function and filters waste products from the blood), and possibly kidney transplantation.
What are the causes of nephritic syndrome?
Nephritic syndrome is the result of inflammation affecting small groups of blood vessels, known as glomeruli, in the kidneys. As the glomeruli are the kidneys’ main filter units, this inflammation disrupts the kidneys’ ability to adequately filter blood. The inflammation can originate in the kidneys themselves or be the result of infection or injury elsewhere in the body. It can occur in people of any age, including children.
Primary glomerular diseases: Such as IgA nephropathy (Berger’s disease) or membranoproliferative glomerulonephritis. IgA nephropathy is a very common cause of nephritic syndrome.
Bacterial infections: Such as methicillin-resistant staphylococcus aureus (MRSA), pneumococcal pneumonia, typhoid, infective endocarditis, or secondary syphilis. Nephritic syndrome following a streptococcal throat infection is fairly common, especially in children.
Viral infections: Such as hepatitis B, mumps, measles, chicken pox or glandular fever (mononucleosis).
Multisystem systemic/inflammatory diseases: Such as vasculitis, Goodpasture’s Syndrome, granulomatosis with polyangiitis, Henoch-Schönlein purpura, or lupus (systemic lupus erythematosus).
Abdominal abscess: A pocket of infected fluid and pus inside the abdominal cavity. This can be located on or near any organ.
Parasitic infections: Such as malaria.
Nephritic syndrome may also be caused by a number of other conditions.
As there are many underlying conditions for nephritic syndrome, there are different risk factors, such as recent infections, immune system disorders and genetic disorders.
Symptoms and diagnosis
Typical symptoms include passing less urine than normal, having blood in the urine and swelling of the feet or face (edema). Other possible symptoms are flank pain, back pain, headache, shortness of breath and symptoms related to the underlying cause, for example rash and joint pain.
The symptoms of nephritic syndrome differ, depending on whether the acute or chronic form of the syndrome is present.
- Edema in the face and legs: Edema is the accumulation of fluids in the body, usually under the skin, leading to a puffy appearance.
- Low urine volume: Known as oliguria, this is defined as less than 500ml of urine being produced in a 24-hour period.
- Hematuria: Blood in the urine which often, but not necessarily, leads to red discoloration. There are two types of hematuria: microhematuria, which indicates unseen blood, and macrohematuria, in which the blood is visible to the eye.
- High blood pressure: Hypertension, which results from the disruption of kidney function, may also occur. High blood pressure is generally defined as a resting blood pressure of 140/90mmHg or higher in adults,. In children, what constitutes hypertension depends on the age and size of the child.
- Fever, weakness and fatigue
- Appetite loss, vomiting and abdominal pain
- Malaise (a feeling of general unwellness) and nausea may also be present.
Chronic nephritic syndrome usually presents with fairly mild or even undetectable symptoms, which can include:
- Hypertension/high blood pressure
- Kidney failure in later stages
Symptoms of kidney failure can include:
- Itchy skin and/or rash
- Decreased appetite
- Difficulty breathing
In both chronic and acute nephritic syndrome, the urine will usually contain high concentrations of red blood cells, as the blood cells leak out of the damaged glomeruli.
Diagnosis of nephritic syndrome
The diagnosis of nephritic syndrome is typically based on a physical examination of the person and analysis of their urine. People with nephritic syndrome tend to have high blood pressure, so a doctor will check this. A doctor will also look for signs of:
- Abnormalities. Such as dark color or cloudiness in the urine
- Protein in the urine (proteinuria), which may indicate nephrotic syndrome
- Uremia, an excess of urea or creatinine in the blood, or azotemia, an excess of nitrogen-rich waste compounds in the blood
- Increased fluid volume in the body, which may lead to edema
- Reduced filtration in the kidneys, specifically the glomeruli
A kidney biopsy (tissue sample from the kidney) may be performed to investigate the cause of the nephritic syndrome.
Tests and diagnostic procedures
Because nephritic syndrome is a cluster of symptoms rather than a disease in itself, much of the testing that makes up the diagnosis is aimed at determining what the underlying cause is. Another important element in diagnosis is differential diagnosis, as the illness may be nephrosis rather than nephritis.
In examining a person with potential nephritic syndrome, a doctor might carry out the following tests:
Take patient history: A doctor will ask the affected person about the time at which their symptoms began and attempt to determine the point at which the kidneys began to excrete protein into the urine.
Check appearance and colour of urine: Urine that is dark in colour may be very concentrated and contain blood.
Blood pressure: Hypertension can be a sign of disrupted kidney function.
Edema assessment: Edema, or fluid gathering in the tissues, can be a sign that there is not enough protein in the blood and may suggest proteinuria.
Urine dipstick test: A test for blood and protein. They will use a dipstick test, in which a test-strip of paper is immersed in a urine sample, to check for blood and protein in the urine
Urinalysis: A urine sample will be sent to a laboratory to do a precise check for protein levels and red blood cells.
Blood tests: To check levels of electrolytes, creatinine, blood urea nitrogen, immunoglobulins, antibodies, and other substances.
Kidney biopsy: This relatively straightforward procedure may be performed as an outpatient procedure or after hospital admission, depending on the patient’s particular circumstances. It uses only local anesthetic and is done using ultrasound and specialized biopsy needles to remove a small sample of tissue. Kidney biopsies are a very reliable way of distinguishing chronic glomerulonephritis from other, similar, disorders.
The difference between nephrotic syndrome and nephritic syndrome
Both nephritis and nephrosis are among the body’s responses to injury or illness affecting the kidneys. Nephrotic syndrome is characterized by severe proteinuria, i.e.high amounts of protein, including albumin, in the urine, while nephritic syndrome’s major feature is inflammation. Depending on the specific underlying conditions of the two, nephrotic syndrome often is the more serious. In both cases, medical care should be sought as a matter of urgency. Doctors will usually need to order tests to determine whether a patient has nephritic or nephrotic syndrome.[^8
Treatment of nephritic syndrome
Treatment depends on the underlying causes. Medications (such as ramipril, benzapril, candesartan, or valsartan) are typically used to treat the high blood pressure. Medications will also be administered to reduce inflammation in the kidneys.
Generally, doctors will recommend:
- Bed rest
- A diet that is restricted in salt, potassium and fluid
- Medication to control blood pressure, if necessary
- Medication to reduce inflammation
- Medication to remove fluids from the body
- Dialysis to replace kidney function in severe cases
The time it takes to recover from nephritic syndrome varies according to its severity and the underlying cause. Most patients begin to feel better fairly soon, especially if treatment is prompt.
Other names for nephritic syndrome
- Acute nephritis
- Acute glomerulonephritis
- Rapidly-progressing glomerulonephritis
- Chronic glomerular disease
Nephritic syndrome FAQs
Q: Is nephritic syndrome dangerous during pregnancy?
A: Nephritic syndrome indicates a problem with the kidneys, which is of great concern for pregnant people, whose kidneys and other internal organs are already adapting to pregnancy and thus under increased demand. A doctor should be consulted without delay if symptoms occur. Acute nephritic syndrome poses certain health risks to both mother and baby. Chronic nephritic syndrome, though rarer, is also of concern. If nephrotic syndrome occurs, complications for both mother and baby may occur, even if renal function isn’t badly affected. Mothers may experience postnatal problems, such as edema, urinary tract infections and anemia. A doctor should be consulted as soon as possible.
Q: Can I take painkillers if I have or have had nephritic syndrome?
A: There is some evidence that non-steroidal anti-inflammatory drugs (NSAIDS) can worsen existing kidney damage or lead to kidney damage if used in high amounts exceeding the standard dosages over time. Normal dosages, when taken only as directed, are safe. NSAIDs include diclofenac , celecoxib, etoricoxib, indometacin, ibuprofen, ketoprofen, high-dose aspirin (above 300mg per dose), mefenamic acid, and naproxen. High doses of NSAIDs over time can lead to chronic interstitial nephritis. Patients with kidney problems should use NSAIDs only under the direct supervision of a doctor.
Opioids such as morphine, hydrocodone or oxycodone, should generally be avoided, except in post-surgical or severe long-term pain, and would not ordinarily be prescribed by physicians due to their addictive properties.
Acetaminophen, also known as paracetamol, is generally a safe painkiller for use by people with kidney problems or suspected kidney problems. However, overuse of acetaminophen can lead to liver damage. Acetaminophen reduces pain and fever, but is not an anti-inflammatory.
However, all patients should consult a doctor before taking NSAIDs or any other painkillers.
Nature Genetics. “IgA nephropathy, the most common cause of glomerulonephritis, is linked to 6q22-23” November, 2000. Accessed 26 February, 2018. ↩
Kidney International. “Nephrotic syndrome in pregnancy poses risks with both maternal and fetal complications.”. June, 2017. Accessed 23 February, 2018. ↩