What is chronic glomerulonephritis?

Causes

What is chronic glomerulonephritis?

In this article we will describe 10 facts about chronic glomerulonephritis.

Glomerulonephritis is a group of autoimmune kidney disorders characterised by inflammation and damage to the glomeruli, which are tiny filtering units (sieves) within the kidneys.

What is a glomerulus?

A glomerulus is a scrunched up ball of tiny blood vessels (called capillaries) – a bit like mini-worms – and is the tiny filter within the kidney. There are a million in each kidney. The blood is filtered through the sieve-like walls of the capillaries making urine. The glomerular basement membrane (GBM) is the middle wall (of three) of the capillary.

Looped capillaries of glomerulus between the arteriolesThe Glomerulus – Veterinary Histology

Diagrams of a normal glomerulus, and capillaries within it

Proteinuria (protein in the urine), ranging from low to very high, is the hallmark of GN. It is usually at least moderate, or high. It is a sign of damage to the GBM, i.e. the disease has made the GBM too leaky and protein is leaking through it.

1. Definition

Glomerulonephritis refers to a group of diseases that involve inflammation of the glomeruli, which are the tiny filters within the kidneys responsible for filtering blood and removing waste products.

2. Causes

Glomerulonephritis can be caused by various factors, including:

  • Autoimmune disorders. These are of two types:
    • Primary = arising in the kidney alone, e.g. minimal change disease (MCD, see below)
    • Secondary = part of systemic (whole body) disease, e.g. like systemic lupus erythematosus (SLE)
  • Infections – including bacteria such as streptococci that cause Strep A throat and endocarditis (infection of a heart valve); and viruses like Hepatitis B and C, and HIV
  • Certain medications – e.g. hydralazine. This is rare
  • Certain cancers. This also rare.

How these factors cause a GN is unclear. They somehow trigger an exaggerated (and sustained) response of the immune system to whatever is the original trigger.

3. Types

There are two broad types of glomerulonephritis:

  • Proteinuric. The proteinuria (protein in urine) usually ‘nephrotic range’, i.e, high or very high
  • Less proteinuric. There is usually low-moderate level proteinuria. But there can be none
    • IgA nephropathy – the commonest type of GN in adults. Usually presents as micro/macrohaematuria and loin/back pain. Can present as anything (AKI, CKD, proteinuria, nephrotic syndrome)
    • Mesangiocapillary GN – usually presents as CKD; but can present in almost any renal way (like IgA nephropathy)
    • Post-infectious GN – usually presents at nephritic syndrome (or AKI)
    • Rapidly progressive glomerulonephritis (RPGN; or crescentic) GN – usually presents as AKI. Patients are usually very unwell. It can also be linked to epistaxes (nose bleeds) or haemoptysis (coughing up blood), as some types also have autoimmune damage to respiratory tissue.

Although each type has unique characteristics and underlying causes, any one of the 7 types can (rarely) present in non-characteristic ways. For example, IgA nephropathy normally presents as micro/macrohaematuria and loin/back pain. But it can (unusually) present as nephrotic syndrome (like the 3 proteinuric GNs above) or acute kidney injury (AKI; rapid onset kidney failure).

4. Symptoms

The symptoms of GN are highly variable. They can range from no symptoms to:

  • Rashes, and joint pain
  • Haematuria (blood in the urine). This may be microhaematuria (blood that you cannot see) or macrohaematuria (that you can)
  • Proteinuria (protein in the urine)
  • Loin/back pain
  • Swelling in legs (oedema) or shortness of breath – signs of fluid overload
  • High blood pressure
  • Decreased urine output in very severe cases.
5. Diagnosis

Diagnosis typically involves a combination of medical history and physical examination, urine and tests and a renal ultrasound. The ultrasound is done partly to check there are two kidneys (as a renal biopsy is likely to follow) and partly to exclude other diagnoses.

A battery of renal (kidney) immunological blood tests are also done. These can help with deciding which GN the patient has. But they are not reliable. They can be positive for diseases you don’t have, or negative for ones that you do.

This is why a kidney biopsy is almost always done, as a precise diagnosis is not possible without it. It also used to assess the extent of inflammation and damage – and chances of recovery.

6. Treatment

Treatment for glomerulonephritis depends on the underlying cause and the severity of the condition. Some require no treatment.

Most require medication such as angiotensin-converting enzyme inhibitors (ACE, e.g. Ramipril) or angiotensin receptor blockers (ARBs, e.g. Losartan) and/or SGLT2 inhibitors (e.g. Dapagliflozin) – which should be prescribed. These help to reduce the protein levels in the urine.

Diuretics (water tablets) may be required later, if the patient is fluid overloaded (shown by ankle swelling or shortness of breath, SOB).

Some types of GN need ‘special treatment’, with drugs and procedures to suppress the immune system. These include:

Some of these drugs are very strong and have significant side-effects. The decision to use (e.g. in the elderly) has to incorporate a risk:benefit assessment. In other words, it may be ‘safer’ not to use these drugs (or just use the weaker) ones, as the risk of side-effects outweighs the possible benefits. In severe cases, dialysis or kidney transplantation may be necessary. Some forms of GN, especially FSGS, can recur in a transplant.

7. Prognosis

The prognosis for glomerulonephritis is very variable. It depends on the specific type, severity and how early it’s diagnosed and treated. For example, MCD often resolves completely after

8. Risk Factors

Risk factors for glomerulonephritis include a history of certain recurrent infections (such as Strep A throat), other autoimmune diseases, a family history of kidney disease – as some forms of GN can be familial.

9. Prevention

Preventing glomerulonephritis is not easy, as it is a. a group of rare diseases, and b. has so many different causes. Some things can be done. For example, treating streptococcal infections promptly and effectively can help prevent post-infectious glomerulonephritis.

10. Complications

If left untreated or not managed properly, glomerulonephritis often leads to serious complications, including chronic kidney disease (CKD) and end-stage renal failure (ESRF), requiring dialysis and/or a renal (kidney) transplant, or death.

If you suspect you have glomerulonephritis, it is vital to see a hospital kidney specialist (nephrologist), to make an accurate diagnosis and treatment plan. Dialysis can be prevented, or the progression of kidney failure significantly slowed.

Summary

We have described what is chronic glomerulonephritis. We hope it has been helpful.

Other resources

There is more information on glomerulonephritis written by the renal team at UHCW in Coventry.

Minimal change disease
Membranous nephropathy
Focal and segmental glomerulosclerosis
IgA nephropathy
Mesangiocapillary glomerulonephritis
Post-infectious glomerulonephritis
Rapidly progressive glomerulonephritis

Last Reviewed on 25 June 2024

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