The term "glomerulonephritis" encompasses a subset of renal diseases characterized by immune-mediated damage to the basement membrane, mesangium, or the capillary endothelium, leading to hematuria, proteinuria, and azotemia. This activity reviews the evaluation and management of glomerulonephritis and highlights the role of the interprofessional team in improving care for patients with this condition.
Review the etiology of glomerulonephritis.
Summarize the physical findings associated with glomerulonephritis.
Outline the management considerations for the different diseases grouped under the term 'glomerulonephritis'.
Describe interprofessional team strategies for improving care coordination and communication to improve outcomes for patients affected by glomerulonephritis.
The structural and functional unit of the kidney, the 'nephron' consists of a renal corpuscle (glomerulus surrounded by a Bowman capsule) and a renal tubule. Each kidney in an adult human contains around 1 million nephrons.
A fenestrated endothelium forms the inner glomerular layer, followed by a layer composed of various extracellular proteins forming a meshwork called the glomerular basement membrane (GBM). The outer layer has visceral epithelial cells or podocytes, along with mesangial cells. The intricate arrangement provides the basis of the continuous plasma volume filtration that occurs at the glomerular level.
The term "glomerulonephritis" encompasses a subset of renal diseases characterized by immune-mediated damage to the basement membrane, the mesangium, or the capillary endothelium, resulting in hematuria, proteinuria, and azotemia.
Acute forms of glomerulonephritis can result from either a primary renal cause or a secondary illness that causes renal manifestations. Most forms of glomerulonephritis are considered progressive disorders, which without timely therapy, progress to chronic glomerulonephritis (characterized by progressive glomerular damage and tubulointerstitial fibrosis leading to a reduced glomerular filtration rate). This leads to the retention of uremic toxins with subsequent progression into chronic kidney disease (CKD), end-stage renal disease (ESRD) along with their associated cardiovascular diseases.
Etiological classification can be made on the basis of clinical presentation, which can range from severe proteinuria (>3.5 g/day) and edema qualifying for nephrotic syndrome, to a nephritic syndrome where hematuria and hypertension are more prominent while proteinuria is less pronounced.
Minimal change disease
Focal segmental glomerulosclerosis
HIV associated nephropathy
Henoch Schonlein purpura (HSP)
Post streptococcal glomerulonephritis.
Anti-glomerular basement membrane disease
Rapidly progressive glomerulonephritis
Granulomatosis with polyangiitis
Eosinophilic granulomatosis with polyangiitis
Idiopathic crescentic glomerulonephritis
Hepatitis C infection
Membranoproliferative glomerulonephritis (typical presentation is with acute nephritic syndrome, however, sometimes features resembling nephrotic syndrome may occur, additionally)
Glomerulonephritis (GN) is a prominent cause of renal impairment. It leads to 10% to 15% of end-stage renal disease cases in the United States. In most instances, without timely intervention, the disease becomes progressive, eventually leading to morbidity. This makes chronic glomerulonephritis the third most common cause of end-stage renal disease in the United States following diabetes mellitus and hypertension, accounting for 10% of patients on dialysis.
Glomerulonephritis constitutes 25% to 30% of all end-stage renal disease cases. About a quarter of patients present with nephritic syndrome. Progression in most cases is relatively quick, and end-stage renal disease may ensue within weeks or months of the beginning of acute nephritic syndrome.
IgA nephropathy has been found to be the most common cause of glomerulonephritis worldwide. However, the incidence of post-streptococcal glomerulonephritis has declined in most of the developed world. As reported by Japanese researchers, the incidence of postinfectious glomerulonephritis in their country climaxed in the 1990s. Post-streptococcal glomerulonephritis, which accounted for nearly all cases of postinfectious GN in the 1970s, has reduced to about 40-50% since the 1990s, while the percentage of Staphylococcus aureus–related nephritis rose to 30%, and hepatitis C virus–associated glomerulonephritis also increased.
Post-streptococcal glomerulonephritis remains much more prevalent in regions such as the Caribbean, Africa, India, Pakistan, Papua New Guinea, South America, and Malaysia. In Port Harcourt, Nigeria, acute glomerulonephritis in the pediatric age group 3-16 years was 15.5 cases/year, with a male-to-female ratio of 1.1:1; it is not much different currently. An Ethiopian study from a regional dialysis center found that acute glomerulonephritis was the second commonest cause of acute kidney failure requiring dialysis, comprising about 22% of cases. Age-, Gender-, and Race-related Demographics
Acute nephritis can be seen at any age, including infancy. Post-streptococcal glomerulonephritis usually develops in the pediatric population aged 5-15 years. Only 10% of cases occur in patients 40 years old or above. Outbreaks are common in children between 6 and 10 years old.
Acute glomerulonephritis affects males more than females with a male-to-female ratio of 2 to 1. Postinfectious glomerulonephritis has no predilection for racial or ethnic groups.
The underlying pathogenetic mechanism common to all of these different varieties of glomerulonephritis (GN) is immune-mediated, in which both humoral as well as cell-mediated pathways are active. The consequent inflammatory response, in many cases, paves the way for fibrotic events that follow.
The targets of immune-mediated damage vary according to the type of GN. For instance, glomerulonephritis associated with staphylococcus shows deposits of IgA and C3 complement.
One of the targets is the glomerular basement membrane itself or some antigen trapped within it, as in post-streptococcal disease. Such antigen-antibody reactions can be systemic with glomerulonephritis occurring as one of the components of the disease process, such as in systemic lupus erythematosus (SLE) or IgA nephropathy. On the other hand, in small vessel vasculitis; instead of antigen-antibody reaction, cell-mediated immune reactions are the main culprit. Here, T lymphocytes and macrophages flood the glomeruli with resultant damage.
These initiating events lead to the activation of common inflammatory pathways, i.e., the complement system and coagulation cascade. The generation of pro-inflammatory cytokines and complement products, in turn, results in the proliferation of glomerular cells.
Cytokines such as platelet-derived growth factor (PDGF) are also released, ultimately causing glomerulosclerosis. This event is seen in those situations where the antigen is present for longer periods of time, for example, in hepatitis C viral infection.
When the antigen is rapidly cleared as in post-streptococcal GN, the resolution of inflammation is more likely.
Structurally, cellular proliferation causes an increase in the cellularity of the glomerular tuft due to the excess of endothelial, mesangial,and epithelial cells. The proliferation may be of two types:
Endocapillary - within the glomerular capillary tufts
Extracapillary - in the Bowman space including the epithelial cells
In extracapillary proliferation, parietal epithelial cells proliferate to cause the formation of crescents which is characteristic of some forms of rapidly progressive glomerulonephritis.
Thickening of glomerular basement membrane appears as thickened capillary walls on light microscopy. However, on electron microscopy, this may look like a consequence of thickening of basement membrane proper, for instance, diabetes or electron-dense deposits either on the epithelial or endothelial side of the basement membrane. There can be various types of electron-dense deposits, corresponding to an area of immune complex deposition, such as subendothelial, subepithelial, intramembranous, and mesangial. (See the images below)
Features of irreversible injury include hyalinization or sclerosis that can be focal, diffuse, segmental, or global.
Functional Changes Functional changes include the following:
Reduction in creatinine clearance, oliguria, or anuria
Active urine sediments, such as RBCs and RBC casts
This leads to intravascular volume expansion, edema, and systemic hypertension.
Diffuse endocapillary proliferative changes are usually seen. The most common histological patterns observed in the descending order of prevalence are diffuse, focal, and mesangial proliferative glomerulonephritis. Of the different histopathological patterns, one of the following may be seen.
Under light microscopy, a glomerular morphology that is within the normal limits; while a loss of foot processes on electron microscopy (EM).
Hypercellular glomeruli resulting from increased mesangial, endothelial, or parietal epithelial cells population; acute and chronic white blood cells may also be seen in diffuse proliferative glomerulonephritis (GN) while in crescentic GN, crescents made up of leukocytes and epithelial cells may be present.
Basement membrane thickening, a feature highlighted by Periodic acid–Schiff (PAS) stain and electron microscopy. EM will demonstrate electron-dense deposits of immune complexes in or adjacent to the basement membrane. The most common pattern of these deposits is sub-epithelial.
Sclerosis of glomeruli, the end result of glomerular damage from various causes.
History and Physical
It is imperative to obtain a thorough history focusing on the identification of some underlying cause, such as systemic disease or recent infection. Mostly, the patient with acute glomerulonephritis is from the pediatric age group, aged 2-14 years, who acutely develops periorbital puffiness and facial swelling on the background of a poststreptococcal infection. The urine is usually dark, frothy, or scanty, and the blood pressure may be high. Nonspecific symptoms include generalized weakness, fever, abdominal discomfort, and malaise.
With acute glomerulonephritis associated with staphylococcal infection, the patient is more likely to be a middle-aged man or older, often with a diagnosis of diabetes mellitus. The onset may be concurrent with the infection, such as pneumonia, endocarditis, or osteomyelitis; or a skin infection from methicillin-resistant Staphylococcus aureus. Often, hematuria is present.
History should be taken about the onset and duration of the disease. Symptom onset is often abrupt. In acute postinfectious GN, there is usually a latent period of up to three weeks before clinical presentation. However, the latent period varies; it is typically one to two weeks for the cases that occur after a pharyngeal infection and two to four weeks where postdermal infection, such as pyoderma is the cause. If nephritis occurs within one to four days of streptococcal infection it usually means preexisting kidney disease.
Identifying a possible etiologic agent is important. Recent fever, sore throat, arthralgias, hepatitis, valve replacement, travel, or intravenous drug use may be associated. Assessing the outcomes of the disease process is also crucial, such as loss of appetite, pruritis, tiredness, nausea, facial swelling, peripheral edema, and dyspnea.
As the glomerular filtration rate (GFR) is decreased, symptoms like edema and hypertension occur, majorly due to the subsequent salt and water retention caused by the activation of the renin-angiotensin-aldosterone system.
A) Some symptoms occur primarily and include:
Edema (peripheral or peri-orbital) - initially in the dependent areas/areas with low tissue tension
Patients often have an unremarkable physical examination, however, they may present with a triad of edema, hypertension, and oliguria.
The provider should look for the following signs of excess fluid in the body:
Periorbital and/or peripheral edema
High blood pressure
Fine inspiratory crackles due to pulmonary edema
Raised jugular venous pressure
Ascites and pleural effusion
Other signs to look for include the following:
Vasculitic rash (as with Henoch-Schönlein purpura, or lupus nephritis)
Renal angle fullness or tenderness
Abnormal neurologic examination or altered sensorium
Following investigations guide not only in the determination of the potential cause but also in the assessment of the extent of the damage:
Complete blood count - A decreased hematocrit may suggest a dilutional type of anemia. In the background of an infectious cause, pleocytosis may be apparent.
Serum electrolytes - Potassium levels may be raised in patients with severe renal impairment.
Renal function tests - BUN and creatinine levels are raised, demonstrating a degree of renal impairment. The glomerular filtration rate (GFR) may be low.
Liver function tests - May point towards the underlying etiology.
C-reactive protein (CRP)
Complement (C3, C4 levels) - Differentiation may allow the provider to narrow the differentials. Low complement levels indicate the following diseases: cryoglobulinemia, systemic lupus erythematosus, infective (bacterial) endocarditis, and shunt nephritis. Certain renal diseases, such as membranoproliferative GN or poststreptococcal GN may also be considered. Normal complement levels suggest an underlying abscess, polyarteritis nodosa, Henoch-Schönlein purpura, Goodpasture syndrome, idiopathic rapidly progressive GN, immune complex disease, and immunoglobulin G or immunoglobulin A nephropathy. Chauvet et al reported that in patients with new-onset nephritis and low C3 levels anti-factor B autoantibodies may help in distinguishing new-onset poststreptococcal GN from hypocomplementemic C3 glomerulonephritis.
Autoantibodies [ANA, ANCA, anti-ds-DNA, anti-Glomerular basement membrane (GBM)] to outrule collagenopathy as the underlying cause of GN.
Blood culture - Blood culture is indicated when there is fever, immunosuppression, intravenous drug abuse, indwelling catheters, or shunts.
Antistreptolysin O titer (ASOT) - It increases in 60-80% of cases. The rise begins in one to three weeks, peaks in three to five weeks, and returns to baseline in six months. It is unrelated to the severity, duration, and prognosis of renal disease.
The urine is usually dark and the specific gravity is more than 1.020 with RBCs and RBC casts. The 24-hour urinary protein excretion and creatinine clearance may be helpful in establishing the degree of renal impairment and proteinuria. The following parameters are usually helpful:
Microscopy, culture, and sensitivity
Bence Jones protein
Albumin: creatinine/protein: creatinine
Chest X-ray (helps to see for evidence of pulmonary hemorrhage, if any)
Renal ultrasound (helps in assessing the size and anatomy for biopsy)
The examination of glomerular lesions via a renal biopsy provides the diagnosis of glomerulonephritis by answering the following queries:
Approximate proportion of involved glomeruli (focal vs. diffuse)
Approximate involvement of each glomerulus (segmental vs. global)
Presence of hypercellularity
Any evident sclerosis
Any deposits on immunohistology (immunoglobulins, light chains, complement)
Electron microscopy findings - precise localization of deposits. Exact ultrastructural appearance. Podocyte appearance
Presence of tubulointerstitial inflammation, atrophy, or fibrosis
In addition to establishing the etiology, the biopsy also helps determine the severity of the disease. It may also reveal other lesions that could possibly be related to the GN.
Treatment / Management
Secondary glomerular diseases associated with a systemic disease, mostly resolve with the management of the underlying cause. Primary glomerulonephritis is managed supportively, and by specific disease-modifying therapy. The outcome mainly depends on the timely intervention, which, if not done, may lead to a progressive sequence of events causing glomerulonephritis to develop into chronic kidney disease (increasing the risk for simultaneous development of cardiovascular disease), the sequence finally culminates into end-stage renal disease (ESRD).
The management of glomerulonephritis broadly follows two modalities.
A) Specific management revolves around immunosuppression, which in turn is governed by factors like:
The available options include:
Rituximab (a monoclonal antibody that causes the lysis of B-lymphocytes)
Cytotoxic agents (e.g., cyclophosphamide, along with glucocorticoids are of value in severe cases of post-streptococcal glomerulonephritis)
Plasma exchange (glomerular proliferative nephritis, pauci-immune glomerulonephritis – used temporarily till chemotherapy takes effect)
B) With progression into chronicity, general management is done on the lines of chronic kidney disease:
By keeping track of the renal function tests (RFTs), serum albumin, and urine protein excretion rate.
By controlling the BP and inhibiting the renin-angiotensin axis, through Loop diuretics, which serve two purposes; the removal of excess fluid and also the correction of hypertension.
For individuals with severe/refractory hypertension with/without encephalopathy, vasodilators (e.g., nitroprusside, nifedipine) can be used.
By managing the complications associated with progressive chronic disease, including anemia, bone mineral disorders, acidosis, cardiovascular disease, restless legs/cramps.
Appropriate counseling regarding diet.
Preparation for renal replacement therapy (RRT), if needed.
IgA nephropathy: ACE inhibitors/ARBs (3-6 months) are used as they reduce proteinuria. Corticosteroids and fish oil can be prescribed if proteinuria exceeds 1 gm (provided GFR>50) even after the initial therapy. Henoch Schonlein purpura (HSP) is managed on the same lines. Steroids are helpful for gastrointestinal tract (GIT) related symptoms here, too.
Post Streptococcal GN: Supportive treatment and antibiotics to get rid of nephritogenic bacteria.
Anti-GBM Disease: The available options include plasma exchange, corticosteroids, and cyclophosphamide.
Rapidly progressive glomerulonephritis (RPGN): RPGN is treated with corticosteroids and cyclophosphamide.
Plasma exchange is used for anti-GBM/ANCA vasculitis.
For lupus nephritis, monoclonal antibodies are effective.
Minimal change disease: Prednisolone 1 mg/kg (4 to 16 weeks). If relapsing, immunosuppression with greater intensity or for longer durations can be used. Cyclophosphamide and calcineurin inhibitors are effective options.
Focal segmental glomerulosclerosis: Treatment is done initially with ACE inhibitors/ARBs and by controlling BP. Calcineurin inhibitors are 2nd line. Plasma exchange and rituximab are helpful for recurrence in transplants. For primary (idiopathic) disease, corticosteroids should be used.
Membranoproliferative GN: Treatment is done initially with ACE inhibitors/ARBs and by controlling BP. Immunosuppression is useful if no underlying cause is found. Work is currently ongoing to block or modify C3 activation.
Based on the clinical presentation, differentiation needs to be drawn between the nephrotic or the nephritic spectrum. This is important as it helps to narrow down the differentials of the underlying glomerular pathology.
Also, depending on the age group and clinical picture, differential diagnoses will include primary versus secondary causes.
Primary glomerulonephritis presenting as the nephrotic syndrome in young patients is likely to be minimal change disease, while in adults, membranous variety is more likely. In the secondary category, diabetes mellitus has to be ruled out.
When the nephritic syndrome is the main presentation, in children, it is likely to be post-streptococcal. In adults, however, IgA nephropathy should be considered.
When systemic vasculitis involves glomeruli, the cause in the younger age group is Henoch Schonlein purpura, while in adults, granulomatosis with polyangiitis should be suspected.
Lupus nephritis is seen more commonly in young women (20 to 30 years).
Following are some important differentials to be considered while making the diagnosis of glomerulonephritis:
Acute kidney injury
Diffuse proliferative glomerulonephritis
Focal segmental glomerulonephritis
Glomerulonephritis associated with nonstreptococcal infection
Rapidly progressive glomerulonephritis
The following renal syndromes frequently mimic the early stages of acute GN:
Chronic GN with an acute exacerbation
Anaphylactoid purpura with nephritis
Among the Nephritic Spectrum Diseases
Recovery is likely in children with post-streptococcal glomerulonephritis, while adults have a greater tendency to develop rapidly progressive glomerulonephritis (RPGN) and chronic kidney disease (CKD).
IgA nephropathy can lead to three possible outcomes; spontaneous clinical remission in a third of patients, end-stage renal disease (ESRD), in 20 to 40% while the rest have a state of chronic microscopic hematuria.
Henoch Schonlein purpura (HSP) usually results in recovery, if the hematuria is microscopic and the proteinuria minimal. Those who have nephrotic syndrome would more likely develop CKD and, ultimately, ESRD. The simultaneous presence of both nephrotic and nephritic symptoms indicates a very poor prognosis.
With timely and avid treatment, pauci-immune GN usually remits (75% cases). But if left untreated, it carries a very poor prognosis.
Membranoproliferative glomerulonephritis progresses to ESRD inevitably, despite therapy. Also, the frequency of recurrence is high even after a kidney transplant.
Among the Nephrotic Spectrum Diseases
Minimal change disease rarely progresses to ESRD.
Approximately a third of patients with membranous nephropathy who have subnephrotic proteinuria, respond to conservative management. Spontaneous remission has also been seen in cases of heavy proteinuria. However, in others with features of nephrotic syndrome, remission may take up to 6 months, provided adequate treatment is given.
Appropriate treatment does slow the progression of HIV associated nephropathy, but with progression into ESRD, a kidney transplant may be needed.
Amyloid light-chain (AL) amyloidosis takes 2 to 3 years for progression towards ESRD, while for amyloid A (AA) amyloidosis, remission can be achieved by identifying and managing the underlying disease.
Glomerulonephritis may either lead to acute kidney injury (AKI) or may progress gradually to chronic renal failure. AKI is sometimes the initial presentation in rapidly progressive glomerulonephritis with crescent formation. Similarly, vasculitis and Goodpasture syndrome represent other conditions where AKI is associated with glomerulonephritis. Most cases, however, would show progression into chronic glomerulonephritis and eventually lead to CKD and ESRD, requiring the need for dialysis.
Deterrence and Patient Education
It is important to cut down salts from the diet during acute disease.
For progressive disease, dietary restrictions (2 g sodium, 2 g potassium, 40 to 60 g protein; a day) help to reduce the build-up of wastes and also prevent states of fluid overload.
Cessation of smoking is also paramount in decreasing the aggravation of the renal disease.
Education in countering diabetes and elevated blood pressures is also important, through adequate lifestyle modifications and standardized therapy. Patients must also be counseled regarding the control of hyperlipidemias.
Problems with respect to sexual health (e.g., loss of libido) usually can occur in kidney disease, especially in men. Hence, appropriate guidance regarding the same should be provided to the patient.
Patients with nephrotic syndrome and especially those with progression into chronic kidney disease (CKD) are vulnerable to infections, so a seasonal flu vaccine and pneumococcal vaccines are of help for them.
Enhancing Healthcare Team Outcomes
In most instances, the disease follows a progressive course, and the patients often have associated co-morbidities, so the involvement of multiple disciplines and interprofessional communication is of prime importance. While the nephrologist is almost always involved in the treatment of patients with glomerulonephritis, the role of a physician cannot be undermined, considering the fact that the patients usually have other diseases simultaneously. Patients presenting in the outpatient departments with proteinuria/hematuria or both would need further evaluation.
A renal biopsy following the initial laboratory and radiological investigations may be needed to reach a diagnosis. This requires a collective approach involving histopathologists, immunologists, radiologists, and at times, the surgeons. Nurses are important in dispensing appropriate treatment and also assist with the education of the patient and family. Patients with chronic disease need assessment of renal function at regular intervals, so linking up with a local community doctor is important. Those with markedly decreased renal function require dialysis with appropriate scheduling, and so, interacting with the dialysis unit is pivotal. All in all, to improve outcomes, prompt consultation with specialists is recommended, and timely interprofessional communication is imperative to ensure quality health care.
(Click Image to Enlarge)
Fig. 1a (PAS x400) and 1b (Jones methenamine silver x400): Hyperlobulated glomeruli showing mesangial and segmental endocapillary hypercellularity, mesangial matrix expansion, and segmental duplication of basement membranes with mesangial cell interposition. Some peripheral capillary loops appear "wire loop“-like.
Contributed by Agnes Colanta, MD
(Click Image to Enlarge)
Fig. 1c (FITC x400) Immunofluorescence microscopy showing segmental granular IgG staining. C3 and C1q showed similar staining. 1d: Ultrastructural examination showing thickened glomerular basement membranes with subendothelial and subepithelial electron-dense deposits consistent with immune complexes within peripheral loops, and diffuse foot process effacement.
Contributed by Agnes Colanta, MD
(Click Image to Enlarge)
Image courtesy S Bhimji MD
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