What are nephrotic syndrome and nephritic syndrome?

From the Guidelines

Nephrotic syndrome is characterized by massive protein loss in urine, low blood albumin levels, high cholesterol, and swelling, while nephritic syndrome presents with blood in urine, reduced urine output, hypertension, and kidney dysfunction. Nephrotic syndrome is typically defined by proteinuria exceeding 3.5g/day, hypoalbuminemia, hyperlipidemia, and edema, particularly in the legs and around the eyes, with common causes including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, and diabetic nephropathy 1. Some key characteristics of nephrotic syndrome include:

• Massive protein loss in urine (proteinuria exceeding 3.5g/day)
• Low blood albumin levels (hypoalbuminemia)
• High cholesterol (hyperlipidemia)
• Swelling (edema), particularly in the legs and around the eyes On the other hand, nephritic syndrome is often caused by post-streptococcal glomerulonephritis, IgA nephropathy, lupus nephritis, or vasculitis, and presents with:
• Blood in urine (hematuria)
• Reduced urine output
• Hypertension
• Varying degrees of kidney dysfunction Treatment for nephrotic syndrome typically involves corticosteroids like prednisone, ACE inhibitors or ARBs to reduce proteinuria, diuretics for edema, and statins for hyperlipidemia, while treatment for nephritic syndrome depends on the underlying cause but may include antibiotics for infections, immunosuppressants for autoimmune causes, and blood pressure management 1. It's worth noting that both syndromes result from damage to the glomeruli, but nephrotic primarily affects the podocytes causing protein leakage, while nephritic involves inflammation of the glomeruli leading to filtration barrier breakdown and red blood cell leakage. Some important considerations in the management of these syndromes include:
• The risk of other complications of the nephrotic syndrome, including loss of renal function while waiting, must be weighed against early start of immunosuppressive therapy and the risks that all of our current options have in terms of adverse effects 1
• The original rule of thirds with regard to outcome still applies: 1/3 will have spontaneous remission, 1/3 will have persistent proteinuria, and 1/3 will progress slowly to renal failure 1

From the FDA Drug Label

To induce a diuresis or remission of proteinuria in the nephrotic syndrome, without uremia, of the idiopathic type or that due to lupus erythematosus

• Nephrotic syndrome is characterized by the presence of proteinuria (excess protein in the urine), which can lead to a diuresis (increased urine production) or remission.
• The exact definition of nephritic syndrome is not provided in the drug label.
• Based on the information provided, it can be inferred that nephrotic syndrome is a condition that can be treated with prednisone to induce a diuresis or remission of proteinuria.
• However, the drug label does not provide a direct definition or description of nephritic syndrome. 2

From the Research

Nephrotic Syndrome

• Nephrotic syndrome is defined by a triad of clinical features: oedema, substantial proteinuria (> 3.5 g/24 hours) and hypoalbuminaemia (< 30 g/L) 3
• It is often associated with hyperlipidaemia, thromboembolism and an increased risk of infection 3
• The most common cause in children is minimal change glomerulonephritis, while in white adults, it is most frequently due to membranous nephropathy 3
• Diabetic nephropathy is the most common multisystem disease that can cause nephrotic syndrome 3, 4
• Patients typically present with periorbital oedema or dependent pitting oedema, and proteinuria should be documented by a quantitative measurement 3

Nephritic Syndrome

• Nephritic syndrome is a constellation of hematuria, proteinuria, hypertension, and in some cases acute kidney injury and fluid retention characteristic of acute glomerulonephritis 5
• The most common diseases in nephritic syndrome include infection-related glomerulonephritis, IgA nephropathy, lupus nephritis, membranoproliferative glomerulonephritis, and antineutrophil cytoplasmic antibody-associated vasculitis 5
• Nephritic syndrome is associated with hematuria and proteinuria and abnormal kidney function and carries a poorer prognosis, typically associated with hypertension 6
• The predominant cause of the nephrotic syndrome in children is minimal change disease, while the most common causes of nephritic syndrome are post infectious GN, IgA nephropathy and lupus nephritis 6