Nephritic Syndrome

Nephritic syndrome refers to the set of alterations and symptoms caused by inflammation of the renal glomeruli (glomerulonephritis). The glomeruli are the functional units of the kidney and consist of a network of blood capillaries surrounded by an external capsule. They are located in the nephron of the kidney and their function is to filter and cleanse blood plasma, the first stage of urine formation.

Inflammation of the glomeruli prevents proper blood filtration. This leads to a decrease in urine production, which causes nitrogenous substances, such as urea, to accumulate in the blood, and results in the retention of water and salts. The fluid retention, in turn, causes increased blood pressure and edema.

Depending on its development, nephritic syndrome can be:

• Acute nephritic syndrome: develops over a short period.
• Chronic nephritic syndrome: progresses gradually over time.

According to the origin of the syndrome, it can be:

• Primary: inflammation originates in the kidneys.
• Secondary: inflammation is due to an underlying condition.

Symptoms

The characteristic symptoms of nephritic syndrome are:

• Hematuria: blood in the urine.
• Oliguria: decreased urination.
• Edema: tissue inflammation due to fluid retention. It starts in the legs, feet, abdomen, arms, or hands and may extend to the face and eyelids.
• Hypertension.

Additionally, other symptoms may appear:

• General malaise and discomfort.
• Headaches.
• Nausea and vomiting.
• Cough with mucus or foamy material.
• Joint or muscle pain.
• Blurred vision.
• Appearance of bruises.
• Pain in the abdominal flank.
• Breathing difficulties.
• Drowsiness or confusion.

Causes

The causes of primary nephritic syndrome are conditions that damage the glomeruli, the most common of which include:

• Membranoproliferative glomerulonephritis.
• IgA nephropathy.
• Crescentic glomerulonephritis.

Secondary nephritic syndrome, on the other hand, can result from a wide range of disorders:

• Bacterial infections, typically in the skin or throat caused by streptococci (post-streptococcal glomerulonephritis, the most common cause of the syndrome, especially in children). It can also be another type of bacterial infection, such as endocarditis caused by staphylococci or pneumococci.
• Viral infections, such as chickenpox, measles, Epstein-Barr, hepatitis B and C, shingles, or Coxsackie virus.
• Parasitic infections, such as malaria or schistosomiasis.
• Autoimmune disorders, such as systemic lupus erythematosus, diabetes, or Goodpasture syndrome.
• Vasculitis, such as Wegener's granulomatosis, microscopic polyangiitis, Schönlein-Henoch purpura, or cryoglobulinemia.
• Hereditary glomerular disorders, such as Alport syndrome (hereditary nephritis) or thin basement membrane disease.
• Medications that cause kidney damage, such as hydralazine, interferon alpha, non-steroidal anti-inflammatory drugs, lithium, quinine, mitomycin C, or chemotherapy drugs.

Risk Factors

The risk of developing nephritic syndrome increases with the presence of infections or associated disorders and the use of medications that cause kidney damage.

Complications

Nephritic syndrome caused by post-streptococcal glomerulonephritis often leads to acute kidney failure, a sudden and rapidly progressing loss of kidney function that, if untreated, can be fatal. If glomerular inflammation persists for a long time, the resulting damage may progress to chronic kidney failure, which may require dialysis or even a kidney transplant.

In severe cases, fluid accumulation can affect the lungs and cause acute pulmonary edema, resulting in difficulty breathing, pulmonary hypertension, and heart failure.

Prevention

The following measures can help prevent nephritic syndrome:

• Protecting against infections through vaccination, hygiene, and safe sexual practices.
• Early treatment of infections.
• Avoiding the use of medications that cause kidney damage.

Which doctor treats nephritic syndrome?

Nephritic syndrome is diagnosed and treated by nephrology specialists.