Nephrotic Syndrome: Causes, Symptoms, Diagnosis, and Treatment Options

What is Nephrotic Syndrome?

Nephrotic syndrome is a kidney disorder that results in excessive protein loss in the urine due to damage to the kidney’s filtering units, known as glomeruli. Nephrotic syndrome is not a single disease but a syndrome characterized by a collection of symptoms and signs that occur together, potentially caused by various underlying diseases.
The primary feature of nephrotic syndrome is significant protein leakage from the kidneys. In healthy individuals, urine contains virtually no protein; however, in nephrotic syndrome, the urine contains large amounts of protein, a condition known as proteinuria.

The nephron, the functional unit of the kidney, is responsible for urine formation and waste removal from the blood. The glomerulus, a tuft of capillaries within the nephron, plays a crucial role in filtering blood. Damage to the glomerulus leads to glomerulonephropathies, which can be categorized into nephrotic and nephritic syndromes.In nephrotic syndrome, the filtration barrier at the glomerular basement membrane is compromised, resulting in protein leakage into the urine.

Features of Nephrotic Syndrome

• Proteinuria:Abnormally high levels of protein in the urine due to increased permeability of the glomerular filtration barrier.
• Hypoalbuminemia:A significant decrease in albumin levels in the blood as a result of protein loss.
• Edema:Swelling in various parts of the body, especially around the eyes, feet, and hands, due to fluid retention.
• Hyperlipidemia:Elevated levels of lipids (fats) and cholesterol in the blood, often as a compensatory response to low protein levels.

Nephrotic syndrome is primarily linked to damage to the kidneys’ filtering system, allowing proteins, especially albumin, to escape into the urine. The loss of protein can lead to swelling in body tissues due to fluid accumulation and increases the risk of infections.

Risk factors for Nephrotic Syndrome

Certain risk factors can also increase your risk of developing nephrotic syndrome. This includes:

• Having diabetesor lupus
• Chronic NSAID usage
• Genetic mutations
• Taking certain anticancer medications
• Illicit drugs such as heroin and cocaine increases risk
• Having infections such as HIV, hepatitis, and malaria

Types and Causes of Nephrotic Syndrome

Nephrotic syndrome is classified based on its underlying causes, which is essential for diagnosis, treatment, and prognosis. The two main categories are primary and secondary nephrotic syndrome. It occurs due to damage to the glomeruli, the small blood vessels in the kidneys responsible for filtering waste and excess water. When these glomeruli are damaged, excessive protein leaks into the urine, resulting in nephrotic syndrome. The causes are divided into primary and secondary types.

Primary Causes of Nephrotic Syndrome

Primary nephrotic syndrome occurs when the disease originates in the kidneys without an underlying systemic condition. Common primary causes include:

• Minimal Change Disease (MCD):A leading cause of nephrotic syndrome in children, MCD is characterized by glomerular damage that is only visible under an electron microscope. The exact cause is unknown, but it is thought to be related to immune system dysfunction
• Focal Segmental Glomerulosclerosis (FSGS):This condition involves scarring in sections of the glomeruli, which can lead to kidney failure over time. The cause may be genetic, idiopathic, or related to other kidney stressors
• Membranous Nephropathy:This disorder is caused by immune system attacks on the glomerular basement membrane, leading to thickening and protein leakage. It is a common cause of nephrotic syndrome in adults

Secondary Causes of Nephrotic Syndrome

Secondary nephrotic syndrome results from underlying systemic conditions or external factors that affect kidney function. Common secondary causes include:

• Diabetic Nephropathy:The most frequent cause of nephrotic syndrome in adults, it results from prolonged high blood sugarlevels that damage the kidney’s filtering system
• Lupus Nephritis:A complication of systemic lupus erythematosus (SLE), this autoimmune disorder causes inflammation and kidney damage
• Amyloidosis:This condition leads to abnormal protein deposits (amyloid) in the kidneys, disrupting their function and causing proteinuria
• Infections:Chronic infections such as hepatitis B, hepatitis C, and HIV can damage the glomeruli and contribute to nephrotic syndrome
• Medications and Toxins:Certain drugs, including NSAIDs, antibiotics, and exposure to heavy metals, can induce nephrotic syndrome by affecting kidney function

Pathophysiology of Nephrotic Syndrome

Nephrotic syndrome occurs when the glomerular filtration barrier is compromised, allowing large proteins such as albumin to leak into the urine. This protein loss leads to a drop in plasma oncotic pressure, causing fluid to shift from the bloodstream into tissues, resulting in edema. The liver responds by increasing the production of lipids, leading to hyperlipidemia. Additionally, the loss of proteins involved in blood clotting and immune function can increase the risk of thrombosis and infections.

Signs & Symptoms of Nephrotic Syndrome

Symptoms of nephrotic syndrome include:

• Foamy and frothy urine
• Unexplained weight loss
• High blood pressure
• General malaise
• Edema particularly around the abdomen, legs and eyes
• Muscle wasting
• Stomach pain
• Orthostatic hypotension – feeling dizzy when standing or siting
• Fatigue
• Swelling in the feet and hands, and around the eyes
• Weight gain with fluid retention and swelling
• Fever
• Albuminuria greater than 3.5 grams
• Hyperlipidemia
• Hypoalbuminemia
• Loss of appetite

Diagnostic Test & Investigations

Nephrotic syndrome is diagnosed through a combination of clinical evaluation, laboratory tests, and imaging studies.

• History taking
• Physical examination
• Serological Tests
• Ultrasound
• CT Scan or MRI
• Kidney Biopsy
• Urinalysis
• Blood Tests: Blood tests measure albumin levels (hypoalbuminemia), cholesterol levels (hyperlipidemia), and kidney function markers such as creatinine and blood urea nitrogen (BUN)

Treatment of Nephrotic Syndrome

Treatment of nephrotic syndrome focuses on managing symptoms, treating the underlying cause, and preventing complications. The approach varies based on the patient's age, overall health, and severity of the condition.

Medications

Various medications are used to address nephrotic syndrome:

• ACE Inhibitors and Angiotensin Receptor Blockers (ARBs)
• Corticosteroids
• Cholesterol-Lowering Medications - Statins
• Anticoagulants
• Antibiotics or Antiviral Medications
• Diuretics: These medications help eliminate excess fluid through urine, reducing swelling (edema). They must be used cautiously to prevent dehydration and electrolyte imbalances.
• Immune System Modifiers: Immunosuppressive drugs such as cyclophosphamide and calcineurin inhibitors help prevent the immune system from attacking the kidneys.
• Dialysis - In severe cases where kidney function is significantly impaired, dialysis may be required to remove excess fluid, waste products, and toxins from the blood. kidney function and improve quality of life.

Dietary Modifications

Nutritional adjustments play a key role in managing nephrotic syndrome:

• Reducing salt intake helps control fluid retention and minimize swelling
• Low-Fat Diet - Limiting saturated fats and cholesterol can help regulate elevated lipid levels.
• Balanced Caloric Intake
• Eating lean sources of protein such as chicken or fish
• Eating a balanced diet: To help control weight gain

Nursing Management of Nephrotic Syndrome

Here are key strategies to employ in the care of patients with Nephrotic Syndrome

• Monitor T P R and especially BP
• Monitor patient's weight
• Protect patient from infections
• 24-hour urine collection for analysis (protein)
• Give high class protein full diet (recommended 0.6 - 0.8g protein per day 1kg body weight) plus amount equivalent to daily loss
• Low salt diet
• Explain to patient and family the reasons for certain nutrient restrictions
• Fluid retention
• Encourage patient to follow drug regimen
• Encourage bed rest for few days to mobilise oedema
• Ensure ambulation to prevent risk of thrombo - embolism

Can nephrotic syndrome be prevented?

• Make sure your blood pressure is well controlled
• Control your blood sugar
• Finish all antibiotics as prescribed