Nephrotic Syndrome and the Risk of Blood Clots: What You Need to Know

Nephrotic syndrome is a serious kidney disorder that can lead to several life-threatening complications, one of the most concerning being thrombosis. While many are aware of symptoms like swelling and protein in the urine, fewer understand the increased risk of blood clot formation associated with this condition. In fact, thrombotic events—especially venous thromboembolism—are significantly more common in patients with nephrotic syndrome compared to the general population.

Why Does Nephrotic Syndrome Increase the Risk of Blood Clots?

The development of a hypercoagulable (high-clotting) state in nephrotic syndrome is multifactorial. Patients often present with hypoalbuminemia (low blood albumin levels), typically below 25 g/L, and hyperlipidemia (elevated blood lipids). These imbalances trigger changes in blood composition that promote clotting. The liver compensates for low protein levels by increasing the production of clotting factors, while natural anticoagulant proteins like antithrombin are lost through urine. This imbalance creates the perfect environment for thrombosis.

Additionally, platelet hyperactivity and reduced fibrinolysis further contribute to the heightened risk. As a result, even minor circulatory stasis can lead to dangerous clot formation.

Common Sites of Thrombosis in Nephrotic Syndrome

Renal Vein Thrombosis

The most frequently observed thrombotic complication is renal vein thrombosis. It occurs when a clot forms in the vein that drains blood from the kidney. Symptoms may include flank pain, worsening proteinuria, decreased kidney function, or even sudden hypertension. However, some cases are asymptomatic and detected only through imaging studies.

Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE)

Beyond the kidneys, patients are also at increased risk for deep vein thrombosis, particularly in the legs. If left untreated, these clots can dislodge and travel to the lungs, causing a potentially fatal pulmonary embolism. Early recognition and preventive strategies are crucial in high-risk individuals.

Arterial Thrombosis

Although less common than venous events, arterial thrombosis—including stroke and myocardial infarction—can also occur, especially in patients with additional cardiovascular risk factors.

Preventive and Therapeutic Approaches

When serum albumin drops below 25 g/L, many clinicians recommend prophylactic anticoagulation therapy. Low molecular weight heparin (LMWH) is the most commonly used agent due to its predictable dosing, safety profile, and effectiveness in reducing clot formation.

In addition to anticoagulation, managing the underlying cause of nephrotic syndrome is essential. This includes treating primary conditions such as minimal change disease, membranous nephropathy, or diabetic nephropathy. Addressing hypoalbuminemia and hyperlipidemia through medication, dietary adjustments, and immunosuppressive therapies (when appropriate) can significantly reduce the long-term risk of thrombotic complications.

Monitoring and Long-Term Management

Patients diagnosed with nephrotic syndrome should undergo regular monitoring of coagulation markers, albumin levels, and kidney function. Individualized treatment plans, including decisions on anticoagulant duration, should be made in consultation with a nephrologist or hematologist.

Lifestyle modifications—such as maintaining hydration, avoiding prolonged immobility, and adopting a heart-healthy diet—also play a supportive role in minimizing clot risk. With comprehensive care, many patients can achieve remission of their nephrotic syndrome and avoid severe complications like thrombosis.