What are the causes of anasarca?

Causes of Anasarca

Primary Etiologies

Anasarca results from severe fluid accumulation in the interstitial space, most commonly caused by cardiac, renal, or hepatic failure, though the underlying mechanism may involve either increased intravascular hydrostatic pressure, decreased plasma oncotic pressure, or both. 1

Cardiac Causes

• Acute and chronic heart failure is a leading cause of anasarca, resulting from sodium and water retention due to reduced cardiac output and neurohormonal activation of the renin-angiotensin-aldosterone system. 1
• End-stage congestive heart failure commonly presents with profound anasarca causing significant pain and discomfort, particularly affecting dependent areas and the scrotum in male patients. 2
• The fluid retention in heart failure reflects congestion from elevated filling pressures, though peripheral edema may not always correlate with intravascular volume status. 1

Renal Causes

• Nephrotic syndrome is characterized by severe proteinuria, hypoalbuminemia, and anasarca, representing the predominant clinical manifestation of renal amyloidosis. 3
• Approximately 70% of patients with AL amyloidosis develop renal involvement presenting with nephrotic syndrome, significant proteinuria, and anasarca. 3
• Renal failure from any cause can lead to anasarca through impaired sodium and water excretion, particularly when combined with hypoalbuminemia. 1

Hepatic Causes

• Liver cirrhosis produces anasarca through multiple mechanisms including decreased albumin synthesis (low plasma oncotic pressure), portal hypertension, and secondary hyperaldosteronism. 1
• Pre-existing edema of hepatic origin should be distinguished from cardiac-related fluid overload when assessing patients. 1

Hypoalbuminemia from Other Causes

• Severe malnutrition with low albumin levels significantly correlates with postoperative anasarca development, as measured by NRS 2002 scores. 4
• Protein-losing enteropathy, severe burns, or chronic inflammatory conditions can cause sufficient hypoalbuminemia to produce anasarca. 1

Secondary and Less Common Causes

Endocrine Disorders

• Chronic adrenocortical insufficiency can paradoxically cause anasarca when residual adrenal function and mineralocorticoid therapy combine with concomitant heart or liver failure. 5
• The iatrogenic component occurs when appropriate hormone replacement therapy interacts with coexisting medical conditions. 5

Inflammatory and Autoimmune Conditions

• Juvenile dermatomyositis rarely presents with anasarca as the initial manifestation, potentially triggered by parvovirus B19 infection, accompanied by profound muscle weakness and characteristic skin changes. 6
• Systemic vasculitides including granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis can cause renal involvement leading to anasarca. 1

Infectious Causes

• Sepsis and systemic inflammatory response syndrome can produce anasarca through increased vascular permeability and capillary leak, particularly in patients developing acute respiratory distress syndrome. 7
• Infective endocarditis may precipitate acute heart failure with subsequent anasarca development. 1

Venous and Vascular Disorders

• Chronic venous insufficiency produces localized lower extremity edema that must be distinguished from systemic causes of anasarca. 1
• Superior or inferior vena cava obstruction can cause regional anasarca in the distribution of the affected venous system. 1

Postoperative Anasarca

• Major abdominal surgery carries a 29.87% incidence of postoperative anasarca, with significant risk factors including age >60 years, elevated NRS 2002 scores, low albumin levels, and raised leukocyte counts. 4
• Postoperative anasarca predicts poor prognosis with higher Clavien-Dindo complication grades, including 41.67% mortality (grade V). 4
• Pedal edema serves as an early warning sign that may progress to generalized anasarca and multiple organ dysfunction if not recognized early. 4

Key Diagnostic Considerations

• An elevated jugular venous pressure improves the specificity of edema as a sign of cardiac congestion rather than other causes of fluid shifts. 1
• Blood urea nitrogen elevation disproportionate to creatinine may reflect either congestion with fluid retention or dehydration, requiring clinical context for interpretation. 1
• Natriuretic peptides (BNP, NT-proBNP) are secreted in response to volume and pressure overload, helping distinguish cardiac from non-cardiac causes of anasarca. 1

Common Pitfalls

• Anasarca may reflect extravascular volume shifts from low plasma oncotic pressure or high vascular permeability rather than elevated filling pressures, requiring assessment of multiple parameters including JVP. 1
• Body weight changes may not always reflect intravascular volume status, particularly in acute hypertensive heart failure where pulmonary congestion occurs without systemic volume overload. 1
• Pre-existing edema from non-cardiac causes (liver cirrhosis, venous insufficiency, renal failure, hypoalbuminemia) should be documented to avoid misattributing chronic edema to acute cardiac decompensation. 1