A 45-year-old man comes to the emergency department complaining of dyspnea, fatigue, poor appetite, and weight gain over the past 2 weeks. His symptoms started with worsening shortness of breath with exertion. He has been waking up at night breathless for the past few days. He also finds it difficult to open his eyes in the morning due to facial edema. The patient has no other medical problems and takes no medications. His blood pressure is 200/120 mm Hg and pulse is 100/min. Physical examination shows anasarca with distended jugular veins while sitting upright. Lung auscultation shows bibasilar crackles. Urinalysis shows 1+ protein, no nitrite, trace leukocyte esterase, 50 red blood cells, red blood cell casts, and occasional neutrophils. Which of the following is the most likely mechanism of this patient's edema?

Question

A 45-year-old man comes to the emergency department complaining of dyspnea, fatigue, poor appetite, and weight gain over the past 2 weeks.  His symptoms started with worsening shortness of breath with exertion.  He has been waking up at night breathless for the past few days.  He also finds it difficult to open his eyes in the morning due to facial edema.  The patient has no other medical problems and takes no medications.  His blood pressure is 200/120 mm Hg and pulse is 100/min.  Physical examination shows anasarca with distended jugular veins while sitting upright.  Lung auscultation shows bibasilar crackles.  Urinalysis shows 1+ protein, no nitrite, trace leukocyte esterase, >50 red blood cells, red blood cell casts, and occasional neutrophils.  Which of the following is the most likely mechanism of this patient's edema?

Quizplus · Accepted Answer

11ec25c8_d4dc_f54a_bc81_e3225d33219c_MD0003_00 This patient's presentation (anasarca, pulmonary and facial edema, hypertension, and abnormal urinalysis with proteinuria and microscopic hematuria) suggests acute nephritic syndrome with fluid overload. The table summarizes the primary mechanisms of the most common causes of peripheral edema. Acute nephritic syndrome is primary glomerular damage due to causes such as poststreptococcal glomerulonephritis, IgA nephropathy, lupus nephritis, membranoproliferative glomerulonephritis, and rapidly progressive glomerulonephritis. Primary glomerular damage leads to decreased glomerular filtration rate with eventual development of significant volume overload (eg, pulmonary edema, distended neck veins, anasarca). Abnormal urinary sediment (red blood cells, red blood cell casts) and variable degrees of proteinuria are present on urinalysis. Serum creatinine can also be elevated. The increased volume also leads to hypertension. Significant proteinuria (3+) eventually leads to hypoalbuminemia, which further contributes to the edema. Decreased glomerular filtration rate is also the cause of edema in patients with end-stage renal disease. (Choice A) Pretibial myxedema is a localized nonpitting thickening and induration of the skin over the lower legs, pretibial area, or the dorsum of the feet in patients with Graves' disease. However, anasarca and abnormal urinalysis are usually not seen in patients with hyperthyroidism. (Choice B) Hypoalbuminemia is usually due to excessive albumin loss (eg, nephrotic syndrome, protein-losing enteropathy) or decreased albumin synthesis (eg, cirrhosis or severe malnutrition). It can cause significant peripheral edema but usually does not cause pulmonary edema. Alveolar capillaries have a higher permeability to albumin at baseline (reducing oncotic pressure difference) and greater lymphatic flow than skeletal muscle, protecting the lungs from edema. (Choice C) Cirrhosis can cause portal hypertension as the scarred liver limits blood flow through the sinusoidal network. Cirrhotic patients develop ascites and edema in the lower extremities due to increased venous pressure below the liver. However, the venous pressure above the hepatic veins (eg, jugular venous pressure) is usually reduced or normal. Pulmonary edema typically does not occur in patients with cirrhosis. (Choice E) Renal hypoperfusion can occur in heart failure (decreased cardiac output), which leads to increased renal sodium and water retention and edema. However, the urinalysis in patients with heart failure does not show red blood cells or casts, as seen in this patient. (Choice F) Right ventricular failure is usually due to underlying left heart failure or severe pulmonary disease. It usually manifests with elevated jugular venous pressure and peripheral edema. Patients with severe cases can also develop hepatosplenomegaly, ascites, and anasarca. However, abnormal urinalysis with hematuria would not be expected in patients with right heart failure. Educational objective: Nephritic glomerulonephritis usually presents with urinary sediment containing red blood cells, occasional white blood cells, and red cell or mixed cellular casts. Edema in these patients is due primarily to decreased glomerular filtration rate and retention of sodium and water by the kidneys. References: Acute glomerulonephritis (http://www.ncbi.nlm.nih.gov/pubmed/12743337)

A 45-Year-Old Man Comes to the Emergency Department Complaining of Dyspnea