Cardinal Manifestation of Disease: EDEMA

Cardinal Manifestation of Disease:EDEMA Dr. Meg-angela Christi Amores

Water in the body • Total body water (TBW) • Compartments: • Intracellular Fluid - 75% • Extracellular Fluid (ECF) – 25% • Plasma 25% • Interstitial Fluid 75%

What is edema? • clinically apparent increase in the interstitial fluid volume • weight gain of several kilograms usually precedes overt manifestations of edema

Edema • Anasarca- gross, generalized edema • Ascites and hydrothorax -accumulation of excess fluid in the peritoneal and pleural cavities, respectively, and are considered to be special forms of edema

Pathogenesis • Starling Forces • regulate the disposition of fluid between these two components of the extracellular compartment • hydrostatic pressure within the vascular system and the colloid oncotic pressure in the interstitial fluid – promote movement out into interstitium

Starling Forces • πi – Interstitial Oncotic pressure • πc – capillary oncotic pressure • Pi – interstitial hydrostatic pressure • Pc – capillary hydrostatic pressure

Starling Forces • movement of water and diffusible solutes from the vascular space at the arteriolar end of the capillaries • Fluid is returned from the interstitial space into the vascular system at the venous end and lymphatics

Pathogenesis • Capillary Damage • damage to the capillary endothelium, which increases its permeability and permits the transfer of protein into the interstitial compartment • from drugs, viral or bacterial agents, and thermal or mechanical trauma • hypersensitivity reaction and is characteristic of immune injury • Usually Inflammatory edema

Pathogenesis • Reduction of Effective Arterial Volume • by a reduction of cardiac output and/or systemic vascular resistance • retention of salt and, therefore, of water, ultimately leading to edema • Renal Factors and RAA System • renal retention of Na+ is central • Diminished renal blood flow = renin release • Renin = release angiotensin I = angiotensin II • Angiotensin II - enhancing salt and water reabsorption

Pathogenesis • Others: • Argininine Vasopressin • Endothelin • Natriuretic peptides

Clinical Causes of Edema • Obstruction of Venous Drainage of a limb • Congestive Heart Failure • Nephrotic Syndrome and Hypoalbuminemia • Cirrhosis • Drug-induced Edema • Idiopathic Edema

Obstruction of Venous Return • hydrostatic pressure in the capillary bed upstream (proximal) to the obstruction increases • Alternative route may also be blocked (lymph) • there is trapping of fluid in the extremity • displacement of fluid into a limb occur at the expense of the blood volume in the remainder of the body = dec arterial blood volume - retention of NaCl and H2O

Congestive Heart Failure • accumulation of blood in the venous circulation due to: • impaired systolic emptying of the ventricle(s) • impairment of ventricular relaxation • Low cardiac output leads to: • a decrease in baroreflex-mediated inhibition of the vasomotor center activates renal vasoconstrictor nerves and the RAA system, causing Na+ and H2O retention

Nephrotic Syndrome • Proteinuria • Hypoalbuminemia • diminished colloid oncotic pressure due to losses of large quantities of protein into the urine • NaCl and H2O that are retained cannot be restrained within the vascular compartment • Impaired renal function contributes further to the formation of edema

Nephrotic Syndrome

Cirrhosis • hepatic venous outflow blockade • expands the blood volume and increases hepatic lymph formation • as a potent stimulus for renal Na+ retention • activation of the RAA system, of renal sympathetic nerves, and of other NaCl- and H2O-retaining mechanisms

Drug-Induced • Nonsteroidal anti-inflammatory drugs • Antihypertensive agents • Direct arterial/arteriolar vasodilators • Calcium channel antagonists • A -Adrenergic antagonists • Steroid hormones • Cyclosporine • Growth hormone

What caused the edema? • Ascites • jaundice, and spider angiomas • collateral venous channels • = CIRRHOSIS

What caused the edema? • Gallop rhythm • Dyspnea • basilar rales • Venous distention • Hepatomegaly • Cardiomegaly • = HEART FAILURE

What caused the edema? • Blood in urine • Proteinuria • Hypoalbuminemia • = NEPHROTIC SYNDROME

Distribution • thrombophlebitis, chronic lymphangitis, resection of regional lymph nodes, filariasis • =LOCALIZED • Heart failure, nephrotic syndrome, cirrhosis • =GENERALIZED

For the next meeting, read on Stroke Syndromes • Harrison’s Principles of Internal Medicine 17th edition

Cardinal Manifestation of Disease: EDEMA