Chapter 036. Edema (Part 5)

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This syndrome, which occurs almost exclusively in women, is characterized by periodic episodes of edema (unrelated to the menstrual cycle), frequently accompanied by abdominal distention. Diurnal alterations in weight occur with orthostatic retention of NaCl and H2O, so that the patient may weigh several pounds more after having been in the upright posture for several hours. Such large diurnal weight changes suggest an increase in capillary permeability that appears to fluctuate in severity and to be aggravated by hot weather. There is some evidence that a reduction in plasma volume occurs in this condition with secondary activation of the...

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Chapter 036. Edema (Part 5) Idiopathic Edema This syndrome, which occurs almost exclusively in women, is characterized by periodic episodes of edema (unrelated to the menstrual cycle), frequently accompanied by abdominal distention. Diurnal alterations in weight occur with orthostatic retention of NaCl and H2O, so that the patient may weigh several pounds more after having been in the upright posture for several hours. Such large diurnal weight changes suggest an increase in capillary permeability that appears to fluctuate in severity and to be aggravated by hot weather. There is some evidence that a reduction in plasma volume occurs in this condition with secondary activation of the RAA system and impaired suppression of AVP release.
Idiopathic edema should be distinguished from cyclical or premenstrual edema, in which the NaCl and H2O retention may be secondary to excessive estrogen stimulation. There are also some cases in which the edema appears to be diuretic-induced. It has been postulated that in these patients chronic diuretic administration leads to mild blood volume depletion, which causes chronic hyperreninemia and juxtaglomerular hyperplasia. Salt-retaining mechanisms appear to overcompensate for the direct effects of the diuretics. Acute withdrawal of diuretics can then leave the Na+-retaining forces unopposed, leading to fluid retention and edema. Decreased dopaminergic activity and reduced urinary kallikrein and kinin excretion have been reported in this condition and may also be of pathogenetic importance. Idiopathic Edema: Treatment The treatment of idiopathic cyclic edema includes a reduction in NaCl intake, rest in the supine position for several hours each day, and the wearing of elastic stockings (which should be put on before arising in the morning). A variety of pharmacologic agents, including angiotensin-converting enzyme inhibitors, progesterone, the dopamine receptor agonist bromocriptine, and the sympathomimetic amine dextroamphetamine, have all been reported to be useful when administered to patients who do not respond to simpler measures. Diuretics may be helpful initially but may lose their effectiveness with continuous administration; accordingly, they should be employed sparingly, if at all.
Discontinuation of diuretics paradoxically leads to diuresis in diuretic-induced edema, described above. Localized Edema (See also Chap. 243) Edema originating from inflammation or hypersensitivity is usually readily identified. Localized edema due to venous or lymphatic obstruction may be caused by thrombophlebitis, chronic lymphangitis, resection of regional lymph nodes, filariasis, etc. Lymphedema is particularly intractable because restriction of lymphatic flow results in increased protein concentration in the interstitial fluid, a circumstance that aggravates retention of fluid. Generalized Edema The differences among the three major causes of generalized edema are shown in Table 36-2. Table 36-2 Principal Causes of Generalized Edema: History, Physical Examination, and Laboratory Findings Organ History Physical Laboratory System Examination Findings
Cardiac Dyspnea Elevated Elevated urea with exertion jugular venousnitrogen-to-creatinine prominent—often pressure, ventricular ratio common; elevated associated with (S3) gallop;uric acid; serum sodium orthopnea—or occasionally withoften diminished; liver paroxysmal displaced orenzymes occasionally nocturnal dyspnea dyskinetic apicalelevated with hepatic pulse; peripheralcongestion cyanosis, cool extremities, small pulse pressure when severe Hepatic Dyspnea Frequently If severe, infrequent, except if associated withreductions in serum associated with ascites; jugular venousalbumin, cholesterol, significant degree of pressure normal orother hepatic proteins ascites; most often a low; blood pressure(transferrin, fibrinogen); history of ethanol lower than in renal orliver enzymes elevated,
abuse cardiac disease; one ordepending on the cause more additional signsand acuity of liver of chronic liverinjury; tendency toward disease (jaundice,hypokalemia, palmar erythema,respiratory alkalosis; Dupuytren's macrocytosis from contracture, spiderfolate deficiency angiomata, male gynecomastia; asterixis and other signs of encephalopathy) may be present Renal Usually Blood pressure Albuminuria, chronic: may be may be elevated;hypoalbuminemia; associated with hypertensive orsometimes, elevation of uremic signs and diabetic retinopathy inserum creatinine and symptoms, selected cases;urea nitrogen; including decreased nitrogenous fetor;hyperkalemia, metabolic appetite, alteredperiorbital edema mayacidosis,
(metallic or fishy) predominate; hyperphosphatemia, taste, altered sleeppericardial friction rub hypocalcemia, anemia pattern, difficultyin advanced cases(usually normocytic) concentrating, with uremia restless legs or myoclonus; dyspnea can be present, but generally less prominent than in heart failure Source: From Chertow. The great majority of patients with generalized edema suffer from advanced cardiac, renal, hepatic, or nutritional disorders. Consequently, the differential diagnosis of generalized edema should be directed toward identifying or excluding these several conditions.