Unit 4 - Edema Flashcards
what is edema defined as?
palpable swelling produced by expansion of interstitial fluid volume
-can be diffuse or localized
when does edema become clinically apparent?
not until interstitial volume has increased by at least 2.5 to 3 L
what is the pathophysiology of edema formation?
2 basic steps
- alteration in capillary hemodynamics favoring movement of fluid from vascular space into interstitium
- retention of dietary or intravenously-administered Na and water by kidneys
why doesn’t hemoconcentration and shock occur in edema?
some of the fluid stays in vascular space instead of going to interstitium, helping to return plasma volume toward normal
- change in capillary hemodynamics results in most of retained fluid to return to interstitium –> edema
- thus the net effect is appropriate expansion of total EC volume (as edema) with maintenance of plasma volume closer to normal levels, to restore tissue perfusion
what are the possible causes of edema?
- increased capillary hydraulic pressure
- decreased plasma oncotic pressure
- increased capillary permeability
- lymphatic obstruction (lymphedema)
- myxedema
what occurs in increased capillary hydraulic pressure?
increased venous pressure by blood volume expansion
- -heart failure (CHF)
- -renal disease
- -cirrhosis
- -pregnancy
- -constriction/restriction
- -venous obstruction
what occurs in decreased plasma oncotic pressure?
- hypoalbuminemia, malnutrition/malabsorption
- nephrotic syndrome
- decreased hepatic albumin synthesis (liver failure)
what occurs in increased capillary permeability?
- burns
- ARDS w/ sepsis-induced cytokine release increases pulmonary capillary permeability
- malnutrition
- angioedema
what occurs in myxedema?
hypothyroidism
- accumulation of interstitial albumin
- low lymphatic flow
what are compensatory factors to prevent edema?
- lymphatic flow and contractility increase with tissue edema and remove excess filtrate
- fluid entry into interstitium
- -raises interstitial hydraulic pressure, reducing pressure gradient that favors filtration
- -lowers interstitial oncotic pressure, by dilution and lymphatic mediated removal of interstitial proteins
what are the most common causes of generalized edema?
- heart failure
- cirrhosis
- nephrotic syndrome and other renal diseases
- premenstrual edema and pregnancy
- anemia
what is pertinent history if there is peripheral edema?
- right-sided heart failure
- pericardial disease
- renal disease (malaise, nausea, weight loss)
- local venous or lymphatic disease
what is pertinent history if there is ascites?
- cirrhosis
- weight gain
- increased abdominal girth
- gynecomastia
- spider angiomata/telangiectasia
what is intermittent edema commonly caused by?
premenstrual symptom
what history should you be aware of for all edema?
- any disorder (CAD, HTN, alcohol abuse)
- medications that can cause cardiac, hepatic, renal disease
what should you look for on cardiovascular exam with edema?
- heart rate
- diaphoresis
- S3 gallop
- heart murmurs
- cardiac rub
- JVD
what should you look for on pulmonary exam with edema?
crackles and wheezing
what should you look for on abdominal exam with edema?
- ascites (shifting dullness, fluid wave)
- hepatojugular reflex (press on liver of people with early right-sided failure; the column of JVD goes up)
- cirrhosis
- signs of protal HTN
- splenomegaly
- masses
- asterixis
- palmar erythema or Papal sign
what is nonpitting pedal edema diagnostic of?
- lymphatic obstruction
- lymphedema
- pretibial myxedema
what does localized edema look like?
- angioedema
- urticaria
- cellulitis
- erysipelas (localized rash due to infection in superficial lymph or dermis)
what does entire limb edema look like?
- acute unilateral limb edema (perform duplex US)
- if DVT: give anticoagulant
- if no DVT: consider cellulitis, obstruction from neoplasm, radiation, lymphedema
what should you order for edema?
- CBC
- CMP (complete metabolic panel)
- -electrolytes
- -renal/liver function tests
- -urinalysis
- -oximetry
- CXR
- EKG and echo
if there is no active cardiac, hepatic, or renal disease or anemia found in generalized/bilateral edema, what should you look for and do?
- venous insufficiency –> leg elevation and compression stockings
- medication –> stop Rx
if there IS active cardiac, hepatic, or renal disease or anemia found in generalized/bilateral edema, what should you look for and do?
- establish cause, if not known
- start/increase diuretics
- begin cause-specific treatment
what is treatment for edema?
- reversal of the underlying disorder (if possible)
- dietary sodium restriction (to minimize fluid retention)
- compression stockings
- diuretic therapy and other medications (if needed)
what is the only indication for immediate/urgent treatment of edema?
left-sided CHF and pulmonary edema
-otherwise do it slowly to avoid hemodynamic collapse or exacerbation of other medical problems
