Edema 水腫概論
目錄
為了不讓之前在醫學上的耕耘就此付諸東流，擬定了定期複習醫學 issue 寫成回顧概論文章的計畫。
Data source:
Pathophysiology
- Increased capillary hydraulic pressure 增加血液中淨水壓
- Hypoalbuminemia (ex: liver cirrhosis) 低血液白蛋白濃度
- Increased capillary permeability 微血管通透性增加，可能原因是一些細胞激素的種類增加
- Cytokine (ex: TNF, IL-1, IL-10, Prostaglanding) secretion
- Ex: 燙傷、發炎、感染、過敏
- Lymphatic obstruction lymphedema (ex: axillary dissection for breast cancer ) 淋巴循環系統阻塞
- Myxedema (hypothyroidism) 黏液性水腫
Compensation mechanism
- 為了代償血管內的水分流失，腎臟會傾向吸收更多水分 (to compensate the fluid loss in vessels, the kidney tend to water retention with Na+ reabsorption)
- Angiotension II
- Norephinephrine
- Aldosterone
- Antidiuretic hormone
- may cause vicious cycle
- 為了代償血管內的水分流失，腎臟會傾向吸收更多水分 (to compensate the fluid loss in vessels, the kidney tend to water retention with Na+ reabsorption)
Etiology
- Heart failure
- Liver cirrhosis
- Nephrotic syndrome and other forms of kidney disease
- Premenstrual edema and pregnancy
- Drug-induced edema
- Thiazolidinedione (TZD)類口服降血糖藥 (pioglitazone, rosiglitazone), PPAR, may increase Na+ reabsorption in the renal collecting duct (like Aldosterone)
- Calcium channel blockers (dihydropyridine, Norvasc), CCB, dilatation of the precapillary sphincter
- NSAID, inhibit renal prostaglandin synthesis, exacerbate edema in patients with underlying heart failure or cirrhosis
- Fludrocortison: unusual
- Estrogen, promote Sodium reabsorption, primarily in patients with impaired estrogen metabolism due to hepatic disease
- Pramipexole, a dopamine agonist used in the treatment of Parkinson disease and restless legs syndrome,
- Docetaxel, used in the treatment of metastatic breast cancer
- Refeeding edema (quite unusual)
Evaluation
Types
- Peripheral edema
- Pulmonary edema
- Ascites
- Lymphedema
- Periorbital and scrotal edema
Pitting edema definition
- More common 較常見的 edema 類型
- Presence of tissue depression after pressure is applied to the edematous area for at least five seconds 水腫處壓迫五秒後仍繼續塌陷
- Excess interstitial water in response to pressure
- If note -> suspect hypothyroidism or lymphatic obstruction
Distinguish
- Acute onset or chronic
- BIlateral or unialteral
Acute unilateral Leg edema 急性單側腳水腫
- Most dangerous → consider the DVT, the wells score combined with D-dimer to rule out
- Not DVT, consider:
- Muscle strain or twist injury
- Paralyzed limb with leg swelling
- Lymphangitis or lymph obstruction
- Venous insufficiency
- Popliteal (Baker’s) cyst
- Cellulitis
- 最常見症狀：紅腫熱痛加發燒，不過有些血管有問題的也有可能表現類似症狀
- Some patients with venous insufficiency develop a low-grade, nonbacterial cellulitis, which resembles infectious cellulitis,
- May-turner syndrome:
- younger females (20-30 year-old)
- acute pain and swelling of the entire left lower extremity
- with or without venous thrombosis.
Chronic unilateral or asymmetric edema 慢性單側水腫
- Most common: lower extremity chronic venous disease
- history of thrombophlebitis in affected leg
- longstanding → pigmentary changes and skin ulceration
- Less common:
- Primary or secondary lymphedema
- history of inguinal or pelvic lymph node dissection
- radiation therapy
- initially pitting, but became non-pitting for cutaneous fibrosis occurs
- Complex regional pain syndrome (複雜性局部疼痛症候群)
- 4-6 weeks after limb truma
- pain, edema, and alteration in skin color and temperature
- 複雜性局部疼痛症候群｜皮膚變得異常敏感？｜熱河診所
- Pelvic neoplasm compromising venous return
- Suspected when Compression Ultrasonography (CUS) showed a outflow obstruction
- Ovarian cancer
- Endometrial cancer
- Bladder cancer
- Lymphoma
- Prostate cancer
- Primary or secondary lymphedema
- Most common: lower extremity chronic venous disease
Acute bilateral leg edema 急性雙側水腫
- Uncommon
- Most likely etiology:
- Side effect of medications
- Acute heart failure
- Dyspnea, orthopnea, ,paroxysmal nocturnal dyspnea, tachypnea ,tachycardia, rales, or distended neck veins
- Acute nephrotic syndrome
- urine dipstick positive for protein
- Bilateral DVT, often associated with malignancy
Chronic bilateral leg edema 慢性雙側水腫
- Heart failure
- Pulmonary hypertension
- Renal disease
- Liver disease
- Pelvic neoplasm
- Constrictive pericarditis
- Idiopathic edema
- Premenstrual edema
- Malnutrition
Arm edema
- trauma, infection, superficial thrombophlebitis, or inflammatory arthritis, apparent in history
- Extremity venous thrombosis should be suspected when none of the etiologies noted
- Acute bIlateral upper edema is rare, may be seen on superior vena cava syndrome
Pulmonary edema
- Uncomplicated cirrhosis is not associated with pulmonary edema, in contrast to cardiac and renal disease
- Pulmonary edema not occurred in isolated hypoalbuminemia
Lymphedema
- Most common in developed countries: ALND
- Most common in worldwide: filariasis
Treatment
When must edema be treated?
- Pulmonary edema 是最危險需立即處理的
- 其他的如果沒有立即性危險，可以慢慢脫水，尤其是對 Cirrhosis 的病人來說，如果過度脫水導致的低血鉀、代謝性鹼中毒、還有快速的體液容積變化有可能會加重 hepatic encephalopathy
Consequence of the diuretic use
- Reduction in cardiac output on patients with heart failure
- Diuretic-induced fluid removal leads to increased secretion of the three “hypovolemic” hormones (renin, norepinephrine, and antidiuretic hormone)
- Despite the reduction in the effective arterial blood volume, most patients benefit from the appropriate use of diuretics.
- Pulmonary congestion improved
- Relief of symptoms of fatigue and bloating with noncardiac cause of edema
- Decrease in effective arterial blood volume impair tissue perfusion condition:
- Severe heart failure in very low baseline effective arterial blood volume
- Rapid fluid removal in cirrhosis
- Monitoring:
- BUN and Crea
- Any symptoms imply decline in tissue perfusion: fatigue, weakness ,postural dizziness, lethargy or confusion
- Impaired renal function SHOULD NOT occurred after the appropriate use of diuretics
How rapidly should edema fluid be removed?
- Generalized edema due to heart failure, the nephrotic syndrome, or primary sodium retention
- the edema fluid can be mobilized rapidly since most capillary beds are involved
- With anasarca (全身水腫), removal of 2 to 3 liters of edema fluid or more in 24 hours
- 300 to 500 mL/day : the maximum amount that can be mobilized by most patients with isolated ascites (腹水但沒有周邊水腫的)
- Diuretics should be carefully used in Venous insufficiency, lymphedema, and malignant ascites
- Generalized edema due to heart failure, the nephrotic syndrome, or primary sodium retention
Diuretics Options
- Generally begin with loop diuretics: furosemide
- Monitoring BUN, crea, and electrolyte complication
- Preferred regimen in different condition:
- Cirrhosis: spironolactone (to prevent hypokalemia) and loop diuretics
- Heart failure: just monitor the signs of hypoperfusion
- Nephrotic syndrome: higher dose of diuretics is needed because transport of the diuretic into the tubular lumen is impaired.