肝外胆汁淤积是由于肝脏外或肝门内的胆管受到机械性阻塞所致。

肝脏肿大，肝内胆管广泛扩张。胆管在门管区增生。梗阻部位上方胆汁感染导致胆管炎；胆管内有脓液，可能被小脓肿包围。

临床症状和体征进一步证实了生化紊乱：

• 粪便呈苍白色 - 没有胆红素到达胃肠道转化为粪胆素
• 深橙色尿液 - 结合胆红素回流到血液中并通过尿液排出
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Extrahepatic cholestasis results from the mechanical obstruction to large bile ducts outside the liver or within the porta hepatis.

The liver is enlarged and the intra-hepatic bile ducts widely dilated. The bile ducts proliferate in the portal zones. Infection of the bile above the obstruction leads to cholangitis; the ducts contain pus and may be surrounded by small abscesses.

The biochemical derangement is reinforced by clinical symptoms and signs:

• pale stool - no bilirubin reaching gastrointestinal tract for conversion to stercobilin
• dark orange urine - reflux of conjugated bilirubin into blood and excretion in urine

一、胆外胆汁淤积的病因Aetiology of extrahepatic cholestasis

任何空腔器官阻塞的原因可分为管腔内原因、壁内原因和壁外原因：

• 胆管管腔阻塞：
  • 胆结石
  • 寄生虫：
    • 包虫病
    • 肝吸虫
    • 蛔虫
  • 医源性：
  • T 管后胆管造影
    
    
• 壁画阻碍：
  • 先天性闭锁
  • 创伤性狭窄，例如壶腹部狭窄
  • 硬化性胆管炎
  • 胆管癌
    
    
• 壁外阻塞：
  • 胰头癌
  • 壶腹部癌
  • 胰腺炎
  • 肝门肿瘤（通常是继发性沉积）
  • 慢性十二指肠溃疡

最常见的原因有：

• 胆管结石
• 胰头癌

The cause of obstruction of any hollow organ may be divided into luminal, mural and extramural causes:

• obstruction of the lumen of the bile ducts:
  • gall stones
  • parasites:
    • hydatid disease
    • liver fluke
    • round worms
  • iatrogenic:
  • post-T-tube cholangiography
    
    
• mural obstruction:
  • congenital atresia
  • traumatic stricture e.g. ampullary stricture
  • sclerosing cholangitis
  • cholangiocarcinoma
    
    
• extramural obstruction:
  • carcinoma of the head of pancreas
  • carcinoma of the ampulla of Vater
  • pancreatitis
  • porta hepatis tumours (often secondary deposits)
  • chronic duodenal ulceration

The most common causes are:

• gallstones in the bile duct
• carcinoma of the head of the pancreas