liver

liverMohamed Riad

EmbryologyThe liver and biliary ducts arise from diverticulum that appears on the ventral aspect of the foregut:

- The cranial part becomes the liver. - The caudal part forms the ventral aspect of the pancreas. - The intermediate bud forms the gall bladder.

AnatomyThe liver is the largest gland in the body (Wt 1.5 Kg= 2%of body weight).

Classic descriptions: The liver is divided into 4 lobes (Right, Left, Caudate and Quadrate lobe). Now, segmental anatomy of the liver: surgical anatomy

Surgical anatomyThe hepatic veins (Rt., Left and middle) divide the lobe into sectors, and the sectors into segments. Each of these segments has its own smaller branch of bile duct, hepatic artery and portal vein. There are 4 sectors divided into 8 segments. Any of these segments can be excised if its duct and vessels are ligated

Blood supply: Arterial: 75% of the blood is supplied by the portal vein. 1500 ml reaches liver per minute through it. While, the rest of blood reach liver through common hepatic artery from celiac Axis. It ascends in the hepato-duodenal ligament giving rise to right gastric and gastro-duodenal arteries before dividing at the hilum into right &left branches.

Venous: There are three major hepatic veins (Left, Right, and Middle) which end into I.V.C. The middle hepatic v. drains the medial segment of left lobe and the inferior part of the anterior segment of right lobe. It usually ends in the left hepatic v. The left hepatic vein drains the lateral segment of the left lobe. The right hepatic vein drains the posterior surface and much of the anterior surface of the right lobe.

Lymphatics: Superficial lymphatics end into posterior mediastinum. Deep lymphatics end into porta hepatis.

INJURIES OF THE LIVERAetiology: Liver injuries are not common in civilian life. It is the second organ to be injuried after spleen.Injuries may be caused by stabs, bullets, run-over accidents and blunt trauma

Pathology: The injury may be in the form of:1. A sub-capsular haematoma.2. A longitudinal or stellate tear. 3. Extensive laceration or central rupture of the liver parenchyma. 4. Rupture of the vessels and ducts in the hilum of the liver is usually fatal, but fortunately rare.

Clinical features: There may be general manifestations of internal haemorrhage associated with, pain, tenderness, and rigidity over the liver and abdomen. Percussion may reveal the presence of blood in the peritoneum (shifting dullness) and diagnostic peritoneal lavage (DPL) may confirm the diagnosis.

Investigations: 1 Ultrasonography and C.T scanning: Recommended in all suspected cases. 2- X-ray chest erect position: May show elevation of the diaphragm by a haematoma and/or associated rupture viscous (gas under diaphragm)

Treatment:General measures for shock. Laparotomy is usually needed to suture the tear(s) using mattress sutures. Necrotic tissues should be removed to avoid infection and secondary haemorrhage. Packs are also better avoided because they increase the chances of infection and it is better to ligate or suture the vessels. A thoracic extension of the wound may be needed to control bleeding from deep lacerations. Segmentectomy or Lobectomy may be done in severe lacerations.

The most serious complications are infection with secondary haemorrhage and haemobilia. N. B: In haemobilia a communication occurs between one of the blood vessels and a bile duct. This may lead to severe gastro-intestinal bleeding. Surgical exploration to ligate the vessel is needed.

INFECTIONS OF THE LIVERI. Pyogenic liver abscessHighly fatal disease. Prognosis depends on early diagnosis. Causes (types): According to source of infection, pyogenic liver abscess may be: Cholangitic abscess: secondary to ascending cholangitis, usually multiple Pyaemic abscess: secodary to portal pyaemia, usually multiple. Haematogenous abscess: bacterial (usually staphylococci) reach the liver through hepatic artery from a distant focus (endocarditis, osteomyelitis .. etc). Usually solitary Idiopathic in which source of infection could not be traced.

A-Pyaemic liver abscessThese rare infections occur in the course of portal pyaemia, secondary to suppurative appendicitis or colonic diverticulitis . The liver is enlarged and tender. It is studded with multiple small abscesses walled by ragged liver tissue.Jaundice is common and the prognosis is bad.

Treatment: Blood transfusion, antibiotics, fluids and treatment of the original cause. Rarely a solitary abscess may form in the liver and needs surgical drainage (either by open drainage or per-cutaneous guided drainage under US or CT).

B-Cholangitic abscess:Secondary to ascending cholangitis .The commonest cause of suppurative cholangitis is obstruction of the common bile duct by a stone and therefore a history of long standing gall bladder disease is obtained. Infection ascends along the bile ducts leading to suppuration in the intra-hepatic ducts and formation of multiple small abscesses.

Clinically: There is fever with rigors, vomiting and marked jaundice. The liver is painful, enlarged and tender.

Treatment: Removal of the cause of obstruction by ERCP and stent and drainage of the common bile , or Percutaneous transhepatic drainage (PTD) guided by US or CT. or open surgical drainage.

II. Amoebic liver abscessAetiology: The infection reaches the liver from the colon, by portal circulation. A history of amoebic dysentery is common, but liver involvement usually occurs after subsidence of the colonic lesion, sometimes there is a lag period of several months or even years.

Pathology: Site: The postero-superior part of the right lobe is the commonest site. Number: It is usually solitary, rarely more than one abscess may be found. Size: It is usually big in size and may occupy the whole right lobe of the liver. Contents: It contains brownish material formed of necrotic liver tissue and haemolysed red blood corpuscles (chocolate-coloured pus). Wall: At first the wall is formed of necrotic liver tissue but as the abscess becomes chronic a fibrous wall develops. There is minimal leucocytic reaction in the wall. Amoeba is found in the wall and not in the pus.

Complications: Pleural effusion: in the form of a sympathetic reaction.

2. Rupture into: Pleura causing empyema. Bronchus with expectoration of a big amount of pus. The peritoneal cavity or into a viscus as the gall bladder. 3. Secondary infection: by pyogenic organisms.

Clinical features: Males are affected more than females. Onset is insidious with pyrexia, loss of weight and upper abdominal pain or discomfort. The patient is toxic with an earthy or muddy complexion (a combination of anaemia, toxaemia and mild jaundice). The fever is usually of the low grade type. However it may be hectic with rigors when secondary infection starts.

As the disease progresses, the patient's general condition deteriorates. He begins to complain of pain in the lower part of the chest and sometimes in the right shoulder region (irritation of the diaphragm).

Examination: In early cases the liver is enlarged, smooth and tender.Intercostal tenderness is usually elicited. In late cases a swelling in the upper part of the abdomen may be detected.

Investigations:US: Is of great value in diagnosis and localization. CT scan: is also of great value in diagnosis and localization.Plain X-ray : may shows impaired movement of the diaphragm and pleural effusionAspiration: reveals the characteristic chocolate coloured pus .Therapeutic test: by emetine for 2 days may show marked improvement . (old)Blood examination: shows leucocytosis and eosinophilia .

Treatment: Medical treatment:

Metronizadol (Flagyl) is effective and not toxic (500 mg. t.d.s.). Antibiotics are given with it for secondary infection.When a large abscess is formed sonar guided aspiration may be done.

Surgical drainage: This is indicated When there is a large abscess. Superadded secondary infection. Failure of medical treatment and aspiration. Abscess of the left lobe of the liver, for fear of bursting into the pericardium, is better drained early

Routes of drainage: Posteriorly placed abscess is drained by Extraserous approach (extraperitoneal extrapleural) after subperiosteal resection of last rib. Anteriorly placed abscess is drained by a subcostal incision.

HYDATID CYSTThis is the commonest cyst of the liver, but it is not common in Egypt. Mostly discovered accidently during routine investigations

Clinical features: Painless enlargement of the liver. A cystic swelling may be found, and on percussion a hydatid thrill may be detected. Allergic manifestations: due to an occasional leak from the cyst. Features of complications: which include rupture (into peritoneum, pleura, lung or bowel), calcification which may be seen in X-ray films and rarely anaphylactoid reaction.

Investigations: US, CT and MRI may confirm the diagnosis. Casoni's test: Injection of fresh hydatid fluid intradermally produces a reaction in 95% of cases. Complement fixation and haemagglutination tests: Serum of patient against hydatid fluid as an antigen. They are positive in 100 % of cases. These serological tests are less frequently used today, but can help confirm the diagnosis in difficult cases. Blood examination: shows eosinophilia. X-ray: may show calcification of the cyst.

Treatment: The treatment is surgical. The wound must be isolated by dark green towel packs soaked with freshly prepared Eusol solution or concentrated saline solution and 10 cc of the same solution are injected into the cyst before trying to remove it. The aim is to destroy the contents to avoid implantation of daughter cysts. The cavity left behind is obliterated by stitches if it is small, or left open if it is big and putting part of omentum inside. A drain is left and the wound is closed.

Medical treatment mebendazol or albendazole 400-600 tds for one month may be advised post-operative to prevent recurrence.