Spleen

• Spleen


  An organ located in the upper left part of the abdomen that filters blood and plays a role in the immune system
• Fetal splenic tissue development

  Develops from mesoderm in the dorsal mesogastrium

  
• Normal adult spleen


  • Weight of 75–250 g
  • Lies in the left hypochondrium between the gastric fundus and the left hemidiaphragm, with its long axis lying along the 10th rib

  
• Splenic artery


  1. Arises from the coeliac axis and runs along the upper border of the body and tail of the pancreas, giving small branches

  2. Short gastric and left gastroepiploic branches pass between the layers of the gastrosplenic ligament
• Splenic vein


  1. Formed from several tributaries that drain the hilum

  2. Runs behind the pancreas, receiving several small tributaries from the pancreas before joining the superior mesenteric vein at the neck of the pancreas to form the portal vein
• Lymphatic drainage of the spleen

  1. Efferent vessels in the white pulp run with the arterioles and emerge from nodes at the hilum

  2. These nodes and lymphatics drain via retropancreatic nodes to the coeliac nodes

  
• Innervation of the spleen

  Sympathetic nerve fibres run from the coeliac plexus and innervate splenic arterial branches
• Functions of the spleen

  • Immune
  • Filter function
  • Pitting
  • Reservoir
  • Cytopoiesis
• Splenectomy harms the patient
• Investigations of the spleen

  • Full blood count, reticulocyte count and tests for haemolysis
  • Splenomegaly associated with portal hypertension; abnormal tests of liver function
  • Endoscopic evidence of oesophageal varices

  
• Sinistral or segmental portal hypertension may result from isolated occlusion of the splenic vein by pancreatic inflammation or tumour
• Radiological imaging of the spleen

  • Plain radiology
  • Ultrasonography
  • Computerised tomography (CT) scan with contrast enhancement
  • Magnetic resonance image (MRI) scanning
  • Radioisotope scanning

  
• Congenital abnormalities of the spleen

  • Splenic agenesis
  • Polysplenia
  • Splenunculi
  • Hamartomas
  • Non-parasitic splenic cysts

  
• True cysts


  Form from embryonal rests and include dermoid and mesenchymal inclusion cysts
• False cysts


  May result from trauma and contain serous or haemorrhagic fluid
• The spleen is a common site for pseudocyst development following a severe attack of pancreatitis

  
• Splenic artery aneurysm


  • Twice as common in females
  • Usually situated in the main arterial trunk
  • More likely to be associated with arteriosclerosis in elderly patients
• Asymptomatic splenic artery aneurysm

  Unlikely to be palpable, although a bruit may be present
• Ruptured splenic artery aneurysm


  Symptoms mimic those of splenic rupture
• Treatment of splenic artery aneurysm

  1. Splenectomy and removal of the diseased artery

  2. Embolisation or endovascular stenting following selective splenic artery angiography
• Splenic infarction


  Commonly occurs in patients with a massively enlarged spleen from myeloproliferative syndrome, portal hypertension or vascular occlusion produced by pancreatic disease, splenic vein thrombosis or sickle cell disease

  
• Symptoms of splenic infarction

  • Asymptomatic
  • Left upper quadrant and left shoulder tip pain
• Diagnosis of splenic infarction is by a contrast-enhanced CT scan
• Treatment of splenic infarction

  Conservative, and splenectomy should be considered only when a septic infarct causes an abscess
• Causes of splenic rupture

  • Blunt abdominal trauma, particularly (left upper quadrant of the abdomen)
  • Iatrogenic injury to the spleen (complication of any surgical procedure)
  • Rupture of a malarial spleen

  
• Rupture of a malarial spleen is common in tropical countries, and following 'trivial' injury is not infrequent
• Hypersplenism


  An indefinite clinical syndrome characterised by splenic enlargement, any combination of anaemia, leucopenia or thrombocytopenia, compensatory bone marrow hyperplasia and improvement after splenectomy
• Causes of splenic abscess


  • Infected splenic embolus
  • Associated with typhoid and paratyphoid fever, osteomyelitis, otitis media and puerperal sepsis
  • Associated with pancreatic necrosis or other intra-abdominal infection
• Complications of splenic abscess

  • Left subphrenic abscess
  • Peritonitis
• Treatment of splenic abscess

  1. Treat the underlying cause

  2. Drainage of the splenic abscess by percutaneous means under radiological guidance
• Haemangioma


  The most common benign tumour of the spleen and may rarely develop into a haemangiosarcoma

  
• The spleen is rarely the site of metastatic disease

  
• Lymphoma


  The most common cause of neoplastic enlargement of the spleen, and splenectomy may play a part in its management

  
• Myelofibrosis


  Results from an abnormal proliferation of mesenchymal elements in the bone marrow, spleen, liver and lymph nodes
• Indications for splenectomy


  • Trauma (accidental or operative)
  • Oncological (part of en bloc resection, diagnostic, therapeutic)
  • Haematological (spherocytosis, purpura (ITP), hypersplenism)
  • Portal hypertension (variceal surgery)

  
• Preoperative preparation for splenectomy

  1. Transfusion of blood, fresh-frozen plasma, cryoprecipitate or platelets if there is a bleeding tendency

  2. Antibiotic prophylaxis appropriate to the operative procedure
• Technique of open splenectomy

  1. Incision (midline, transverse left subcostal, or rarely thoracoabdominal)

  2. Passage of a nasogastric tube

  3. Division of the gastrosplenic ligament and short gastric vessels

  4. Suture-ligation of the splenic vessels at the superior border of the pancreas

  5. Exclusion of accessory splenic tissue

  6. No need to drain the wound if haemostasis is secured adequately
• Postoperative complications of splenectomy

  • Haemorrhage resulting from a slipped ligature
  • Haematemesis from gastric mucosal damage and gastric dilatation
  • Left basal atelectasis and pleural effusion
  • Damage to adjacent structures (stomach, pancreas)
  • Thrombocytosis
  • Post-splenectomy septicaemia
• Prophylaxis against post-splenectomy sepsis

  1. Appropriate and timely immunization

  2. Antibiotic prophylaxis, education and prompt treatment of infection

  3. Penicillin, erythromycin or amoxicillin, or co-amoxiclav for oral prophylaxis

  4. Cefotaxime, ceftriaxone or chloramphenicol for intravenous treatment in penicillin/cephalosporin allergy
• Vaccinations recommended for splenectomy patients

  • Pneumococcus (repeated every 5 years)
  • Meningococcus (repeated every 5 years)
  • Haemophilus influenzae (repeated every 10 years)
  • Yearly influenza vaccination