The pancreas Flashcards
What is the function of the pancreas?
The pancreas is involved in blood sugar control and metabolism within the body, and also in the secretion of substances which help digestion. Classically, these are divided into an “endocrine” role, relating to the secretion of [insulin] and other substances within pancreatic islets and helping control blood sugar levels and metabolism within the body, and an “exocrine” role, relating to the secretion of enzymes involved in digesting substances from outside of the body
How is pancreatitis classified based on severity of organ injury?
Much like the liver, the pancrease is dividied into lobules with central ducts draining the lobules. There are different patterns of lobule injury: -Periductal necrosis: Necrosis of the acinal cells adjacent to the ducts (generally due to duct obstruction e.g. gall stones0 -Panlobular necrosis: Necrosi of the whole acinar lobule (generally due to drugs/toxins/viruses/metabolic insults that cause direct damage) -Perilobular necrosis: Necrosis of the peripheries of lobules (generally due to poor vascular perfusion e.g. shock/hypothermia)
Describe the aetiology (causes) of acute pancreatitis
I GET SMASHED -Idiopathic (20%) -Gallstones (40% or other obstructive lesions) -Ethanol (35%) -Trauma (15%) -Steroids -Mumps (+CMV, EBV) -Autoimmune (SLE, polyarteritis nodosa) -Scorpion venom -Hyper/hypo (hyperlipidaemia, hypercalcaemia, hypothermia) -ERCP -Drugs (thiazides, sulphonamides, ACE inhibitors, NSAIDs)
Describe the pathology of pancreatitis
-An intial insult to the pancreas leads to leakage of activated pancreatic enzymes into the pancreatic and peripancreatic tissue, causing an acute inflammatory reaction. -A common example is gall stones damaging the ampulla of vater, which allows gastric contents up the pancreatic duct, where they can activate the pro-enzymes -The liberation of digestive enzymes results in extensive local tissue necrosis, particularly fat necrosis -Litres of extracellular fluid collect in the gut, peritoneum and retroperitonium
What are the potential early complication of acute pancreatitis?
-Shock (hypovolemic, septic) -ARDS (due microthrombi in pulmonary vessels) -Renal failure -Disseminated intravascular coagulation (widespread activation of the clotting cascade that results in the formation of blood clots in the small blood vessels) -Hypocalcaemia -Hyperglycaemia
What are the late complications of late pancreatitis? (not an objective)
-Pancreatic pseudocyst -Abscesses -Bleeding from elastase eroding a major vessel -Thrombosis of the splenic/gastroduodenal arteries causing bowel necrosis -Fistulae
Describe the clinical presentation of acute pancreatitis
Symptoms: -Gradual/sudden onset severe epigastric pain -Classically radiates to the back and may be relieved by sitting forward -Nausea/vomiting is prominent Signs: -Tachycardia (shock in severe disease) -Fever -Ileus (obstruction of bowel) -Jaundice (30%) Rigid abdomen -Cullen’s sign: periumbilical discolouration due to haemorrhage into the peritoneal space -Grey-Turner’s sign: discolouration in the flanks due to retroperitoneal hemorrhage, or bleeding behind the peritoneum Insert pic The bruising signs occur after 48 hours, and are an indicator of grave prognosis
What bloods would you do for suspected acute pancreatitis?
Why?
Bloods:
- Baseline FBC, CRP, U&E, LFT, glucose and calcium to assess progression
- Raised serum amylase (>1000U/ml)
- Very sensitive if measured within 24 hours of onset and >3x normal
- Will also be raised in cholecystitis, GI perforations and mesenteric infarction
- Raised serum lipase is more sensitive and specific
- ABG to monitor oxidation and acid-base status (early resp failure can occur)
What imaging would you do for suspected acute pancreatitis?
Why?
Imaging:
- AXR - may show sentinal loop/small bowel ileus/exclude other causes (on admission)
- Erect CXR - to assess perforations (on admission)
- CT - can show enlarged pancreas with stranding, abcess, collections, necrosis or pseudocyst (USS not diagnostic) (done at 48-72 hours to assess severity of necrosis)
- MRCP - better visualizing of collections, and also the ductal system
- Endoscopic USS - new method, rarely used
What severity scoring system is used in the management of acute pancreatitis?
Modified Glasgow criteria (PANCRREAS): 3 or more positive factors within 48 hours onset suggest severe pancreatitis and should prompt transfer to HDU/ITU;
- PaO2
- Age > 55
- Neutrophils: WBC >15x109/L
- Calcium <2mmol/L
- Renal: Urea >16mmol/L
- Enzymes: LDH>600iu/L, AST >200iu/L
- Albumin <32g/L
- Sugar: glucose > 10mmol/L
other systems do exist such as APACHE II and Ranson criteria
Given a patient with suspected pancreatitis what basic biochemical and haematological tests need to be interpreted?
Serum amylase, LFTs, U&Es, FBC
What are the signs and symptoms of a pancreatic cancer location in the head of the pancreas?
- Presents earlier with painless jaundice (Obstructive), but pain may develop as the disease progresses
- On examination there will be signs related to obstructive jaundice (yellowing of skin and eyes, itching, paler stools, darker urine)
- Courvoiser’s sign (an enlarged, palpable gallbladder in patients with obstructive jaundice) in some cases or a palpable abdominal mass
- Hepatosplenomegaly or ascites are also common
What are the signs and symptoms of a pancreatic cancer location in the body/tail of the pancreas?
- More likely to present late with dull abdominal pain radiating through to the back, partially relieved on sitting forwards
- Non specific B symptoms ( systemic symptoms of fever, night sweats, and weight loss)
- Often no physical signs on examination
Describe the morphology and pathology of carcinoma of the pancreas
The majority of pancreatic malignancies are ductal adenocarcinomas, with 60% in the head, 25% in the body and 15% in the tail of the pancreas
Islet cell tumours make up <2% of pancreatic neoplasms, with smptoms related to the excess hormone being secreted. They are usually solitary, but can occur as part of MEN (multiple endocrine neoplasia) syndrome:
- Insulinoma - symptomatic hypoglycaemic events (often mornings or on exertion), as well as gross weight gain. 90% are benign
- Glucoagoma - often asymptomatic, secondary diabetes may develop
- Somatostatinoma - present with diabetes (insulin release inhibited), achlorrhydria (gastrin release inhibited) and gallstones (CCK release inhibited)
- VIPoma - vasoactive intestinal peptide release causes profound diarrhoea
