Key facts:
Authors: Tofunmi Oni, Richard Lin, Anil Ghosh and Asif Haq
Top Tip: Aggressive fluid replacement is required to counter third space fluid losses
Key Differential Diagnoses
- Hepato-biliary (Cholecystitis-Cholangitis, Biliary colic, Hepatitis)
- Gastro (Bowel obstruction, Perforation)
- Vascular (Abdominal aortic aneurysm, Mesenteric ischaemia)
- Medical (Myocardial infarction)
Key Investigations
- Amylase (>1000u/ml)
- Lipase (preferred where available, better sensitivity and specificity)
- ABG
- FBC, CRP, Coagulation screen
- U+E, LFT, Calcium, Glucose
- ECG, CXR (erect), AXR
- US (to look for GS) ± CT Abdomen
Note: calculate Ransons Criteria (≥3 admit to ITU) at presentation and 48h
Key Treatment
- NBM
- FLUID RESUSCITATION, analgesia, anti-emetic
- Conservative with organ support (eg Renal, Liver, Cardiac)
Key Management Decisions
- Early: ITU?
- Later: MRCP-ERCP, CT guided aspiration, Surgery
Background
IV fluid replacement, and oxygen, is required until vital observations improve and urine output is satisfactory
Introduction
- Pancreatitis ranges from mild (abdominal pain and vomiting) to severe (pancreatic necrosis and a systemic inflammatory process with shock and multiorgan failure). Majority subside in 3-10 days
- In 80% of cases the acute pancreatitis is mild and resolves without serious complications
- Accounts for 3% of all cases of abdominal pain admitted to hospital
- It is easy to think there is no acute problem. There is. It is not uncommon for 5-6 litres of fluid to be trapped in the gut, peritoneum and retroperitoneum - hence the phrase the 'internal burn'
- Diagnosis is based on clinical presentation and raised serum amylase and lipase levels. But a normal amylase does not exclude the diagnosis (BestBets, 2002)
- Biliary tract disease (60%) and alcohol (20%) account for most cases; 10% unknown, 10% rare
- Initial treatment is supportive, with aggressive IV fluid replacement, analgesics, anti-emetics and fasting; later, treat the cause (GS, alcohol)
- 10% mortality (40% with infected pancreatic necrosis)
Note: all patients with severe acute pancreatitis should be closely monitored and may require HDU or ITU level care due to persisting organ failure
Definition
- An inflammatory process in the pancreas leading to autodigestion of the gland by its own enzymes
Etymology
- The word 'Pancreas' is from the Greek word 'Pankreas'; Pan, meaning ‘all’ and Kreas meaning flesh. Probably owing to the homogenous macroscopic appearance of the organ
- Probably first described by Aristotle between 384-322 BC
Epidemiology
- Incidence = 14.5-20.7/ 100,000 per year in the UK
- Race - 3 times higher in blacks than whites. These racial differences are more pronounced for males than females
- Sex - affects males more often than females. This varies to a degree between sexes with men more likely to have alcohol as the aetiology and women more likely to have gall stones as the aetiology
- Idiopathic pancreatitis has no clear predilection for either sex
- Age - median age at onset depends on the aetiology. The following are median ages of onset for various aetiologies:
- Alcohol - 39 years
- Biliary tract - 69 years
- Trauma - 66 years
- Drug-induced - 42 years
- ERCP - 58 years
- AIDS - 31 years
- Vasculitis - 36 years
Causes
- Cholelithiasis (60%): a stone wedged within the common bile duct or Ampulla of Vater leads to back flow of pancreatic enzymes and their extravasation within the parenchyma
- Alcohol (20%) - increases the accumulation of digestive enzymes within cells and also increases the permeability of ducts to these enzymes
- Rare causes include:
- Iatrogenic (ERCP or any form of abdominal or chest surgery, incl CABG)
- Trauma (can be minimal, eg seat belt of car, bicycle handle bar)
- Infections (viral, bacterial, other)
- Vasculitides
- Metabolic (hyperlipdaemia, hypercalcaemia, hypothermia, pregnancy)
- Drugs - NSAIDS, Azathioprine, Thiazides, Steroids
- Pancreatic carcinoma (3% present with acute pancreatitis)
- Congenital abnormalities - eg Pancreas divisum, Annular pancreas (diagnosed on MRCP), cystic fibrosis
Note: 10% unknown
Causes (Mnemonic)
- Causes can be remembered by the mnemonic: 'GET SMASHED': Gallstones, Ethanol, Trauma, Steroids, Mumps, (and Coxsackie B virus), Autoimmune, Scorpion venom or Surgery, Hyperlipidaemia (Hypercalcaemia, Hypothermia), ERCP, Drugs
Types
- Acute: A process that transpires on a backdrop of no previous inflammation, and returns to normal after the occurrence resolves
- Chronic: There is chronic inflammation with evidence of irreversible structural changes in the pancreas
Risk factors
- Gallstones
- Excessive chronic alcohol consumption
- Congenital disorders
Symptoms
- Classically epigastric, but can be central abdominal, or right upper quadrant pain, or generalised pain (radiating to back in 50%, which can be relieved by leaning forward)
- Usually constant pain, with onset over hours (esp alcohol); though can be sudden (esp GS), mimicking perforation or AAA
- May be a history of recent alcohol binge or previous biliary colic
- Chest pain is a well recognised alternative presentation
- Nausea/Vomiting
- Fever
Key questions
- "Have you ever had a gall stone or this type of pain previously?"
- "Have you had any procedures or surgery recently?" (eg ERCP, Cardiac surgery)
- "Do you or any of your family have high fat levels in the blood?"
- "Have you ever been a regular heavy drinker?"
- "What tablets do you take?"
Signs
- Tachycardia
- Tachypnoea
- Fever
- Jaundice
- Hypotension
- Abdominal tenderness, guarding, rigidity, rebound; bowel sounds usually absent
- Signs of bleeding in pancreatic bed (take days to develop):
- Cullen’s sign (bluish discoloration of peri-umbilical area)
- Grey Turner’s sign (bruising seen around the flanks)
Note: an abdominal mass may indicate a pancreatic pseudocyst or abscess
Assessment Scores
- Modifi R et al have published a very good review of assessment scores
Assessment Score 1 (Ransons Criteria, ≥3 admit to ITU)
Each of the following adds one point
Present on admission
- > 55 years old
- WBC >16,000 cells per mm3
- BM > 11mmol/L
- LDH > 350 IU/L
- AST > 250 IU/L
Developing during the first 48 hours
- Hct decrease by > 10%
- BUN level increase > 1.8mmol/L (blood urea nitrogen)
- Arterial oxygen saturation less than 60 mmHg
- Base deficit > 4 mEq/L
- Serum Calcium < 2mmol/L
- Estimated fluid sequestration > 600 mL
Interpretation:
- 0-2: minimal mortality rate, medical therapy treatment on normal ward
- 3-5: 10-20% mortality rate, admit to ITU
- >5 after 48hours: 50% mortality rate, associated with systemic complications (any one system failure requires admission to ITU or review)
Assessment Score 2 (Glasgow Criteria, ≥3 admit to ITU)
3 or more in the first 48 hours suggests severe pancreatitis, admit to ITU. Mnemonic - PANCREAS
- PaO2 <8kPa
- Age > 55
- Neutrophils - WBC > 15×109/L
- Calcium < 2 mmol/L
- Renal function – urea >16mmol/L
- Enzymes - LDH >600 iu/L; AST >200 iu/L
- Albumin < 32g/L
- Sugar - Blood glucose >10mmol/L
Investigation
The severity of the disease does not correlate with the serum amylase; use assessment scores. There are other causes of a raised amylae
Blood
- Amylase (>1000u/ml); rises quickly (4-6h from onset pain) and returns to normal after 3-5 days
Note: there are other causes of a raised amylase (1-4x upper limit of normal; including renal failure and pregnancy). DKA can cause an amylase >5x upper limit of normal, like pancreatitis - Lipase (preferred where available, better sensitivity and specificity)
- ABG
- FBC (WC↑), CRP, coagulation screen
- U+E (ARF?), LFT (↑Bili, ALT, GGT, ALP suggests GS pancreatitis), Calcium (↓?), Glucose (↑?))
Note: this should be followed by daily measurements of FBC, U&E, Ca2+, glucose, CRP; ABG if appropriate; daily measurement of amylase not necessary as not a prognostic indicator
Other
- ECG: to exclude MI
- CXR (erect): to exclude perforation; may have pleural effusion, usually L-sided or bilateral
- AXR (supine): ? other cause of abdominal pain (eg bowel obstruction); also look for absence of left psoas shadow (retroperitoneal fluid↑) and the 'sentinel loop' (a dilated gas-filled duodenum)
- US: all patients require an US to detect GS or a stone in CBD. It has no role in the diagnosis of pancreatitis; as pancreas difficult to see in 25-50%. Endoscopic ultrasonography (EUS) can be used as an accurate alternative approach to screen for cholelithiasis
Note: if the diagnosis is in doubt, request an urgent CT abdomen
AXR ('sentinel loop' of dilated gas-filled duodenum)
Key Investigation
- Serum amylase (levels can be normal even if pancreatitis is severe, as levels start to fall with the first 48hrs)
Specialist Investigations
- CT: Primarily to investigate severity and associated complications. It is not current practice to investigate with a CT early in management. It is indicated in patients with persisting organ failure, signs of sepsis, or deterioration in clinical status 6-10 days after admission, or uncertain diagnosis
- If more than 30% necrosis of pancreas on CT, patient may require transfer to a specialist unit for ITU care, interventional radiological, endoscopic or surgical procedures
- MRCP: accurate and safer than ERCP - used to identify patients with GS pancreatitis who require therapeutic ERCP (eg cholangitis, jaundice)
CT abdomen
CT severity index (Balthazar Grade)
CT grade
- A = Normal pancreas (0 points)
- B = Oedematous pancreatitis (1)
- C = B plus mild extrapancreatic changes (2)
- D = Severe extrapancreatic changes including one fluid collection (3)
one fluid collection - E = Multiple or extensive extrapancreatic collections (4)
Necrosis
- None = 0
- One third = 2
- One third to one half = 4
- Half = 6
Interpretation: CT severity index = CT grade + necrosis score
Complications
- 0–3 8%
- 4–6 35%
- 7–10 92%
Deaths
- 0–3 3%
- 4–6 6%
- 7–10 17%
Differential Diagnoses
- Hepato-biliary (Cholecystitis-Cholangitis, Biliary colic, Hepatitis)
- Gastro (Bowel obstruction, Perforation)
- Vascular (Abdominal aortic aneurysm, Mesenteric Ischaemia)
- Medical (Myocardial Infarction)
Treatment
Finding the cause of the attack is not the immediate priority
Treatment
(first line)
Drugs
- Analgesia: Pain control achieved according to the WHO analgesic ladder i.e. Paracetamol, NSAIDS (if no contraindication), Opiates (eg IV/IM MORPHINE 5-10mg)
- Antiemetic: eg IV/IM CYCLIZINE 50mg
- Start insulin sliding scale if BG >12 mmol/L
Procedures - Insert cannula immediately and deliver IV infusion of crystalloids until observations normalise and urine output stays at >0.5ml/kg/hour
- If hypoxic on ABG, give high flow oxygen (keep SaO2 >95%); also correct acidosis if present on ABG
- Urinary catheter
- CVP line in selected patients
Supportive measures (nursing)
- NBM
- NG tube with aspiration may be necessary if continuous vomiting
- Feeding - nasogastric route preferred if tolerated, effective in 80%. May require nasojejnal feeding or parenteral feeding (TPN)
- Hourly measurements of pulse, BP, urine output, O2 saturation
Key Management Decisions
- If and when surgery is indicated:
- Extensive necrotising pancreatitis may require surgical procedures such as pancreatectomy
Treatment (second line)
Drugs
- Antibiotics: Infection of a necrotic pancreas is a serious complication of pancreatitis and several studies have shown benefit in the use of prophylactic antibiotics to improve outcome. Since these studies used varying antibiotics and length of treatments a collective regime has not been decided upon
- However antibiotics with a high secretion within the biliary system are normally used; eg IV AMPICILLIN 250-500 mg 4x/day, or a third generation cephalosporin, eg IV CEFTRIAXONE 1-2 g od; for a maximum of 14 days
Procedures - ERCP with gall stone removal if progressive jaundice. In 80% GS pancreatitis, stone is passed spontaneously
- Consider TPN to reverse the catabolic state
- Surgery may be indicated if there is a no haemodynamic improvement when optimum medical treatment is being delivered, eg if inflammatory process seen to erode into major vessels on imaging, or if severe pancreatic necrosis, with infection. Surgery has no role in mild acute pancreatitis or in severe pancreatitis with sterile necrosis. Consider transfer of patient to a specialist unit, especially if has pancreatic necrosis
- Cholecystectomy if gallstones detected during the same admission or within 2 weeks
Prescribing issues
- Do NOT use pethidine
Stop
- Alcohol; Drug 'causes' (eg NSAIDS, Thiazides; and Azathiprine, Steroids, after DW prescribing physician)
Admit?
- Yes
Bed plan
- Surgical admission ward
- Consider transfer to a specialist unit if patient very unwell
- ± ITU if worsening vital signs
Referrals
- General surgery
- ± ITU
The Rest
Even though it takes 48h to fully assess the severity of the disease with most assessment scores, this should not delay the ITU decision
Maxim
- 'Fluid fluid fluid'
Complications (20%)
- Short term: Shock, ARDS, ARF, DIC, sepsis, hypocalcaemia, hypomagnesaemia
- Medium-Long term: Pancreatic necrosis (possibly infected), pseudocyst (more common in alcohol related vs GS, 15 vs 3%), abscess (more comon in GS), bleeding (erosion into large vessels), thrombosis (splenic/gastroduodenal arteries, causing bowel necrosis)
Pancreatic pseudocyst
Follow-up
- General surgery: paying attention to physical examination as well as amylase and lipase levels
Prognosis
- 10% mortality (40% with infected pancreatic necrosis); sepsis commonest cause of death
- Mortality highest on first episode
- 15% recur
- Ranson, Glasgow and APACHE II scores can be used to predict severity
- CRP (>150 mg/L) at 48h and obesity are independent predictors of survival
Prognostic scoring system (APACHE II)
- Takes into account acute physiology score, age and chronic health problems in order to predict severity.
- Severe pancreatitis if score > 8 after 24hours of admission
2° Prevention
+ Health promotion
- Avoid alcohol, especially binge drinking; refer patient to Community Alcohol Service if necessary
- Avoid abdominal trauma
- Avoid risk factors such as fatty meals - diet high in carbohydrates and low in fats
Don't forget
- Give fluid immediately
- Pain can be of sudden onset (mimicking perforation or AAA)
- Use assessment score regularly (as severity of disease does not correlate with amylase)
- A normal amylase does not exclude pancreatitis
- It can affect young people as well
- Consider transfer to specialist unit in complicated cases
Red flags
- Shock
- Body system failure
Synonyms: acute necrotising pancreatitis, chronic pancreatitis, inflammation of pancreas
