Acute Pancreatitis

Definition
Acute inflammatory process of the pancreas with variable involvement of regional or remote tissues

Epidemiology
1–5/10,000
Predominant age:
- Acute pancreatitis: None
- Chronic pancreatitis: 35–45 years (usually related to alcohol)
Male = Female

Aetiology
I - idiopathic.(10%) Thought to be hypertensive sphincter or microlithiasis.
G - gallstone. (40%)
E - ethanol (alcohol) (35%)
T – trauma (usually in children), tumour
S - steroids
M - mumps (paramyxovirus) and other viruses (Epstein-Barr virus, CMV)
A - autoimmune disease (Polyarteritis nodosa, Systemic lupus erythematosus)-in pt <40
S - scorpion sting , snake bites
H - hypercalcemia, hyperlipidemia/hypertriglyceridemia and hypothermia
E - ERCP (4%) , emboli
D - drugs (SAND - steroids & sulfonamides, azathioprine, NSAIDS, diuretics such as furosemide and thiazides, & didanosine) and duodenal ulcers

Pathophysiology

• begins with injuries to acinar cells or impairment of zymogen granules secretion.
• lysosomal and zymogen granule fuse, enabling trypsin production
• trypsin triggers auto-digestion by zymogen activation cascade
• secretory vesicles extrude into the interstitium, attracting inflammatory cells
• Activated neutrophills release superoxide, proteolytic enzyme
• Macrophages release cytokines (tumour necrosis factor alpha, IL-6, IL-8)
• Mediators cause increased pancreatic vascular permeabilityà haemorrhage, edema, necrosis.

Presentation
epigastric/central abdomen dull, boring and steady pain, sudden onset, increasing severity. may radiate to back, relieved by sitting forward
nausea, vomiting
fever, tachycardia, shock
jaundice (28%)
ileus, rigid abdomen, tenderness
periumbilical discoloration (Cullen’s sign) or in the flanks (Grey Turner’s sign) – due to methaemalbumin formed from digested blood tracks around the abdomen

* Cullen’s sign

* Grey Turner’s sign

Less common sign

• Körte's sign (pain or resistance in the zone where the head of pancreas is located (in epigastrium, 6–7 cm above the umbilicus)
• Kamenchik's sign (pain with pressure under the xiphoid process)
• Mayo-Robson's sign (pain while pressing at the top of the angle lateral to the Erector spinae muscles and below the left 12th rib (left costovertebral angle(CVA))

Differential Diagnosis
Acute cholecystitis, organ rupture, AAA, PUD, any acute abdomen

Investigation

FBC	an admission hematocrit > 47% may inidicate more severe disease Leukocytosis may represent inflammation or infection
ABG	if pt is dyspnoeic, monitor oxygenation, acid base status
CRP	24-48 hours after presentation
Calcium, magnesium, cholesterol, and triglycerides	search for an etiology of pancreatitis (hypercalcemia or hyperlipidemia) or complications of pancreatitis (hypocalcemia resulting from saponification of fats in the retroperitoneum).
Amylase	↑ amylase (>1000u/ml, falls after 2d) may be normal (in 10% of cases)
Lipase	rises 4 to 8 hours from the onset lipase more sensitive & specific (falls after 7-14d)
LFT	ALT >150 U/L suggests gallstone pancreatitis and a more fulminant disease course.
Serum electrolytes, BUN, creatinine, glucose	electrolyte imbalances, renal insufficiency, and pancreatic endocrine dysfunction
LDH, BUN, and bicarbonate	Measured at admission and at 48h to determine Ranson Criteria
IgG4	evaluate for autoimmune pancreatitis
Abdomen U/S	if suspect gallstone + AST↑, FNA- for bacterial infection
Endoscopic U/S	evaluating the cause of severe pancreatitis, particularly microlithiasis and biliary sludge, and can help identify periampullary lesion
Abdominal CT scanning	Indicated for severe pancreatitis scan within the first 72h Acute pancreatitis. Pancreatic necrosis. Note the nonenhancing pancreatic body anterior to the splenic vein. Also present is peripancreatic fluid extending anteriorly from the pancreatic head.
MRI	alternative for CT, in pt with contrast allergy or renal insufficiency. Image: Focal pancreatitis involving pancreatic head. Pancreatic head is enlarged with adjacent ill-defined peripancreatic inflammation and fluid collections
ERCP	Indication: severe acute gallstone pancreatitis that is not responding to supportive therapy or with ascending cholangitis with worsening signs and symptoms of obstruction, This patient with acute gallstone pancreatitis underwent endoscopic retrograde cholangiopancreatography. The cholangiogram shows no stones in the common bile duct and multiple small stones in the gallbladder. The pancreatogram shows narrowing of the pancreatic duct in the area of the genu, the result of extrinsic compression of the ductal system by inflammatory changes in the pancreas.
AXR	Limited role in acute pancreatitis detect free air in the abdomen, ‘sentinel loop’ of proximal jejunum (solitary air-filled dilatation)
erect CXR	exlude other causes, eg perforation.

Criteria for Severity
Several examples of scoring system:

Scoring System	Criteria
Modified Glasgow Criteria	Pa O2 <8kPa Age >55 Neutrophils WCC> 15x 109/L Calcium < 2mmol/L Raised urea >16mmol/L Enzymes: LDH>600iu/L, AST >200iu/L Albumin<32g/L Sugar : blood glucose >10 mmol/L
Ranson's Criteria	Present on Admission - GA LAW Glucose (blood) greater than 200 mg/dl Age >55 years LDH (serum) > 350 I.U./L AST >250 I.U./L WBC > 16,000/ul Developing During the First 48 Hours: - C HOBBS Calcium (serum) < 8 mg/dl Hematocrit fall > 10% Oxygen (arterial) saturation l< 60 mm Hg BUN increase>  8 mg/dl. Base deficit > 4 meq/L Sequestration of fluid > 600 ml
Computed Tomography Severity Index (CTSI)/ Balthazar score	Balthazar Grade Appearance on CT CT Grade Points Grade A Normal CT 0 points Grade B Focal or diffuse enlargement of the pancreas 1 point Grade C Pancreatic gland abnormalities and peripancreatic inflammation 2 points Grade D Fluid collection in a single location 3 points Grade E Two or more fluid collections and / or gas bubbles in or adjacent to pancreas 4 points

Dx for severe pancreatitis : Ranson score >3, APACHE score >8, modified Glasgow score >3.  Balthazar score – proven to be more accurate

Management

Fluids	(large 0.9% saline) to stabilize vital signs, urine flow >30mL/h, urinary catheter & consider CVP monitoring
Nutrition	Early initiation of enteral nutritional supplementation TPN (2nd line)has been shown to reduce mortality rate
Antibiotics	imipenem. (Controversial)
Analgesia	pethidine or morphine(may cause sphincter of oddi to contract more but it is a better analgesic, no CI)
Monitor	Hourly pulse, BP, urine output, daily FBC, U&E, Ca, glucose, amylase, ABG
If worsening	take to ICU. O2 if PaO2 ↓. Suspected abscess/necrosis(CT) à PTN +laparotomy & debridement. Antibiotic controversial (imipenem)
ERCP	if suspected CBD stone or clinical deterioration. Not in acute condition
Follow up	Ensure alcohol incontinence Within weeks to months after onset: check for signs of intra-abdominal infection, pancreatic pseudocyst, intra-abdominal hemorrhage, colon perforation, obstruction or fistulization, and multiorgan system failure. CT-guide needle aspiration in the setting of necrotizing pancreatitis Repeat CT/US to monitor complication (eg. pseudocyst)
Surgery for infected pancreatic necrosis	indication: infected pancreatic necrosis, diagnostic uncertainty, complications. Closed management - necrosectomy with closed continuous postoperative lavage Open management - necrosectomy with planned staged reoperations at definite intervals (up to 20+ reoperations in some cases)
Management for pancreatic pseudocyst	Definition Pseudocyst-peripancreatic fluid collections persisting for more than 4 weeks are termed acute pseudocysts. Pseudocysts lack an epithelial layer and, thus, are not considered true cyst. Imaging * CT scan of a large symptomatic pancreatic pseudocyst abutting the posterior wall of the stomach. Investigation fluid in lesser sac, T↑, a mass + persistent ↑ amylase/LFT: 40% resolve spontaneously 6-12wk, supportive mgt until thick wall has formed,drainage externally or into stomach , biopsy to rule out malignancy. Indication for intervention symptomatic (pain, bleeding, or infection) larger than 7 cm and are rapidly expanding Percutaneous aspiration for pt with very large fluid collection Endoscopic technique by transpapillary or transmural techniques The proximal end of the stent is placed into the cyst cavity Success rate= 83%, complication rate = 12% Transmural enterocystostomy for noncommunicating pseudocysts Success rate= 85%, complication rate = 17% Surgical cyst-enterostomy Internal pseudocyst enteric anastomosis operative mortality rate of 3-5%
Pancreatitic abscess	Pancreatic abscesses generally occur late in the course of pancreatitis. Many of these respond to percutaneous catheter drainage and antibiotics. Those that do not respond require surgical debridement and drainage.

Complications

Early	Shock, ARDS, renal failure, Disseminated intravascular coagulation (DIC), sepsis, SIRS, Ca2+↓
Late(>1wk)	pseudocyst (most common) Pancreatic necrosis Infection (Within the first 1-3 weeks) abscess bleeding (eg: splenic artery), thrombosis fistula, recurrent oedematous pancreatitis.

Prognosis
80% improve rapidly
20% have at leat one complication from which 1/3 die
Ranson scoring:

• Ranson score of 0–2: Minimal mortality
• Ranson score of 3–5: 10–20% mortality
• Ranson score of >5: >50% mortality