acute pancreatitis

ACUTE PANCREATITIS

Dr.mohamed soliman

Definition

• Acute inflammatory process of pancreas with variable involvement of other regional tissues

or remote organ systems

General Features

• Best diagnostic clue: Enlarged pancreas, fluid

collections & obliteration of fat planes

• Location: Pancreas and peripancreatic tissue

• Size: Pancreas increased in size, focal or diffuse

involvement

Grayscale Ultrasoundo In mild pancreatitis sonographic signs may be subtle or normal

o Enlarged, hypoechoic pancreas: Due to interstitial edema

o Blurred pancreatic outline/margin: Due to pancreatic

edema and peripancreatic exudate

o Enlarged heterogeneous pancreas in patients with

intrapancreatic necrosis or hemorrhage

o Dilated pancreatic duct due to duct compression by

edematous pancreas

o Inflammatory change in soft tissues around

pancreas/kidneys

o Gallstone or intraductal calculi)

Grayscale Ultrasound

o Complications• Pancreatic pseudocyst: Well-circumscribed, unilocularcystic lesion within pancreas or peri-pancreatic tissue• Pancreatic/peri-pancreatic fluid collection• Pancreatic abscess or infected collections:Thick-walled, mostly anechoic with internalechoes and debris• Vascular complications: Pseudoaneurysmformation and porto splenic venous thrombosis,Doppler USG helps for diagnosis• Pancreatic ascites and pleural effusion (usually left –sided)

Radiographic Findings

o Sentinel loop: Mildly dilated, gas-filled segment of small bowel with or without air-fluid levels

o "Colon cutoff" sign

• Markedly distended transverse colon with air

• Absence of gas distal to splenic flexure caused by

colonic spasm due to spread of pancreatic

inflammation to proximal descending colon

CT Findings

• CECT

o Focal or diffuse enlargement of pancreas with ill-defined margino Heterogeneous enhancement: Areas of nonenhancement indicates necrotic element

o Infiltration of peripancreatic fato Detection of complications

• Pancreatic/peripancreatic collection +/- infection:Rim-enhancing fluid density

• Pseudoaneurysm: Cystic vascular lesion, enhances like adjacent blood vessels

• Portal/splenic venous thrombosis: Nonenhancement of thrombosedvein

• Chest: Pleural effusions & basal atelectasis

MR Findings

• T2WI FSo Fluid collections, pseudocyst, necrotic areas: Hyperintenseo Gallstones or intraductal calculi: Hypointense• Tl c+o Heterogeneous enhancement pattern• Non enhancing decreased signal areas (necrosis!fluidcollection/pseudocyst)• Vascular occlusions can be easily demonstrated• MRCP

o All fluid-containing structures: Hyperintenseo Dilated or normal main pancreatic duct (MPD)

Imaging Recommendations• Best imaging tool: CECT, ultrasound• Protocol advice

o Role of ultrasound in acute pancreatitis: Although ultrasound is an ideal initial examination in acutely ill patient, it has certain diagnostic limitations in early acute pancreatitis• Changes of pancreatitis may be quite subtle and the pancreas may initially appear normal

• Transducer pressure cannot be applied on the abdomen as the patient often has severeabdominal pain• Associated distended colon, and small bowel obscures visualization of pancreas and

peri pancreatic soft tissueso Ultrasound is useful in

• Detection of gallstone/choledocholithiasis• Survey of potential complications such as pseudocyst/pancreatic abscess formation

• Provide real time guidance for interventional procedures (e.g., aspiration of peri-pancreatic collection/ abscess)

o CECT helps in better delineation of extent of pancreatitis, detection of pancreatic necrosis and complications, prediction of clinical outcome

DDx: Acute Pancreatitis

Infiltrating Pancreatic Carcinoma

• Irregular, heterogeneous, hypoechoic mass

• Abrupt obstruction & dilatation of pancreatic duct

• Regional nodal metastases: Splenic hilum & porta hepatis

• Contiguous organ invasion

o Duodenum, stomach & mesenteric root

DDx: Acute Pancreatitis

Lymphoma & Metastases

• Nodular, bulky, enlarged pancreas due to infiltration

• Retroperitoneal adenopathy

• Peripancreatic infiltration (obliteration of fat planes)

• Primary may be seen in case of metastatic infiltration

DDx: Acute Pancreatitis

Chronic Pancreatitis

• Atrophic pancreatic parenchyma• Intraductal/parenchymalcalcifications• Lack of peri-pancreatic fluid collection• Functional pancreatic exocrine/endocrineinsufficiency

DDx: Acute Pancreatitis

Perforated Duodenal Ulcer

• Penetrating ulcers may infiltrate anterior pararenal

space, simulating pancreatitis

• Less than 50% of cases have evidence of extraluminal

gas or contrast medium collections

• Pancreatic head may be involved"Shock" Pancreas

• Infiltration of peripancreatic & mesenteric fat planes

following hypotensive episode (e.g., blunt trauma)

• Pancreas itself looks normal or diffusely enlarged

Etiology- Acute Pancreatitis

o Alco h 01/gallstones/ meta bolic/ infection/tra uma/ drugs

o Pathogenesis: Due to reflux of pancreatic enzymes,

bile, duodenal contents & increased ductalpressure

• MPD or terminal duct blockage

• Edema; spasm; incompetence of sphincter of Oddi

Acute Pancreatitis

Gross Pathologic & Surgical Features

• Bulky pancreas, necrosis, fluid collection & pseudocystMicroscopic Features

• Acute edematous pancreatitis

o Edema, congestion, leukocytic infiltrates

• Acute hemorrhagic pancreatitis

o Tissue destruction, fat necrosis & hemorrhage

Staging, Grading or Classification Criteria

• CT classification: Five grades based on severityo Grade A: Normal pancreaso Grade B: Focal or diffuse enlargement of gland, contour irregularities & heterogeneous attenuation,noperipancreatic inflammationo Grade C: Intrinsic pancreatic abnormalities &associated inflammation in peri pancreatic fato Grade D: Small & usually single, ill-defined fluid collectiono Grade E; Two or more large fluid collections, presence of gas in pancreas or retroperitoneum• Most important criterion: Presence & extent of necrotizing pancreatitis (nonenhancing parenchyma)

CLINICAL ISSUES

Presentation• Most common signs/symptomso Acute onset epigastric pain, often radiating to backo Tenderness, fever, nausea, vomiting• Lab datao Increased serum amylase & lipaseo Other: Hyperglycemia, increased lactate dehydrogenase(LDH), leukocytosis, hypocalcemia, fall in hematocrit, rise in blood urea nitrogen (BUN)Demographics• Age: Usually young & middle age group• Gender; Males more than females

Natural History & Prognosis

• Complicationso Pancreatic• Fluid collections, pseudocyst, necrosis, abscess

o Gastrointestinal• Hemorrhage, infarction, obstruction, ileus

o Biliary: Obstructive jaundice

o Vascular: Pseudoaneurysm, porto-splenic vein thrombosis, hemorrhage

o Disseminated intravascular coagulation (DIC), shock, renal failure

• Prognosiso Early detection with minor complications: Goodo Late detection with major complications: Pooro Ranson criteria/APACHE II criteria help predict

prognosiso Infected pancreatic necrosis: Almost 50% mortality even with surgical debridement

Treatment

• Conservative

o Nil by mouth (NPO), gastric tube decompression,

analgesics, antibiotics

• Treat complications of acute pancreatitis

o Infected or obstructing pseudocysts require drainage: Surgical or percutaneous routes

o Infected necrosis needs surgery/catheter drainage

DIAGNOSTIC CHECKLIST

Consider

• Rule out other pathologies which can cause

"peripancreatic infiltration"

Image Interpretation Pearls

• Bulky, irregularly enlarged pancreas with obliteration of peripancreatic fat planes, fluid collections, pseudocyst or abscess formation

Transversetransabdominalultrasound shows a swollen pancreatic body with ill-defined heterogeneous hypoechoic echopattern. The pancreatic head and

tail are less severely affected.

head

body

tail

Transverse transabdominalultrasound shows focal

enlargement of pancreatic head with homogeneous

hypoechoic echo pattern in focal pancreatitis.

Note normal echo pattern of pancreatic body.

body

head

Transverse transabdominalultrasound shows diffuse,hypoechoic,

enlarged pancreatic

parenchyma.

Note the presence of mild pancreatic ductaldilatation

pancreas

Transverse CECTshows an

inflamed pancreas with

peripancreatic stranding . The adjoining duodenum

appears inflamed with an

edematous wall.

Note a calculus in the gallbladder

Gall stone

duodenum

Transverse

transabdominal ultrasound

shows a large heterogeneous

collection involving the

pancreatic head and body

compatible with abscess

formation, resulting from

infected phlegmon.

Transverse transabdominal

ultrasound shows subtle

swelling with hypoechoic

echo pattern of the

pancreatic tail, compatible

with focal pancreatic

necrosis.

Transverse transabdominalultrasound

shows a large, ill-defined,

anechoic/hypoechoic

collection in the

pancreatic body in acute

pancreatitis.

Longitudinal transabdominal

ultrasound shows a large

heterogeneous fluid

collection in the anterior

peripancreatic area. Note the pancreatic body is

compressed by the fluid

collection.

pancreas

Fluid collection

Enhanced ct

Acute pancreatitis .. hypoechoic

Pancreas after resolution

A

B

c