Chronic Pancreatitis (Lab and Instrumental Diagnosis).pptx

Laboratory and instrumental investigations of chronic pancreatitis.

1. Laboratory & Instrumental Investigations in Chronic Pancreatitis Jonathan Wong Group 26 ⬇

2. LABORATORY INVESTIGATIONS

3. 1. BIOCHEMICAL ANALYSIS Normal or slightly elevated serum amylase and lipase levels ↓ serum levels of fat-soluble vitamins (A, D, E, K) ↑ serum bilirubin & ↑ alkaline phosphatase (due compression of the intrapancreatic portion of bile duct by pancreatic edema or fibrosis) ↑ serum triglycerides (in cases of chronic pancreatitis due to hypertriglyceridemia) ↑ serum levels of immunoglobulin G4 (IgG4) (in patients with type I autoimmune pancreatitis)

4. 2. 72-HOUR FECAL FAT TEST Results : Increased in fecal fat (steatorrhea) The patient is placed on 100 g/day fat diet and stool is collected daily for 3 days. Individual with normal pancreatic function excreted < 7% of tota l fat ingested while in pancreatic insufficiency, patients excrete > 20% of fat . Simple and cheap test for assessing pancreatic function, to determine if patient has significant steatorrhea. Has limited role in diagnosis of chronic pancreatitis (require high degree of pancreatic insufficiency to have positive test).

5. 3. 2-HOUR POST-PRANDIAL BLOOD GLUCOSE / GLUCOSE TOLERANCE TEST Results : ↑ Elevated serum glucose level, 2 hours post-prandial

6. 4. SECRETIN STIMULATION TEST Principles : Secretin is a hormone made by the small intestine. Secretin stimulates the pancreas to release a fluid (bicarbonate) that neutralizes stomach acid and aids in digestion. Patient is given IV secretin and the pancreatic secretions (released into the duodenum) are aspirated with a nasogastric tube and analyzed over a period of about 2 hours. The secretin stimulation test measures the ability of the pancreas to respond to secretin. Results : Decreased pancreatic secretion

7. INSTRUMENTAL INVESTIGATIONS

8. 1. PLAIN ABDOMINAL X-RAY Plain abdominal radiograph shows extensive pancreatic calcifications . Calcifications in chronic pancreatitis is the most specific feature, however, it occurs late in the course of the disease.

9. 2. ABDOMINAL ULTRASOUND Abdominal US may show increase in size of the pancreas , increase in echogenicity of the parenchyma , areas of fibrosis and atrophy , the presence of parenchymal calcifications , a dilated pancreatic duct and pancreatic duct stones. Ultrasound is of limited diagnostic utility in the diagnosis of chronic pancreatitis since the pancreas may not be visible due to body habitus or overlying intestinal gas.

10. Abdominal US shows atrophic pancreas with dilated main pancreatic duct (short arrow) with intraductal calculi (arrow)

11. 3. ENDOSCOPIC ULTRASOUND (EUS) Transabdominal US has a limited scope in the assessment of pancreas in obese individuals and gaseous abdomen. This limitation is overcome by EUS, as the high frequency transduces in EUS is in close proximity to the pancreas, hence visualizing it better. Results: Ductal (hyperechoic foci, hyperechoic strands, lobular contour, cysts) Parenchymal (main duct dilatation, duct irregularity, visible side branches, stones) abnormalities. EUS should only be used if the diagnosis is in question after cross-sectional imaging (CT/MRI). It is invasive and lacks specificity.

12. EUS in a patient with chronic pancreatitis shows echogenic strands (arrow) in the head of pancreas (A). EUS in another patient with chronic pancreatitis (B) shows dilatation of main pancreatic duct (arrow) and side branches (short arrow)

13. 4. CT-SCAN CT is the recommended first-line for the diagnosis of chronic pancreatitis as it is widely available and is able to image the entire pancreas and pancreatic duct. Findings: Presence of pancreatic calcification , focal or diffuse enlargement of the pancreas , ductal dilation , and/or vascular complications .

14. CT (A) – Shows extensive pancreatic calcifications (arrows) CT (B) – Shows pancreatic atrophy (arrow) and a small cystic area (short arrow) CT (C-E) – Pancreatic duct irregularity and varying degrees of dilatation A large pseudocyst is also seen in CT (D)

15. 5. MRI / MRCP MRI including MRCP gives more detailed images of the pancreatic duct. Drop in signal on T1-weighted sequences are useful markers for chronic pancreatitis and appear to hold promise for earlier diagnosis than is possible with CT. The ductal findings on early disease can range from a normal-looking main pancreatic duct (MPD) to mild irregularity of MPD and side branches. With more advanced pancreatitis, there is progressive glandular atrophy, irregularity of the pancreatic duct contour with focal areas of narrowing and dilatation, and ectasia of the side branches.

16. Diffusion weighted MRI (DWI) in normal patient and patient with chronic pancreatitis: Axial T1-weighter image (A) in a normal subject shows diffuse hyperintensity of the pancreas (arrow). The corresponding DWI (B) shows no diffusion restriction (arrow) Axial T1-weighted image in a patient with focal autoimmune pancreatitis (C) shows a hypointense lesion in the tail of pancreas.

17. 6. s-MRCP (Secretin-enhanced MRCP) Findings : Abnormal exocrine function S-MRCP is suggested when the diagnosis of chronic pancreatitis is not confirmed following cross-sectional imaging with CT/MRI or EUS and clinical suspicion remains high. s-MRCP allows for better visualization of the main and side branch pancreatic ducts by stimulating the release of bicarbonate from the pancreatic duct cells.

18. 7. Endoscopic Retrograde Cholangiopancreatography (ERCP) ERCP which was once considered as the gold standard test for CP is seldom used for diagnosis of CP at present. Although ERCP gives the most detailed images of the pancreatic duct, it is no longer use for the diagnosis of chronic pancreatitis because of alternative imaging modalities and the associated risk of complications. s-MRCP has replaced diagnostic ERCP as it is as accurate and far safer. ERCP is reserved for therapy in chronic pancreatitis to remove stones or stent pancreatic ducts strictures.

19. In patients with early chronic pancreatitis (A), mild dilatation of the main pancreatic duct (arrow) and side branches (short arrow) is seen. Marked ductal dilatation (arrow) with a dominant stricture (show arrow) is shown in B. Another patient (C), strictures (arrow) and intraductal calculi (short arrow) are seen.