Chronic pancreatitis: A diagnostic dilemma

Table 3 A summary of the APA diagnostic guidelines (2014)

Topic		Level
Epidemiology and risk factors	Data on population-based estimates are emerging	C/L
	A small fraction of patients progress from AP to CP	C/M
	Alcohol/smoking are independent risk factors for CP. Both are associated with disease progression and their risks are likely multiplicative	S/H
	The spectrum of risk factors for CP has broadened	C/L
	Genetic discoveries are rapidly uncovering new susceptibility factors. Knowledge of gene-environment interactions may translate into new diagnostic and treatment paradigms	S/M
Pathological Definitions	CP is characterized by atrophy and fibrosis of the exocrine tissue with or without chronic inflammation	-
	Scarring of the parenchyma may be focal, patchy or diffuse	-
	Progressive fibrosis and atrophy may lead to exocrine insufficiency followed by endocrine insufficiency	-
	Autoimmune pancreatitis can mimic pancreas carcinoma	-
Ultrasound and CT	Ultrasound and CT are best for late findings of CP but are limited in the diagnosis of early or mild pancreatitis	C/M
	Intraductal pancreatic calcifications are the most specific and reliable sonographic and CT signs of CP	S/M
	CT is helpful for the diagnosis of complications of CP	S/M
	CT is helpful for the diagnosis of other conditions that can mimic CT	C/L
MRI imaging	Compared with ultrasound and CT, MRI is a more sensitive imaging tool for the diagnosis of CT	C/M
	Ductal abnormalities are very specific and reliable MRI signs of CP	C/L
	Signal intensity changes in the pancreas, seen on MRI, may precede ductal abnormalities and suggest early CT	C/L
	Stimulation of the pancreas using IV secretin may improve the diagnostic accuracy in the detection of ductal and parenchymal abnormalities seen on CT	C/L
Endoscopic ultrasound	The ideal threshold number of EUS criteria necessary to diagnose CP has not been firmly established, but the presence of 5 or more or 2 or less strongly suggests or refutes the diagnosis of CP	S/L
	The EUS features of CP are not necessarily pathologic and may occur as a normal aging, as a normal variant, or due to the nonpathologic asymptomatic fibrosis in the absence of endocrine/exocrine dysfunction	S/L
	The relatively poor IOA for EUS CP features limits the diagnostic accuracy and overall utility of the EUS for diagnosing CP	S/M
ERCP	ERP is rarely used for diagnostic purposes	S/M
	The correlation between the Cambridge criteria and histology is highest in advanced CP	S/M
	Multiple confounders limit the interpretation of ductal changes by Cambridge criteria	S/L
Indirect PFTs	Indirect PFTs generally are sensitive for steatorrhea and useful in quantifying the degree of exocrine insufficiency	C/L
	Indirect PFTs are moderately sensitive and specific for diagnosing advanced CP but are less so for diagnosing early CP	C/S
	The FE-1 assay, polyclonal assay more than monoclonal, can be limited in specificity, especially if the stool has is watery and/or in the presence of small bowel disease	C/L
	Faecal chymotrypsin may be useful in detecting compliance with exogenous pancreatic enzyme supplementation	C/L
	Faecal fat assays are sensitive for steatorrhea but are of limited utility due to the cumbersome nature of patient collection and laboratory handling of samples. In addition, strict adherence to dietary recommendations for several days is required	C/M
Direct PFTs	Direct PFTs have high sensitivity for detecting late CP, but lower sensitivity (70%-75%) for early CP	S/L
	The traditional secretin and CCK PFTs performed with the aortoduodenal tube pancreas fluid collection are highly accurate but require fluoroscopy for confirmation of tube placement and are not widely utilized	S/M
	The ePFT has good correlation with the traditional Dreiling PFT	S/M
Correlation of imaging and function with histology	As structural severity worsens in CP, exocrine function declines	S/M
	Both EUS and PFT results correlate with fibrosis in CP	C/L
	A combined approach (e.g., EUS/ePFT) could improve detection of minimal change CP (MCCP)	C/L

Levels relate to level of recommendation (conditional; strong)/level of evidence (low; moderate; high). AP: Acute pancreatitis; CP: Chronic pancreatitis; CT: Computed tomography; MRI: Magnetic resonance imaging; IV: Intravenous; EUS: Endoscopic ultrasound; IOA: Inter-observer variability; PFTs: Pancreatic function tests; FE-1: Fecal elastase-1; CCK: Cholecystokinin; ePFT: Endoscopic PFT; MCCP: Minimal change chronic pancreatitis.