Pancreatic Disorders: A Comprehensive Review

# Pancreatic Disorders: A Comprehensive Review ## Summary The **pancreas** is a vital organ performing both **exocrine** and **endocrine** functions. **Exocrine failure**, primarily due to conditions like **chronic pancreatitis**, leads to **malabsorption** and **steatorrhea**. In contrast, **endocrine failure** results in **diabetes mellitus**. **Acute pancreatitis**, often caused by **gallstones** or **alcohol**, involves the premature activation of **trypsin** within the pancreas, leading to **autodigestion**. It typically presents with severe **epigastric pain** and elevated **amylase/lipase** levels. **Pseudocysts** are a common complication of acute pancreatitis. **Chronic pancreatitis** is characterized by progressive **fibrosis** and destruction of pancreatic parenchyma, most commonly from chronic **alcohol abuse**. This leads to recurrent pain, steatorrhea, and eventually diabetes. **Pancreatic neoplasms** range from benign **serous cystadenomas** to highly aggressive **pancreatic ductal adenocarcinoma (PDAC)**. PDAC typically affects the **head of the pancreas**, causing **painless jaundice**, and carries a grim prognosis due to late diagnosis and rapid metastasis. **Diabetes mellitus** involves either autoimmune destruction of **beta cells** (Type 1) or a combination of **insulin resistance** and relative insulin deficiency (Type 2). Both types lead to microvascular and macrovascular complications. Various **pancreatic cysts**, including pseudocysts and true cysts (serous, mucinous), also present distinct clinical and pathological features, with **mucinous types** carrying significant malignant potential. ## Key Points * **Exocrine Pancreas**: **Acinar cells** produce digestive enzymes (**amylase, lipase, trypsin**); failure leads to **malabsorption** and **steatorrhea**. * **Endocrine Pancreas**: **Islets of Langerhans** contain **beta cells** (insulin), **alpha cells** (glucagon), and **delta cells** (somatostatin); failure leads to **diabetes**. * **Acute Pancreatitis Pathogenesis**: Premature activation of **trypsin** within the pancreas, leading to **autodigestion**. * **Causes of Acute Pancreatitis (GET SMASHED)**: **Gallstones** (most common overall), **Alcohol** (most common in recurrent cases), **Hypercalcemia**, **Hypertriglyceridemia**, **Trauma**, **Drugs**, **ERCP**. * **Acute Pancreatitis Key Histo Finding**: **Necrotic acini with preservation of ducts**. * **Chronic Pancreatitis Pathogenesis**: Repeated bouts of inflammation leading to **fibrosis** and destruction; **chronic alcohol** is the most common cause. * **Chronic Pancreatitis Key Sequence**: **Steatorrhea** (exocrine failure) comes **BEFORE diabetes** (endocrine failure). * **Pancreatic Ductal Adenocarcinoma (PDAC) Location**: 60-70% occur in the **HEAD** of the pancreas. * **PDAC Survival**: 5-year survival is typically **<10%**, one of the worst prognoses. * **PDAC Key Genetic Mutation**: **KRAS activating mutation** (>90% of cases). * **Courvoisier Sign**: **Painless jaundice** + **palpable non-tender gallbladder**, classic for pancreatic head cancer. * **Trousseau Syndrome**: **Migratory thrombophlebitis**, associated with tumor hypercoagulability in PDAC. * **Type 1 Diabetes Mellitus (T1DM)**: **Autoimmune destruction of β cells** leading to absolute insulin deficiency, associated with **HLA-DR3/DR4** and **insulitis**. * **Type 2 Diabetes Mellitus (T2DM)**: **Insulin resistance** + relative insulin deficiency, strongly linked to **obesity** and characterized by **islet amyloid deposits (IAPP)**. * **Pancreatic Pseudocyst**: Most common complication of acute pancreatitis; **NO epithelial lining**. * **Mucinous Cystadenoma**: Has **HIGH malignant potential**, requires resection. ## Detailed Notes ### Pancreas Basics The **exocrine pancreas**, composed of **acinar cells**, produces digestive enzymes such as **amylase, lipase, and trypsin**. Failure of these functions leads to **malabsorption** and **steatorrhea**. The **endocrine pancreas** consists of the **islets of Langerhans**, which contain **beta cells** (producing insulin), **alpha cells** (producing glucagon), and **delta cells** (producing somatostatin). Failure of the endocrine functions results in **diabetes**. ### 1. Acute Pancreatitis #### Classification Acute pancreatitis can be classified as **interstitial (mild)**, involving only edema with a good prognosis, or **necrotizing (severe)**, characterized by hemorrhage and necrosis, which carries a high mortality rate. #### Pathogenesis The core mechanism of acute pancreatitis is the **premature activation of trypsin** inside the pancreas. This activated trypsin then triggers other enzymes like elastase, phospholipase, and lipase, leading to the **autodigestion** of pancreatic tissue. Trypsin is considered the master activator; its premature activation initiates the entire cascade. #### Causes — GET SMASHED | Cause | Key Point | |---|---| | **Gallstones*