Pancreatic Endocrine Disorders

Pancreatic Endocrine Disorders

Pancreatic Endocrine Disorders

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Pancreatic Islets & DM Patho - Islet Insights

  • Islet Cells & Hormones: (📌 A-G, B-I, D-S, PP-P)
    • α-cells: Glucagon (↑glucose)
    • β-cells: Insulin (↓glucose), Amylin
    • δ-cells: Somatostatin (inhibitory)
    • PP (γ)-cells: Pancreatic Polypeptide
  • Diabetes Mellitus (DM) Patho:
    • T1DM: Autoimmune β-cell destruction (insulitis, Type IV HSR) → absolute insulin deficiency. HLA-DR3/DR4.
    • T2DM: Insulin resistance + β-cell dysfunction → relative insulin deficiency. Islet amyloid (IAPP) deposition. Pancreatic islets: Normal vs. Type 1 Diabetes

⭐ Insulitis (lymphocytic infiltration of islets) is pathognomonic for Type 1 DM.

Insulinoma - Sweet & Lowdown

  • Most common functional PanNET; β-cell tumor secreting excess insulin.
  • Clinical Features: Recurrent hypoglycemia.
    • Neuroglycopenic: confusion, blurred vision, seizures, coma.
    • Autonomic (adrenergic): sweating, palpitations, tremor, anxiety.
  • Diagnosis:
    • 📌 Whipple's Triad:
      1. Symptoms of hypoglycemia.
      2. Low plasma glucose (e.g., < 50 mg/dL).
      3. Relief of symptoms with glucose administration.
    • Key Labs (during hypoglycemia): ↑ Insulin, ↑ C-peptide, ↑ Proinsulin; ↓ β-hydroxybutyrate.
    • Negative oral hypoglycemic agent screen.
  • Localization: Endoscopic ultrasound (EUS) is gold standard. CT/MRI.
  • Pathology: Typically solitary, benign (>90%), small (<2cm). ~5-10% associated with MEN1.
  • Treatment: Surgical resection (curative). Diazoxide, octreotide for unresectable cases.

⭐ Elevated C-peptide and proinsulin levels differentiate insulinoma from factitious hypoglycemia (exogenous insulin use).

EUS of pancreatic tumor with biopsy needle

Gastrinoma (ZES) - Acid Attack!

  • Gastrin-secreting neuroendocrine tumor (NET) causing Zollinger-Ellison Syndrome (ZES).
  • Locations: Duodenum (most common), pancreas. Often within the "Gastrinoma triangle".
  • Pathophysiology: ↑ Gastrin → parietal cell hyperplasia → massive ↑ HCl secretion.
  • Clinical Features:
    • Multiple, refractory, or distal (e.g., jejunal) peptic ulcers.
    • GERD, abdominal pain.
    • Chronic diarrhea, steatorrhea (low pH inactivates pancreatic enzymes).
  • Diagnosis:
    • Fasting serum gastrin (FSG): > 100 pg/mL (suspect); > 1000 pg/mL with gastric pH < 2 (diagnostic).
    • Secretin stimulation test: Paradoxical ↑ gastrin > 200 pg/mL from baseline.
    • Endoscopy: Prominent gastric folds.

⭐ Approximately 20-30% of gastrinomas are associated with Multiple Endocrine Neoplasia type 1 (MEN1).

  • Treatment: High-dose Proton Pump Inhibitors (PPIs); surgical resection if localized. Gastrinoma Triangle Locationoka

Other PanNETs - Rare Hormone Havoc

TumorHormone ↑Key Features / SyndromeNotes / LocationMalignancy
GlucagonomaGlucagon📌 4 D's: Dermatitis (necrolytic migratory erythema - NME), Diabetes (mild), DVT, DepressionTail/BodyHigh
VIPomaVIPWDHA Syndrome: Watery Diarrhea, Hypokalemia, Achlorhydria (Verner-Morrison)Tail/Body~50%
SomatostatinomaSomatostatinDiabetes mellitus, cholelithiasis, steatorrhea, hypochlorhydriaHead/PeriampullaryHigh

⭐ Necrolytic migratory erythema (NME), an erythematous rash with blistering, crusting, and scaling, is a pathognomonic feature of glucagonoma.

Pancreatic neuroendocrine tumor on CT

High‑Yield Points - ⚡ Biggest Takeaways

  • Insulinomas: Most common functioning PanNET, usually benign; cause hypoglycemia, Whipple's triad.
  • Gastrinomas (ZES): Cause multiple peptic ulcers; often malignant and associated with MEN1 syndrome.
  • Glucagonomas: Characterized by necrolytic migratory erythema, diabetes, and DVT.
  • Type 1 DM: Autoimmune destruction of pancreatic β-cells leading to absolute insulin deficiency.
  • Type 2 DM: Due to insulin resistance and relative insulin deficiency; islet amyloid deposition is common.
  • VIPomas: Result in WDHA syndrome (Watery Diarrhea, Hypokalemia, Achlorhydria).

Practice Questions: Pancreatic Endocrine Disorders

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VIPoma is associated with which syndrome?

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Flashcards: Pancreatic Endocrine Disorders

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Cells in insulinoma are _____morphic

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Cells in insulinoma are _____morphic

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