Congenital Disorders of Pancreas

Pancreas Divisum

MCQ - Congenital Variants of Pancreatic Ductal Anatomy

Explanation:

• Pancreas divisum (PD) is the most common congenital variation of pancreatic ductal anatomy.

Explanation:

• Pancreatic Divisum:

  • C/F = most of the patients are asymptomatic
  • pathophysiology : occurence of recurrent acute / chronic pancreatitis is a matter of debate if this is due to pancreas divisum because even after sphincteroplasty of minor papillae there is still risk of pancreatitis
  • Sensitivity of EUS : close to 90%
  • IOC = MRCP but if there is any doubt go for EUS

  • Risk does not increase or decrease with complete/ incomplete divisum

    

(MCQ) Gene associated with recurrent pancreatitis with PD ? A - SPINK1 B-PRSS1 C-CFTR D-anionic trypsinogen gene

Spectrum of Pancreas Divisum

1. Normal Pancreatic Duct Anatomy
   • A: Normal duct with the duct of Santorini
     • The normal configuration where both the main pancreatic duct (duct of Wirsung) and the accessory duct (duct of Santorini) are present.
   • B: Normal duct without the duct of Santorini
     • The normal configuration where only the main pancreatic duct (duct of Wirsung) is present, and the accessory duct is absent.
2. Pancreas Divisum Variants
   • C: Pancreas divisum
     • The dorsal and ventral ducts remain separate.
     • The duct of Wirsung drains the uncinate process and head of the pancreas into the major papilla.
     • The duct of Santorini drains the majority of the head of the pancreas.
   • D: Dorsal duct only
     • The dorsal duct is the only functional duct.
     • The duct of Wirsung is absent.
   • E: Functional pancreas divisum
     • There is a filamentous communication between the ducts, allowing some degree of drainage from both ducts.

Figure Reference

Figure 103.6:

• Illustrates the spectrum of pancreas divisum, including the normal duct anatomy and various configurations of pancreas divisum.
  • A: Normal duct with duct of Santorini
  • B: Normal duct without duct of Santorini
  • C: Pancreas divisum with separate dorsal and ventral ducts
  • D: Dorsal duct only, with the duct of Wirsung absent
  • E: Functional pancreas divisum with filamentous communication between ducts

Multiple Choice Question (MCQ)

Which of the following represents the most common variant of pancreas divisum?

a. Normal duct with duct of Santorini

b. Normal duct without duct of Santorini

c. Pancreas divisum with separate dorsal and ventral ducts

d. Dorsal duct only with the duct of Wirsung absent

e. Functional pancreas divisum with filamentous communication between ducts

Answer: c. Pancreas divisum with separate dorsal and ventral ducts

Explanation:

• The most common variant of pancreas divisum involves the dorsal and ventral ducts remaining separate. In this configuration, the duct of Wirsung drains the uncinate process and head of the pancreas into the major papilla, while the duct of Santorini drains the majority of the head of the pancreas.

Abnormal Pancreaticobiliary Maljunction

APBJ:

(MCQ) • Not true about ABPJ? A-defined by long common channel more than 1 cm B-ABPJ without biliary duct dilatation can be managed conservatively C-More common in Asian population D-All patients with Type 1 CDC have ABPJ

Explanation:

• Japanese Definition of APBJ:
  • Both sphincters must unite beyond the sphincter complex ( no mention of length of common channel)
• Junction of PD and CBD outside duodenal wall
• Biliopancreatic reflux
• Higher in Asian population
• All patients with type 1 CDC
• Pressure in PD>CBD----reflux of contents
• Malignancy even in absence of CDC

• KOMI classification of APBJ:

  

  

• 2 types of presentation:

  • associated with extrahepatic biliary ductal dilatation =
    • Excision of Extrahepatic biliary apparatus with RY HJ
  • associated without Dilatation =
    • can be managed with prophylactic simple cholecystectomy but some say Excision of extrahepatic bile duct with RY HJ needed. BUT CANNOT BE MANAGED CONSERVATIVELY

MCQ - Anomalous Pancreaticobiliary Ductal Junction

Explanation:

• In anomalous pancreaticobiliary ductal junction, the main pancreatic and common bile ducts join to form a common channel (usually measuring more than 15 mm) proximal to the sphincter of Oddi.

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Annular Pancreas

(MCQ) Ring of pancreatic tissue in annular pancreas is derived from - A- Ventral pancreas B- Dorsal pancreas C- Duodenal tissue D-Both A &B

(MCQ) Not true about annular pancreas ?

A - Presents with pain abdomen and bilious vomiting in children B-Most common congenital anamoly is Down syndrome C- Double bubble sign on plain x ray D-duodenojejunostomy is treatment of choice

Explanation:

• Tip of Left ventral bud adheres to duodenum and forms ring
• Presentation:
  • Children:
    • Non bilious vomitting ( due to prepapillary obstruction)
    • Polyhydramnios
    • symptoms of obstruction
    • associated with many congenital anamolies ; MC is Down syndrome [ TEF, malrotation also seen]
  • Adults:
    • Most Commonly Asymptomatic (50-70%)
    • Pain is Most Common symptom
• Duodenoduodenostomy has replaced duodenojejunostomy as the treatment of choice be- cause it has a lower incidence of postoperative complications, particularly obstruction and blind-loop syndromes.

MCQ - Annular Pancreas

Explanation:

• Annular pancreas generally presents in the newborn period, with 75% of cases presenting in the first week of life.
• Radiographs showing the "double bubble" sign, classically attributed to duodenal atresia, may be seen in more than 88% of patients.
• Emesis may be bilious (up to 50%) or more commonly nonbilious (>90%).
• Duodenoduodenostomy is the treatment of choice for annular pancreas due to the lower incidence of obstruction and blind-loop syndromes.
• The most common congenital abnormality associated with annular pancreas is Down syndrome.

Theories in Annular Pancreas:

• Lecco Theory: Adherence of the right ventral pancreatic bud to the duodenum before gut rotation results in a partial or complete ring of pancreatic tissue around the duodenum.
• Baldwin Theory: The left ventral bud persists to form the annular pancreas.
• Kamisawa Theory: The tip of the left ventral bud adheres to the duodenum and stretches to form a ring. The exact location of this attachment in relation to the bile duct determines the final arrangement of the annular duct.
• Preampullary obstruction resulting in nonbilious vomiting has been reported to be more common in annular pancreas than in other causes of duodenal obstruction (94% vs. 10%).

GI Abnormalities Associated with Annular Pancreas:

• Intestinal malrotation
• Tracheoesophageal fistula
• Mobile right colon
• Omphalocele
• Nonrotation
• Duodenal atresia
• Situs inversus
• Cardiac anomalies
• Genitourinary abnormalities

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Heterotopic Pancreas

MCQ - Heterotopic Pancreatic Tissue

Explanation:

• Heterotopic pancreatic tissue is found in:
  • Stomach (24%)
  • Duodenum (32%) ? ? ?
  • Jejunum (29%)
  • Meckel diverticulum (15%)
  • Gallbladder (3%)
• Heinrich histological classification of heterotopic pancreas:
  • Type 1: Normal pancreatic tissue components present, including ducts, acini, and islets.
  • Type 2: Few acini and multiple ducts, absence of endocrine elements.
  • Type 3: Presence of ducts. Acini and islet cells are absent.

(MCQ) • Most common location of heterotopic pancreas ?

A-Stomach • B-Duodenum • C-Jejunum • D-spleen

Explanation:

• Stomach ›duodenum
• Mostly asymptomatic
• Ulcers, bleeding
• Central umblication

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Congenital Hyperinsulinemia

Explanation:

• Congenital hyperinsulinemia involves an inactivating mutation in the subunit of the ATP-dependent potassium channel.
• It is the malfunction, not the proliferation, of beta cells that is responsible for the condition of hyperinsulinemia.
• The preferred terminology now is idiopathic hyperinsulinism of infant or adult.
• The term nesidioblastosis is not recommended for hyperinsulinism or islet aggregates in an atrophic pancreas.

MCQ - Congenital Hyperinsulinism Severity and Treatment

Explanation:

• Inactivating mutations in the KATP channel are the most common and severe form of congenital hyperinsulinism (CHI).
• GDH CHI (glutamate dehydrogenase CHI) is the second most common form and is known as hyperinsulinism and hyperammonemia (HI/HA) syndrome. It presents with recurrent episodes of hypoglycemia that are less severe than in KATP-CHI.
• First-line medical therapy for infants with CHI is diazoxide, a KATP channel agonist. Patients with GDH-CHI, SCHAD-CHI, and perinatal stress-induced hyperinsulinism typically respond well to diazoxide.
• Octreotide is used as a second-line medical therapy for infants unresponsive to diazoxide.

Additional Information:

• CONGENITAL HYPERINSULINISM (CHI):
  • Dysregulated insulin secretion resulting in persistent mild to severe hypoglycemia.
  • Occurs at a frequency of 1 in 30,000 to 50,000 live births.
  • Mutations in six genes are associated with CHI:
    • Sulfonylurea receptor 1 (SUR-1; encoded by ABCC8)
    • Potassium inward rectifying channel (Kir6.2; encoded by KCNJ11)
    • Glucokinase (GK; encoded by GCK)
    • Glutamate dehydrogenase (GDH; encoded by GLUD1)
    • Short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD; encoded by HADH)
    • Ectopic expression on beta-cell plasma membrane of SLC16A1 (encodes monocarboxylate transporter 1 [MCT1])
• Inactivating mutations in the KATP channel: Most common and severe form of CHI.
• GDH CHI: Second most common form, also known as hyperinsulinism and hyperammonemia (HI/HA) syndrome.
• First-line pharmacologic therapy: Diazoxide.
• Second-line medical therapy: Octreotide for infants unresponsive to diazoxide.
• Diffuse form of CHI: Diffuse hyperfunction of pancreatic beta cells with enlarged nuclei, without increased beta-cell proliferation rate or mass.

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Noninsulinoma Pancreatogenous Hypoglycemia Syndrome (NIPHS)

Explanation:

• Insulinoma is indeed the most common cause of hyperinsulinemic hypoglycemia.
• NIPHS (Noninsulinoma Pancreatogenous Hypoglycemia Syndrome) is characterized by excessive pancreatic beta cell function, with pathologic changes including pancreatic islet hyperplasia and dysplasia, and beta cells budding from and in apposition to pancreatic ductal structures.
• NIPHS is typically a disease of infancy but can occur in adults, where it can be challenging to differentiate from insulinoma. Postprandial hypoglycemia within 4 hours of a meal is the hallmark of NIPHS, helping to differentiate it from insulinoma.
• Like insulinoma, patients with NIPHS may have a positive 72-hour fast, with episodes of hypoglycemia associated with inappropriate elevation of insulin, C-peptide, and proinsulin levels.
• Nesidioblastosis is a clinical diagnosis of exclusion, confirmed on pathologic examination of the pancreas and clinical response to treatment.
• Treatment for NIPHS includes 95% distal pancreatectomy, dietary control, and medical therapy with diazoxide and somatostatin analogues.

Additional Information:

NIPHS vs. Insulinoma:

• NIPHS:
  • Postprandial hypoglycemia within 4 hours of a meal.
  • Pathologic changes in the pancreas including islet hyperplasia and dysplasia.
  • Diagnosis confirmed through exclusion of insulinoma and pathologic examination.
  • Treatment involves pancreatectomy, dietary control, and medical therapy.
• Insulinoma:
  • Typically presents with fasting hypoglycemia.
  • Diagnosis confirmed through imaging studies and biochemical tests.
  • Treatment usually involves surgical removal of the tumor.