Required Knowledge base to manage patients
with pancreatic insufficiency associated with Cystic fibrosis
Dr A.J. Chandrasekhar
Primary manifestations of
pancreatic involvement in cystic fibrosis
-
Fat maldigestion
-
Protein maldigestion
-
Fecal losses
Patho-physiology of
pancreatic insufficiency in Cystic fibrosis
The disorder is characterized by
-
Epithelial secretary dysfunction
-
Ductal obstructive lesions throughout multiple organ systems
-
Disturbances of mucus and electrolyte
secretion
-
Defective chloride permeability has been
described in Pancreas.
Normally, the pancreas secretes in response to
secretin.
-
Chloride
-
Bicarbonate
-
Water
In cystic fibrosis this response is greatly diminished, resulting in
-
Dehydrated
secretions
-
High protein concentrations
-
Thickened mucus.
The pancreatic lesions are in
general caused by obstruction of small ducts by secretions and cellular debris
although stenosis of large pancreatic ducts is occasionally seen.
Pathological findings of
Pancreas in Cystic fibrosis.
When severely affected, the pancreas is shrunken, cystic, fibrotic, and fatty.
Histologically
-
Hyperplasia and necrosis of ductular and centroacinar
cells
-
Inspissated secretions
-
Blockage of pancreatic ductules
-
Encroach upon acini, causing flattening and atrophy of the epithelium
-
Cystic spaces fill with calcium-rich, eosinophilic concretions.
-
A mild inflammatory reaction may be present around
obstructed acini, and progressive fibrosis gradually separates and replaces the pancreatic lobules.
-
The islets of Langerhans are spared in most cases until late in the
process and are concentrated in the shrinking pancreas.
Radiological features of
Pancreatic disease in Cystic fibrosis
Calcification, although rare, may be apparent on radiographs.
Ultrasonography, magnetic resonance imaging
(MRI), and computed tomographic (CT) scanning all can
document the progression of pancreatic disease in cystic fibrosis.
There are three general patterns of abnormality seen on MRI:
-
complete replacement with fatty tissue
-
a
small atrophic pancreas with partial replacement with fat (often a hyperintense
rim)
-
diffuse atrophy without evidence of fatty
replacement
ERCP: Duodenal aspirate in
patient with pancreatic insufficiency due to Cystic fibrosis Duodenal aspirates from patients with cystic fibrosis and complete pancreatic achylia
are of
-
Small volume
-
Viscous
-
Contain low concentrations of pancreatic enzymes
and bicarbonate.
CCK and secretin fail to stimulate fluid or enzyme secretion.
Patients
without absorptive defects may have normal or even elevated concentrations of pancreatic enzymes, but pancreatic secretions remain scanty and viscid and contain low
concentrations of bicarbonate even after stimulation.