Notes by dr Claudio Italiano
IPE derives from an alteration of the production, release or degradation of pancreatic enzymes, which leads to poor digestion and malabsorption of nutrients, especially lipids. IPE can be caused by various pathological conditions, including acute or chronic pancreatitis, cystic fibrosis, pancreatic neoplasms, abdominal surgery, such as gastrectomy or duodenopancreatectomy. The most common symptoms of IPE include steatorrhea (excessive presence of fats in the stool, which make them shiny and greasy), weight loss, pain and abdominal cramps. Symptomatology is always related to inadequate digestion of lipids. During the clinical course, while the digestion of proteins and starch continues to occur within physiological levels even in the presence of a severe form of IPE, the malabsorption of lipids becomes the main sign and the cause of clinical symptoms and nutritional deficiencies. The poor digestion of lipids results in malnutrition, resulting from the lack of absorption of the fat-soluble vitamins A, D, E, K and the reduction of the intake of micronutrients and circulating lipoproteins, conditions associated with a risk of morbidity and secondary mortality greater than that present in the general population. The malabsorption of lipids can be caused by several factors: reduced production of pancreatic lipases, destruction of the glandular parenchyma, obstruction of the pancreatic duct, surgical resection.
Failure to digest lipids can also cause or exacerbate disorders of gastrointestinal motility, altering neuro-hormonal regulation. In fact, the presence of undigested food in the intestine modifies the production of CCK, which results in a rapid emptying of the stomach and in an altered antroduodenal and biliary motility. The rapid transit of food at the intestinal level prevents an adequate emulsion of lipids with bile and pancreatic enzymes, altering the digestive process and absorption and modifying the functionality of the pancreas. IPE was also found in 43% of insulin-dependent diabetics and in 33% of patients with type 1 diabetes, probably as a complication of endocrine pancreatic insufficiency. In these patients TIPE manifests itself in a weak-moderate form; the levels of lipase, all> 10%, do not seem to justify the use of therapy.
The evaluation of the functionality of the exocrine pancreas has a relevant role in the diagnosis of primary or secondary Pediatric diseases known or after gastrointestinal surgery, or in cases of unidentified chronic pancreatitis through imaging techniques. The results of the diagnostic tests can also provide indications regarding the possible administration of enzyme replacement therapy. The diagnosis of IPE can be performed by direct or indirect enzymatic measurements in different biological samples. The secretin test is the simplest and commonly used direct measurement. This test is performed using a gastroduodenal tube, used for sample collection, performed at 15-minute intervals, for one hour after secretin stimulation. However, the gold standard for an accurate evaluation of the functionality of the exocrine pancreas is the test of secretin-cerulein or secretin-pancreozimine.
Loss of pancreatic parenchyma; obstruction of the pancreatic duct.
Chronic pancreatitis
Cystic fibrosis
Severe acute pancreatitis
Carcinoma of the pancreas
Pancreatic resectionInsufficienza pancreatica esocrina secondaria
Inadequate release of CCK / secretin;
decrease in intraluminal pH in the small intestine, or uncoordinated secretion
of pancreatic enzymes and bicarbonate following a meal
Celiac disease
Crohn's disease
Gastric resection
Gastric by-pass
Pancreaticoduodenectomy
of Whipple
Short bowel syndrome
Zollinger-Ellison syndrome
Direct measurements of enzymatic levels have two disadvantages: the cost and
the need to be carried out in specialized centers. Faecal elastase-1 testing is
one of the most frequently used indirect tests for the diagnosis of advanced IPE,
but shows little sensitivity for the diagnosis of early stages of pancreatic
insufficiency. The use of tests for the determination of steatorrhea at 24 and
72 hours is less frequent, although the gold standard for the diagnosis of poor
digestion of lipids is the quantification of the absorption coefficient of
lipids (CFA), carried out after the determination of the steatorrhea by means of
theVan de Kamer test. These indirect tests are characterized by limited
compliance by patients, who must follow a standard diet containing about 100 g
of daily lipids for 5 consecutive days and collect the faeces produced in the
last 3 days before the test. The difficulty of handling samples during
laboratory tests adds additional difficulty to the tests. Recently, the indirect
13C-MTG (mixed 13C-triglyceride breath) test was introduced into the diagnostic
routine, a simple and effective measurement. The labeled substrate, given to the
patient together with the meal, is hydrolyzed in the intestine by the pancreatic
enzymes, absorbed and metabolized in the liver. Following hepatic metabolism,
13C02 is released, eliminated through respiration. The portion of exhaled 13C02
reflects the functionality of the exocrine pancreas and is quantified by mass
spectrometry. The test has sensitivity over 90%.
| Biological liquid | Diagnostic tests | Mild IPE | Severe IPE | Comment |
| Serum | • Pancreatic enzymes • Plasma amino acids |
•Low • Good (non-specific) |
• Low • Good (non-specific) |
|
| Breath | • Octanoate test • Sampling spot of the breath |
• Low • Need for evaluation |
•Good • Need for evaluation |
• Expensive |
| Duodenal juice | • Stimulation with secetine and cerulein • Sampling during ERCP with secretin stimulation • Evaluation with CPRM and stimulation with secretin |
• High
• Low |
• High
• Low
|
•Disappointed, laborious, expensive • Invasive, laborious, expensive • Expensive |
| Urine | • PABA test •Pancreolauryl test |
• Low • Low |
• Good • Good |
• Not on the market • Not on the market |
| feces | • Faecal chemotripsin |
•Discrete
|
discrete |