US of the upper abdomen
Abdominal imaging
Case TypeClinical Cases
Authors
Matos Elizabeth, Florim Sofia, Coelho Paula, Portugal Pedro
Patient19 years, female
A 19-year-old female patient with Crohn’s disease was admitted to the emergency department with acute epigastric pain and incoercible vomiting. Laboratory testing revealed leucocytosis with neutrophilia and increased amylase (9 x N), lipase (35 x N) and PCR levels. The patient started azathioprine (AZA) 15 days prior.
At the emergency department, an abdominal US was done. It depicted the following:
-An enlarged pancreas with diffuse globosity - of the head, body and tail - showing a discrete, homogeneous and diffuse reduction of its normal echogenicity
-A peripancreatic anechoic fluid blade anteriorly to the head and body of the pancreas, surrounding the second part of the duodenum
-Concentric wall thickening of the second part of the duodenum
-A concentric and hypoechogenic wall thickening of the distal ileum – without surrounding oedema, peritoneal fluid or fluid collections
-Hepatobiliary abnormal findings, including vesicular lithiasis, were absent.
Crohn’s disease (CD) is a transmural inflammatory bowel disease than may involve any part of the gastrointestinal tract, with many known extra-intestinal manifestations and complications.
Acute pancreatitis (AP) has a higher incidence in patients with CD as in the general population, although with an equal severity and prognosis. [1, 3] It is an uncommon complication (with a reported incidence of 1.4%) that most occurs often after the diagnosis of CD. [1] Young age (third decade) and female gender are risk factors. [1]
The diagnosis is challenging, due to the similar clinical manifestation of CD recurrence, and AP as outlined in the American College of Gastroenterology (ACG) criteria: the presence of 2 out of 3 criteria (abdominal pain consistent with AP; serum lipase and/or amylase greater than 3 times the upper normal limit; and characteristic findings on abdominal imaging). Lipase is considered more specific enzyme [1]; and CT or MRI are the preferred techniques for diagnosis.
It has been described an unspecific elevation of pancreatic enzymes in patients with CD without pancreatitis, with a correlation between those levels and the activity of intestinal involvement [2]; although in these patients AP usually presents with a higher degree of enzyme elevation (> 3 x N), specially of lipase. On the other hand, if enzyme levels are not measured, abdominal pain can be erroneously attributed to recurrence [1].
The aetiology is determined by history, physical examination and imaging. Biliary lithiasis and drugs used for the treatment of CD are the most common aetiological factors [1, 2].
Currently, the involvement of the pancreas as an extra-intestinal manifestation of CD remains unclear [1].
In drug-induced AP, the establishment of causality is challenging.
Azathioprine (AZA) is mainly used in CD patients as a first-line immunosuppressant in steroid-dependent patients. Dose-dependent adverse events (i.e. myelosuppression and hepatotoxicity) often respond to dose reduction. On the other hand, idiosyncratic reactions such AP, generally demand discontinuation [3].
The incidence of AZA-induced AP is low (3-7% in the literature) and the pathologic mechanism is not clear – a hypersensitivity reaction with the production of antibodies against pancreas (PAbs) is accepted as a possible one [1]. It is treated with hospitalisation and supportive care, and generally with AZA discontinuation.
Imaging plays a major role in the evaluation of Crohn’s disease patients with acute abdominal pain. Although uncommon, complications of disease – such as AP - must be kept in mind and excluded.
[1] Jasdanwala S., Babyatsky M. (2015) Crohn’s Disease and Acute Pancreatitis: A Review of Literature. JOP, J Pancreas (Online) 16 (2): 136-142 (PMID: 25791546)
[2] Noomen CG, Veenendaal RA, Verspaget HW. (2008) Gastroduodenal Crohn’s Disease and Pancreatitis. Gastroenterology & Hepatology 4 (7): 496-498 (PMID: 21960927)
[3] Teich N., Mohl W., Bokemeyer B. et al. (2016) Azathioprine-induced Acute Pancreatitis in Patients with Inflammatory Bowel Diseases – A Prospective Study on Incidence and Severity. Journal of Crohn’s and Colitis 10(1): 61-68 (PMID: 26468141)
URL: | https://eurorad.org/case/15126 |
DOI: | 10.1594/EURORAD/CASE.15126 |
ISSN: | 1563-4086 |
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