Mis Tareas

“Radiological imaging of abdominal infections and inflammatory disease”

Carolina Whittle, MD, Giancarlo Schiappacasse, MD, Francesca Maccioni, MD3.
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Introduction

This chapter is focused on infectious intra-abdominal processes that occur as acute abdominal presentation, with abdominal pain or fever syndrome, corresponding to one of the most frequent causes of consultation inthe emergency services.

Basic knowledge of the clinical problem

The pathologies that can cause an abdominal infectious disease are numerous. The most frequent to be considered: intestinal origin (appendicitis, enteritis, ileitis and colitis, diverticulitis), urinary origin (pyelonephritis, perinephric abscess), biliary-pancreatic origin (hepatitis, cholecystitis, cholangitis and liverabscess), other (peritonitis, apendangitis, peri hepatitis, panniculitis).
The patient went to consultation for acute abdominal pain, diffuse or focal, fever and chills, vomiting, altered bowel transit, general unwell, among others. The general practitioner will request laboratory tests to assess function of various organs and evidence that guide him to infections, among them the hemogram with whiteblood count, sedimentation rate, and C-reactive protein stand out. Conventional radiology, ultrasound (US), computed tomography (CT) and magnetic resonance (MRI) are the diagnostic imaging methods that can help.

The clinical questions

There are broad ranges of causes that may present with abdominal pain or sepsis. The physician should be able to collect all patient information regarding age,sex, ethnic group, and characteristics regarding the pain, such as localization and intensity. All findings at physical examination and lab results are important to obtain a proper differential diagnosis, and therefore to determine the appropriate imaging testing required.
The radiologist’s role should be to provide an adequate diagnostic approach to be able to answer some of the doubts posed bythe referring physician, which determine the urgency to be solved. Some of them could be if there is an infectious disease involved, and the need of emergent surgery.
Most of the methods that are useful in these settings, including ultrasound, computed tomography and magnetic resonance, are usually available in any Department of Radiology of large Hospital or Clinic.
The following diagnosticalgorithm, depending on the clinical orientation, age, condition of the patient and the centre of attention, is proposed. In general, for acute abdominal pain, an abdominal ultrasound study is the first line examination and, according to the findings, the diagnostic algorithm can stop here or continue with CT or MR based on clinical and imaging suspicion.

Hospitals and clinics should establishtheir own guidelines to standardize attention in terms of diagnosis, hospitalization, and follow-up. In acute abdominal symptom, it is recommended after the clinical history, physical and laboratory examination, then to perform any imaging technique. The study can be started with a CT scan, particularly in very acute or severe cases, but it is generally reasonable to begin with an abdominalultrasound and to decide, according to the imaging findings, either to start a therapy or to continue the investigation with CT or MRI according to the clinical suspicion and imaging results. This is especially valid in the pediatric and women population, especially but not only during pregnancy period, given the differential diagnosis with gynaecological symptom and the need to avoid radiation exposure.(1)

Methodological considerations

US Techniques

Ultrasonographic study should be performed with medical sonographic instrument using low frequency multifrequency convex transducers (5-1 MHz), and high frequency multifrequency linear transducers (12 - 7 MHz), according to lesion location and characteristics of the subject to examine. The images must be obtained at least in two planes,...