It has only been in the last several decades that abscesses within deep compartments, particularly within the abdomen and pelvis, have become safely accessible with imaging guidance. Since that time, percutaneous abscess drainage has become the standard of care in children. We review the clinical features, diagnosis, and image-guided management of abdominal and pelvic abscesses in children.

ACHALASIA, defined as failure or inability to relax, when applied to the LX. esophageal cardia most accurately designates a familiar clinical and pathologic disease entity. The term mega-esophagus refers to the presence or development of a dilated esophagus in association with achalasia of the cardia, and must be so restricted. Less acceptable in the light of present knowledge is the older term cardiospasm, which has been defined as a functional type of obstruction of the esophagus at or near the esophageal hiatus, usually associated with dilatation of the thoracic esophagus. 1 Effler and Rogers 2 differentiate cardiospasm from mega-esophagus, but the two conditions may be essentially the same, differing only in degree and duration. We have seen patients with achalasia without esophageal dilatation who later developed mega-esophagus. The purpose of this paper is to review briefly the etiology, clinical features, and treatment of achalasia and mega-esophagus, and to present the reports of five cases that demonstrate the diagnostic findings, the treatment, and some of the complications of the condition. Etiology The etiology of achalasia is not known. It rarely is associated with gross organic disease of the esophagus. Most proposed explanations of the etiology have focused on the nervous control over the lower esophagus. Hurst 3 in 1930 reported that some patients with achalasia had degenerative changes in Auerbach's plexus in the lower esophagus. He observed that the abdominal esophagus failed to relax in front of the contractional wave. Knight 4a in 1934 experimentally reproduced this condition in cats by high bilateral vagotomy. He also was able to prevent or to relieve the condition experimentally by sectioning the sympathetic nerve supply to the cardiac end of the stomach and lower esophagus. He 4b later employed left gastric sympathectomy in the treatment of some patients with achalasia and reported good results in a few. Mitchell 5 and others