Diaphragm of the Gallbladder: A Rare Cause of Acalculous Acute Cholecystitis

Abstract

Acute acalculous cholecystitis is rare, even in pediatrics, although children are more likely to be affected than adults. Among the predisposing factors, congenital anomalies have been uncommonly recorded (1–4). A child with acute cholecystitis secondary to congenital diaphragm of the gallbladder is reported. A brief review of embryology, clinical features, and treatment of this exceptional entity is also presented. CASE REPORT An 8-year-old boy was1 referred with worsening abdominal pain, fever, and vomiting of 24 hours' duration. Physical examination showed right-side abdominal tenderness in a very uncomfortable child. Blood sample revealed leukocytosis. Ultrasonography (US) demonstrated a distended, thickened gallbladder with no calculi. A laparotomy was performed with the suspicion of acute cholecystitis. A distended and edematous gallbladder with focal areas of necrosis was found, and a cholecystectomy was performed. Histologic examination confirmed the diagnosis of gangrenous acute cholecystitis and revealed a transverse diaphragm, clearly separating the fundus from the infundibulum (Fig. 1). The postoperative course was uneventful, and the child continued to be well at 1-year follow-up.FIG. 1.: Open surgical specimen showing a transverse infundibular diaphragm (arrow).DISCUSSION Acute acalculous cholecystitis is a rare condition in pediatric practice. Predisposing factors, such as systemic infections (Salmonella, Escherichia coli, Pseudomonas, Staphylococcus epidermidis, and Clostridium welchii), trauma, major surgery, burns and dehydration are usually present. Additional conditions such as hypoperfusion, ischemia, parenteral hyperalimentation, and narcotics use have also been described. Congenital obstructive anomalies are possible causative factors but have been uncommonly reported in the literature (1–4). The pathophysiology of acute acalculous cholecystitis is not clear. All mentioned factors result in gallbladder ischemia due to organ hypoperfusion or overdistension. Narcotics may cause biliary stasis and spasm of the sphincter of Oddi. A long period of fasting causes a sludge-filled cystic duct, acting as a barrier when oral alimentation is reinstated. Cystic duct obstructions, whether extrinsic or intrinsic, may also induce gallbladder distension and ischemia, a mechanism probably involved in our patient (3,4). Congenital gallbladder anomalies are rare and affect its location, shape or number. The diaphragm of the gallbladder, also designated as congenital hourglass gallbladder, is the least common anomaly (5). The gallbladder develops from the caudal portion of the foregut's hepatic diverticulum. This caudal portion, also designated cystic bud, is a solid structure that normally vacuolizes after the seventh week of gestation. Additional buds are often present but usually regress. Alteration of these embryologic processes may be the origin of gallbladder anomalies such as the double, the bilobed, the multiseptate, or even the absent gallbladder. Incomplete vacuolization was believed to be responsible for the transverse diaphragm found in our patient (5–7). The clinical presentation of gallbladder diaphragm is often indolent, with lengthy histories of recurrent abdominal pain (5,8,9). As far as we know, the case in our patient is the first reported of acute acalculous cholecystitis secondary to diaphragm of the gallbladder. Abdominal US is helpful for diagnosis of anatomical gallbladder anomalies affecting its shape, size, and position (5–9). Multiple linear echogenic septations without acoustic shadows arising perpendicularly from the wall are the essential US diagnostic features of multiseptate gallbladder (6,7). Isolated septa are also readily recognized by US; diaphragms may result in a bilobed or hourglass gallbladder appearance. Cholecystograms, scintigraphy, and computed tomography may also be helpful in the diagnosis of septate gallbladder (5,6,8,9). In the present patient, US could have recognized the gallbladder diaphragm but the clinical picture and sonographic features of acute cholecystitis steered us away from the precise diagnosis. In this clinical setting, desquamated gallbladder mucosa is the main differential diagnosis of septations. It is seen as multiple nonshadowing linear densities, but these are haphazardly arranged in the lumen and do not arise from the wall of the gallbladder (6,7). Acalculous acute cholecystitis in childhood is the cause of significant rates of morbidity and mortality, probably related to the high incidence of gangrene. Therefore prompt recognition is important, and early cholecystectomy should be undertaken (1–5).