VARICELLA INFECTION AS A CAUSE OF ACUTE PANCREATITIS IN AN IMMUNOCOMPETENT CHILD

Abstract

Apart from cystic fibrosis, exocrine pancreas pathology, mainly acute pancreatitis (AP), is rare in childhood. Blunt abdominal trauma, infectious diseases, toxic agents and systemic diseases are the most frequent causes of AP in childhood. Different viruses can cause AP, 1–4 but association with varicella is unusual and is generally observed in adults 5, 6 or immunocompromised patients. 7–10 We describe the case of a pediatric patient with AP caused by varicella virus infection. Clinical observation. An 8-year-old girl was admitted to the emergency unit because of acute abdominal pain during the previous 48 h. Pain was colicky and located in the periumbilical area. In the previous 24 h fever (38.5°C) and intractable vomiting were present. The family history was positive for cholelithiasis. No history of abdominal trauma or drug ingestion was present. On physical examination no signs of dehydration were observed, palpation of the entire abdomen was painful and peristaltic movements were present. Face, trunk and extremities showed a diffuse vesicular exanthem, which had appeared 1 day before the pain. New lesions were forming during the time of admission. The blood count showed 8300 leukocytes/mm 3 (68% neutrophils, 6% band forms, 20% lymphocytes and 6% monocytes). Blood culture was negative and coagulation studies were normal. Hyperglycemia (165 mg/dl) and hyperamylasemia (1929 IU/l; normal, 20 to 220 IU/l) as well as hyperamylasuria (10189 IU/l) were found. Amylase/creatinine clearance ratio was normal. The alanine aminotransferase (45 IU/l), calcium, sodium and potassium values were normal. Plain chest radiography was normal, and an initial abdominal ultrasonography examination demonstrated a small amount of free fluid. Conservative treatment consisted of fasting, gastric decompression with nasogastric tube, intravenous fluids, type 2 histamine antagonists and analgesics. Vomiting disappeared but abdominal pain increased becoming more selective and located at the right lower quadrant. Forty-eight hours from the time of admission, signs of peritonitis were evident; a second abdominal sonography demonstrated increased thickness of the appendicular wall, increased fluid content in the intestinal loops in the right flank and periappendicular swelling. A second blood count was performed, and an increase of band forms was observed. An exploratory laparotomy demonstrated no appendicular inflammation. Peritoneal fluid obtained at laparotomy was analyzed and cultured, with no abnormal findings. The highest amylase value (2812 U/l) was observed at 24 h, after which the values decreased until normal at 10 days. The patient also had elevated values of immunoreactive trypsin (82.2 ng/ml; normal range in children, 8 to 26 ng/ml) and lipase (348 IU/l; normal, 5 to 190 IU/l). Demonstration of specific IgM antibodies at admission and increase of specific IgG antibodies in successive determinations confirmed varicella etiology. The patient did well, with clinical and biochemical normalization in a few days. She continues to be normal at the 6-year follow-up. Discussion. Acute pancreatitis in adults is generally caused by biliary lithiasis and alcohol consumption. In childhood causes are different. Abdominal blunt trauma is the leading cause of pediatric AP; 20 to 25% are considered idiopathic, and ∼10 to 15% appear after a viral infection. 3, 4 Mumps is the most frequent viral infection associated with AP, but it has also been observed in association with coxsackie B, rotavirus, rubella, enterovirus, Epstein-Barr virus, hepatitis A and B and also after measles, mumps and rubella vaccination. 1–4 Varicella-zoster virus has been associated with AP in immunocompromised patients with severe hematologic illnesses (lymphoblastic leukemia, Hodgkin’s disease), posttransplantation (liver or bone marrow) and in patients infected with HIV. 8–10 The majority of patients described with corticosteroid or chemotherapeutic treatment who were infected by varicella-zoster virus developed disseminated varicella with pancreatic involvement identified only at necropsy. 8 AP in HIV-infected patients is not unusual and is caused by opportunistic microorganisms such as cytomegalovirus, Candida spp. and Mycobacterium avium. Only occasionally is varicella-zoster described as a causal agent of AP in these patients. 10 We have found only two references of varicella as a cause of AP in immunocompetent patients; both were adults. In the first case initial infection was pulmonary, evolving to multiorgan failure with liver and pancreatic involvement. 5 In the second case, although initial evolution with conservative management was favorable, pseudocysts and partial ductal and duodenal obstruction developed. 6 We have also found the case 7 of a 16-year-old boy with AP and disseminated varicella who had been diagnosed 8 years previously with Stage IV neuroblastoma treated with adrenectomy and autologous bone marrow transplantation. At the time of varicella infection he had adrenal insufficiency, hypothyroidism and chronic hepatitis. He was receiving corticosteroids and thyroxin. It is necessary to emphasize that the occurrence of severe abdominal pain in immunocompromised children with varicella is associated with risk of life-threatening infection, although the precise etiology is not clear and pancreatitis is seldom diagnosed. To our knowledge the case we have presented is the first described in the literature of acute pancreatitis secondary to varicella infection in an immunocompetent child.