Hyperbilirubinemia as a Possible Predictor of Appendiceal Perforation in Acute Appendicitis: A Prospective Study

Acute appendicitis, a common abdominal surgical emergency, can mostly be diagnosed clinically by assessing the symptoms and physical findings but confirmation of the diagnosis solely depends upon the histopathological study of the resected appendix specimen, being supplemented by a few laboratory tests and ultrasonography (USG). In spite of all these available investigations, the diagnosis of acute appendicitis, because of its nebulous presentation and the variability of signs, remains a Herculean task for the surgeon.

This is a prospective study conducted on 125 patients diagnosed with acute appendicitis and posted for appendicectomy. Total serum bilirubin (TSB), and total leucocyte count (TLC) were done in all cases. USG of the abdomen was done in all the cases to confirm the diagnosis and to rule out other causes of acute abdomen. TLC more than 11 x 10³ cells/µL and TSB more than 1.1 mg/dL were considered positive. They were operated on and their diagnoses were confirmed post-operatively by histopathological examination. Patients were subdivided according to histopathological findings into: normal appendix (n = 11), uncomplicated acute appendicitis (n = 86), gangrenous appendicitis (n = 10) and perforated appendix (n = 18). Laboratory results, operative findings, and histopathological findings were compiled, analyzed, and compared with reference values.

Out of 125 patients, 114 (91.2%) were histologically positive for acute appendicitis, while 11 (8.8%) had normal histology. TLC was elevated in 95 (76 %) patients and it was normal in 30 (24%) cases. Among the patients with leucocytosis, only 90 (94.74%) had positive histology for acute appendicitis, while the remaining five (5.26%) had normal histology. Among the 30 patients who had normal TLC, 24 had positive histology for acute appendicitis, while the remaining six had normal histology. The specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were 78.95%, 54.55%, 94.74%, and 20%respectively. Similarly, 67 patients (53.6%) had elevated TSB, while it was within normal limits in 58 (46.4%) patients. From the patients with hyperbilirubinemia, 65 (97.01%) had positive histology for acute appendicitis, while the remaining two (2.99%) had normal histology. Among 58 patients who had normal TSB, 49 had positive histology for acute appendicitis, while the rest nine had normal histology. The specificity, sensitivity, PPV, and NPV are 57.02%, 81.82%, 97.01%, and 15.52% respectively. However, when both TLC and TSB were compared as markers of appendicular perforation, the sensitivity, specificity, PPV, and NPV of total serum bilirubin were found to be 89.29% against 21.43%; 53.49% vs. 2.33%; 38.46% vs. 6.67% and 93.88% vs. 8.33% of total leukocyte counts respectively.

Elevated total serum bilirubin could be used as a better predictor of appendiceal perforation in acute appendicitis.