What is the role of urinalysis in the workup of pediatric appendicitis?

Updated: Oct 25, 2018
  • Author: Adam C Alder, MD; Chief Editor: Carmen Cuffari, MD  more...
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Urinalysis is useful for detecting urinary tract disease, including infection and renal stones. However, irritation of the bladder or ureter by an inflamed appendix may result in a few urinary WBCs. The presence of 20 or more WBCs per high-power field (hpf) suggests a urinary tract infection.

Hematuria may be caused by renal stones, urinary tract infection, Henoch-Schönlein purpura, or hemolytic-uremic syndrome. However, small numbers of red blood cells (RBCs) can be found in as many as 20% of patients with appendicitis when an overlying phlegmon or abscess lies adjacent to the ureter. Typically, urinary RBCs are fewer than 20/hpf.

Ketonuria is suggestive of dehydration and is more common with perforated appendicitis.

Normal urinalysis results have no diagnostic value for appendicitis. However, a grossly abnormal result may suggest an alternative cause of abdominal pain

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