How to manage dysuria in a patient with suspected acute appendicitis?

Dysuria in Acute Appendicitis: Recognition and Management

Dysuria in a patient with suspected acute appendicitis is a recognized atypical presentation that should not delay diagnosis or treatment—proceed immediately with imaging (ultrasound first-line, followed by CT if inconclusive) and surgical consultation, as urinary symptoms occur in approximately one-third of appendicitis cases and are associated with pelvic or retrocecal appendix positions. 1

Understanding the Clinical Phenomenon

Urinary symptoms in acute appendicitis are more common than traditionally recognized:

• Dysuria occurs in approximately one-third of patients with acute appendicitis, with right flank pain and dysuria being the most frequent urinary manifestations 1
• The pathophysiology involves the inflamed appendix in close proximity to the right distal ureter and urinary bladder, causing irritation of these structures 2
• Pelvic and retrocecal appendix positions are specifically associated with higher incidence of voiding symptoms 1
• Interruption of sacral nerve stimulation from intraabdominal inflammation can produce urinary retention, frequency, and dysuria 2, 3

Critical Diagnostic Pitfall to Avoid

The presence of urinary symptoms should NOT exclude the diagnosis of acute appendicitis—this is a common and dangerous error. 1 Patients may present with isolated dysuria without classic appendicitis symptoms, and this atypical presentation can lead to missed or delayed diagnosis. 4

Urinalysis Findings and Their Interpretation

Urinalysis abnormalities are common in appendicitis and should not mislead you:

• Pyuria (>10 WBC/hpf) occurs in approximately 1 in 7 patients with appendicitis 1
• Microhematuria (>3 RBC/hpf) occurs in approximately 1 in 6 patients 1
• Proteinuria appears in 1 in 7 patients 1
• These urinalysis findings are NOT useful to rule out acute appendicitis 1
• Pyuria is more frequent in patients aged 15-19 years, while microhematuria is more common in females 1

Immediate Management Algorithm

Step 1: Clinical Assessment

• Apply validated clinical scoring systems (AIR score or AAS score in adults) to stratify risk, even when urinary symptoms predominate 5
• Document peritoneal signs including rebound tenderness, guarding, and right lower quadrant tenderness 5
• Do not be falsely reassured by the absence of classic periumbilical pain migrating to the right lower quadrant 4

Step 2: Laboratory Evaluation

• Obtain WBC with differential and CRP 5
• Perform urinalysis, but interpret abnormal findings as potentially consistent with appendicitis rather than excluding it 1
• Both elevated WBC and left shift together have a positive likelihood ratio of 9.8 for appendicitis 5

Step 3: Imaging Strategy

• Initiate with point-of-care ultrasound (POCUS) or formal ultrasound as first-line imaging, which has sensitivity of 91% and specificity of 97% when performed by experienced operators 6
• Look for appendiceal diameter ≥6-7 mm, non-compressibility, and appendiceal tenderness 6
• Examine the retrovesicular space carefully for fluid collections or abscess, as these may be the first clue in patients presenting with isolated urinary symptoms 4
• If ultrasound is inconclusive or negative but clinical suspicion remains high, proceed immediately to CT abdomen/pelvis with IV contrast 7, 5

Step 4: Definitive Management

• Initiate broad-spectrum antibiotics immediately once appendicitis is confirmed or strongly suspected 8
• Obtain urgent surgical consultation for appendectomy, which remains the standard of care 8, 9
• Do not delay antibiotics or surgical intervention based on atypical presentation with urinary symptoms 8

Age-Specific Considerations

• Patients older than 59 years show higher frequency of urinary symptoms, proteinuria, and urinary casts with appendicitis 1
• In pediatric and adolescent patients, isolated dysuria can be the sole presenting complaint of perforated appendicitis 4, 2
• Children aged 3-15 years may present with right renal colic, dysuria, frequency, and urinary retention as cardinal symptoms 2

Special Clinical Scenarios

Urinary retention or anuria: Consider acute appendicitis in the differential diagnosis of patients presenting with back pain and urinary retention, even without abdominal pain 3. After bladder catheterization and urine output restoration, proceed with abdominal imaging if clinical suspicion exists.

Duration of symptoms: The duration of abdominal pain and evolution stage do not have statistical relationships with the presence or absence of urinary symptoms or urinalysis findings 1, so do not use symptom duration to exclude appendicitis in patients with dysuria.