What is the best course of action for a patient with suspected appendicitis, presenting with mild right lower quadrant pain and a normal white blood cell (WBC) count, in order to avoid missing the diagnosis?

Management of Suspected Appendicitis with Mild Symptoms and Normal WBC

Admit the patient for serial abdominal examinations every 6-12 hours with repeat laboratory testing to avoid missing the diagnosis. 1

Why Admission is Critical in This Clinical Scenario

The absence of fever and normal WBC count do not exclude appendicitis and are present in approximately 50% of cases. 1, 2 Clinical determination of appendicitis based on initial presentation alone has an unacceptably high negative appendectomy rate of 25%, and classic symptoms are present in only half of patients. 3, 1

Key Clinical Pitfalls

• Normal laboratory values are frequently seen in early appendicitis, particularly in pediatric patients, making discharge based solely on these findings dangerous. 1, 4
• The combination of normal WBC and absence of fever significantly reduces the probability of appendicitis but does not eliminate it, with a negative predictive value of approximately 90-96% depending on age group. 4
• Discharging this patient home risks missing early appendicitis or other serious pathology that may evolve over the next 6-12 hours. 5, 2

The Value of Serial Observation

Serial abdominal examinations over 6-12 hours allow detection of evolving peritoneal signs (guarding, rigidity, rebound tenderness) that may not be present at initial presentation. 1 This approach is particularly important because:

• Atypical presentations are common, occurring in approximately 50% of appendicitis cases. 1
• Delays in diagnosis increase perforation risk, which carries perforation rates of 18-19% with significantly increased morbidity, mortality, and length of stay. 1
• Repeat WBC count during observation can reveal evolving leukocytosis that supports the diagnosis. 5

Imaging During Observation

If clinical findings remain equivocal after serial examination or symptoms worsen during observation, proceed immediately to CT abdomen and pelvis with IV contrast. 5, 1 This imaging approach provides:

• Sensitivity of 85.7-100% and specificity of 94.8-100% for diagnosing appendicitis. 5, 1
• Identification of alternative diagnoses in 23-45% of cases with right lower quadrant pain. 5
• CT without enteral contrast is acceptable and avoids delays, with sensitivity of 90-100%. 1

Why Discharge is Inappropriate

Discharge with return precautions is only appropriate for truly low-risk patients with clinical scoring systems (APPE score ≤8), which this patient does not clearly meet given the presence of right lower quadrant pain. 5 The risks of discharge include:

• Missing early appendicitis that will progress to perforation within 24-48 hours. 1
• The patient may not recognize worsening symptoms or may delay return to the emergency department. 5
• NSAIDs for pain control can mask evolving symptoms and delay diagnosis. 5

Recommended Management Algorithm

1. Admit for observation with serial abdominal examinations every 6-12 hours. 5, 1
2. Repeat complete blood count in 6-12 hours to assess for evolving leukocytosis. 5
3. Proceed to CT abdomen/pelvis with IV contrast if:
   • Symptoms persist or worsen during observation 5, 1
   • New peritoneal signs develop (guarding, rigidity, rebound) 5
   • Clinical picture remains equivocal after initial observation period 1
4. Maintain hydration and provide mild pain control, avoiding opioids that can mask symptoms. 5

The combination of clinical observation with imaging when indicated provides the highest diagnostic yield while minimizing unnecessary surgery and avoiding missed diagnoses. 2