A 10‑week pregnant woman presents with right foot pain, a single uterine contraction, fever of 38.4 °C, and no respiratory symptoms; what is the likely diagnosis?

Likely Diagnosis: Acute Appendicitis or Sepsis (Possibly Group A Streptococcal Infection)

This 10-week pregnant woman with right foot pain, fever of 38.4°C, and a single uterine contraction most likely has either acute appendicitis or an early severe infection (particularly Group A streptococcal sepsis), and requires immediate emergency evaluation with ultrasound followed by MRI if needed, along with urgent infectious workup and empiric antibiotics.

Clinical Reasoning

The combination of fever (38.4°C) and a uterine contraction in early pregnancy is concerning and warrants urgent evaluation. While the right foot pain seems unrelated, the constellation of symptoms suggests a systemic infectious process.

Primary Diagnostic Considerations:

1. Acute Appendicitis (Most Common Surgical Emergency in Pregnancy)

• Appendicitis occurs in 1 in 20 women of childbearing age presenting with abdominal symptoms 1
• Most commonly manifests in early to mid-pregnancy 1
• Can present atypically in pregnancy with referred pain patterns
• The single uterine contraction may represent irritation from an inflammatory process
• Critical point: Pregnant women are more likely to present with complicated (perforated) appendicitis, and perforation carries higher risk of fetal loss 1

2. Group A Streptococcal Sepsis (Life-Threatening)

• Presents with flu-like symptoms and high fever (94% of cases) 2
• Characteristic finding: infection-induced strong uterine contractions (73% of cases) 2
• Can progress rapidly to shock (91% of cases) 2
• Historical mortality: 58% maternal, 66% fetal - though improved with early antibiotics 2
• Typically affects multiparous women in third trimester, but can occur earlier 2

3. Other Infectious Causes

• Pyelonephritis (11% of fever cases in pregnancy) 3
• Common viral infections (37% of fever cases) 3
• Chorioamnionitis (5% of fever cases, though less likely at 10 weeks) 3

The Right Foot Pain

While seemingly unrelated, consider:

• Septic emboli (if severe infection with bacteremia)
• Thrombophlebitis (pregnancy is hypercoagulable state)
• Musculoskeletal pain (common in pregnancy but wouldn't cause fever) 4, 5

Immediate Diagnostic Approach

Step 1: Emergency Assessment

• Vital signs: Check for tachycardia, hypotension (signs of sepsis/shock)
• Fetal assessment: Confirm fetal viability with ultrasound at 10 weeks
• Physical examination:
  • Abdominal tenderness location (appendicitis may present atypically in pregnancy)
  • Right foot examination for cellulitis, abscess, or thrombophlebitis
  • Uterine tenderness or contractions

Step 2: Laboratory Workup

• Complete blood count (leukocytosis expected in pregnancy, but left shift concerning)
• Blood cultures (before antibiotics)
• Urinalysis and urine culture (rule out pyelonephritis)
• C-reactive protein/procalcitonin (if available)
• Comprehensive metabolic panel (assess organ function)

Step 3: Imaging Strategy

For suspected appendicitis 1, 6:

• Start with transabdominal and transvaginal ultrasound (safe, no radiation)

  • Sensitivity 61-81% for appendicitis in pregnancy 6
  • Can identify alternate diagnoses

• If ultrasound inconclusive, proceed to MRI abdomen/pelvis (preferred over CT)

  • Sensitivity 100%, specificity 93.6% for appendicitis 6
  • No radiation exposure
  • Most commonly used approach: US + MRI (41% of cases) 1
  • Can rule out appendicitis even if appendix not visualized (if no ancillary signs present) 6

• CT should be avoided unless MRI unavailable and clinical suspicion very high 1

For foot evaluation:

• Ultrasound Doppler if concerned about deep vein thrombosis
• Plain radiograph if concerned about osteomyelitis (minimal radiation)

Immediate Management

Empiric Antibiotic Therapy (Do Not Delay)

Given the severity of potential diagnoses, start broad-spectrum antibiotics immediately after cultures obtained:

1. If appendicitis suspected:

   • Ampicillin-sulbactam or ceftriaxone + metronidazole
   • Safe in pregnancy

2. If Group A Streptococcal sepsis suspected 2:

   • Penicillin G (high dose) + clindamycin (clindamycin inhibits toxin production)
   • Consider IVIG (91% survival when used) 2
   • Early antibiotic use associated with 71% survival vs. much lower without 2

3. If pyelonephritis suspected:

   • Ceftriaxone or ampicillin + gentamicin

Warning Signs Requiring Immediate Intervention 7

The patient should be monitored closely for:

• Regular and painful uterine contractions (sign of severe infection or abruption)
• Persistent excessive shortness of breath
• Severe chest pain
• Vaginal bleeding
• Persistent dizziness or faintness
• Signs of shock: hypotension, tachycardia, altered mental status

Critical Pitfalls to Avoid

1. Delaying antibiotics while awaiting imaging results - In pregnancy with fever and contractions, early antibiotics improve outcomes dramatically 2

2. Dismissing atypical presentations - Appendicitis can present with referred pain patterns in pregnancy; the uterine contraction may be the key warning sign

3. Assuming viral illness - While common viral infections account for 37% of fever in pregnancy 3, the combination with uterine contractions demands aggressive workup

4. Over-reliance on leukocytosis - Pregnancy causes physiologic leukocytosis; look for left shift and clinical deterioration

5. Radiation concerns delaying diagnosis - MRI is safe and highly accurate; use it liberally in pregnant patients with suspected appendicitis 1, 6

Disposition

This patient requires hospital admission for:

• Continuous fetal and maternal monitoring
• Intravenous antibiotics
• Serial examinations
• Completion of imaging workup
• Surgical consultation if appendicitis confirmed

The 22% complication rate in pregnant patients with confirmed fever 3 and the potential for rapid deterioration with Group A Streptococcal infection 2 make outpatient management inappropriate.