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Pregnant Patient Returns!

Answer: D

Appendicitis in the pregnant patient

  • Most common cause of acute abdomen in the pregnant patient
  • Most common non-obstetric cause of surgical emergency in pregnancy
  • Overall incidence of appendicitis is not changed during pregnancy but the severity might be increased; incidence: 1/1500 pregnancies
  • Delay in diagnosis remains the leading cause of morbidity in this disease process. Early diagnosis is important because of increased rate of fetal loss and maternal mortality.
  • The incidence of perforation is 25%, and if surgery is delayed more than 24hrs, the incidence of perforation increases to 66%
  • Ruptured appendicitis is associated with a 30% chance of fetal loss in the 1st and 2nd trimester, and as high as 70% in the 3rd trimester, compared to 3-5% risk without rupture
  • Maternal mortality is 4% with ruptured appendicitis.
Symptoms

  • Almost always, abdominal pain is present
  • Nausea is almost always present; vomiting in 2/3 patients
  • Anorexia is less common that non-pregnant patients – only in 1/3-2/3 patients
  • Location of appendix:            
      • 1st trimester: appendix will be at McBurney’s point
      • 2nd trimester: appendix is displaced upward and laterally, usually periumbilical or just right of this area
      • 3rd trimester: near the gallbladder or diffuse
  • Postpartum day 10: appendix returns to its normal position
Signs

  • Direct abdominal tenderness is observed most commonly
  • Rebound tenderness is present in 55-75% of patients
  • Abdominal muscle rigidity is observed in 50-65% patients
  • Psoas irritation is less common than non-pregnant patients
  • Rectal tenderness is usually present, especially in the 1st trimester
  • Fever and tachycardia are variable – not sensitive signs.
Workup

  • Leukocytosis is difficult to interpret, since WBC is often high as 15,000 in pregnancy.  Severe disease can occur with normal WBC.  Granulocytosis (left shift) suggests an infectious etiology.
  • Urinalysis: sterile pyuria is observed in 10-20% of patients with appendicitis
  • Graded compression ultrasound is 1st choice (very operator dependent, sensitivities range from 50-100%, specificities 33-92%, negative predictive values – 64-88% for sonographic diagnosis of appy in general adult population). Retrocecal or elevated appendix may be difficult to find sonographically, and a ruptured appendix may be hard to find on ultrasound (sensitivity is 28.5% versus 80.5% in a nonperforating appendicitis)  Therefore, a negative US examination does not exclude the possibility of appendicitis, and if there remains a high clinical suspicion, additional imaging should be considered. It is not useful if >35 weeks, as the graded compression technique is not able to visualize the appendix clearly.  
  • 2nd line is MRI without contrast – especially in the 2nd and 3rd trimester, in which US is difficult. Both T1W and T2 sequences are performed. Imaging sequences: axial, sagittal, coronal T2 weighted single-shot fast spin echo (SSFSE), axial T1-weighted dual gradient-echo, axial true fast imaging with steady-state precession (FISP), and axial STIR.  
  • 3rd line is CT – can be performed in the 2nd and 3rd trimester if MR imaging is unavailable or there is lack of expertise.
Treatment

  • Laparoscopy
Thanks to Ingrid Lim (Abdominal pain in the pregnant patient, 2011).


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