January 2007 Abdominal Pain in a Pregnant Patient Megan Browning, Harvard Medical School Year III 1
HPI Ms.O is a 21yo pregnant female (23+6 weeks gestation) Woke with 5/10 crampy abdominal pain followed by nausea, vomiting, Pain intensified over 12 hours Presented to the ED at St. Luke s Hospital Diagnostic tests and an imaging study were inconclusive. Monitored over next 12 hours Transferred to BIDMC 24 hours after the onset of pain ROS Occasional flatus No hx of pain after eating, flank pain, dys/hematuria, hematochezia, melana, vaginal discharge, new sexual partners, PID, no ingestion of exotic foods/undercooked meats 2
Ms.O s story continues Physical Exam (pertinent points) Vitals T 99.4 BP 123/79 P 91 O2sat 98% HEENT Dry mucous membranes Abdomen Gravid, Distended, marked RUQ and moderate diffuse abdominal tenderness, no rebound or guarding, negative Rovsing s sign Pertinent Labs WBC 13.9 UA negative LFTs normal Amylase and Lipase normal 3
DDX: abdominal pain in the pregnant patient Acute Appendicitis Acute Cholecystitis Intestinal Obstruction Nephrolithiasis Gastroenteritis *Special concerns during pregnancy* Ligamentous Laxity, Preterm Labor, Abruption, Miscarriage, and Ovarian Torsion 4
RLQ Anatomy Female pelvic anatomy Netter,2003 The female abdomen and pelvis is full of structures that may develop pathology and result in abdominal pain. The history, physical, labs, and studies, help narrow the list of possible offenders. 5
Anatomy of the appendix http://z.about.com/d/p/440/e/f/7028.jpg The vermiform appendix projects off of the cecum distal to the ileocecal valve. 6
Definition Inflammation of the appendix due to obstruction by fecalith (appendicolith), lymphoid hyperplasia, or rarely, parasite, foreign bodies, or tumor Classic Presentation Peri-umbilical (visceral) pain followed by nausea and vomiting that ultimately migrates to become right lower quadrant (somatic) pain within 24 hours Associated Acute Appendicitis Findings Rovsing s sign, leukocytosis (>10,000), tachycardia, hypotension Incidence during Pregnancy 0.05-0.07% (similar to general population) 7
Diagnostic Challenges in Pregnancy 1 st trimester 2 nd trimester 3 rd trimester www.pamf.org/pregnancy/first www.pamf.org/pregnancy/second www.pamf.org/pregnancy/third Anatomic Changes Enlarging uterus displaces appendix cephalad Creasy, 1984. Separation of visceral & parietal peritoneum (impaired pain localization) Physiologic Changes Masking of leukocytosis (normal pregnancy WBC range 6-16,000) Increased blood volume blunts tachycardia and hypotension 8
Appendicitis in pregnancy: a risky situation A pregnant woman with appendicitis Increased risk of perforation (43%) compared to general population 4-19%) If perforation occurs, risk of fetal mortality increases from 1.5% to up to 35% Appendectomy during pregnancy Usual risks of surgery Spontaneous abortion Preterm labor premature delivery Levine, 2006 and Augustin, 2006 9
Imaging studies in appendicitis CT Scan Sensitivity 94% Specificity 95% Ultrasound Sensitivity 86% Specificity 81% MRI Sensitivity 100% Specificity 94% Key Findings Diameter > 7mm Fluid filled structure Wall thickening >3mm periappendiceal fluid Appendicolith Humes and Simpson,2006 and Pedrosa et al, 2006 10
Companion Patient #1: Appendicolith Frontal Plain Film Appendicolith (Lateral to S.I. Joint) http://www.learningradiology.com 11
Mullins, Rhea and Novelline, 2003 Megan Browning, HMSIII Companion Patients #2 and 3: Appendicitis on CT Scan CT with oral contrast Findings: 11 mm appendix fat stranding CT with colon contrast Image from PACS Blind tip Appendicolith Drawback: Exposure to ionizing radiation. 12
Appendiceal Imaging modalities during Pregnancy Graded-Compression Sonography Benefits: readily available and no associated ionizing radiation Drawbacks: operator dependent, pain and/or gravid uterus may hinder exam, a normal or perforated appendix may not be visualized MRI Benefits: no ionizing radiation and excellent sensitivity and specificity Drawbacks: limited availability, contraindications, cost, claustrophobia 13
Companion Patients #4 and 5: Appendicitis on Graded-Compression Sonography How is it performed? Compress abdomen with high resolution transducer Identify terminal ileum Scan for cecal tip and adjacent appendix What are the findings? Enlarged, fluid-filled appendix Transverse US Appendicolith Periappendiceal Inflammation Sagittal US Sivit and Applegate, 2003 Sivit and Applegate, 2003 Sagittal US 14
Companion patient #6: Appendicitis on MRI How is it performed? Oral contrast is given 1 hour prior to the study Patients are placed feet first into the magnet. Numerous images* are obtained during breath holds (20-24 seconds) Exam time takes approximately 30 minutes What are the findings? Dilated tubular appendix Periappendiceal edema C=cecum, U=uterus Coronal fat-sat SSFSE Pedrosa et al, 2006 Sagittal SSFSE 15
MRI in Pregnancy Advantages of MRI Protocols HASTE or SSFSE images have less motion artifact and can visualize periappendiceal fat stranding Fat-saturated T-2 images reveal high-intensity-signal inflammatory fluid Fat-saturated T-1 images reveal hemorrhage Safety of MRI in Pregnancy Radiofrequency pulses may cause tissue heating No adverse fetal affects have been linked to MRI Gadolinium is used cautiously in 2 nd and 3 rd trimesters, avoided in the 1st Current Practice at BIDMC Perform MRI only when ultrasound is inconclusive Use extra caution with MRI during the first trimester 16
Back to our patient... Ms.0 is tearful and complaining of continuous 8/10 pain in her abdomen worst in her RUQ She undergoes Graded-Compression Sonography 17
Our Patient Ms.O s Ultrasound Study Sagittal gallbladder normal gallbladder Sagittal rt. ovary normal rt. ovary (good flow on doppler) Sagittal rt. kidney Proximal ureter 1.6 cm Rt.Hydronephrosis (common in pregnancy) No appendix is visualized. 18 Images from PACS
Proximal Appendix Megan Browning, HMSIII Ms.O s MRI Imaging Study Axial SSFSE Images with oral contrast Mid Appendix (site of obstruction) Normal caliber, non-fluid filled Appendicolith (intraluminal low-signal-intensity foci) Right hydronephrosis Distal Appendix 9mm diameter, high-signal-intensity fluid-filled lumen Images from PACS
More of Ms.O s MRI Imaging Study Coronal SSFSE with oral contrast Appendiceal Tip 8.75mm diameter (normal <7mm) High intensity fluid within lumen Minimal periappendiceal inflammation 20 Image from PACS
Ms.O s hospital course Diagnosis Acute appendicitis involving the distal 3.5 cm Intervention Emergent appendectomy with removal of mottled appendix and perforated tip Pathologic Diagnosis Acute gangrenous appendicitis, average diameter 1.3 cm and obstructing fecalith in the lumen. Outcome Ms.O recovers gradually and is sent home on post-op day 9 in stable condition. 21
Take Home Points Appendicitis in Pregnancy Clinical signs and symptoms of appendicitis may be masked Delayed diagnosis may lead to perforation Surgery may lead to premature delivery and fetal loss Ultrasound is the initial imaging modality of choice MRI is performed if the ultrasound is inconclusive Key findings include an enlarged fluid-filled appendix and periappendiceal inflammation 22
References Netter F. H., M.D. Atlas of Human Anatomy, Third Edition; John T. Hansen, Ph.D. Consulting Editor. Teterboro, NJ.: Icon Learning Systems, 2003. Creasy R.K., M.D., Resnick R., M.D. Maternal-Fetal Medicine, Principles and Practice; Philidelphia, PA.: W.B. Saunders Company, 1984. Levine D., MD. Obstetric MRI. Journal of Magnetic Resonance Imaging 2006; 24: 1-15. Goran Augustin, Mate Majerovic, Non-obstetrical acute abdomen during pregnancy, European Journal of Obstetrics&Gynecology and Reproductive Biology (2006), doi:10.10/ejogrb.2006.07.052 Humes D., Simpson, J. Acute Appendicitis. BMJ 2006; 333: 530-534. Pedrosa I., M.D., Levine D., M.D., Eyvassadeh A., M.D., Siewert B., M.D., Ngo L., Ph.D., Rofsky N., M.D. MR Imaging Evaluation of Acute Appendicitis in Pregnancy. Radiology 2006; 238: 891-899. Mullins M., Rhea J, Novelline R. Review of Suspected Acute Appendicitis in Adults and Children using CT and Colonic Contrast Material. Seminars in Ultrasound, CT, and MRI 2003; 24: 107-113. Sivit C., Applegate K. Imaging of Acute Appendicitis in Children. Seminars in Ultrasound, CT, and MRI 2003; 24: 74-82. Brown M., Birchard K., Smelka R. Magnetic Resonance Evaluation of Pregnant Patients with Acute Abdominal Pain. Seminars in Ultrasound CT and MRI 2005; 26: 206-211. http://z.about.com/d/p/440/e/f/7028.jpg http://www.learningradiology.com/images/giimages1/gigallerypages/appendicolith.jpg http://www.pamf.org/pregnancy/first/fetal.html 23
Acknowledgements Pamela Lepkowski Larry Barbaras, Webmaster 24
any? s Baby O. courtesy of BIDMC PACS 25