Infection Prevention and Gynecologic Surgery

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Shout out to Taylor DeGiulio for today’s episode idea! We’re doing a pretty close reading of ACOG PB 195 if you want to follow along!

SSI represents the most common complication after GYN surgery, however definitions of this may surprise you. The National Surgical Quality Improvement Program (NSQIP) divides SSI up into three broad categories, with their definitions below:

  1. Superficial incisional: occurs within 30 days of surgery, involving only skin or subcutaneous tissue.

  2. Deep incisional: occurs within 30 days of surgery without an implant, or within 1 year of surgery with an implant, and involves deep soft tissues (rectus muscle, fascia).

  3. Organ space: occurs within 30 days of surgery without an implant, or within 1 year of surgery with an implant, and involves any other area manipulated during operative procedure (i.e., osteomyelitis if bone, endometritis or vaginal cuff for GYN, etc.)

  • In addition to satisfying these time and location definitions, an SSI also must have one of the following characteristics present:

    • Purulent drainage from the area of infection.

    • Spontaneous dehiscence or deliberate opening of a wound by the surgeon, with organisms subsequently obtained from an aseptically collected culture; or not cultured, but the patient displays signs/symptoms) of infection (i.e., fever, localized pain or tenderness, redness, etc.).

    • Abscess or other evidence of infection noted on examination.

    • Diagnosis of infection made by surgeon or attending physician.

In GYN surgery, our threats for infection lie primarily from vaginal organisms or skin organisms; however we may also come into contact with fecal content or enteric contents as well. Thinking about the organisms we’re helping to bolster defense against will help in selecting a preventive antibiotic. Thinking about the wound class is a simple way to characterize this:

ACOG PB 195

ACOG also recommends a number of perioperative considerations/techniques to reduce SSI:

  1. Treat remote infections - this one seems pretty obvious. If there’s an infection going on, like a skin infection or a UTI, it’s likely best to postpone surgery in favor of treating the infection!

  2. Do not shave the incision site - Preoperative shaving by patients themselves has actually been shown to be likely harmful, increasing the risk of infection by introducing a nidus for infection remote from surgery. If hair needs to be clipped, it should be done immediately pre-op with electric clippers.

  3. Prevent preop hyperglycemia - blood glucose should be targeted to < 200 mg/dL for both non-diabetic and diabetic patients before proceeding with surgery. Performing a preoperative random blood sugar prior to major surgery is a practice our hospital has implemented to identify diabetes in our patients, and to prevent SSI.

  4. Advise patients to shower or bathe with full body soap on at least the night before surgery -We found it fairly surprising that no particular soap is recommended over another. Many offices offer patients a chlorhexidine soap for use the night before surgery. The soap significantly reduces risk of cellulitis versus no bathing.

  5. Use alcohol-based preop skin prep, unless contraindicated - chlorhexidine-alcohol combinations have been proven in RCTs and meta-analyses to be superior to povidine-iodine for preoperative skin preparation. For mucosal sites such as the vagina, where high alcohol concentrations should not be used due to irritation risk, povidine-iodine or chlorexidine soap solutions should be used.

  6. Maintain appropriate aseptic technique - Of course, right? But in addition, our surgical technique does matter! Effective hemostasis while preserving vital blood supply, maintaining normothermia and reducing operative time, gentle tissue handling, avoiding inadvertent injuries, using drains when appropriate, and eradicating dead space can all help to reduce risk of SSI.

  7. Minimize OR traffic - safety bundles that have included components to reduce opening of OR doors during cases have been shown to reduce SSI.

  8. For hysterectomy, consider preop screening for bacterial vaginosis - prior to routine use of antibiotic prophylaxis for hysterectomy, use of metronidazole pre-op in patients who screened positive for BV reduced SSI. These studies haven’t been repeated with systematic antibiotic prophylaxis, but given the data, ACOG does state that screening is reasonable at the preop visit.

Alright, now time for the antibiotics! We dive deeper in the podcast, but PB 195 will give you the quick version here in the tables:

ACOG PB 195

ACOG PB 195

Gestational Trophoblastic Disease

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On today’s podcast, we welcome Jenna Emerson, MD, the current 3rd year fellow in gynecologic oncology and alumnus of the residency at Brown University / Women and Infants! Jenna takes us today through the often confusing world of GTD (or GTN, or GTT).

GTD encompasses several distinct disease entities, including complete and partial molar pregnancy, invasive moles, gestational choriocarcinoma, and placental-site trophoblastic tumors (PSTT).

Molar Pregnancies are a form of non-invasive GTD, and will be encountered by the general OB/GYN. It’s estimated 1:600 TABs will pathologically be molar pregnancies. 20% will lead to malignant GTD and require treatment, with complete moles more often leading to malignancy than partial moles.

The distinction of complete versus partial moles make for great test questions, though the management is the same. There are two main distinctions:

  • Karyotype – partial is triploid, complete is diploid

  • Clinical features – complete is completely weird, while partial only partially weird. Though the ACOG PB 53 has since been retired, this table is helpful in going over the main differences:

ACOG PB 53

Moles generally present with first trimester bleeding or characteristic US findings (“snowstorm appearance”). Initial management requires a number of steps for evacuation or hysterectomy. Be sure to check out the NCCN guidelines (membership required, but free!) for review.

Malignant GTD occurs post-molar if bHCG plateaus, increases, or is persistently positive. This ultimately requires staging per FIGO criteria:

NCCN / FIGO

NCCN / FIGO

If disease is low risk and local disease only, management is hysterectomy vs repeat D&C. A second curettage for low risk cures 40% of patient, and avoids need for chemotherapy. This is a change from traditional teaching, based on a prospective trial published in 2016.

If this surgical management is unsuccessful while following bHCG, then it’s time to move to chemotherapy. Low risk disease is treated with single agent chemo (MTX or Actin-D). Per GOG174, Actin-D has a higher complete response rate, but is more toxic than MTX. High risk disease is treated with EMACO. Check out the NCCN guidelines for more information on these regimens. 

Choriocarcinoma and Placental Site Trophoblastic Tumor

  • Choriocarcinoma can follow term pregnancies (50%), moles (25%), or non-term histologically normal pregnancies (25%). They have early systemic mets, and require chemotherapy. The staging system is the same as above to decide single vs. multi-agent therapy. These are very vascular, so the classic CREOG answer is that you should not biopsy a suspected choriocarcinoma!

  • PSTT, epithelioid trophoblastic tumor – both of these are very rare and can follow any pregnancy. These should be referred to specialized centers, and are most commonly treated with hysterectomy.

Diagnostic Dilemmas

We reviewed a number of scenarios that can pose diagnostic challenges. In brief:

  • Malignant GTD following non-molar pregnancies

    • In the case of persistent AUB for > 6weeks after pregnancy, a bHCG should be checked to rule out new pregnancy or GTD

  • Choriocarcinoma as malignancy of unknown primary 

    • Mets have been reported in pretty much every body site.

    • Serum beta (which will almost certainly be above discriminatory zone) and pelvic US to r/o pregnancy allow for diagnosis.

  • Phantom hCG – heterophile antibodies

    • Positive serum hCG testing can result due to relatively non-specific circulating antibodies which bind to secondary antibody in a sandwich assay (antigen 🡪 primary antibody detects antigen-labeled secondary antibody, which detects primary antibody and has detectable indicator).

    • Several ways to identify: pos serum with neg urine (antibodies aren’t shed in the urine but bHCG glycoprotein is), value doesn’t decrease with serial dilutions, or can send to a separate lab which may use separate secondary assay.

  • Postmenopausal hCG

    • Baseline small amount of hCG produced by the pituitary – rises in peri- and post-menopausal, during chemo. Typically beta is 5 or less but can occasionally be higher. Confirm by checking LH – if LH is consistent with menopause, this confirms pituitary source.

Adnexal Masses Part 1: Imaging

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Today we’re embarking on a multi-part series through adnexal masses.

To frame our initial conversation on imaging features of adnexal masses, we’ve relied heavily on a golden piece of literature from the Radiological Society of North America, detailing the features and management of these findings on imaging. This paper contains a super nice table that should be considered a table-side reference for your own viewing of images.

Generally speaking, signs more suggestive of malignancy include:

  • Patient age/menopausal status: One of the biggest contributing risk factors, even before you know what the cyst looks like. In postmenopausal women with asymptomatic adnexal masses, the incidence of malignancy approaches 30%, while it is only 6-11% in premenopausal women.

  • Large size: cysts greater than 5cm should receive consideration for surgical intervention or closer follow up in premenopausal women. In postmenopausal women though, even small 1cm cysts should be considered for close interval follow up at a minimum.

  • Thickness: thicker walls (>3mm) portend more significant pathology.

  • Septations: multiple septations are also concerning for malignancy, though again this corresponds with the thickness; thinner septations may suggest more likely benign disease.

  • Nodularity: cysts with nodules or calcifications, particularly with vascularity, are more concerning.

  • Contents: one of the more nuanced findings; however, can help determine etiology: i.e., cysts with a reticular or lacy appearance are more suggestive of hemorrhagic cysts, while hyper echoic lines and dots with areas of acoustic shadowing are more suggestive of dermoid cysts.

Be sure to also check out ACOG PB 174 (membership required) and/or the OBG Project’s helpful bulleted summary! We definitely think looking through images alongside descriptive text is the primary way to learn this information, and we hope the podcast can help supplement that for some of you.

Abnormal Uterine Bleeding: The Basics

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Today we talk through the varied etiologies and a basic workup for a common GYN complaint: abnormal uterine bleeding. ACOG PB 128 makes for good companion reading for women of reproductive age.

The terminology of AUB has changed quite a bit, and you may still hear older terms being used. “Dysfunctional uterine bleeding” or DUB has fallen out of favor, as have terms such as metrorrhagia or menorrhagia, yielding instead to simpler terminology such as prolonged menstrual bleeding and heavy menstrual bleeding, respectively. The terms such as oligomenorrhea (bleeding cycles > 35 days apart) and polymenorrhea (cycles < 21 days apart) are also in use to some degree.

Heavy bleeding is difficult to discern, but for research purposes has been described as >80cc blood loss per cycle. In clinical practice, this is obviously impractical, so we rely on subjective descriptions of heavy bleeding to guide care.

The biggest takeaways from this episode include the PALM-COIEN classification of bleeding by FIGO, as well as the common culprits of bleeding by age group. Remember also the criteria for working up for disorders of coagulation, which we’ve put here (though contained in the practice bulletin).

Stay tuned for future episodes about the treatments of these various etiologies, or check out our friends at The OBG Project for excellent summaries of guidelines and new literature!

ACOG PB 128

ACOG PB 128

ACOG PB 128

Management of an Early Unlocated Pregnancy

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Today we’re bringing back Dr. Erin Cleary one more time before she transitions to her new role as an MFM fellow at the Ohio State University! Dr. Cleary today talks with us on early pregnancy of unknown location - a common problem in the office or the emergency department/triage.

Women presenting to the ED with first trimester bleeding, pain, or both, have had a demonstrated prevalence rate of ectopic pregnancy up to 18% in some studies. Ruptured ectopic is a leading cause of pregnancy-related mortality in the first trimester, accounting for 2.7% of pregnancy-related deaths overall in 2011-2013. Proper identification and management of early, unlocated pregnancy is life-saving!

Dr. Cleary was kind enough to put together her high points from this episode for our blog post today:

H&P:

  • Any patient with an unlocated pregnancy should be considered to have a potential ectopic pregnancy.

    • Women with prior ectopic, regardless of method of treatment, are at risk for ectopic in a subsequent pregnancy (three- to eightfold higher compared with other pregnant women).

    • If pregnancy is present while IUD is in place, risk of ectopic is 1 in 2 pregnancies for the levonorgestrel IUD and 1 in 16 pregnancies for the copper IUD.

    • Women with a history of PID have an approximately threefold increased risk of ectopic pregnancy

  • Pelvic exam. THIS MUST BE DONE.

Beta-HCG

  • The threshold for a positive qualitative β-hcg test is 20-50 milli-int units, depending on test. For quantitative serum tests, the threshold is 5-10 milli-int units, and 1-2 milli-int units, for ultrasensitive tests.

  • The β-hcg concentration doubles every 29 to 53 hours during the first 30 days after implantation of a viable, intrauterine pregnancy.

  • When ectopic pregnancy is on the differential, a qualitative test is not sufficient. A serum quantitative value is essential to:

    • 1. Interpret imaging (“discriminatory zone”)

    • 2. Have a baseline in the event the β-hcg must be trended

The Discriminatory Zone

  • Definition: A concept that there is a quantitative β-hcg level above which the landmarks of a normal intrauterine pregnancy (yolk sac and embryo) should be visible on ultrasound.

    • Therefore, the absence of a gestational sac when β-hcg level is above the DZ is strongly suggestive of nonviable pregnancy, with 50-70% being ectopic.

  • Pelvic ultrasound is the gold standard first line imaging modality in early pregnancy and for evaluation of suspected ectopic pregnancy

  • Imaging results will fall into 1 of 5 main categories

    • IUP with normal adnexa. Normal pregnancy!

    • IUP with abnormal adnexa. Although rare, must evaluate for heterotopic pregnancy, or presence of both an intra and extra-uterine pregnancy.

    • No IUP, extra-uterine mass with YS/FP. Confirms ectopic pregnancy.

    • No IUP, adnexal mass without YS/FP. Suspicious for ectopic pregnancy

    • No IUP, normal adnexa. Differential includes normal but early IUP, failed IUP, or unidentified ectopic.

  • A patient with a confirmed ectopic requires evaluation and counseling by an OBGYN to evaluate candidacy for medical or surgical evaluation.

Management:

  • Expectant management: serial quantitative β-hcg level assessment ~q 48 hours, only for stable patients.

    • Scenario A: The β-hcg level rises appropriately (doubles approximately every 2 days).

    • Scenario B: The β-hcg level falls precipitously.

    • Scenario C: The β-hcg level neither rises appropriately nor drops precipitously. Now we should be MORE concerned about ectopic pregnancy, but abnormal IUP is also on the differential.

  • Repeat pelvic imaging is very helpful

  • Every patient who is stable and an appropriate candidate to trend β-hcg levels will eventually declare herself, with either a located IUP, a failed IUP/SAB, or a confirmed or presumed ectopic pregnancy.

We will cover ectopics for surgical and medical management in a future episode, so stay tuned!