Presentation and diagnosis
Most patients with CSP are asymptomatic. Symptoms can, however, include light vaginal bleeding that is either painless or associated with mild to moderate abdominal pain.7,10 There are no signs or symptoms that are pathognomonic for CSP.
Diagnosis is performed using transvaginal ultrasound (TVUS). Transabdominal ultrasound has been used to diagnose CSP but TVUS continues to be the imaging modality of choice.
Figure 1 shows four ultrasonographic findings that have been described as diagnostic of CSP:
1. Empty uterine cavity with bright hyperechoic endometrial stripe
2. Empty cervical canal
3. Intrauterine mass in the anterior part of the uterine isthmus
4. Absence of the myometrium, absent or thin between the bladder and gestational sac, measuring less than 5 mm8,12, 13
Using 3D sonography of the lower uterine segment may help to clarify this pathological entity (Figures 2 and 3). Magnetic resonance imaging (MRI) may be an option for diagnosis and evaluation, but the literature appears to demonstrate that overall, TVUS with color Doppler is superior and that MRI should be reserved for inconclusive or difficult-to-diagnose cases.10 Once a diagnosis is made, management should be multidisciplinary, and management options should be reviewed with the patient.
Because CSP is rare, management has largely been described in the literature in case reports and small cases series, as summarized here. We will outline different treatment options that have been most frequently chosen including what we do in our institution.
There are multiple considerations for management of CSP. Goals of care are to treat the CSP with complete resolution and to ensure the mother’s safety. Keys to optimizing clinical outcomes include identification and termination of an early gestation and a multidisciplinary approach to management.10
Methotrexate (MTX) is standard treatment for many types of ectopic pregnancy and has also been used to treat CSP effectively. Patients who are pain-free, hemodynamically stable, and have an unruptured CSP < 8 weeks’ gestation are candidates for MTX.10 This type of medicine stops cells from dividing. It can be used as a way (other than surgery) to treat a pregnancy that’s implanted outside the uterus (ectopic pregnancy). The drug can be given via intra-sac or local injection, as systemic therapy, or in a combination of systemic therapy and intra-sac injection.
Local injection appears to work well but additional surgical treatment or systemic medical management often is required (Table 1). Administration of a single injection of MTX, potassium chloride (KCL), hyperosmolar glucose, or crystalline trichosanthin under TVUS or transabdominal ultrasound guidance has been used.5,6,10,12
Systemic MTX is commonly used for tubal or cervical ectopic pregnancies. Reassuring results have been reported with systemic regimens, with and without intra-sac medication injections, for CSP. Both single-dose and multidose protocols have been used.12,15 The standard single-dose regimen for MTX is 50 mg/m2 whereas the multidose protocol includes four doses of MTX 1 mg/kg given on Days 1, 3, 5, and 7 with alternating days of folinic acid
0.1 mg/kg.8,15 Patients with ectopic pregnancies and HCG levels < 5000 mIU/mL appear to respond best to systemic MTX.7
In many case series, a combination of systemic therapy and intra-sac injections have been used as first-line management of CSP. In these regimens, the intra-sac injections have been done primarily with KCL or methotrexate at the doses shown in Table 1.10,13,14
The authors report no potential conflicts of interest with regard to this article.
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