Neurosurgery and Pregnancy Flashcards
- Which one of the following best describes the risk of subarachnoid hemorrhage during pregnancy?
a. Lowest during the first trimester
b. Highest during the puerperium
c. Highest during the second trimester
d. Lowest during the third trimester
e. Highest during labor
f. Not increased during pregnancy, labor, or puerperium
f. Not increased during pregnancy, labor, or puerperium
A 28-year-old left-handed female who is 14 weeks pregnant presented to the emergency department with worsening headache, vomiting and drowsiness. CT head scan showed a large right frontal tumor with significant edema. After 48 h of dexamethasone her headache has improved but she still has a mild left-sided arm weakness. Which one of the following would be most appropriate?
a. Permit gestational advancement to second trimester
b. Craniotomy and tumor resection followed by chemoradiotherapy
c. Cesarean section followed by neurosurgery
d. Iatrogenic termination followed by neurosurgery
e. Radiotherapy alone until fetal maturity
established
b. Craniotomy and tumor resection followed by chemoradiotherapy
Treatment should adhere to the treatment options
as in nonpregnant women. The optimal time to
perform the procedure during pregnancy is still
a matter of debate. It is recommended to delay surgery if possible until after the first trimester to
reduce the miscarriage risk—surgery during the
second and third trimesters surgery is considered
safe. Delay can cause progressive neurologic deterioration and increasing risk of urgent intervention (resection and cesarean section). Due to the significant complications of prematurity (e.g.
respiratory diseases, bradycardia, necrotizing
enterocolitis, intraventricular hemorrhage, hypoglycemia and feeding problems, sepsis and
seizures) iatrogenic preterm birth should be
avoided whenever possible by postponing or continuing treatment until a term delivery can be
achieved. The decision of performing an elective
cesarean section preterm is often based upon the
risk of increased intracranial pressure associated
with bearing-down efforts during the second stage
of labor. Nonetheless, if patients are clinically stable and carefully discussed, and the individual risk of rapid tumor growth has been evaluated, gestational advancement until fetal maturity should be considered, as well as the attempt to have a vaginal delivery. Balance between waiting for fetal maturation and risk of intrauterine death (secondary to maternal death) remains difficult in patients with highly malignant tumors.
A recent study summarized long-term data of
children after antenatal exposure to chemotherapy (and/or radiotherapy) found a cardiac outcome equal to the general population, and no adverse effects of treatment on the general health and age-appropriate neurocognitive (IQ, attention, behavior, memory) development. Estimations of the absorbed fetal dose were between 0.01 and 0.1 Gy (10-100 mGy) for patients who received whole brain RT by a 3D conformal technique and many of the toxic effects will only be induced above the deterministic threshold of
0.1 Gy. Most studies reporting on the administration of radiotherapy to brain tumors showed that the fetal exposure never exceeded this threshold dose. These radiotherapy schedules are therefore considered safe. Still, proper shielding should always be used to further reduce the fetal dose and it is recommended to discuss treatment with a radiation physicist and to use a phantom to estimate the fetal dose as accurate as possible in order to counsel parents on the potential risks of radiation-induced toxicity.
At what gestational age is it generally accepted that a ruptured cerebral aneurysm should be managed by cesarean section under general anesthesia followed by immediate aneurysm exclusion?
a. 26 weeks
b. 28 weeks
c. 30 weeks
d. 32 weeks
e. 34 weeks
e. 34 weeks
For ruptured cerebral aneurysms in pregnant
women generally the aneurysm should be treated
first and the pregnancy allowed to continue to
term, except in cases of rupture during labor
when delivery should be completed prior to aneurysm treatment. For gestational ages less than 26 weeks, proceed as best for the mother and if aneurysm treatment is successful vaginal deliveryshould be attempted. For gestational ages beyond 34 weeks, cesarean section under general anesthesia, followed immediately by aneurysm exclusion, is advised. Between 26 and 34 weeks, aneurysm exclusion should proceed and, if the fetus is stable, pregnancy allowed to continue to term. Deciding whether to undertake endovascular coiling or surgical clipping is difficult. In view of the progressive hormonal and hemodynamic changes in pregnancy, ISAT data may not be applicable;
additionally complications such as coil prolapse
require antiplatelet agents that need to be considered in unexpected labor or emergency cesarean section soon after coiling. Such issues
certainly require detailed discussion between
the neurosurgeon, neuroanesthetist, obstetrician
and patient.
According to available evidence, which one of the following statements is most correct regarding the timing of cerebral arteriovenous malformation rupture during pregnancy?
a. Most AVMs rupture during the first and second trimesters
b. Most AVMs rupture during the puerperium
c. Most AVMs rupture during the second trimester
d. Most AVMs rupture during the second and third trimesters
e. Most AVMs rupture during labor
f. Same rate of AVM rupture throughout pregnancy and puerperium
a. Most AVMs rupture during the first and second trimesters
It is accepted that the overall rate of hemorrhage
from cerebral AVMs is not increased during
pregnancy compared to nonpregnant periods of
life. However, in pregnant patients with intracranial AVMs it is important to know that most ruptures occur in the second and third trimester, and not during the first trimester, labor or puerperium. The definitive management of AVMs in pregnancy thus follows standard neurosurgical
guidelines. In general, those with fully treated
AVMs before 35 weeks gestation unassisted vaginal delivery should be possible. In those with
unruptured intracranial AVM, the risk of hemorrhage during vaginal delivery is recognized to be low with the use of epidural analgesia and an
assisted second stage. In contrast, elective cesarean section has been advocated for women with an untreated or partially treated AVM, especially if it has bled during pregnancy.
Back pain in pregnancy is most likely due to the action which one of the following hormones?
a. FSH
b. Oestrodiol
c. Oxytocin
d. Progesterone
e. Relaxin
e. Relaxin
This is a hormone released during pregnancy to
cause ligamentous laxity in preparation for parturition. Women with severe pelvic girdle pain in pregnancy have significantly higher serum levels
of relaxin than those who are pain free.
A 36-year-old female who is 20 weeks pregnant presents with sciatica, saddle anesthesia and urinary incontinence. MRI of the lumbosacral spine reveals a significant L5/S1 disc prolapse with compression of cauda equina nerve roots. What would be your preferred option?
a. Anterior discectomy in supine position with 30° lateral decubitus tilt
b. Discectomy in lateral decubitus position
c. Discectomy with patient prone on fourposter frame
d. Iatrogenic termination and proceed to discectomy in prone position
e. Laminectomy only in lateral decubitus position
c. Discectomy with patient prone on fourposter frame
Pregnant women who have progressive neurological deficit at 34-36 weeks’ gestation or later
should undergo induction of delivery or cesarean
section before, or at the same time as, they undergo spinal surgery; pre-partum surgical treatment should be considered in patients who
develop progressive neurological deficits before
34 weeks. The decision regarding timing of spinal
surgery should be made in close consultation with
the obstetrician, as uncertain dating of gestational
age could greatly affect the infant’s outcome. In
addition, inducing labor before the neurological
injury is treated could cause increased neurological injury in the patient because of the rise in epidural venous pressure that occurs during labor. In cases of true cauda equina syndrome or severe motor weakness occurring at later gestational ages (>34 weeks), cesarean delivery should be strongly considered over induction of labor to avoid more severe neurological deficits after delivery. Brookfield et al. used the prone position in pregnant patients with lumbar disc herniation after 20- and 32-weeks’ gestation by use of a fourposter laminectomy frame to provide pressure relief over the abdomen; it is unnecessary to use the technically difficult lateral decubitus position.
Diagnostic imaging in women of child-bearing
age is limited to MRI scanning as the initial,
and when possible the only, confirmatory and
surgical planning diagnostic procedure. Intraoperative fluoroscopy is unlikely to deliver teratogenic fetal radiation doses but if any question about termination of pregnancy arises input from both an obstetrician and a medical physicist who can accurately calculate the exact dose of radiation to which the fetus was exposed. In the pregnant patient, only the surgical procedure that is necessary to alleviate neurological deficit should be performed.
The additional risk of childhood cancer above the natural risk (1 in 500) per CT head performed on a pregnant female is approximately:
a. Less than 1 in 1,000,000
b. 1 in 1,000,000 to 1 in 100,000
c. 1 in 100,000 to 1 in 10,000
d. 1 in 10,000 to 1 in 1000
e. 1 in 1000 to 1 in 200
a. Less than 1 in 1,000,000
Fetal radiation doses of less than 50 mGy are
not associated with increased fetal anomalies or
fetal loss throughout pregnancy; fortunately,
radiation doses of all diagnostic imaging examinations using ionizing radiation routinely used in a trauma evaluation should be well below this threshold (by comparison fetal dose from natural background radiation during pregnancy is
0.5-1.0 mGy)
Body CT examinations of pregnant trauma
patients should be performed with intravenous
iodinated contrast as it improves detection of both
maternal and fetal injuries by providing vascular
contrast in organs and opacification of vascular
structures,including the placenta. The use ofiodinated contrast material to obtain one diagnostic CT study is preferable to obtaining a nonenhanced CT study that may be nondiagnostic and necessitate repeat imaging. In a seriously injured pregnant patient, multiple or repeat imaging examinations could result in a fetal radiation dose that exceeds 50 mGy. In these situations, it is important to recognize the risks of ionizing radiation to the fetus, which depend on the stage of the pregnancy:
A 31-year-old female who is 34 weeks pregnant is involved in a high-speed RTA. She is immobilized by paramedics at the scene and transferred to your emergency department. She is GCS 15/15 but becomes hypotensive and tachycardic. What action would
you take immediately?
a. Place in left lateral position
b. Manually push the uterus to the left
c. Start a vasopressor
d. Intermittent fetal monitoring
e. Continuous cardiotocography
f. Fetal blood sampling
a. Place in left lateral position
Trauma, which affects 5-7% of all pregnancies, is
the leading cause of nonobstetric maternal mortality. Fetal loss rates approach 1-5% inminor injuriesand 40-50% in life-threatening trauma, but as minor trauma ismuch more commonit is the major cause of fetal loss. Stabilization of the mother involves resuscitation used with any trauma patient, bearing in mind that if she is more than 20 weeks pregnant, she should be placed in the 30°left lateral decubitus position to prevent systemic hypotension caused by compression of the inferior vena cava by the gravid uterus. For imaging studies that require the patient to lie flat for an extended time, use of the 30% left lateral decubitus position during imaging should be strongly considered. In addition, blood
products should be administered to maintain a
hematocrit level higher than 30% for optimal fetal
oxygenation. After the patient has been stabilized,
ultrasound should be performed to determine the
gestational age of the fetus and whether a fetal heart rateis present. For a fetus older than 24-26weeks of gestational age, continuous external fetal monitoring (cardiotocography; CTG) should be used as it would be viable outside the uterus and should be delivered if there is evidence of fetal distress
Which one of the following is a major potential risk to the fetus exposed to MRI sequences employing time-varying gradient electromagnetic fields?
a. Developmental delay
b. Acoustic noise damage
c. Magnetophosphenes
d. Peripheral nerve and muscle stimulation
e. Implant
b. Acoustic noise damage
To minimize these potential risks, it is recommended that MR imaging of pregnant patients is performed at field strengths of 1.5 T or less. In addition, MR imaging protocols for pregnant patients should be tailored to include the minimum number of sequences required to answer the particular clinical question. Gadolinium is considered a pregnancy category C drug by the
FDA, which means that animal studies have
shown adverse effects but adequate data are not
available in humans, and the potential benefits
may warrant its use in pregnant women if it is
considered critical for evaluation. Typically, the
use of gadolinium-based contrast material is not
necessary in pregnant trauma patients because
essential clinical information can be obtained
with nonenhanced MR imaging. Gadoliniumbased contrast material can be used for imaging
pregnant trauma patients in rare circumstances
when it is believed to be absolutely necessary
for diagnosis.
A 31-year-old female who is 28 weeks pregnant presents to your emergency department with a self-terminating tonic-clonic seizure and currently has postictal confusion. She is under close monitoring for her hypertension and proteinuria. Which one of the following would you administer first?
a. Lorazepam
b. Diazepam
c. Valproate
d. Magnesium
e. Phenytoin
f. Levetiracetam
d. Magnesium
Empirical evidence supports the effectiveness of
magnesium sulfate in preventing and treating
eclamptic seizures. Therapeutic levels of magnesium can be obtained by administering a 6-g intramuscular loading dose followed by 2 g/h
intravenous infusion, or alternatively with a
2- to 4-g intravenous bolus followed by a
1 g/min infusion, or a combination of both.
The goal serum concentration is considered to
be 4-8 mg/dL (2.0-3.5 mol/L). Magnesium is
excreted in the urine; thus, impaired renal function may affect serum levels. Magnesium therapy
has a narrow therapeutic index and symptoms of
toxicity include loss of deep tendon reflexes at
blood levels of 8-12 mg/dL, respiratory depression at concentrations of >14 mg/dL, muscular
paralysis and respiratory arrest at levels >15-
17 mg/dL. Cardiac arrest can occur above
30 mg/dL. Recommended treatment for toxicity
includes calcium gluconate.
Women with aneurysmal subarachnoid hemorrhage 10 weeks pregnant and oculomotor palsy. She agrees to DSA and coil embolization and the aneurysm is secured. Postoperatively she asks about the possibility of terminating her fetus due to the probable harmful effects of the radiation exposure required in her treatment. Which one of the following actions would you take in the first instance?
a. Organize a medical termination while she is still an inpatient
b. Explain that the likely dose was much lower than the generally accepted thresh old for causing fetal harm
c. Recommend amniocentesis
d. Advise her to discuss the risks with a medical physicist
e. Arrange an obstetric review
b—Explain that the likely dose was much
lower than the generally accepted threshold
for causing fetal harm.
Aneurysms are diagnosed by digital subtraction angiography (DSA) or, increasingly, by CT angiography. Furthermore, coil embolization requires prolonged use of DSA. Concerns exist regarding fetal radiation exposure. A phantom study has demonstrated that the effective radiation dose to the fetus during DSA for coil embolization is so small that it confers no additional risk to the fetus. If there is still concern then a medical physicist should be consulted
A 32-year-old with VP shunt placement 8 years ago for hydrocephalus following foramen magnumdecompression is considering pregnancy
Shunt malfunction in pregnancy:
a. Cesarean section under epidural anesthesia
b. Cesarean section under GA
c. CT or MRI during pregnancy
d. Induced hypocarbia
e. Magnesium sulfate
f. Preconception CT or MRI
g. Prophylactic antibiotics
h. Revision of ventriculoperitoneal shunt
i. Shunt tap for pressure and CSF MCS
j. Vaginal delivery with assisted second stage
k. Ventriculoatrial
shunt or third ventriculostomy
Preconception CT or MRI
A36-year-old with VP shunt is undergoing a planned vaginal delivery with assisted second stage.
Shunt malfunction in pregnancy:
a. Cesarean section under epidural anesthesia
b. Cesarean section under GA
c. CT or MRI during pregnancy
d. Induced hypocarbia
e. Magnesium sulfate
f. Preconception CT or MRI
g. Prophylactic antibiotics
h. Revision of ventriculoperitoneal shunt
i. Shunt tap for pressure and CSF MCS
j. Vaginal delivery with assisted second stage
k. Ventriculoatrial
shunt or third ventriculostomy
Prophylactic antibiotics
A 23-year-old with VP shunt develops headache, nausea, vomiting and a single generalized tonic-clonic seizure which self-terminates after 1 min. She does not have a pre-existing diagnosis of epilepsy and is not on antiepileptics. Blood pressure is 140/90 and urine dip shows 2+ leukocytes, negative nitrites, no ketones and no protein.
Shunt malfunction in pregnancy:
a. Cesarean section under epidural anesthesia
b. Cesarean section under GA
c. CT or MRI during pregnancy
d. Induced hypocarbia
e. Magnesium sulfate
f. Preconception CT or MRI
g. Prophylactic antibiotics
h. Revision of ventriculoperitoneal shunt
i. Shunt tap for pressure and CSF MCS
j. Vaginal delivery with assisted second stage
k. Ventriculoatrial
shunt or third ventriculostomy
Shunt tap for pressure and CSF MCS
A32-year-oldfemalewithaprevioushistory of molar pregnancy 6 months ago presents with a generalized tonic-clonic seizure. CThead shows a right frontal hemorrhagic space occupying lesion and CT chest shows multiple pulmonary lesions.
Neurological disease in pregnancy:
a. Cerebral venous sinus thrombosis
b. Choriocarcinoma
c. Chorea gravidarum
d. Idiopathic intracranial hypertension
e. Lymphocytic hypophysitis
f. Lymphoma
g. Pituitary macroadenoma
h. Pre-eclampsia/Eclampsia
i. Reversible posterior leukoencephalopa
thy syndrome
j. Sheehan’s syndrome
Choriocarcinoma
Choriocarcinoma is a rare tumor of trophoblastic origin; 90% have lung metastasis at presentation and cerebral metastases are a common mani festation. Approximately 15% of tumors follow normal pregnancies, but most are discovered monthsafterpregnanciescharacterizedbysponta neous abortion or by vaginal bleeding, premature labor, and anenlarged uterus duetoamolarpreg nancy. Women with cerebral metastases present with seizures, hemorrhage, infarction, or gradu ally progressive deficits. The tumor may invade the sacral plexus, cauda equina, or spinal canal. A ratio of serum: CSF hCG of >1:60 suggests the presence ofchoriocarcinomabrainmetastasis.
