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33 2nd 3rd month GA: shoulder girdle Rapid progression with Abortion n/a Died 3 months after
weakness respiratory impairment abortion
38 3rd 6th month: R hand atrophy Mild progression C/S 34 weeks general Healthy Slowly progressive
Sobrino- 32 2nd 1 year prior to pregnancy Rapid progression Vacuum assisted vaginal. Healthy Not stated
Bonilla, Epidural
Leveck, 2005 25 3rd 14 weeks GA: L sided weakness, Rapid progression with Vacuum assisted vaginal Died 9 months
severe dysphagia respiratory failure 29 weeks, postpartum
no motor function 34 weeks

GA ¼ gestational age; SVD ¼ spontaneous vaginal delivery; C/S ¼ cesarean section; R ¼ right; L ¼ left; n/a ¼ not applicable; PROM ¼ Premature rupture of the membranes; PEG ¼ Percutaneous
endoscopic gastrostomy
Modified from: Chio, A., Calvo, A., Di Vito, N. et al. Amyotrophic lateral sclerosis associated with pregnancy: report of four new cases and review of the literature. ALS and Other Motor Neuron
Disorders 2003; 4: 45“8.
Table 10.3 Clinical features of adult-onset motor neuron disorders

Progressive Brachial
Amyotrophic muscular Spinal muscular Primary lateral Progressive Monomelic amyotrophic
lateral sclerosis atrophy atrophy sclerosis Kennedy disease bulbar palsy amyotrophy diplegia

Typical Asymmetrical Asymmetrical Symmetrical Asymmetrical Symmetrical Initially limited Asymmetrical Symmetric proximal
distribution Distal Distal Proximal or Distal Proximal to bulbar Restricted to upper extremities
of weakness distal muscles 1“2
UMN signs Present Absent Absent Present Absent Present Absent Absent
LMN signs Present Present Present Absent Present Present Present Present
Sensory loss Absent Absent Absent Absent Modest Absent 20% Absent
Genetics AD (10%) SOD Unknown AR, AD, SMN Unknown XLR CAG repeats Unknown Unknown Unknown
mutation (2%) gene (no reported (no reported
implicated familial cases) familial cases)
Distinct UMN and LMN Pure LMN Pure LMN Pure UMN Gynecomastia, Weakness Progression Preservation of
features signs with disorder with disorder disorder with diabetes initially over 2“3 respiratory and
usually rapid usually usually with indolent mellitus, limited to years with bulbar function
progression indolent progressive course impotence, bulbar subsequent with slow
course proximal infertility muscles. May stabilization progression
weakness over progress Typically
decades rapidly to ALS young age of
or be relatively onset

Abbreviations: Autosomal dominant (AD); Autosomal recessive (AR); Cytosine “ adenine “ guanine nucleotide (CAG); Lower motor neuron (LMN); Superoxide dismutase (SOD); Survival motor
neuron (SMN); Upper motor neuron (UMN); X-linked recessive (XLR)
Reproduced with permission from: Strong, M. & Rosenfeld, J. Amyotrophic lateral sclerosis: a review of current concepts. ALS and Other Motor Neuron Disorders 2003; 4: 136“43.
Chapter 10

Postpolio syndrome
The largest series describing ALS in pregnancy is from a 1956
study in Guam, where the incidence of ALS is 100 times the
Pathophysiology and effect on pregnancy
expected rate.135 In this series, 17 women underwent 21 pregnan-
Postpolio syndrome (PPS) is a degenerative disease of the anterior
cies, all had vaginal deliveries. Some women with very advanced
horn cells of the spinal cord. It is estimated that there are between
ALS at the time of conception died during their pregnancy. There
250 000 to 300 000 polio survivors in the USA. Postpolio syndrome
appears to be no specific effect of pregnancy on the course of ALS,
usually develops 25“30 years after the original infectious epi-
nor any special obstetric complications.135 This is supported by
sode.141 Until recently, the diagnosis of PPS required a history of
case reports, where pregnancy did not alter median survi-
paralytic polio; however, PPS can occur in those patients exposed
val.126,127,128,130,136 However, as disease progression is rapid, it
to polio who only suffered a mild, flu-like illness. The diagnosis of
should be expected that the parturient will decline during preg-
PPS is one of exclusion, after ruling out other adult-onset motor
nancy. One case report describes a 25-year-old woman present-
neuron disorders (see Table 10.3).142,143
ing at 22 weeks™ gestation with left-sided weakness of 8 weeks™
Typical symptoms include leg-length discrepancy, asymmetric
duration, as well as severe progressive dysphagia.131 She had a
progressive weakness, limping, and scoliosis. However, the most
marked decrease in respiratory function (FVC 53%). By 29 weeks™
prominent symptom is fatigue: both generalized and secondary
gestation she required a tracheostomy because of inability to
to peripheral muscle weakness.142,144 Muscle pain occurs in up to
clear secretions. By 34 weeks™ gestation, despite plasmapheresis,
80% of affected individuals, and nerve compression syndromes in
she had no motor function. Labor was induced and she had a
49%.145 Women are more likely than men to suffer from muscle
healthy baby, but the woman died nine months postpartum.131
and joint pain. Cold intolerance is another feature of PPS.144
The respiratory demands of pregnancy may result in acute
Electromyelography (EMG) shows typical widespread neurogenic
respiratory failure in women with ALS. Establishment of baseline
changes in all four limbs. Despite the mildness of the original
respiratory function early in pregnancy, with regular follow-up by
polio, PPS can be full-blown and have a significant effect on
a respirologist is necessary. Pulse oximetry during labor is recom-
daily living. The cause of PPS is not clear, but is likely due to
mended, as the additional respiratory stress from labor may be
degeneration of enlarged motor neurons, which have grown in
poorly tolerated.130 Again, there is no specific treatment for ALS;
response to the original polio, within an overall population of
however, plasmapheresis has been tried. Supportive therapy dur-
reduced motor neuron units.146 Postpolio syndrome tends to be
ing pregnancy includes provision of adequate nutritional sup-
a slowly progressive disease: respiratory effects and dysphagia are
port.137 Vaginal delivery should be expected, as the pelvic floor
the most concerning features.147
is relaxed and uterine contractility unaffected.
Similar to the other degenerative motor neuron diseases, the
respiratory muscles are often significantly affected in PPS, and
Anesthetic considerations for labor and delivery
bulbar symptoms result in laryngeal dysfunction with inability to
There is essentially no information in the literature about the
protect the airway.141
anesthetic management of the parturient with ALS. Most case
There are only three reported cases of pregnant women with
reports deal with the obstetrical management and do not include
PPS, all of whom had severe respiratory disease requiring non-
anesthetic data. However, in 1998 Jacka described epidural
invasive ventilation prepregnancy.148 All had successful term
anesthesia for C/S in a primiparous woman with familial ALS
pregnancies, with vaginal deliveries not requiring anesthesia.
who developed respiratory failure at 32 weeks™ gestation.128 This
Vital capacities (VC) ranged from 240 to 280 ml and were not
patient required bilevel positive airway pressure (BiPap) post-
affected by the pregnancy. Clearly earlier recommendations
operatively, but tolerated a T4“5 intraoperative block reasonably
about avoiding pregnancy when VC is less than one litre did not
well with a PaCO2 of 70 (55 preoperatively). This woman devel-
hold true.149
oped acute respiratory failure ten days postpartum requiring
long-term ventilation.
Anesthetic considerations
Epidural anesthesia has been used successfully in nonparturi-
ents with ALS.138,139,140 One must weigh the risks of using regional There is limited information about the anesthetic management of
patients with PPS, although a good review has been published.144
anesthesia in a patient with active progressive neurological dis-
ease versus the benefits, recognizing that new neurological defi- There are only two case reports in the English language literature
cits postpartum are likely due to the disease. Epidural morphine that discuss anesthesia in patients with PPS. One case was
has been used for postoperative analgesia, notably in a woman uneventful, but in the other a 51-year-old woman died after
undergoing hysterectomy for endometrial carcinoma.139 This suffering a postoperative cardiac arrest.141,150 The cause was
patient had significant preoperative respiratory compromise thought to be secondary to a respiratory arrest from sensitivity
with an FVC of 34% of that predicted, but had no difficulty toler- to opioids combined with undiagnosed sleep apnea, both part of
ating a T5 block, or the epidural morphine. her PPS. Awareness of the potential for significant respiratory
General anesthetic considerations must include airway protec- compromise, bulbar dysfunction, sensitivity to anesthetic agents,
tion because of bulbar dysfunction, avoidance of succinylcholine, and cold intolerance are important; otherwise, general principles
sensitivity to nondepolarizing muscle relaxants (so avoid if pos- of anesthetic management are based upon the patient™s physio-
logic and neurologic status.141,144 There is no scientific data to
sible), and depression of respiratory function post anesthesia
or surgery. support theoretical concerns of neurotoxicity of local anesthetics

3 Nervous system disorders

in patients with PPS, therefore the choice of regional versus gen-
Table 10.4 Forms of spina bifida occulta according to tissue
eral anesthesia is an individual decision.
of origin

Mesodermal Neural Ectodermal
Transverse myelitis
Defective laminar Distal hydromyelia Nevi
Transverse myelitis is a rare inflammatory disease of the spinal
cord, associated with infections and autoimmune disorders such
Diastematomyelia Spinal cord adhesions Hairy patches
as systemic lupus erythematosus (SLE). There are eight published
Intra/extradural (without obvious Dermal sinuses
cases of pregnancy in patients with transverse myelitis, one sec-
bands cause)
ondary to schistosomiasis infection.28,39,151,152,153,154,155 The most
Lipomas Meningocele manque Cutaneous dimples
common presenting symptom is back pain with progressive para-
Dermoid cyst (aborted herniation
paresis. Management includes specific therapies for the under-
of nerve roots)
lying disease, high doses of steroids, and plasmapheresis.155
If patients with transverse myelitis have complete physiologic
spinal cord transection, they should be treated as SCI patients.
Obstetrical complications include preterm labor, unattended
delivery, and UTIs. Autonomic hyperreflexia is a potential risk.

Friedreich ataxia
Friedreich ataxia is an uncommon inherited neurodegenerative Hairy
disease affecting the spinocerebellar tracts. It is fully discussed in
Chapter 8.

Spinal dysraphism
Spinal dysraphism describes a variety of congenital abnormal-
ities, which arise as a result of failed closure of the neural tube. It
is divided into: spina bifida cystica (or aperta), which includes
meningocele, myelomenigocele, rachschisis, and anencephaly;
and spina bifida occulta, which encompasses a wide range of
minor defects of mesodermal, neural, or ectodermal origin (see
Figure 10.4, Table 10.4). The solitary finding of defective laminar
arches, which may itself be a variant of normal, is not usually
described as spina bifida occulta.156 The incidence of spina bifida
cystica varies from 0.5 to 2.5 per 1000 births in North America and
the UK respectively, but is decreasing due to folate supplementa-
Figure 10.4 Grades of spina bifida. A: spina bifida occulta; B: meningocele;
tion preconception and improved antenatal screening.157 The
C: myelomeningocele.
incidence of spina bifida occulta ranges from 10 to 50% of the
adult population based on the presence of radiological defects in
the vertebral spinous processes and lamina.158,159
Early repair of meningoceles and myelomeningoceles, as well patients were all less than 20 years old, and 54% had lumbar disc
disease at L3“4, L4“5 or L5“S1.160 Sixty percent of spina bifida
as advances in the treatment of the complications such as infec-
occulta occur between L4 and S2 levels.161 The clinical signifi-
tion and hydrocephalus, has resulted in an increasing number of
spina bifida cystica patients reaching childbearing age.158 There cance of isolated bony arch abnormalities is not yet established,
are numerous case reports describing the management of labor but spina bifida occulta has been associated with chronic back
and delivery in these patients. problems, enuresis, and neurological problems reflecting its
many variants.159
Magnetic resonance imaging improves the diagnosis of occult
Spina bifida occulta
spinal dysraphism, defining lesions missed on plain radio-
graphs.162,163 The anomalies detected include tethered cord, dia-
A CT scan of patients with low back pain or sciatica found spina
bifida occulta at S1 in 207 of 1200 patients aged 18 to 72 with a stematomyelia, syringocele, and diplomyelia. Patients with cord
decreased incidence in the older patients. Of the patients with abnormalities have cutaneous stigmata in 50“70% of cases, but
only 30% are symptomatic.163,164,165 Patients with isolated ver-
occulta lesions, 82% had posterior disc herniation at L4“5 or
L5“S1.159 Another study found a high incidence of lumbar disc tebral arch anomalies usually have neither cutaneous stigmata
nor underlying cord anomalies.161
degeneration in young patients with spina bifida occulta. These

Chapter 10

scoliosis usually undergoes rapid progression with growth.175,176
Anesthetic management of patients with spina
bifida occulta Congenital scoliosis also occurs due to bony abnormalities such
as hemivertebrae and multiple rib fusions. Progression is slower,
There are few implications for obstetrical anesthesia manage-
and often significant kyphosis is present. Tethered cord syn-
ment of the patient with spina bifida occulta. Most cases are
drome may also cause scoliosis.177 The surgical treatment con-
asymptomatic and consist of an isolated bony defect at a low
sists of releasing the tethered cord and spinal instrumentation.
spinal level. Regional anesthesia is not contraindicated, and the
The release of a symptomatic tethered conus often arrests pro-
only recommendation is to perform the block at a site remote
gression of the curvature in patients with lumbosacral but not
from the level of the anomaly. There is an increased potential for
thoracic lesions.174 Progressive lordosis and kyphosis are also
accidental dural puncture as the supporting ligaments, specifi-
significantly reduced.
cally the interspinous ligament and the ligamentum flavum, may
be abnormal at the lesion.166 The epidural space may be discon- Deterioration in function may occur in spina bifida cystica
because of development of syringomyelia or shunt dysfunction.177
tinuous at this point and inadequate or failed blocks may result.157
Many patients have poor hand control and manipulative difficul-
Patients with occulta lesions who have underlying cord anoma-
ties despite the distance of the lesion from the cervical cord.178
lies often have cutaneous signs, and may have neurological signs
and/or symptoms. These patients should be assessed antepartum
Impact of pregnancy on spina bifida cystica
by an anesthesiologist so that relevant neurological data and
There are several features of spina bifida cystica that affect the
consultations can be obtained. This also provides an opportunity
course of pregnancy and delivery (see Table 10.5). The manage-
to discuss issues relating to regional anesthesia, such as direct
ment of patients with significant kyphoscoliosis is discussed in
trauma to the low-lying tethered cord, an increased potential for
Chapter 7. Spina bifida cystica patients are often less mobile
problem blocks, and dural puncture. The majority of spina bifida
during pregnancy as their weight increases, making them more
occulta lesions are at low lumbar or sacral levels, and are fairly
susceptible to DVT and decubitus ulcers. The changes in the
trivial anatomic anomalies that have little impact on regional
lumbosacral spine resulting from hormonal relaxation of the
anesthesia. If symptoms (leg pain and weakness with or without
ligaments and the expanding abdominal girth may adversely
cutaneous stigmata) suggest a tethered spinal cord (see tethered
affect wheelchair fitting and mobility.179 Impaired renal function
cord syndrome), an MRI should be obtained prior to performing
may worsen due to the increased incidence of UTIs. An increase
neuraxial anesthesia, to determine the level of termination of the
spinal cord.167 in abdominal pressure created by the expanding uterus may
impair diaphragmatic function in the spina bifida cystica patient,
especially those of short stature or with scoliosis. Diaphragm
Spina bifida cystica
fatigue during labor may occur, resulting in the need for ventila-
tory support and operative delivery.149
The long-term outlook for patients with spinal bifida cystica has
improved168,169 since a large-scale study from 1983 noted a 48%
early mortality rate.170 Most spina bifida cystica patients have Table 10.5 Neurological and structural residua in adults with
surgery in the first 24 hours of life. Improved surgical techniques spina bifida
and better treatment of infection and hydrocephalus have
Implications for pregnancy and
reduced early mortality to 3“8%. However, approximately 24%
Abnormality delivery
of infants born with spina bifida cystica will die by early adult-
hood, with the later deaths mainly attributable to shunt mal- Sacral agenesis May permit vaginal delivery despite
function.171 Most patients develop hydrocephalus (a Chiari II small pelvis.
malformation is usually associated with significant cystic lesions) Pelvic abnormalities Abnormal lies and presentations that
but not all require placement of shunts. There is a lower incidence (contracted, may preclude vaginal delivery.
of tethered cord syndrome due to improved closure techniques, misshapen)
although by age ten, 19% of patients experience some cord tether- Short stature Respiratory problems as uterus
ing.171 A follow-up study of spina bifida cystica patients operated expands. More likely to have C/S.
on between 1978 and 1986 found that 84% of patients were Scoliosis (may be severe) Cardiorespiratory. Mobility problems.
ambulatory,168 reflecting the fact that repaired lumbar meningo- Technical difficulties with regional
celes usually have only mild neurological deficits confined to the anesthesia.
lower limbs.166 Tethered cord syndrome Neurological deterioration. Cord
There are associated anomalies of the gastrointestinal, skeletal, trauma with regional anesthesia.
cardiac, and renal systems that may affect development.172,173 Shunts Raised ICP. Infection.
Myelomeningocele is a dynamic neurological disease that even- Chronic bladder Worsened during pregnancy. Renal
tually produces orthopedic, neurologic, and genitourinary com- problems impairment.
plications. Progressive spinal deformities occur in up to 90% of Motor and sensory No labor pain. Autonomic
patients, with findings of scoliosis, kyphosis, and lordosis.171,174 deficits hyperreflexia. Precipitous labor.
Developmental paralytic scoliosis is the most common resulting
C/S ¼ cesarean section; ICP ¼ intracranial pressure
from an imbalance of the paravertebral muscles. This form of

3 Nervous system disorders

Medical and obstetrical management spina bifida patients may be decreased. Theories to explain this
finding include altered dural permeability and abnormally small
Patients with spina bifida cystica should consult with medical
volume epidural space surrounding the lesion.165,188 Tidmarsh
and obstetric personnel prior to conception to ensure the
published sixteen cases of spina bifida, both occulta and cystica,
medical aspects of their disease are optimized. There is no clear
of whom ten received a labor epidural.157 Six blocks were uncom-
evidence that there is an increased risk of fetal abnormalities in
plicated and provided good analgesia; however, four were less
women with spina bifida cystica, but there are case reports from
past decades documenting fetal malformations.180,181 Genetic than ideal: one dural puncture, one high block, and two provided
inadequate caudal analgesia. Additional sacral analgesia may be
counseling preconception is recommended. Respiratory function
necessary, such as a pudendal block.
should be assessed, and followed in patients with compromise
Some consider spinal anesthesia contraindicated because of
and those at risk for decompensation during the pregnancy.
the unpredictability of local anesthetic dose requirements.166,179
Patients with shunt-controlled hydrocephalus require assess-
On the other hand, Brome191 and Nuyten190 successfully used
ment of shunt function and the sites of peritoneal drainage
spinal anesthesia for C/S. Both authors opined that spinal
should be noted. A survey of shunt-dependent women found
anesthesia is technically easier and provides a more predictable
that 9 of 70 women had an increase in headaches during preg-
nancy.182 Seven women required shunt revisions during preg- block. Nuyten used a spinal catheter to manipulate the level of
block.190 The risk of cord damage by needle insertion is minimal if
nancy, and 23 patients experienced shunt failures in the first six
one chooses a site below the anatomic lesion level.
months postpartum.
If the patient has a shunt, confirm appropriate shunt function
Many spina bifida patients have short stature and/or a con-
and normal intracranial pressure (ICP) before performing neur-
tracted pelvis that may preclude vaginal delivery, so the pelvis
axial block.182 In spina bifida cystica patients with a lesion level
should be assessed early in pregnancy. Patients may have had
above T5“7, there is the potential for AH during labor. However,
prior pelvic x-rays, usually for orthopedic evaluations and these
may be suitable to assess pelvic adequacy.183 such lesions are extremely rare as they usually occur with other
CNS malformations that are incompatible with life.
Latex sensitization and allergy affect up to 72% of children with
spina bifida cystica if exposed to latex since birth.184 Recognition An increasing number of spina bifida cystica patients will have
children in the future, and the management issues specific to this
of this serious problem resulted in latex avoidance measures with
a large decrease in the prevalence of latex sensitization;185,186 syndrome must be recognized. These patients require antepar-
tum assessment by an anesthesiologist so that all options are
however, the current adult population with spina bifida have a
analyzed and discussed. Obstetric anesthetic care of the spina
high likelihood of latex allergy.
bifida patient provides many challenges. In its mildest form,
There are numerous case reports dealing with management of
spina bifida occulta, there may be an increased risk of accidental
pregnancy and parturition in spina bifida cystica. Some common
dural puncture while performing epidural blocks. The more
complications include preterm labor, UTIs, difficult pelvic exam-
severe spina bifida cystica patients may present with significant
inations due to leg contractures, and problems in those patients
with uretero-ileostomies (damage during C/S).180,183,187,188,189 scoliosis, surgically scarred backs, respiratory compromise,
as well as obstetric problems such as preterm labor and pelvic
There is consensus that C/S should be performed for obstetric
reasons only.183 abnormalities that preclude vaginal delivery. In the past, most
patients did not receive regional anesthesia for labor and C/S
Anterior sacral meningocele is an extremely rare form of spina
was often performed under GA. An increasing number of reports
bifida cystica that may not be diagnosed until puberty or even
document successful epidural and spinal anesthesia in these
during pregnancy (compression of neural sac by growing uterus).
patients.157,179,188,189,191 There is an excellent review of the anes-
Implications for pregnancy include associated sacral and
thetic considerations for the parturient with a neural tube
coccygeal malformations, and the effect of the sacral mass on

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