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informed of the possible need for prolonged postoperative
patient has significant respiratory compromise or bulbar involve-
mechanical ventilation.94
ment that dictates securing the airway prior to surgery. Combined
Worsening of symptoms during the postpartum period can
spinal“epidural analgesia has been used successfully for labor and
delivery in a woman with severe MG.87 Ester local anesthetics may occur, so the patient should remain in a high-dependency unit.
have a prolonged half-life due to the decreased cholinesterase
activity in patients on anticholinesterase medication. This may
Friedreich ataxia
lead to problems with local anesthetic toxicity or extensive epi-
Friedreich ataxia (FA) is a progressive, cardio- and neurodegen-
dural block. Therefore, amide local anesthetics are recommended
erative disorder that affects both the central and peripheral ner-
for epidurals and spinals. Intrathecal and epidural opioids can be
vous systems. Prevalence of FA is estimated to be 1: 29 000“50 000,
used with appropriate postoperative monitoring for respiratory
making it the commonest inherited ataxia.95 The incidence is
depression. Should GA be necessary, it can be performed safely
higher in Caucasians, with males and females affected equally.
provided the patient is optimally prepared and neuromuscular
It is transmitted by autosomal recessive inheritance and is caused
function is adequately monitored during and after surgery.
by GAA trinucleotide repeat expansion, or point mutations, in the
It is controversial whether anticholinesterase medication
frataxin gene on chromosome 9q13. This mutation causes a
should be maintained or discontinued preoperatively. Problems
reduction in frataxin, a highly conserved protein, found in pro-
of continuing therapy include potentiation of vagal responses,
karyotes and eukaryotes, which is required for efficient regulation
inhibition of plasma cholinesterase (hence prolongation of ester
of cellular iron homeostasis.96 In health, frataxin is found in high
local anesthetics and succinylcholine), and possible cholinergic
quantities in the brain, spinal cord, heart, and pancreas, the
crisis. However, in a patient who is physically or psychologically
organs most affected by FA. Deficiencies in this protein lead to
dependent or who has more than ocular symptoms, it is better to
mitochrondrial accumulation of iron, which may promote injury
continue medication.
due to oxidative stress.97
Another important issue is preoperative measurement of mus-
The diagnostic criteria98 and clinical problems of the disease
cle strength for postoperative comparison. The disease, rather
are described in Tables 8.12 and 8.13, although molecular testing
than the neuromuscular block, may prevent patients with
has shown that the phenotypic spectrum of FA is wider than once
myasthenia from reaching full strength, despite treatment.
thought. The manifestations vary in part with the number of GAA
Therefore, before the administration of anesthetic drugs that
expansions. Longer GAA repeats cause a more profound frataxin
may interfere with neuromuscular transmission, a control EMG
deficiency and are associated with earlier onset, shorter time to
or train-of-four should be recorded.
loss of ambulation, a greater frequency of cardiomyopathy, and
Ketamine, thiopental, and propofol have been used success-
fully for induction of GA in these patients.90,91 Cardiac and vas- increased severity of the disease. The major clinical manifesta-
tions of FA are neurological dysfunction, cardiomyopathy, and
cular tone is unaffected in MG and increased cardiovascular
diabetes mellitus.
depression has not been reported at induction.

2 Musculoskeletal disorders

Table 8.12 Diagnostic criteria for Friedreich ataxia Table 8.13 Clinical features of Friedreich ataxia

Autosomal recessive inheritance Organ Disease process Anesthetic implications
Age of onset < 25 years
CNS Ataxia Altered response to
Progressive gait and limb ataxia
muscle relaxants
Absent tendon reflexes in lower limbs
Dysarthria Hyperkalemic response
Electrophysiological evidence of axonal sensory neuropathy
to succinylcholine
(with normal/slightly raised motor nerve conduction velocity)
Loss of deep tendon reflexes ? Unpredictable
Dysarthria a
response to
Areflexia a in all four limbs
Pyramidal leg weakness a
muscle relaxants
Distal loss of joint position and vibration sense a
Posterior column signs Muscle weakness
Weakness/decreased muscle Increased risk of
Criteria, except as marked, within five years of symptom onset.
a tone, bulbar dysfunction aspiration/chest
Eventually universal but generally not found in patients within five
years of onset of symptoms.
Distal muscle wasting (50%)
Extensor plantar response
The most frequent presenting symptom is an ataxic gait,
although it is occasionally preceded by scoliosis or cardiac symp-
CVS Cardiac muscle disease Dysrhythmias (atrial
toms. The average age of onset of symptoms is 15 years (range
2“51 years) and time from onset to being confined to a wheelchair
EKG abnormalities Cardiac compromise
is 11 years (range 1“25 years). Death occurs mainly due to cardio-
respiratory problems related to scoliosis and cardiac abnormal-
ities. Histological changes in the heart consist of diffuse
Spine Kyphoscoliosis (mostly Decreased
myocardial fibrosis and degeneration of the cardiac muscle
thoracic) cardiopulmonary
fibers.99 Electrocardiogram abnormalities are found in up to
95% of patients with FA, the commonest being ST or T wave
Possible corrective surgery Technical problems with
abnormalities. Abnormal echocardiographic findings are detect-
(e.g. Harrington rods) spinal/epidural block
able in many FA patients, the most frequent finding being con-
Eyes Optic atrophy (25%)
centric LV wall thickening and asymmetric septal hypertrophy.99
Nystagmus (20%)
Overt diabetes mellitus or impaired glucose tolerance was found
Abnormal extra-ocular
in approximately one third of FA patients, the majority requiring
insulin.98 In addition, more than 50% of patients have progressive
Ears Sensorineural deafness (10%)
Pes cavus Æ equinovarus
Treatment of FA involves symptomatic support and antioxidants
deformity (75%)
to reduce the free radicals. In one study, treatment with idebenone
(a free-radical scavenger) appears to significantly reduce the LV Associated diseases include diabetes mellitus (10%), impaired
mass in FA patients with hypertrophic cardiomyopathy.100 glucose tolerance (20“30%) and increased incidence of seizures.
CNS ¼ central nervous system; CVS ¼ cardiovascular system;
EKG ¼electrocardiogram
Effect of pregnancy on Friedreich ataxia
Advances in medical management have resulted in more women
with FA attaining reproductive age. In a series of 24 pregnancies magnesium is not recommended for the management of preterm
in 17 women with FA, all women delivered live babies at term.101 labor or preeclampsia in women with FA.103 Indomethacin may
Ninety-six percent delivered vaginally and only two pregnancies be a suitable treatment for preterm labor but coexisting diabetes
were complicated by preeclampsia. There was no increased risk or cardiac disease may deter the use of beta-mimetic agents or
of obstetric complications. However, although few problems with calcium channel blockers.
pregnancy have been reported, the superimposed physiologic
changes of pregnancy have the potential to aggravate cardiores-
Anesthetic management
piratory problems in FA patients. One report described a preg-
nancy in a woman with FA that was complicated by dyspnea and The main perioperative risk in women with FA is cardiopulmonary
palpitations, and increasing dysarthria and arm weakness in the compromise. Heart disease at the time of presentation of FA occurs
third trimester. No explanations for this deterioration were in 86“95% of patients while long-term follow-up shows cardiac
offered but her symptoms resolved six weeks™ postpartum.102 involvement in 100% of patients.99 The severity of the cardiomyo-
Another woman with FA received MgSO4 as a tocolytic agent pathy may not correlate with that of the neurological condition.
and developed severe weakness and respiratory distress. Hence, Progressive kyphoscoliosis may produce ongoing restriction of

Chapter 8

Table 8.14 Advantages and disadvantages of different anesthetic techniques in patients with Friedreich ataxia

Epidural Spinal General

# perioperative respiratory problems unless high block
Advantages Rapid onset Good airway control in patients
with gross muscle weakness
Cardiovascular stability with slow administration Easier technique than
Provides excellent postoperative analgesia preventing Provides good postoperative
#SVR and "HR (especially with cardiac patients) analgesia
Disadvantages Technical difficulties in patients with kyphoscoliosis Technical difficulties in Possible succinylcholine-
patients with induced hyperkalemia
" incidence of patchy block in patients with ? "sensitivity to NDMR
Sudden sympathetic block
kyphoscoliosis may compromise patients
with hypertrophic

SVR ¼ systemic vascular resistance; HR ¼ heart rate; NDMR ¼ nondepolarizing muscle relaxants

pulmonary function with a decrease in vital capacity and total lung accompanying developmental defects in both the neurological
system as well as various viscera (see Table 8.15).112 It has an
capacity. In addition, corrective surgery for scoliosis may make
incidence of 1 in 3000“10 000 live births.113 The origin of the joint
regional anesthesia difficult. Preoperative evaluation of the patient
should concentrate on cardiac and pulmonary function with an EKG deformities are primarily neurogenic in >90% AMC (resulting
and echocardiogram in all patients and pulmonary functions tests from peripheral and/or central nerve dysfunction) and the rest
are myogenic (resulting from primary muscular degeneration).112
where appropriate. Baseline neurologic deficits should be documen-
ted, especially if regional techniques are contemplated. General Conditions that interfere with fetal movement, such as maternal
anesthesia104,105,106,107 and all forms of neuraxial anesthetics (LEA, MG, may also produce neonatal AMC.114 Although the etiology
SAB, and CSE)108,109,110,111 have been used with success in pregnant remains unknown, in the majority of cases, there is a significant
and nonpregnant patients with FA (see Table 8.14). Reports about reduction in the number of anterior horn cells throughout the
patient responses to NDMR in FA are conflicting, although most spinal cord, particularly in the cervical and lumbar regions.
studies indicate normal responses.104,105,106 However, it seems pru- Damage to the anterior horn cells typically produces weakness,
dent to use small, incremental doses of NDMR and to monitor atrophy of muscles, and hyporeflexia without sensory loss. In
neuromuscular block intraoperatively. Although succinylcholine addition, demyelinization of pyramidal tracts, motor roots, and
has been used in patients with FA, it has the potential to produce peripheral nerves has been reported. Pathological changes occur-
severe hyperkalemia. Where there is severe muscle wasting or rapid ring in the myogenic type of AMC include a progressive muscular
progression of weakness, succinylcholine is contraindicated. dystrophy with a reduction in both number and size of muscle
fibers in addition to fibrous and fatty degeneration.112
In order to avoid muscle relaxants, SAB was successfully admin-
istered for elective C/S in a parturient without cardiomyopathy.110 The exact etiology, inheritance, and pathogenesis of AMC is
Many of these patients have hypertrophic cardiomyopathy, which unknown in most cases and there is a considerable disease spec-
may be asymptomatic until sudden death. As SAB may cause trum and varied associated organ disorders. Most cases are spora-
precipitous hypotension, it should only be used in those patients dic and the natural history and prognosis are difficult to predict.
with FA who have had an extensive cardiac assessment. Epidural No matter the etiology, all causes of AMC are associated with
anesthesia provides a good alternative with a slow incremental decreased fetal movements (fetal akinesia). In general, the earlier
onset and greater hemodynamic stability.108 Other safe alter- in gestation the reduction in the movements begins, the more
natives for maintaining hemodynamic stability include incremen- severe the contractures become. Arthrogryposis multiplex con-
tal intrathecal anesthesia using a spinal catheter or low-dose genita is seen primarily in the pediatric population, and pregnant
administration of the intrathecal component of a CSE.111 patients are unusual due to the rarity of the disease, the chronic
disability, and the incidence of other associated abnormalities. As
a result, it is impossible to determine the effect of pregnancy on
Arthrogryposis multiplex congenita
the disease and vice versa. However, the risk of thromboembo-
Arthrogryposis multiplex congenita (AMC) refers to a hetero- lism is likely to be greater in this population in view of reduced
geneous group of disorders characterized by multiple joint mobility. Prophylaxis against thromboembolism should be con-
contractures (distal joints more affected than proximal) with asso- sidered in all pregnant women with AMC. Decreased respiratory
ciated hypotonia and muscle-mass wasting. The deformities are reserve and skeletal abnormalities may increase the likelihood of
operative and premature delivery.115
present at birth and are often progressive. Frequently, there are

2 Musculoskeletal disorders

Table 8.15 Associated abnormalities in arthrogryposis Table 8.16 Anesthetic concerns in patients with
multiplex congenita arthrogryposis multiplex congenita

Organ Abnormality Concern Abnormality

Joints/extremities Contracture-limited or fixed flexion Airway Difficulty due to micrognathia, high-arched
Absence of patellas palate, cervical spine deformities, facial
Syndactylism abnormalities, muscle contractures
Bilateral club foot Associated Congenital heart disease “ reduced cardiovascular
Head/neck Micrognathia conditions reserve
High-arched palate Pulmonary disease due to myopathy and scoliosis
Mandibulofacial dysostosis Renal abnormalities “ altered drug handling, renal
Craniosynostosis function
Facial abnormalities Seizures
Tracheal stenosis Intravenous Joint contractures and scarring from surgery can
CVS Congenital heart disease (10%) e.g. PDA, AS, access make intravenous access difficult
coarctation of aorta, cyanotic heart General Induction agents
" sensitivity due to # muscle mass
disease anesthesia
Spine Vertebral abnormalities Muscle relaxants
Kyphoscoliosis Nondepolarizing
" sensitivity due to # muscle mass
Spina bifida
Sacral agenesis Succinylcholine
Respiratory system Restrictive lung disease Possible hyperkalemic response
Hypoplastic lungs Inhalation agents
" sensitivity due to # muscle mass
Tracheoesophageal fistula
Genitourinary Renal abnormalities Increased incidence of hypermetabolism on
system exposure to anesthetic agents rather than actual
Absence of vagina/uterus link with malignant hyperpyrexia
CNS CNS abnormalities Regional Difficulty due to skeletal abnormalities “
Increased incidence of seizures anesthesia kyphoscoliosis
Abnormalities in spinal cord
CVS ¼ cardiovascular system; PDA ¼ patent ductus arteriosus;
Altered spread of local anesthetics
AS ¼ aortic stenosis; CNS ¼ central nervous system
Abnormalities in cerebrospinal fluid production
and reabsorption
Medicolegal consequences of neuronal damage
Anesthetic management Decreased accessibility to nerves due to
There are several reports in the literature on the anesthetic man-
agement of AMC patients116,117,118,119,120 and parturients with
AMC.121,122,123 Table 8.16 outlines the major anesthetic concerns.
Full assessment of the patient is necessary with particular con- Indeed, one case series of 398 anesthetics in patients with AMC
reported no cases of MH.116 It is thought that the increase in
sideration to the airway and cardiorespiratory status. Respiratory
problems may arise from the myopathy and skeletal deformities. temperature seen in some patients with AMC is due to hyper-
metabolism unrelated to MH.123
These include alveolar hypoventilation, atelectasis, restrictive
respiratory pattern, decreased ability to cough, and an increased Advantages of LEA for labor include excellent analgesia, main-
incidence of aspiration. The presence of significant scoliosis may tenance of cardiovascular and respiratory function with slow
lead to reduced lung volumes, increased work of breathing, incremental doses of local anesthetic, and flexibility to provide
abnormal ventilation/perfusion ratios, and hypoxemia, which anesthesia without resorting to GA and airway manipulation.
may proceed to carbon dioxide retention, pulmonary hyper- However, identifying the epidural space may be technically diffi-
tension, and cor pulmonale. As a result AMC patients may be cult because of scoliosis or corrective surgery. In addition, skeletal
sensitive to opioids and more prone to respiratory depression. contractures may make positioning difficult. Intravenous PCA
Most cases of anesthetic management of AMC patients have may provide a reasonable alternative for labor analgesia, using
described the difficult airway scenario in pediatric patients. small incremental doses of opioids.
Patients with AMC may react abnormally to induction agents, Three cases of C/S in AMC women have been reported in the
inhalational agents, and muscle relaxants.122 There have been literature.121,122,123 Quance described a 21-year-old (45 kg)
several reports of hyperthermia in some AMC children, but wheelchair-bound patient with marked kyphoscoliosis and pelvic
it is not proven that these were malignant hyperthermia (MH). and lower-limb deformities, without any associated primary

Chapter 8

Table 8.17 Classification of Ehlers-Danlos syndrome

Skin Bruising/ Joint
Subgroup Inheritance hyperextensibility Skin fragility bleeding hypermobility Other

Classical (formerly AD Mild“severe Mild“severe Mild“severe Mild“severe 60% of all EDS
EDS I and II)
Benign AD Mild Mild Mild Severe 30% of all EDS
(formerly EDS
Vascular (formerly AD Mild Severe Severe Limited to digits Blood vessel/visceral
EDS IV) rupture
Kyphoscoliosis AR Moderate“severe Moderate“severe Moderate“severe Moderate“severe Congenital scoliosis
(formerly EDS VI)
Eye involvement
(microcornea, scleral
perforation, retinal
Arthrochalasia AD Moderate Moderate Mild“moderate Severe CHD Scoliosis
(formerly Hypotonia
Dermatosparaxis AR Moderate Moderate Severe Moderate
(formerly EDS

AD ¼ autosomal dominant; AR ¼ autosomal recessive; EDS ¼ Ehlers-Danlos syndrome; CHD ¼ congenital hip dislocation

respiratory or cardiac problems.121 Elective C/S was planned at subgroups of EDS using Roman numerals has now been revised.
term due to severe pelvic deformities. The preferred epidural An updated classification system differentiates EDS into six pri-
technique failed due to unilateral block. Spinal anesthesia was mary subgroups, in addition to some more rare forms of the
disease.124 Unfortunately, confusion arises as both classifications
not considered because of the possibility of abnormal spinal-cord
CSF dynamics and the risk of a high block. Therefore, GA was now occur in the literature.
induced using thiopental, succinylcholine, and fentanyl and The main features of EDS comprise skin hyperextensibility
maintenance with oxygen, nitrous oxide, and isoflurane. The (increased elasticity and extension), joint hypermobility
procedure was uneventful except for minimal difficulty with an (increased laxity and extension of joints) and connective tissue
fragility.125 Although sharing the cardinal features of the syn-
unexpected grade III laryngoscopy. A possible reason for the
epidural-block failure is that patients with AMC have an drome, the severity of each varies widely among the subgroups
increased incidence of spina bifida occulta and sacral agenesis, (see Table 8.17). In addition, each subgroup of EDS represents a
which may affect the spread of the local anesthetic. clinical spectrum of abnormalities. The vascular subgroup of EDS
Rozkowski and coworkers reported successful anesthesia for a is at particular risk of premature death from arterial rupture either
arising spontaneously or with trauma.126
C/S using a spinal catheter to administer incremental doses of
local anesthetic.122 This particular technique was used because it The exact prevalence of EDS is unknown due to undiagnosed
was considered a safer and more predictable method of obtaining milder forms of this condition, although an estimate of 1:5000 has
been given.125 Ehlers Danlos syndrome is most prevalent among
an adequate block. The only side effect was mild shortness of
breath due to a high block. Spooner described a 26-year-old Caucasians, with men and women being equally affected. The
parturient with lumbosacral scoliosis requiring a C/S.123 Despite commonest types of EDS are the classical (approximately 60%),
difficulties in locating the epidural space, a CSE was performed hypermobility (approximately 30%), and vascular (approximately
successfully without perioperative complications. 6%) subgroups. The other types of EDS are extremely rare.
The basic defect results in deficient or defective collagen, and is
caused by mutations in structural collagen genes or in genes
Ehlers Danlos syndrome
coding for enzymes involved in their posttranslational modifica-
The Ehlers Danlos syndrome (EDS) is a group of inherited con- tion. Many types of collagen occur and these proteins are essen-
nective tissue disorders, which differ clinically, genetically, and tial for development and organogenesis, cell attachment, and
biochemically. The original classification of over ten different platelet aggregation, in addition to providing tensile strength to

2 Musculoskeletal disorders

Table 8.18 Disease manifestastions of Ehlers-Danlos syndrome

Organ Dysfunction Anesthetic/surgical implication

Skin Hyperextensibility Scarring “ difficult IV access
Fragility Poor wound healing “ sutures hold poorly
Fragility “ careful taping/padding perioperatively
Careful patient positioning/padding
Musculoskeletal Hypermobility of joints, effusions, hemarthrosis, dislocations,
premature degenerative joint disease
Spinal malalignment/ spondylolisthesis (however, spinal-cord Technical difficulties with regional
compression rare)
Kyphoscoliosis Cardiovascular/respiratory compromise
Hematologic Bruising after minor trauma although, in most, excessive abnormal Postoperative hemorrhage
bleeding is normally not a problem except for type IV “ hematologic Possible contraindication to spinal/epidural
complications due to abnormalities in walls of large/small blood Spontaneous rupture of arteries/veins
vessels Aneurysms
Gastrointestinal tract Hiatal hernia, GIT bleeding Risk of aspiration, anemia
Viscera Spontaneous rupture of viscera (e.g. uterus/GIT) Shock “ depends on organ involved

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