Charcot-Marie-Tooth Disease

Charcot-Marie-Tooth Disease (CMT)

-Charcot-Marie-Tooth disease (CMT) is a neuromuscular disorder characterized by length-dependent degeneration of the motor and sensory nerve fibers, with a prevalence of 1 in 2,500 (about 200,000 patients in the European Union).

-Anesthesia is administered to this population more frequently than to normal people, as CMT patients often need orthopedic surgery to correct muscle imbalance and limb deformities, and for osteosynthesis of bone fractures as they are prone to falls.

Anesthetic Management Complications:

1-Malignant hyperthermia.

2-Prolonged responses to neuromuscular blocking drugs.

3-Drug toxicity is caused by inappropriate doses in case of severe muscle wasting.

4-Medication-induced exacerbation of neuropathy.

5-Associated deformities such as scoliosis.

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 Chiari Malformations

-The Chiari malformation is a term encompassing a range of hindbrain maldevelopments.

-Problems include underdevelopment of the cranial fossa and overcrowding of the normally developed hindbrain, the risks of descent of hindbrain structures below the foramen magnum, and intermittent obstruction to CSF outflow from the fourth ventricle.

-There may be a relatively high CSF pressure in the head and a relatively lower one in the spine.

Types of Chiari Malformations:

There are four types.

Type I:

-Downward herniation of cerebellar tonsils of at least 3–5 mm below the foramen magnum and hindbrain overcrowding results in direct compression of the tissue.

-Clinical symptoms thus relate to CSF disturbances and direct compression of nervous tissue; they include headaches, pseudotumor-like episodes, a syndrome resembling Meniere’s disease, lower cranial nerve signs, and spinal cord disturbances without syringomyelia.

-It is mostly seen in young adults.

Type II (Arnold–Chiari):

-It is the most important and includes; thoracolumbar myelomeningocele, hypoplasia of the posterior fossa, and displacement of the cerebellar vermis, brainstem, and fourth ventricle.

-It presents in infancy or early childhood.

Type III: rare

-Dilated the fourth ventricle with cervical meningomyelocele.

Type IV: rare

-Cerebellar hypoplasia.

Other abnormalities:

1. May be associated with syringomyelia or syringobulbia, other skeletal abnormalities of the skull base and cervical vertebrae, or myelomeningocele. Syringomyelia is the term for an expanding, longitudinal cystic cavity within the spinal cord. In the communicating variety, there is continuity between the syrinx and the CSF in the central canal.

2. May need decompression of foramen magnum or cervical spine.

3. Progressive hydrocephalus may occur which needs shunt surgery.

4. Obstructive sleep apnea.

5. Recurrent pulmonary aspiration.

6. May exhibit abnormal autonomic control.

7. Patients may present with respiratory arrest.

8. Sudden unexpected death may occur.

Anesthetic Problems:

1. Increased ICP may lead to coning.

2. Symptoms may start after a dural puncture.

3. Bolus injections into the epidural space may lead to ICP increases in susceptible individuals.

4. Sleep apnea may occur in Chiari type I.

5. Acute cardiovascular collapse secondary to inadvertent brainstem compression in an infant.

Anesthetic Management:

1. A careful history should be taken in a patient with a ventriculoperitoneal shunt, to check for any signs that it is nonfunctioning. If there is doubt, referral to a neurosurgeon is indicated. This is particularly important if the notes are absent, there is poor history or lack of follow-up.

2. Try to prevent anything likely to increase ICP, such as coughing, or hypercarbia from heavy sedation or analgesia.

3. Avoid straining in labor. Epidural anesthesia for Cesarean section was performed in a patient with type I Chiari who had a previous difficult tracheal intubation. Small doses of local anesthetic should be titrated gradually, to avoid sudden distension of the epidural space or decreases in arterial pressure.

4. Spinal anesthesia should be avoided.

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