Neuromuscular disorders during pregnancy can be either hereditary or acquired. The physiologic changes of pregnancy may increase the risk of complications from these neuromuscular disorders, sometimes affecting both mother and fetus. Patients may develop compression neuropathies and radiculopathies during pregnancy, labor, and delivery.
Acquired neuropathies can be divided into mononeuropathies (affecting only one nerve), mononeuropathy multiplex (affecting single nerves at different sites of the body), or polyneuropathies (that are diffuse, usually symmetric and generalized). Mononeuropathy is usually caused by compression or trauma of a nerve at a specific site. These peripheral entrapment neuropathies are common during pregnancy and may lead to severe discomfort. Pregnancy itself may predispose patients to some of these entrapment neuropathies, which are mostly benign in their evolution and prognosis and will resolve spontaneously in the postpartum period. Delivery may predispose patients to compression or stretching of some nerves and plexuses that may precipitate symptoms. Prompt clinical evaluation and, when necessary, an electrophysiologic evaluation may aid in the diagnosis and subsequent management. Polyneuropathies are caused by systemic diseases or axonal nerve injuries resulting from metabolic or toxic etiologies or from demyelinating diseases of peripheral nerves.1
Hereditary nerve and muscle disorders may place patients at risk during pregnancy. These patients need additional counseling about the possible transmission of the disease to the fetus.
Table 23-1 summarizes the classification of the most common peripheral neuropathies.
TABLE 23-1Peripheral Neuropathies Classification ||Download (.pdf) TABLE 23-1 Peripheral Neuropathies Classification
Hereditary neuropathy with liability to pressure palsies
Hereditary brachial plexus neuropathy
2. Muscle disorders
Facioscapulohumeral muscular dystrophy (FSHD)
Limb-girdle muscular dystrophies
1. Muscle disease
Polymyositis and dermatomyositis
2. Neuromuscular junction
3. Root, plexus, peripheral nerve
Acute inflammatory demyelinating polyradiculoneuropathy (AIDP)
Idiopathic facial nerve palsy (Bell palsy)
Median neuropathy at the wrist (carpal tunnel syndrome)
Lateral femoral cutaneous neuropathy (meralgia paresthetica)
Lumbar radiculopathy and plexopathy (lumbosacral plexus lesions)
Sciatic and common fibular (peroneal) neuropathy
Charcot-Marie-Tooth (CMT) is a hereditary peripheral neuropathy, also called hereditary motor sensory neuropathy (HMSN) that includes several disorders caused by mutations in various myelin genes that affect its structure, formation, and maintenance. It is a chronic demyelinating disorder of peripheral nerves affecting both motor and sensitive roots.2 Patients usually experience distal leg weakness and distal muscular atrophy, foot deformities, and sensory deficits (Figure 23-1). Deep tendon reflexes can be diminished or absent. Depending on the severity of the disease, it can affect respiratory muscles and thoracic vertebral anatomy, impacting patient respiratory function during pregnancy and affecting delivery and anesthetic care.
Distribution of affected muscles and peripheral nerves in different neuropathies. CMT, Charcot-Marie-Tooth disease; LGMD, Limb-girdle muscular dystrophy; FSHD, facioscapulohumeral dystrophy; LGMD, Limb-Girdle Muscular Dystrophy; SMA, spinal muscular ...