Episode 6: Neuropathy in Pregnancy and Postpartum

Ann is a busy mom of three kids - but can she really be "too busy" to notice that half of her face is not moving? In this episode we discuss Bell's Palsy and other "high yield" neuropathies that can occur in pregnancy and postpartum. Featuring obstetrical medicine and infectious disease expert Dr. Erica Hardy, and neuromuscular expert Dr. Kara Stavros. Dr. Julie Roth hosts.

Key Takeaways:

• Bell's Palsy is characterized by weakness or paralysis of one side of the face - both the upper and lower face - with reduced eye blinking, sometimes with impaired taste and hearing. Patients can get numbness, tingling and pain in the face or behind the ear.
• A short course of steroids is evidence-based in nonpregnant patients with Bell's Palsy, although less is known about the use of steroids in pregnancy and postpartum period for this condition.
• Carpal Tunnel Syndrome (CTS) is the most common peripheral neuropathy in pregnancy; it presents with achy wrist and arm pain and tingling in the fingers, worse at night, relieved by shaking out the hand. It can be managed conservatively with wrist splints during pregnancy and symptoms usually resolve after delivery.
• An enlarged uterus can compress nerves and the lumbosacral plexus in the pelvis during pregnancy, and prolonged labor and delivery is also a risk factor for some lower limb neuropathies. A careful history and exam can make the diagnosis of these neuropathies, and treatment is supportive, including physical therapy and where needed, pain control. 
• The overall prognosis for recovery from pregnancy- and postpartum-related neuropathies is very good.

Written Case: Bell's Palsy and Other Neuropathies in Pregnancy and Postpartum

Stephanie Chang, MD’19, Dr. Niharika Mehta and Dr. Julie Roth

A 37 year old G3P3 woman presents to her internist at two weeks postpartum with complaints of numbness, pain and weakness of the left side of the face. Onset of symptoms was within one week prior to delivery. She had noticed that the left side of her face was mildly numb, and she had attributed this to stress. She underwent caesarian section for breech presentation. Her pregnancy was otherwise uncomplicated. After delivery, she noticed mild weakness of the left face, worsening in the few days prior to presentation, with pain behind the left ear. Her husband told her that she was not blinking the left eye normally. She also noticed that when she drank water, it would dribble down her chin.

What are the diagnostic considerations in this case? And how would you differentiate?

Muscle weakness on one side of the face raises concern for paralysis of cranial nerve VII, also known as the facial nerve. Facial muscle paralysis can result from injury anywhere along the path from the cerebral motor cortex to the corticobulbar tract, and on to the facial nucleus and CN VII itself.  It is therefore important to differentiate between central lesions involving the brain, such as stroke or tumor, and peripheral causes affecting the nerve, such as Bell’s Palsy.

Central causes often present with an upper motor neuron pattern of symptoms, including paralysis of the contralateral lower muscles of facial expression only, with muscles on the forehead left intact. Also, although these patients will lack voluntary control of facial muscle movement, they will exhibit spontaneous movement in response to emotional input. Thirdly, patients with central causes of facial paralysis may also demonstrate other neurological findings – the arm or leg might be involved, speech might be affected, and vision might be affected, depending on the location of the lesion.  If a stroke is suspected, neuroimaging and appropriate work-up must be performed ASAP.

Bell’s Palsy is a peripheral cause of unilateral facial paralysis that affects the facial nerve itself. Typically, patients with Bell’s Palsy present with isolated facial weakness that progresses to complete paralysis within a few days.[1] While the facial nerve is not responsible for sensation, it is not unusual for these patients to have a subjective feeling of tingling or numbness of the face (with no sensory deficit on neurological exam), and with pain that is often localized to or around the ear. A lower motor neuron pattern of facial weakness is seen, defined as complete paralysis of one side of the face – forehead included.  Patients will lack both voluntary and spontaneous movement of the facial muscles, and may also demonstrate increased sensitivity to loud sounds in one ear and loss of taste from the anterior two-thirds of the tongue. An important clue to the clinician diagnosing Bell’s Palsy is reduced (or absent) blinking on the side of the facial paralysis – a finding not typically seen in stroke or other central nervous system causes.

In encountering a patient with Bell’s Palsy, other diagnostic considerations include herpes zoster, Ramsay Hunt (varicella zoster affecting the 7th and typically also the 8th cranial nerve), Lyme disease, HIV, tumors, mass lesions, Guillain-Barre, sarcoidosis, Sjogren Syndrome, and a rare condition known as the Melkersson-Rosenthal syndrome, in which a single patient may be prone to multiple bouts of Bell’s Palsy.  A careful exam, paying particular attention to the presence of vesicles in the ear canal, masses in the parotid gland, systemic symptoms such as fever, and the presence of other neurological findings, can help to rule out these causes.

On exam, she has impaired movement of the left upper and lower face, reduced blink rate of the left eye, and incomplete closure of the left orbicularis oculi. Hearing is intact to finger rub, and sensation is normal – though there is some subjective numbness and pain in the cheek and around the ear. The remainder of the cranial nerve exam is normal, as is the remainder of the neurological exam. She is afebrile. After a lower motor neuron pattern of weakness is identified, the patient is diagnosed with Bell’s palsy.

What testing is needed, if any?

In the general population, Bell’s Palsy is often attributed to an infectious etiology, which then causes an inflammatory reaction and demyelination of the facial nerve. Reactivation of latent herpes simplex virus, infection with Lyme disease, and varicella zoster have been implicated. Testing for Lyme can be performed if the patient lives in an endemic area and presents at a time of year that the disease is present. For example, In the northeastern United States, Lyme disease is a major cause of Bell’s Palsy, and so it is common clinical practice to send Lyme titers on patients who present with acute Bell’s Palsy both at presentation, and sometimes repeat testing six weeks after onset if initially negative.

For an isolated Bell’s Palsy without systemic symptoms, lumbar puncture is not necessary. Systemic symptoms like fever, joint pain, or other cranial nerve involvement would warrant lumbar puncture.

How is this condition treated?

Corticosteroids (prednisone, prednisolone) are typically administered early. Steroids may help relieve associated pain, and in nonpregnant patients with Bell’s Palsy, they have been shown to improve the chances of complete recovery.[2] Their  use in pregnancy, however, is less well established. The addition of empiric antiviral therapy (acyclovir, valacyclovir) for Bell’s Palsy does not appear to confer additional benefit.[3]

If a causative condition like Lyme disease is diagnosed, appropriate treatment such as antibiotics would be indicated. In pregnancy, amoxicillin can be used, whereas outside of pregnancy, doxycycline is used.[4]

Supportive treatment during this time can include methylcellulose eye drops (artificial tears), temporary patching to prevent corneal abrasions, and physical therapy to prevent muscle contracture.[5]

Why might this patient be at risk for Bell’s Palsy?

The incidence of Bell’s Palsy in pregnancy is up to six times higher than the incidence in the general population, with the majority of cases occurring during the third trimester or early post-partum period.[6] The reason for the increased incidence of the disorder is unknown, although it is hypothesized to result in part from immune and hormonal factors, as well as the increase in total body water (and resultant extracellular fluid) that occurs during pregnancy.

During the third trimester and early postpartum period, women have the highest extracellular fluid content, and it is hypothesized that edema, fluid retention and venous congestion compress the facial nerve within the stylomastoid foramen and fallopian (facial) canal, resulting in a compression neuropathy.  This hypothesis is supported by the fact that pregnant patients with Bell’s Palsy also have significantly higher rates of gestational hypertension and preeclampsia, two states also associated with increased pressure and fluid overload.[7]

Other hypotheses include  hypercoagulability leading to focal ischemia of the nerve.[8] In any case, the facial nerve and other peripheral nerves of pregnant women may be at higher risk for injury. 

What other peripheral neuropathies can occur in pregnancy and the postpartum period?

Carpal tunnel syndrome is the most frequent mononeuropathy in pregnancy, and is hypothesized also to be due to fluid retention and edema.  Symptoms often do not resolve immediately after delivery, but the majority will spontaneously resolve one to three years post-partum.[9] Treatment is conservative and includes wrist splints or rest, physical therapy, and local injections.

Some neuropathies, like Bell’s Palsy and carpal tunnel syndrome, may appear towards the end of pregnancy without a clear inciting cause, while other mononeuropathies, particularly involving the lower limbs, may result from direct compression of the nerve during the pregnancy itself or in labor and delivery.[10] In the absence of a clear cause, entrapment neuropathies should prompt clinicians to look for other features of preeclampsia, a pregnancy specific condition characterized by hypertension and proteinuria, which can present with significant edema, including swelling in the nerve sheath leading to entrapment.

Lower extremity neuropathies are also common in the postpartum period, and are associated with nulliparity and a prolonged second stage of labor.[11] After delivery, these neuropathies may need to be differentiated from spinal or epidural anaesthesia-related factors. Differentiation begins with a detailed history – including anaesthesia, details of the pregnancy, labor and delivery, and clinical symptoms of pain, weakness, parethesias and sensory loss. A neurological exam can pick up a specific pattern of abnormal motor weakness, sensation and reflexes. The most common of these lower limb compression neuropathies are listed below.

During pregnancy, the lateral femoral cutaneous nerve can be entrapped at the anterior iliac spine or through the inguinal ligament, resulting in sensory symptoms such as burning, numbness, tingling, and pain in the anterior and lateral thigh.  This is often due to weight gain and is more common in patients with diabetes or a large fetus. This condition is also called meralgia paresthetica, and treatments for the pain (if severe) might include neuropathic pain medications such as low-dose tricyclic antidepressants (TCAs), gabapentin, or even injection to the nerve (lateral femoral cutaneous nerve block), administered by a trained clinician.

Femoral neuropathy can result from prolonged periods of time in the lithotomy position, tight clothing, and excess weight.  In addition to experiencing sensory symptoms in the anterior thigh and medial lower leg, patients may also experience weakness of hip flexion and knee extension, resulting in leg buckling, weakness, and falls. Hip abduction and adduction is preserved, and there is no foot drop in this condition. The patellar reflexes (knee jerk) might be reduced or absent.

Peroneal neuropathy can be bilateral due to its superficial location, and is especially common in thin people or while holding legs back during delivery.  It can result in sensory symptoms in the lateral aspects of the lower leg and foot, as well as foot drop, or a “slapping gait.” The hip girdle muscles are unaffected.

The obturator nerve can be compressed between the child’s head and the pelvis, and can result in numbness and pain in the groin and medial thigh as well as weakness in abduction or internal rotation of the thigh. Extension and flexion at the knee and movement of the foot would be unaffected.

For such neuropathies, bracing, physical therapy, and topical pain medications are treatment, as most will resolve spontaneously. EMG/NCS testing can be considered if symptoms are very prolonged. This testing involves thin needles placed into muscles and electrical impulses applied to nerves; the testing itself can be uncomfortable for patients. Though EMG/NCS is considered safe in pregnancy, the diagnosis of these neuropathies is usually made clinically wherever possible. However, if signs and symptoms deviate from the typical compression mononeuropathy patterns described above, including an atypical or more prolonged course, this might suggest a more widespread problem such as a lumbosacral radiculopathy related to anesthesia (multiple nerves and nerve roots affected), or lumbosacral plexopathy due to compression in the pelvis. In these cases, MRI of the lumbar spine would be advised, possibly in addition to pelvic imaging such as CT or MRI to exclude hematoma or mass compressing the lumbosacral plexus, and EMG/NCS to evaluate for a more extensive lumbosacral plexopathy.

Additionally, isolated palsies of other cranial nerves have been documented in pregnancy, including palsies of CN III, V, VI,[12] and XII,[13] some in the context of preeclampsia. Because these particular neuropathies are very rare, the workup for these conditions should include brain MRI or skull base CT to exclude a compressive mass along these nerves.

Are there labor and delivery implications for women with Bell’s Palsy or peripheral neuropathy during pregnancy?

Bell’s palsy in pregnancy has no particular implications when it comes to a labor and delivery plan. Compression neuropathies that occur during labor and delivery can be hard to avoid, but it is important to note that a prolonged labor, or remaining in one position, may put women at risk.

The patient notes that after delivery, her face gradually improved to baseline over the course of a few weeks.

What do you tell her if her symptoms had not resolved within three months?

Nerves regrow at a speed of 0.3-1mm/day – thus the speed and totality of recovery from Bell’s Palsy is variable. Over 50% of women will have full recovery within a few months, and another 35% will recover within one year.[14] If function has not returned in 6-16 months, surgery (hypoglossal-facial nerve anastomosis, for example) can restore partial function.

REFERENCES:

[1] Vrabec JT, Isaacson B, Van Hook JW. Bell’s palsy and pregnancy. Otolaryngology - Head and Neck Surgery 2007; 137(6): 858-61.

[2] Sullivan FM, Swan IRC, Donnan PT et al. Early Treatment with Prednisolone or Acyclovir in Bell's Palsy. New England Journal of Medicine 2007; 357:1598-1607.

[3] Engstrom M, Bert T, Stjernquist-Desatnik A, et al. Prednisolone and valaciclovir in Bell's Palsy: a randomised, double-blind, placebo-controlled multicentre trial. Lancet Neurology 2008 Nov;7(11):993-1000.

[4] Walsh CA, Mayer EW, Baxi LV. Lyme Disease in Pregnancy: Case Report and Review of the Literature.2006. Obstetrical & Gynecological Survey. Vol 62, No. 1, pp. 41-50.

[5] Cohen Y. Bell Palsy Complicating Pregnancy: A Review. Obstetrical & gynecological survey 2000; 55(3): 184 - EOA.

[6] Klein A. Peripheral nerve disease in pregnancy. Clinical obstetrics and gynecology 2013; 56(2): 382 - EOA.

[7] Katz A, Sergienko R, Dior U, Wiznitzer A, Kaplan DM, Sheiner E. Bell's palsy during pregnancy: Is it associated with adverse perinatal outcome? The Laryngoscope 2011; 121(7): 1395-8.

[8] Cohen Y. Bell Palsy Complicating Pregnancy: A Review. Obstetrical & gynecological survey 2000; 55(3): 184 - EOA.

[9] Padua L, Pasquale AD, Pazzaglia C, Liotta GA, Librante A, Mondelli M. Systematic review of pregnancy-related carpal tunnel syndrome. Muscle & Nerve 2010; 42(5): 697-702.

[10] Massey EW and Guidon AC. Peripheral neuropathies in pregnancy. (Neurology) Continuum (Minneap Minn) 2014; 20(1):100-114.

[11] Klein A. Peripheral nerve disease in pregnancy. Clinical obstetrics and gynecology 2013; 56(2): 382 - EOA.

[12] Gilca M. Multiple Concomitant Cranial Nerve Palsies Secondary to Preeclampsia. Journal of neuro-ophthalmology 2015; 35(2): 179 - EOA.

[13] Femia G, Parratt JDE, Halmagyi GM. Isolated reversible hypoglossal nerve palsy as the initial manifestation of pre-eclampsia. Journal of Clinical Neuroscience 2012; 19(4): 602-3.

[14] Klein A. Peripheral nerve disease in pregnancy. Clinical obstetrics and gynecology 2013; 56(2): 382 - EOA.