Parsonage-Turner Syndrome Revisited

Posted by Daniel Rubio, Drexel University College of Medicine Class of 2014

Parsonage-Turner Syndrome (PTS) is an inflammatory disorder that affects the brachial plexus an important network of nerves which lies deep in the armpit (axilla) giving off nerve brachnes including the axillary, radial, musculocutaneous, ulnar and median nerves which supply power to the shoulder and entire upper extremity.

What does PTS look like?

Unlike other brachial plexopathies, PTS begins spontaneously, without any prior injury to the arm, neck, or axilla.  The classical presentation is severe pain followed by patchy weakness in the shoulder, biceps, and the muscles controlling the thumb and first two fingers (index and middle).  It may also present with a finding known as winged scapula: the shoulder blade sticks out more from the back especially when pushing yourself off a wall.  Weakness may be so severe that the muscles may actually shrink (atrophy).  Pain may be found in the shoulder and along the outside of the upper arm and the thumb-side (lateral) of the forearm and hand.  Pain symptoms usually occur before the weakness and may last up to 4 weeks.  Patients may experience alteration in sensations in the upper extremity, specifically increased sensitivity to touch and temperature and/or tingling.  Symptoms may affect one or both sides, but they usually are asymmetric if they both sides.

 

What causes PTS?

Approximately 50% of patients describe some type of stressful event or illness prior to the onset of symptoms: infection, exercise, surgery, pregnancy, or vaccination.

Diagnosing PTS

Your neurologist can make the diagnosis based on signs and symptoms (especially if you do the above dance); however, sometimes further testing is required to ensure accurate diagnosis.  Suspicion of PTS should occur based upon pattern of initial sudden and severe pain followed by weakness in the upper extremity and slow recovery.  The neurologist may use nerve conduction studies and needle electromyography to document denervation to support clinical suspicion.  Blood tests and imaging rarely help make the diagnosis of PTS.

Help doctor! Fix me?

There is currently no specific treatment for PTS and management usually involves symptom relief.  Pain relief with short course of narcotics may be necessary.  A short course of steroids may be given, which may or may not help relieve symptoms or hasten recovery.  Physical therapy may be prescribed to maintain range of motion and decrease risk of atrophy.  Despite the above measures, there is no treatment to quicken recovery.

When will I be cured?

Recovery of symptoms begins 1-3 months following onset of symptoms; however, maximal recovery may take up to 1-3 years and some patients may be left with residual symptoms.

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Ticked off at Neuro Lyme Disease

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Post Prepared by Dr. Mohammed Nasir Yousuf Shah,

PGY-3 Internal Medicine, Monmouth Medical Center

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Case Report

A 36 year old otherwise healthy male noticed a facial droop when he woke up one morning and looked in the mirror. There was associated pain at the angle of the right jaw like a “toothache” and also numbness to along right side of tongue.

He had been experiencing occipital headache with neck pain for the previous 3 days.  The headache was throbbing in character, worse when laying his head back on a pillow. He denied any other neurological symptoms.

Further questioning revealed that 2 months ago he suffered 2 tick bites on his thigh; but did not experience any fever, chills or rash at that time.

Physical examination showed prominent facial droop in the lower half of the right side of the face with inability to puff the cheek on the right and some mild weakness in the upper half of the right side of the face with reduced wrinkling of the forehead. He also had impaired taste sensation along the right side of the tongue. The rest of the neurological exam was normal.

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His brain imaging study was normal, but CSF analysis revealed low glucose and elevated protein and pleocytosis with increased lymphocytes indicating a diagnosis of aseptic meningitis.

Given the history of tick bite 2 months prior and the characteristic 7th cranial nerve palsy, a presumptive diagnosis of neurological Lyme disease was made and the patient was started on intravenous ceftriaxone.

Meanwhile Lyme serologies and antibodies to B. Burgdorferi in CSF were tested and the patient was discharged on IV ceftriaxone.

The results of the serological and CSF testing returned positive for Lyme disease a few days later.

Discussion

Background:

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Borrelia burgdorferi is the organism responsible for Lyme disease which affects several organ systems and is transmitted by the bite of infected ticks belonging to the genus Ixodes.

Skin, the site of inoculation, is involved in 80 percent or more of infected individuals followed by joint involvement.

The third most common site is the nervous system, which is involved in 10 to 15 percent.

Clinical manifestations:

Nervous system involvement begins during early disseminated Lyme disease, when spread of the spirochetes can result in meningeal seeding. Acute neurologic involvement usually occurs weeks to several months after the tick bite and may be the first manifestation of Lyme disease. In contrast, certain neurologic problems, such as a more indolent, disseminated polyneuropathy, may develop months to a few years after the initial infection.

Lymphocytic meningitis, cranial neuropathy and radiculoneuritis constitute the classic triad of acute, early neurologic Lyme disease.

Clinical findings of nervous system Lyme disease are divided into disorders of the peripheral vs. central nervous system.

Peripheral nervous system

In early disease, two peripheral nerve manifestations are particularly common and form part of the classic triad.

Cranial neuropathies: These tend to occur early in infection and are usually abrupt in onset. Virtually any cranial nerve can be involved, but the seventh (facial) is by far the most common, occurring in 8 percent of cases.

Since facial nerve palsy is uncommon in young children, Lyme disease should be strongly considered as the cause of facial nerve palsy affecting a child who has been in an endemic area. In adults in endemic areas, during spring through fall, a significant percentage of facial nerve palsies are attributable to Lyme disease. Involvement can be bilateral and because bilateral facial nerve palsies are generally uncommon, Lyme disease should be suspected in patients with potential recent exposure.

Radiculoneuritis: This is reported in 3 percent of cases of Lyme disease and is often missed. It can mimic a mechanical radiculopathy (eg, sciatica) with radicular pain in one or several dermatomes, accompanied by corresponding sensory, motor and reflex changes. This disorder should be considered in patients in endemic areas presenting in spring through autumn with severe limb or truncal radicular pain without an apparent mechanical precipitant.

Central nervous system

The most common form of CNS involvement is lymphocytic meningitis. Rarely, inflammation of the brain and/or spinal cord parenchyma (an encephalomyelitis) can occur.

Meningitis: Lymphocytic meningitis, alone or in combination with cranial nerve or spinal nerve root involvement, represents the most common form of central nervous system involvement. Clinically it is indistinguishable from viral meningitis, with headache, fever, other systemic symptoms, photosensitivity, and neck stiffness.

Encephalopathy: Patients may experience fatigue, cognitive slowing, and memory difficulty. However, these symptoms are nonspecific and are frequent concomitants of many inflammatory disorders.

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Diagnosis

The diagnosis of nervous system Lyme disease rests on three elements:

  • Since the disease is transmitted exclusively by bites of Ixodes ticks, there must be the possibility of exposure
  • The clinical disorder should include objective evidence of nervous system Lyme disease
  • Laboratory testing (positive two tier Lyme serologies with or without positive CSF Lyme antibodies)

Serologic testing: With the exception of the first 4 to 6 weeks of infection, when the specific immune response may not yet have developed sufficiently to provide a measurable antibody response, serologic testing for antibodies to B. burgdorferi is highly sensitive and specific for the diagnosis of Lyme disease and thus in such cases the absence of detectable antibodies in the serum is strong evidence against the diagnosis.

The two-tier strategy, which is recommended by the US Centers for Disease Control and Prevention, uses a sensitive enzyme-linked immunosorbent assay (ELISA) followed by a Western blot. If the ELISA is positive or equivocal, then the same serum sample should be tested by Western blot. If the ELISA is negative, the sample needs no further testing.

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CSF analysis: In Lyme meningitis the CSF typically has a modest pleocytosis of up to several hundred lymphocytes and/or monocytes per microL. The CSF protein concentration is usually moderately elevated, and is typically no greater than about 200 to 300 mg/dL (2 to 3 g/L).

CSF antibodies: The sensitivity for testing the CSF for intrathecal production of antibodies to B. burgdorferi is poor and a negative test does not exclude CNS Lyme disease if clinical circumstances support the diagnosis.

Imaging:  Since Lyme encephalomyelitis is so rare, MRI of the brain and spine is only rarely abnormal in Lyme disease. When present, the MRI reveals areas of increased signal on T2 and FLAIR sequences.

Electrophysiologic testing: In patients with a peripheral neuropathy, electrophysiologic assessment (electromyography and nerve conduction studies) can be helpful and typically reveal findings consistent with a patchy axonal polyneuropathy (ie, a mononeuropathy multiplex).

Approach to diagnostic testing

Assessment of the patient with possible nervous system Lyme disease must be tailored to the specific presentation. It can be sufficient to simply administer oral antibiotics to patients with recent exposure, a positive serology and an appropriate clinical syndrome.  However a lumbar puncture may still be necessary if there is a strong clinical suspicion of meningitis, primarily to exclude other, potentially more dangerous pathogens.

CSF studies should include cell count, protein and glucose concentrations, and gram stain and bacterial cultures.

CSF and serum should both be sent for anti-B. burgdorferi antibodies and VDRL should be measured.

Neuroimaging, preferably by MRI, should precede the lumbar puncture if the patient has clinical evidence of parenchymal brain involvement. Depending on the findings on imaging,

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Treatment

Lyme meningitis is generally self-limited, even without treatment.

Oral doxycycline is effective for early disseminated Lyme disease with neurologic manifestations, including meningitis. Doxycycline has moderately good penetration into the CSF and has oral bioavailability >98 percent, making oral dosing equivalent to intravenous dosing.

Lyme patients with isolated facial nerve palsy are treated with oral doxycycline (100 mg orally twice daily). Antibiotic therapy does not have a major impact on the outcome of facial palsy. However, treatment is recommended to prevent other complications of disseminated Lyme disease. The majority of patients with Lyme facial palsy recover. The prognosis is worse for patients with bilateral facial palsy compared with unilateral palsy.

Lyme patients with radiculoneuritis, meningitis or other neurologic complications are typically treated using parenteral therapy with ceftriaxone (2 g intravenously once daily) for at least 14 days.

There are no diagnostic tests that can determine clearance of infection or predict the success of therapy. Resolution of neurological symptoms is often delayed and persistence of symptoms is not necessarily indicative of treatment failure.

Treatment recommendations are the same for both the early and late neurologic manifestations of Lyme disease.

 

New Hope for Nerve Injury Patients

Nerves are complicated structures, made of many axons (the actual connections or wires) some surrounded by a layer of myelin shealth (insulation), all bundled together with connective tissue into a giant cable.

Nerve injuries come in different varieties, depending on the mechanism and severity of the trauma:

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The three categories of nerve injury Neurapraxia (top), Axonotomesis (middle) and Neurotmesis (bottom).

The mildest injury is neurapraxia, which is a short area of segmental demyelination.  Because the underlying axon is left intact, recovery can occur within days to week by simple remyelination.

The more severe injuries axonotomesis and neurotmesis involve axonal injury.  Once the axon is injured, the whole segment distal to the injury undergoes a pre-programmed process of degeneration called Wallerian degeneration:

Wallerian degeneration – the axon distal to (right of) the injury degenerates.

Even if the nerve injury is repaired, or gets better on it’s own, the axon has to grow back all the way from the injury site to the end of the nerve at the muscle before functional recovery can occur.

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Even if a severed nerve is repaired (in this case by direct suturing), the axons have to regrow down the entire distal nerve segment before functional recovery can occur

Axonal regrowth is slow, occurring at a rate of no more than 1mm/d.

If we have a patient with a proximal nerve injury, for example a brachial plexus injury:

nevre injuryAxonal regrowth will have to occur over 600-800mm to restore function to the hand, and that will take more than 2 years, by which time the muscle may have deteriorated so much it can no longer receive a new nerve supply and recover.

However, new research in animals has led to a technique that reconnects the severed ends of a nerve, allowing it to begin carrying messages again very quickly, restoring conductivity before Wallerian degeneration has a chance to begin. This allows for almost immediate function recovery after nerve repair surgery.

In the experiments, the severed nerve are exposed and treated with chemical compounds to keep the axonal ends open, then the two nerve ends are sutured together, and are finally treated with more chemicals that cause the nerve ends to fuse.  Rats treated with his technique got better as soon as they began to recover from the surgery.

Researchers hopes to try the approach on people within a year.

Click here for a link to the full story.

Comparing treatment options for trigeminal neuralgia

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First line of treatment for patients with trigeminal neuralgia TGN should always be medical, usually the anticonvulsant carbamazepine (Tegretol®), which provides at least partial pain relief for 80% to 90% of patients.  Common side effects include dizziness, drowsiness, forgetfulness, unsteady gait, and nausea. However, carbamazepine and other drugs prescribed do not always remain effective over time, requiring higher and higher doses or a greater number of medications taken concurrently, causing many patients to experience side effects serious enough to warrant discontinuation.

A study from the 1980s followed 143 TGN patients treated with carbamazepine (CBZ) over a 16-year period.  The drug was effective initially with few mild side effects in 99 patients (69%). Of these, 19 developed resistance between 2 months and 10 years after commencing treatment, and required alternative measures. Of the remaining 80 (56%), the drug was effective in 49 for 1-4 years and in 31 for 5-16 years. Thirty-six patients (25%) failed to respond to CBZ initially and required alternative measures, as did 8 (6%) who were intolerant of the drug.

Surgical treatment of TGN is reserved for people who still experience debilitating pain despite best medical management. Surgical options include gamma knife “radiosurgery” (GKS) and the more invasive microvascular decompresion (MVD).

Another study from 2008 compared outcomes for 80 consecutive TGN patients treated surgically with either MVD (36 patients) or GKS (44 patients) over 4-8 years:

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TGN KMG

In sum, MVD was more likely than GKS to achieve and maintain pain-free status in TGN,but  both procedures provided similar early patient satisfaction rates.  MVD is therefore preferred for younger healthy patients, while GKS is preferred for older patients with co-morbidies or contraindications, but neither should be considered unless medical therapy has already been tried and failed.

Neuromuscular respiratory failure

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Each lung is composed of >300 million tiny membrane bound sacs of air sacs (alveoli) which if spread out would cover a piece of ground roughly the size of a tennis court.  The purpose of this giant membrane is to exchange oxygen from the air for carbon dioxide from the blood stream.

lungs1

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If the lungs become congested (or filled with fluid) from infection (pneumonia) or heart failure, it becomes harder to extract oxygen from the air:

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Treatment includes adding extra oxygen to the air to make this process more efficient.

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However, gas exchange across the alveoli can only occur if fresh air is brought into the lungs, and stale air is moved out, a process known as ventilation.  The diaphragm and muscles of the chest wall act like a giant bellows to make this happen:

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These muscles can become weak in nerve or muscle diseases such as Guillain-Barré syndrome, polio, amyotrophic lateral sclerosis (ALS), Duchenne Muscular Dystrophy and myasthenia gravis.

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These patients are evaluated by pulmonary function testing, which will usually show a low forced vital capacity, low cough flow, and in advanced cases, elevated end-tidal carbon dioxide level.

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Patients with this type of ventilatory failure do not need extra oxygen, their lungs can extract oxygen from air normally, they need mechanical assistance moving air across their lungs:

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lungs2

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Early neuromuscular respiratory muscle weakness causes nocturnal hypoventilation.  This is because the weakened diaphragm is even more inefficient when laying supine in bed with the stomach contents pressing up on it.

Nocturnal hypoventilation presents with daytime sleepiness, early morning headaches, fatigue, and impaired cognition.

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Click here to take an on-line test, and find out how sleepy you are during the day.  If you score 10 or higher, you might have a problem!

Nocturnal hypoventilation is best treated using a non-invasive respirator at night, either with a face or nose mask:

nippv

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Other patients use a negative pressure respirator vest, or cuirass, which requires the patient to wear an upper body shell  attached to a pump which actively controls the respiratory cycle:

cuirass

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Neuromuscular respiratory failure also leads to an ineffective cough, which in turn predisposes patients to aspiration, retention of secretions, or pneumonia.  Affected patients need to learn to use the cough assist machine when they get a minor respiratory tract infection to help them clear their secretions and prevent pneumonia:

cough assist

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More severe neuromuscular ventilatory failure leads to rapid shallow breathing, accessory respiratory muscle use, thoracoabdominal paradox (inward motion of the abdomen during inspiration), and ultimately high blood levels of carbon dioxide.

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Thoracoabdominal paradox – Normal (upper) abdomen moves outward with inspiration (diaphragm contraction). NM weakness (lower) abdomen moves in when patient inspires using accessory muscles.

In these cases, respiratory support is needed day and night.

Some patients can continue to use non invasive respiratory support, sleeping with a face or nose mask, and using a mouth piece intermittently during the day:

mouth

Others cannot tolerate noninvasive ventilation or have anatomic abnormalities that preclude fitting of noninvasive ventilators.  Some disease, such as advanced ALS and Duchenne muscular dystrophy, affect the upper airway muscles as well as the diaphragm, impairing swallowing and compromising airway protection from aspiration.  These patients can chose to be managed with invasive respiratory support using a tracheotomy and conventional ventilator.

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Click here and and here to find out more about the management of neuromuscular respiratory failure.