Neuropathy Presentation II: El Paso, TX. Chiropractor, Dr. Alexander Jimenez continues the overview with neuropathy part II. Continued are the most common neuropathies to be seen in practice. Because the human body is composed of many different kinds of nerves which perform different functions, nerve damage is classified into several types. Neuropathy can also be classified according to the location of the nerves being affected and according to the disease causing it. For instance, neuropathy caused by diabetes is called diabetic neuropathy. Furthermore, depending on which nerves are affected will depend on the symptoms that will manifest. The complications which follow neuropathy depends on the type of nerves that are damaged. According to Dr. Jimenez, different neuropathies can cause numbness and/or tingling sensations, increased pain or the loss of ability to feel pain, muscle weakness along with twitching and cramps, even dizziness and/or loss of bladder control function.

Sciatic Nerve Entrapment

• Piriformis Syndrome
• Peroneal Nerve Entrapment
• Tarsal Tunnel Syndrome

Sciatic N. Piriformis Syndrome

Causes

• Anatomic variation
• Piriformis overuse/tension

Exam

• Positive Lase?gue test possible
• Doctor extends patient’s leg passively, while patient is lying supine positive test if maneuver is limited by pain
• Tenderness and palpable tension in piriformis muscle which elicits symptoms

Sciatic N. Peroneal Nerve Entrapment

• Peroneal or Fibular branch of Sciatic nerve entrapped at the fibular head
• Tinel’s sign may be present at fibular head/neck
• Usually affects common peroneal nerve, therefore motor and sensory symptoms can be seen
• Weakness of ankle dorsiflexion and eversion (tibialis anterior m.)
• Sensory disruption on the dorsum of the foot and lateral aspect of the calf

Sciatic N. Tarsal Tunnel Syndrome

• Tibial nerve impinged in the tarsal tunnel
• Sensory changes in the sole of the foot
• Tinel’s sign may be present with percussion posterior to the medial malleolus

Radiculopathy

• A mononeuropathy – located in one specific area
• Neuropathy involving spinal nerve roots
• Presents as changes in sensory and/or motor function affecting a single or a few nerve root level(s)
• Most commonly seen radiculopathies include:
• Sciatica
• Cervical radiculopathy

Common Causes Of Radiculopathy

• Disc herniation
• Osteophytes
• Spinal Stenosis
• Trauma
• Diabetes
• Epidural abscess or metastasis
• Nerve sheath tumors (schwannomas and neurofibromas)
• Guillain-Barre? syndrome
• Herpes Zoster (shingles)
• Lyme disease
• Cytomegalovirus
• Myxedema/Thyroid disorder
• Idiopathic neuritis

Narrowing Down Common Causes Of Radiculopathy

• Disc Herniation

• Most commonly affected nerve roots are C6, C7, L5 & S1

• Spinal Stenosis

• Lumbar stenosis may produce neurogenic claudication
• Pain & weakness with ambulation
• Cervical stenosis may present with mixed picture of radiculopathy and myelopathy due to long tract involvement

• Trauma

• May cause compression, trauma or avulsion of the nerve roots

• Diabetes

• More likely to cause a polyneuropathy, but mononeuropathy is possible

• Herpes Zoster (Shingles)

• Most often on the trunk, accompanied by vesicular lesions in a single dermatome
• If pain persits past vesicular regression = post-herpetic neuralgia

Patient History Of Radiculopathy

• The patient will often complain of burning pain or tingling that radiates or shoots down an affected area in a dermatomal pattern.
• Sometimes patient will complain of motor weakness, however if onset is recent, there is often no motor involvement

Exam Of Radiculopathy

• Most often hypoesthesia in the affected dermatome level
• Best to evaluate for pain, as light touch can be difficult for these patient’s to distinguish
• Fasciculations and/or atrophy may be seen if radiculopathy is chronic, due to lower motor neuron being impinged
• Motor weakness may be seen in muscles innervated by the same root level

Orthopedic tests:

• Straight-leg raise test (SLR)

• Pain between 10-60 degrees likely indicates nerve root compression

• Well-leg raise/Crossed straight-leg raise test (WLR)

• If positive, 90% specificity for L/S nerve root compression

• Valsalva Maneuver

• Positive if increase in radicular symptoms

• Spinal Percussion

• Pain may indicate metastatic disease, abscess or osteomyelitis

Examinations: Merck Manual Professional

How To Test Reflexes

How To Do A Sensory Exam

How To Do A Motor Examination

Dermatomes

Testing Cervical Nerve Roots

Testing Lumbosacral Nerve Roots

Specific Radiculopathy Patterns

• T1 radiculopathy can cause Horner’s syndrome

• This is due to affect on cervical sympathetic ganglia
• Ptosis, miosis, anhidrosis

• Below L1, radiculopathies can cause Cauda Equina syndrome

• Saddle anesthesia (sensory loss in S2-S5 distribution)
• Urinary retention or overflow incontinence
• Constipation, decreased rectal tone or fecal incontinence
• Loss of erectile function
• Must be referred for emergency care immediately to prevent permanent dysfunction

Other Patterns Of Neuropathy

• Cape/Shawl distribution of symptoms

• Intramedullary lesion
• Syringomyelia
• Intramedullary tumor
• Central cord damage

• Stocking and Glove Distribution of Symptoms

• Diabetes mellitus
• B12 deficiency
• Alcoholism/hepatitis
• HIV
• Thyroid dysfunction/myxedema

Cape/Shawl Pattern

• Intramedullary lesion such as tumor, syringomyelia or hyperextension injury in patient with C/S spondylosis

• Loss of pain and temp sensation in C/T dermatomes because of arrangement of lateral spinothalamic tract

Stocking & Glove Pattern

• Symmetrical polyneuropathy
• Feet/legs usually affected first, followed by hands/arms
• Vibration sensation in the smallest toes is usually the first thing lost and neuropathy progresses across foot to great toe and then upward through the ankle and leg, then hands, arms and finally trunk if sever
• Most likely cause of this distribution is diabetes mellitus, but other possible causes include B12 deficiency, alcoholism, HIV, chemotherapy treatment, thyroid dysfunction and multiple other causes

Diabetic Neuropathy

• Diabetic neuropathy often presents as a polyneuropathy but can also present as a mononeuropathy, usually with acute onset
• Most common in CN III, femoral and sciatic nerves

Demyelinating Neuropathies

• Acute inflammatory demyelinating polyneuropathy (Guillain-Barre? syndrome)
• Chronic inflammatory demyelinating polyneuropathy

Guillain-Barre? Syndrome (AIDP)

• Onset 1-2 weeks post viral infection
• Progressive weakness
• Loss of DTRs/areflexia
• Paresthesia in hands and feet
• More motor involvement than sensory
• Potential autonomic fiber involvement
• Elevated CSF protein
• EMG/NCV studies indicate demyelination
• May require treatment with plasmapheresis or IV Ig therapy

Chronic Inflammatory Demyelinating Polyneuropathy

• Appears similar to AIDP but does not follow infection
• Symptoms must be present for at least 8 weeks for this diagnosis to be considered
• Anti-inflammatory treatments may help

By Rachel Klein, ND, DC, DACNB

National University of Health Sciences Master of Science (MS) – Advanced Clinical Practice (ACP) MS ACP 551: Clinical Neurology © 2018

Sources

Blumenfeld, Hal. Neuroanatomy through Clinical Cases. Sinauer, 2002.

Evans, Ronald C. Illustrated Orthopedic Physical Assessment. Mosby/Elsevier, 2009.

“Radial Nerve Entrapment: Background, Anatomy, Pathophysiology.” Medscape, 25 Oct. 2017, emedicine.medscape.com/article/1244110- overview#a8.