​Kembara Xtra - Medicine - Peripheral Neuropathy

​Kembara Xtra - Medicine - Peripheral Neuropathy 
A condition affecting any number of motor, sensory, or autonomic nerves in the peripheral nervous system (PNS), either functionally or structurally Peripheral motor involvement results in fasciculations, cramping, weakness, and muscular atrophy.
Disorders of the sensory nerves result in unpleasant symptoms (loss of sensibility, unsteadiness) or exaggerated symptoms (tingling or pain). While short fiber sensory neuropathy (SFSN) affects pin and temperature feeling and results in neuropathic pain, large sensory fiber dysfunction impairs touch and vibration sense.
● The sympathetic and parasympathetic nervous systems are parts of the autonomic nervous system (ANS). Cardiovascular, gastrointestinal, and sudomotor symptoms are brought on by ANS dysfunction.
● From the cell body (sensory ganglionopathy or motor neuronopathy), root (radiculopathy), or plexus (plexopathy), to the nerve (demyelinating or axonal neuropathy), the PNS can be harmed.
● There are three types of peripheral neuropathy (PN): mononeuropathies, multifocal neuropathies, and polyneuropathies.

Prevalence of Epidemiology

The prevalence of PN is thought to be 1% in those under 65 and rises to 7% in those over 65.
According on age, duration of diabetes, glucose management, and type 1 or type 2 diabetes, peripheral neuropathy affects between 6% and 51% of adults with diabetes.

Pathophysiology and Etiology 

Demyelination or axonal degeneration are the causes of PN.
Idiopathic patients make up 30% of PN cases.
Diabetes mellitus, which most frequently appears at around 75% in the pattern of a distal sensory polyneuropathy (DSP), is the most frequent cause of acquired PN.
● The following are some further categories of acquired PN with examples: - Vascular: vasculitis and ischemia
HIV, hepatitis C, cryoglobulinemia, Lyme disease, varicella zoster, and other contagious diseases
Traumatic injuries include those caused by fractured or dislocated bones, slid disks between vertebrae, arthritis, or compression, crush, stretch, or transection. - Autoimmune: lupus, Sjögren's syndrome, and rheumatoid arthritis
- Metabolic: porphyria, celiac disease, hypothyroidism, renal failure, and vitamin B12 insufficiency - Iatrogenic/toxic substances include lead, alcoholism, metronidazole, colchicine, platinum, taxanes, and chemotherapy Neoplastic/paraneoplastic diseases include neurofibromatosis, paraproteinemia, Waldenström macroglobulinemia, and multiple myeloma. Acquired polyneuropathies frequently start exhibiting symptoms distally.
Genetics About half of undetected PN cases are genetic.


Risk Elements 

PN is predisposed by systemic diseases like diabetes and alcoholism.

Accompanying Conditions 

Alcoholism, diabetes, and other ailments connected to acquired forms of PN

Detailed history-taking to look for signs of sensory, motor, or autonomic dysfunction: - A "tightly wrapped" feeling, numbness, tingling, prickling, scorching pain, and a "unsteady gait"
- Proximal weakness (such as trouble rising from a chair) is less common than distal weakness, which shows as foot drop (tripping, foot slapping), or problems with grip.
- Erectile dysfunction, excessive sweating, constipation, orthostatic dizziness, or problems urinating • Onset of symptoms:
Consider an infection (like Lyme disease), a post-infectious dysimmune disorder (like GBS), ischemia (like vasculitis), a toxin, or trauma if the condition is acute.
Consider metabolic, neoplastic, paraneoplastic, or dysimmune processes as subacute processes.
- Chronic: Take into account idiopathic, genetic, or the dysimmune process (CIDP).
Progression might be slow or fast, steady or indolent, monophasic, relapsing, or remitting. Anatomical patterns: diffuse, multifocal, and focal
Ask about comorbidities and family history to help identify whether the problem is hereditary.

clinical assessment 

A functional (sensory: small fiber vs. large fiber vs. mixed, sensorimotor, motor, or autonomic) and anatomical (distal symmetric, multifocal, or focal) pattern of PN should be determined based on the examination.
In a PN that is isolated, cognition is retained.
With focal or multifocal PN, the cranial nerves may be implicated (for instance, bifacial weakness may be brought on by GBS, Lyme disease, or sarcoidosis, among other conditions).
The sensory loss in gloves and stockings is indicative with distal symmetric sensory PN, such as diabetes.
Pure SFSN is suggested by isolated diminished pin, heat feeling, or allodynia.
Large-fiber sensory neuropathy is indicated by decreased vibration and proprioception; when severe, a Romberg sign is present, and gait is wide-based or ataxic.
With distal symmetric axonal PN, distal muscle atrophy and deficits in toe extension and finger abduction are frequently seen.
Weakness is frequently present both proximally and distally in acquired demyelinating PN (e.g., GBS or CIDP).
Deep tendon reflexes in demyelinating PN or distally at the ankles in large-fiber axonal PN may be diminished or absent.
Hammer toes, flat feet, or high arches are signs of inherited PN.

Attention Hemibody impairments or sensory loss below the level of the spinal cord may indicate a process involving the central nervous system (CNS).
Spasticity and hyperreflexia are upper motor neuron symptoms that are absent in PN alone.

Multiple Diagnoses 

Pure sensory neuropathy (SFN, sensory ganglionopathy, polyradiculopathy), distal symmetric sensorimotor axonal neuropathy (DADS PN), polyradiculopathy, and immune-mediated multifocal motor neuropathy (MMN), and motor predominate neuropathy (PN). Mononeuropathy multiplex (plexopathy, polyradiculopathy) Mononeuropathy most commonly brought on by compression, entrapment, or trauma

Initial test results from the laboratory and imaging
CBC, Cr, HbA1C, LFTs, serum protein immunofixation electrophoresis, TSH, vitamin B12 with methylmalonic acid,
 Electromyography (NCS/EMG) and nerve conduction studies (NCS/EMG) distinguish between axonal and demyelinating, anatomic pattern, chronicity, and severity of PN. NCS is the gold standard for the diagnosis of diabetic painful neuropathy (DPN) (3).
 An autonomic reflex screen, a sweat function test, a quantitative sensory test, and an epidermal skin biopsy to assess the function of tiny nerve fibers (4)  Specialized epidermal skin biopsy if NCS/EMG is normal and SFN is suspected  Neuroimaging is typically not recommended in the examination of PN but is helpful in the evaluation of brachial plexopathies, radiculopathies, or other conditions when the CNS is implicated in the symptoms.

Tests in the Future & Special Considerations
Based on the patient's medical history, PN type, and NCS/EMG results, additional blood tests are performed, including those for antitissue transglutaminase, vitamins A, D, and E, zinc, copper, ESR, and CRP.
Consider genetic testing to see if a patient has hereditary PN, and check patients with distal symmetric PN for excessive alcohol consumption.

Caution 

It is best to avoid ordering laboratory batteries (such as peripheral nerve antibody panels) without carefully considering the clinical and NCS/EMG features.
Other/Diagnostic Procedures
If vasculitis, amyloidosis, granulomatous diseases, or neoplastic infiltration are suspected, nerve biopsy (sural or superficial peroneal nerve) may be informative. However, this is rare in late-onset chronic, slowly progressing distal symmetric PN.
 Interpreting Lumbar Puncture Test Results
Demyelinating PN is characterized by abnormally decreasing conduction velocities, conduction block, increased temporal dispersion, or prolonged distal latencies on NCS. Decreased recruitment and myokymia are EMG findings.
Reduced amplitude in motor or sensory responses with comparatively preserved conduction velocities and distal delay on NCS are signs of axonal PN. aberrant spontaneous activity, reduced recruitment, increased length and amplitude, and polyphasicity are all EMG findings.
Reduced ENFD on skin biopsies from the distal leg is supportive with SFN.

Management – Advice on proper shoe fitting and foot care.
Observe feet for early indications of skin damage and deterioration.
 Specific therapy for underlying systemic illnesses

First Line of Medicine
Treatment of neuropathic pain: clinical trials in DPN, postherpetic neuralgia (PHN), or trigeminal neuralgia provide evidence of effectiveness: Anticonvulsants include gabapentin (off-label) for DPN, oxcarbazepine for DPN, carbamazepine for trigeminal neuralgia, pregabalin for DPN and PHN, and gabapentin (on-label) for PHN.  SNRI: venlafaxine or duloxetine for DPN
 Supplements: -lipoic acid, acetyl-L-carnitine; Tricyclic Antidepressants (TCA): amitriptyline or nortriptyline; Patches: lidocaine 5%, capsaicin 8%; Second Line
Off-label use of mexiletine and tramadol for DPN
Fourth Line
For DPN, use tapentadol.


Concerning Referral 
Neurology referral for hereditary PN, probable demyelinating PN, or fast progressing symptoms
Referral to rheumatology for vasculitic PN
 Hematology referral and skeletal examination for paraproteinemia patients  Exercises in gait and balance in physical therapy


Furthermore Treated 

Combination therapy for neuropathic pain may be more efficient than monotherapy (e.g., gabapentin plus TCA, venlafaxine, or tramadol).
Trigeminal neuralgia, DPN, or complex regional pain syndrome (CRPS) may be treated by direct nerve injections, subcutaneous injections of botulinum toxin, or intradermal injections of the toxin.
In cases of chronic dysimmune PN that are recalcitrant, further immunosuppressive medications, such as cyclophosphamide, may be utilized.
Intravenous immunoglobulin (IVIG) is used as immunotherapy for dysimmune PN within the first two weeks after GBS to speed recovery, as a first-line therapeutic option for CIDP, and to prevent subsequent axonal loss in MMN.

 Variable maintenance regimen for CIDP and MMN; loading dose of 2 g/kg body weight administered over 2 to 5 days
Headache, fever, hypertension, and pulmonary embolism are some of the side effects.
Plasma exchange is the first medication to be proven to enhance GBS patients' functional outcomes, with immediate benefits for CIDP. AE: complications with the catheter, hypotension, and others
- Corticosteroids are a first-line treatment for CIDP and can cause remission when either orally or intravenously in pulses.
Treatment of autonomic symptoms: fludrocortisone for orthostatic hypotension, water, midodrine, compression stockings, and abdominal binders - Pyridostigmine (off-label use) for immune-mediated dysautonomia


Surgical Techniques 
Foot and ankle surgery to treat inherited PN symptoms or function Decompressive surgery for entrapment neuropathy (like carpal tunnel syndrome)
 Liver transplantation for amyloidotic PN, radiation therapy, surgery, or bone marrow transplant for osteosclerotic myeloma, POEMS syndrome, plasmacytoma, or both

Alternative Therapies 

Acupuncture, meditation, low-intensity transcutaneous electrical nerve stimulation (TENS), G-agmatine, methylcobalamin, and inositol supplementation may all be beneficial.

Caution 

Except in cases of insufficiency, vitamin B6 supplementation should be avoided because it may produce peripheral neurotoxicity.

Admission 

Patients with suspected GBS should be hospitalised for observation and treatment (30–60% of patients may experience cardiovascular or respiratory failure).

Follow-up Muscle strength was increased with strengthening activities, which may help with function. Flu vaccinations should be avoided in the first year after GBS.


Dietary Assessment for B12 Deficiency, Heavy Metal Toxin Intake, Thiamine Deficiency in Alcohol Use Disorder Patients, and High Carbohydrate Intake in Diabetes Patients.

The prognosis is poor for late-onset idiopathic distal symmetric axonal PNs.
80% of GBS patients recover fully or rather well. Eighty percent of CIDP patients respond to treatment moderately or well, but they may relapse.

An increase in fall risk is linked to PN complications.