Presentation on theme: "Peripheral Neuropathy"— Presentation transcript:
1Peripheral Neuropathy Victor F. Politi, M.D., Medical Director, St. Anthony’s School of Allied Health Professions, Physician Assistant Program
2IntroductionPeripheral neuropathy describes damage to the peripheral nervous system.More than 100 types of peripheral neuropathy have been identified, each with its own characteristic set of symptoms, pattern of development, and prognosis.
3IntroductionImpaired function and symptoms depend on the type of nervesmotor, sensory, or autonomicthat are damaged.
4Introduction Motor nerves Sensory nerves Autonomic nerves control movements of all muscles under conscious control, such as those used for walking, grasping things, or talking.Sensory nervestransmit information about sensory experiences, such as the feeling of a light touch or the pain resulting from a cut.Autonomic nervesregulate biological activities that people do not control consciously, such as breathing, digesting food, and heart and gland functions.
5IntroductionAlthough some neuropathies may affect all three types of nerves, others primarily affect one or two types.Therefore, terms such aspredominately motor neuropathypredominately sensory neuropathysensory-motor neuropathyautonomic neuropathyare often used to describe a patient's condition.
6IntroductionBecause every peripheral nerve has a highly specialized function in a specific part of the body, a wide array of symptoms can occur when nerves are damaged.Some people may experience temporary numbness, tingling, and pricking sensations (paresthesia), sensitivity to touch, or muscle weakness.
7IntroductionOthers may suffer more extreme symptoms, including burning pain (especially at night), muscle wasting, paralysis, or organ or gland dysfunction.
8IntroductionPeople may become unable to digest food easily, maintain safe levels of blood pressure, sweat normally, or experience normal sexual function.In the most extreme cases, breathing may become difficult or organ failure may occur.
9IntroductionSome forms of neuropathy involve damage to only one nerve and are called mononeuropathies.More often though, multiple nerves affecting all limbs are affected-called polyneuropathy.
10IntroductionOccasionally, two or more isolated nerves in separate areas of the body are affected-called mononeuritis multiplex.
11IntroductionIn acute neuropathies, such as Guillain-Barré syndrome, symptoms appear suddenly, progress rapidly, and resolve slowly as damaged nerves heal.In chronic forms, symptoms begin subtly and progress slowly.
12IntroductionSome people may have periods of relief followed by relapse.Others may reach a plateau stage where symptoms stay the same for many months or years.
13IntroductionSome chronic neuropathies worsen over time, but very few forms prove fatal unless complicated by other diseases.Occasionally the neuropathy is a symptom of another disorder.
14IntroductionIn the most common forms of polyneuropathy, the nerve fibers most distant from the brain and the spinal cord malfunction first.Pain and other symptoms often appear symmetrically, for example, in both feet followed by a gradual progression up both legs.
15IntroductionNext, the fingers, hands, and arms may become affected, and symptoms can progress into the central part of the body.Many people with diabetic neuropathy experience this pattern of ascending nerve damage.
16Anatomy The body’s nervous system is made up of two parts. The central nervous system (CNS)The peripheral nervous system (PNS)
17Anatomy The peripheral nerves include: cranial nerves (with the exception of the second)spinal nerve rootsdorsal root gangliaperipheral nerve trunks and their terminal branchesperipheral autonomic nervous system
18Diagnostic ApproachThe differential diagnosis of peripheral neuropathy is significantly narrowed by a focused clinical assessment that addresses several key issues –Does the patient actually have a neuropathy?What is the pattern of involvement?Is the neuropathy focal, multifocal or symmetric?If the neuropathy is symmetric, is it proximal or distal?
19Diagnostic Approach Does the patient actually have a neuropathy? Causes of generalized weakness include motor neuron disease, disorders of the neuromuscular junction and myopathy.Peripheral neuropathy can also be mimicked by myelopathy, syringomyelia or dorsal column disorders, such as tabes dorsalis.Hysterical symptoms can sometimes mimic a neuropathy.
20Diagnostic Approach Is the neuropathy focal, multifocal or symmetric? Focal neuropathies include common compressive neuropathies such as carpal tunnel syndrome, ulnar neuropathy at the elbow or peroneal neuropathy at the fibular headA multifocal neuropathy suggests a mononeuritis multiplex that may be caused, for example, by vasculitis or diabetes
21Diagnostic ApproachIf the neuropathy is symmetric, is it proximal or distal?Most toxic and metabolic neuropathies present as a distal symmetric or dying-back process.Proximal sensory neuropathies are rare and include porphyria.Predominantly motor neuropathies are often proximal and include acquired inflammatory neuropathies such as Guillain-Barré syndrome.An exception is lead neuropathy, which initially affects motor fibers in radial and peroneal distributions.
25Diagnostic ApproachNeuropathies can be categorized according to the fiber type that is primarily involved.Most toxic and metabolic neuropathies are initially sensory and later may involve the motor fibers.
26Diagnostic ApproachPure sensory neuropathies can result from drug toxicity (e.g., thalidomide, cisplatin [Platinol]), paraneoplastic syndromes or nutritional deficiencies.Primarily motor neuropathies include Guillain-Barré syndrome.
27Diagnostic ApproachAlcoholism and diabetes can both cause small-fiber, painful neuropathies
28Diagnostic ApproachAutonomic involvement occurs in many small-fiber neuropathies but can also occur in Guillain-Barré syndrome and is sometimes life-threatening.
29Diagnostic ApproachIt is important to distinguish whether the neuropathy is axonal, demyelinating, or both.This differentiation is best achieved using nerve conduction studies (NCS) and electromyography (EMG).
30Diagnostic ApproachDiabetes, HIV infection and alcoholism can cause several patterns of neuropathy.They most commonly cause a distal, symmetric axonal sensorimotor neuropathy.The second most common presentation in these conditions is a small-fiber, painful neuropathy.
31HistoryThe temporal course of a neuropathy varies, based on the etiology.With trauma or ischemic infarction, the onset will be acute, with the most severe symptoms at onset.Inflammatory and some metabolic neuropathies have a subacute course extending over days to weeks.A chronic course over weeks to months is the hallmark of most toxic and metabolic neuropathies.
32HistoryA chronic, slowly progressive neuropathy over many years occurs with most hereditary neuropathies or with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).Neuropathies with a relapsing and remitting course include Guillain-Barré syndrome.
33History Ischemic neuropathies often have pain as a prominent feature. Small-fiber neuropathies often present with burning pain, lightning-like or lancinating pain, aching, or uncomfortable paresthesias (dysesthesias).
34HistoryDying-back (distal symmetric axonal) neuropathies initially involve the tips of the toes and progress proximally in a stocking-glove distribution.
35History Peripheral neuropathy can present as restless leg syndrome. Proximal involvement may result in difficulty climbing stairs, getting out of a chair, lifting and swallowing, and in dysarthria.
36History The clinical assessment should include: careful past medical history, looking for systemic diseases that can be associated with neuropathy, such as diabetes or hypothyroidism.
37HistoryMany medications can cause a peripheral neuropathy, typically a distal symmetric axonal sensorimotor neuropathy.Detailed inquiries about drug and alcohol use, as well as exposure to heavy metals and solvents, should be pursued.
38History All patients should be questioned regarding HIV risk factors foreign travel (leprosy)diet (nutrition)vitamin use (especially B6)possibility of a tick bite (Lyme disease)
39HistoryThe review of systems may provide clues regarding other organ involvement and the presence of an underlying malignancy.
40Differential Diagnosis of Neuropathies by Clinical Course Acute onset (within days)Subacute onset (weeks to months)Chronic course/ insidious onsetRelapsing/ remitting courseGuillain-Barré syndromeMaintained exposure to toxic agents/medicationsHereditary motor sensory neuropathiesAcute intermittent porphyriaPersisting nutritional deficiencyDominantly inherited sensory neuropathyCIDPCritical illness polyneuropathyAbnormal metabolic stateHIV/AIDSDiphtheric neuropathyParaneoplastic syndromeToxicThallium toxicityPorphyria
41Physical ExaminationA cranial nerve examination can provide evidence of mononeuropathies or proximal involvement.Funduscopic examination may show abnormalities such as optic pallor, which can be present in leukodystrophies and vitamin B12 deficiency.
42Physical ExaminationDirect strength testing of muscles enervated by cranial nerves V, VII, IX/X, XI and XII is important, as mild bilateral weakness can be missed by observation only.
43Physical ExaminationThe motor examination includes a search for fasciculations or cramps, or loss of muscle bulk.Tone is normal or reduced.
44Physical ExaminationThe pattern of weakness helps narrow the diagnosis: symmetric or asymmetric, distal or proximal, and confined to a particular nerve, plexus or root level.
45Physical Examination Deep tendon reflexes are reduced or absent. A bilateral foot drop may result in a steppage gait in which the patient must lift the knees very high in order to clear the toes.Proximal weakness results in an inability to squat or to rise unassisted from a chair.
46Physical ExaminationThe general physical examination can provide evidence of orthostatic hypotension without a compensatory rise in heart rate when autonomic fibers are involved.
47Physical ExaminationRespiratory rate and vital capacity should be evaluated in Guillain-Barré syndrome to assess for respiratory compromise.The presence of lymphadenopathy, hepatomegaly or splenomegaly, and skin lesions may provide evidence of systemic disease.
48Physical ExaminationPale transverse bands in the nail beds, parallel to the lunula (Mees' lines), suggest arsenic poisoning.
49Laboratory Evaluation EMG and nerve conduction studies (NCS) are often the most useful initial laboratory studies in the evaluation of a patient with peripheral neuropathy
50Laboratory Evaluation They can confirm the presence of a neuropathy and provide information as to the type of fibers involved (motor, sensory, or both), the pathophysiology (axonal loss versus demyelination) and a symmetric versus asymmetric or multifocal pattern of involvement.
51Laboratory Evaluation The limitations of EMG/NCS should be taken into account when interpreting the findings.There is no reliable means of studying proximal sensory nerves.NCS results can be normal in patients with small-fiber neuropathiesLower extremity sensory responses can be absent in normal elderly patients.EMG/NCS are not substitutes for a good clinical examination.
52Laboratory Evaluation Subsequent studies should be tailored to the most likely diagnostic possibilities, and to the acuteness and severity of the neuropathy.With an acute progressive neuropathy, a neurologic consultation early in the course of the evaluation is essential.Further evaluation of these patients includes EMG/NCS, lumbar puncture, chest radiograph, electrocardiogram and determination of forced vital capacity.
53Laboratory Evaluation The most common presentation is that of a distal symmetric sensorimotor neuropathy.Initial evaluation should include:fasting serum glucose, glycosylated hemoglobin, blood urea nitrogen, creatinine, complete blood cell count, erythrocyte sedimentation rate, urinalysis, vitamin B12 and thyrotropin stimulating hormone levels.Neurologic assessment may be warranted if the initial evaluation does not produce a diagnosis.
54Laboratory Evaluation CSF is useful in evaluation of myelinopathies and polyradiculopathies.An elevated total protein level with < 5 wbc(albuminocytologic dissociation) is present in acquired inflammatory neuropathy (e.g., Guillain-Barré syndrome, CIDP).
55Laboratory Evaluation Other studies useful in specific clinical contexts are:cytology (lymphoma)special studiessuch as Lyme polymerase chain reaction and cytomegalovirus branched chain DNA (polyradiculopathy or mononeuritis multiplex in AIDS).
56Laboratory Evaluation Nerve biopsy is only helpful in very specific cases to diagnose vasculitis, leprosy, amyloid neuropathy, leukodystrophies, sarcoidosis and, occasionally, CIDP.
57Laboratory Evaluation It can be difficult to document a small-fiber neuropathy because the only abnormalities on neurologic examination may be loss of pinprick and temperature sensation in a distal distribution.
58Laboratory Evaluation EMG/NCS may be normal.Autonomic studies are only helpful if the autonomic fibers are involved.As a result, small-fiber neuropathy remains a primarily clinical diagnosis.
59Laboratory Evaluation The evaluation should include the most likely causes (i.e., diabetes, alcoholism, AIDS).If these studies are normal, a neurologic consultation is recommended.
60TreatmentThe goal of treatment is to manage the underlying condition causing the neuropathy and repair damage, as well as provide symptom relief.
61TreatmentControlling a chronic condition may not eliminate the neuropathy, but it can play a key role in managing it.
62Treatment Neuropathic pain is often difficult to control. Medications :OTC analgesics .antiepileptic drugs, including gabapentin, phenytoin, and carbamazepinesome classes of antidepressants, including tricyclics such as amitriptyline.Mexiletinelocal anesthetics such as lidocaine or topical patches containing lidocaineCodeine/oxycodone
63TreatmentMechanical aids can help reduce pain and lessen the impact of physical disability.Hand or foot braces can compensate for muscle weakness or alleviate nerve compression.Orthopedic shoes can improve gait disturbances and help prevent foot injuries in people with a loss of pain sensation.If breathing becomes severely impaired, mechanical ventilation can provide essential life support.
64TreatmentSurgical intervention often can provide immediate relief from mononeuropathies caused by compression or entrapment injuries.Repair of a slipped disk can reduce pressure on nerves where they emerge from the spinal cord; the removal of benign or malignant tumors can also alleviate damaging pressure on nerves.Nerve entrapment often can be corrected by the surgical release of ligaments or tendons.