PNP pdf - D. Hazim - Muhadharaty

Peripheral neuropathy

D. Hazim

Peripheral Neuropathy:

Peripheral nerves are composed of sensory, motor, and autonomic elements.

Diseases can affect the cell body of a neuron or its peripheral processes, namely the axons or the
encasing myelin sheaths.

Most peripheral nerves are mixed and contain sensory and motor as well as autonomic fibers.
Thus, peripheral neuropathies can impair sensory, motor, or autonomic function, either singly
or in combination.

 MONONEURITIS SIMPLEX

This term signifies involvement of a single peripheral nerve.

 MONONEURITIS MULTIPLEX

Several individual nerves are affected, usually at random and noncontiguous.

 POLYNEUROPATHY

The term “polyneuropathy” denotes a disorder in which the function of numerous

peripheral nerves is affected at the same time. This leads to a predominantly distal and

symmetric deficit, with loss of tendon reflexes except when small fibers are selectively

involved.

Approach to Neuropathic Disorders

  Is it Motor, sensory, autonomic, or combinations?
  Is it focal, symmetrical or asymmetrical?
  Is it Acute (days to 4 weeks), Subacute (4 to 8 weeks) or Chronic (>8 weeks)?
  Is there evidence for a hereditary neuropathy (family history)
  Are  there  any  associated  medical  conditions  (DM,  cancer,  autoimmune,  connective

tissue)?

 Drug history.

Causes of peripheral neuropathy

Idiopathic inflammatory neuropathies

 Acute idiopathic polyneuropathy (Guillain-Barré syndrome)
 Chronic inflammatory demyelinating polyneuropathy.(CIDP)

Metabolic and nutritional neuropathies

  Diabetes
  Hypothyroidism
  Vitamin B

deficiency

Infective and granulomatous neuropathies

AIDS, leprosy, diphtheria, sarcoidosis and sepsis.

Vasculitis neuropathies

 Polyarteritis nodosa
 Rheumatoid arthritis

 SLE

Neoplastic and paraproteinemic neuropathies

 Compression and infiltration by tumor
 Paraneoplastic syndromes

Drug, alcohol and toxin induced neuropathies

Examples of drugs

  Pyridoxine
  Metronidazole
  Dapsone
  Isoniazid

Example of toxin:

Organophosphates

Heavy metal

Lead, Thallium, arsenic

Hereditary neuropathies

Friedreich ataxia, CMT (Charcot-Marie-Tooth).

Compressive neuropathy:

E.g.: carpel tunnel syndrome

Idiopathic Inflammatory Neuropathies

Acute Idiopathic Polyneuropathy (Guillain-Barré Syndrome)

 GBS is an acute or subacute polyneuropathy that can follow minor infective illnesses,

,vaccination ,surgical procedures, or may occur without obvious precipitants

 Clinical and epidemiologic evidence suggests an association with preceding infection

such as Campylobacter jejuni, Cytomegalovirus, Mycoplasma pneumonia, Epstein–
Barr virus etc.

 Its precise cause is unclear, but it appears to have an immunologic basis. Both

demyelinating and axonal forms have been recognized, with distinctive clinical and
electrophysiological features, the demyelinated form is more common.

Clinical Features

Diagnostic criteria for Guillain-Barré syndrome
Required for diagnosis

 Progressive weakness of more than one limb
 Distal areflexia with proximal areflexia or hyporeflexia

Supportive of diagnosis

  Progression for up to 4 weeks
  Recovery beginning within 4 weeks after progression stops
  Relatively symmetric deficits
  Mild sensory involvement
  Cranial nerve (especially VII) involvement
  Autonomic dysfunction
  No fever at onset
  Increased CSF protein after 1 weeks

 CSF white blood cell count ≤10/mL
 Nerve conduction study show slowing or block by several weeks

Against diagnosis

  Markedly asymmetric weakness
  Bowel or bladder dysfunction (at onset or persistent)
  CSF white blood cell count >50 .
  Well-demarcated sensory level.

Excluding diagnosis

 Isolated sensory involvement

Investigative studies

• The cerebrospinal fluid (CSF) often shows a characteristic abnormality, with increased

protein concentration but a normal cell count (cytoalbumino dissociation); abnormalities
may not be found in the first week.

• Electrophysiological studies may reveal marked slowing of motor and sensory

conduction velocity.

Treatment

• Plasmapheresis appears to reduce the time required for recovery and may decrease the

likelihood of residual neurologic deficits and need for ventilation a course of
plasmapheresis usually consists of 40–50 mL/kg plasma exchange (PE) four to five times.

• It is best instituted early, and it is indicated especially in patients with a severe or rapidly

progressive deficit or respiratory compromise.

• Intravenous immunoglobulin (400 mg/kg/d for 5 days) appears to be equally effective

and should be used in preference to plasmapheresis in adults with cardiovascular
instability and in children;

 The two therapies are not additive.



No role for steroid

In the worsening phase of GBS, most patients require monitoring in a critical care setting, with
particular attention to

  Vital capacity
  Heart rhythm
  Blood pressure
  Deep vein thrombosis prophylaxis like heparin and compressive stokes
  Cardiovascular status monitoring, and chest physiotherapy.

As noted, 30% of patients with GBS require ventilator assistance.

Prognosis and Recovery

Approximately 70-75% of patients recover completely, 25% are left with mild neurologic
deficits, and 5% die from respiratory and autonomic dysfunction.

Chronic Inflammatory Demyelinating Polyneuropathy

CIDP is distinguished from GBS by its chronic course.

Onset is usually gradual over a few months or longer, but in a few cases the initial attack is
indistinguishable from that of GBS.

An acute-onset form of CIDP should be considered when GBS deteriorates >9 weeks after onset
or relapses at least three times.

Symptoms are both motor and sensory in most cases, in other respects, this neuropathy shares
many features with the common demyelinating form of GBS.

Types of Diabetic Neuropathy

 Peripheral Neuropathy.

 Proximal Neuropathy (diabetic amyotrophy).

 Autonomic Neuropathy.

 Focal Neuropathy.

Mubark A. Wilkins