Diagnosis of Peripheral Neuropathy

Signs and Symptoms of Peripheral Neuropathy

The signs and symptoms of peripheral neuropathy vary widely and are subject to differences among affected individuals leading to difficulty in diagnosis. In addition, the involvement of more than one type of nerve fiber can add confusion to pinpointing the source of the pain. Symptoms can be divided into two categories: positive and negative.

• Positive symptoms - pain associated with the neuropathy

  • spontaneous pain - pain that is independent of any stimulus, (e.g., burning, stabbing, stinging, freezing, aching, feeling of "broken glass", and/or pins and needles). Many patients experience different types of pain simultaneously (e.g., burning pain as well as shooting or stabbing pain).
  • stimulus-evoked - pain that is experienced in response to an event (e.g., pinprick or finger pressure on a particular spot).

• Negative symptoms - these are associated with a loss of function and include:

  • anesthesia - numbness or absence of pain when it should be felt (e.g., if there is an injury)
  • paresthesia - abnormal sensation
  • tremor
  • gait imbalance

Additional symptoms or sensations associated with peripheral neuropathy include:

• Weakness, loss of grip strength
• Decreased manual dexterity
• Muscle wasting
• Loss of deep reflexes
• Anhidrosis (absence of sweating)
• Orthostatic hypotension (drop in blood pressure upon sitting up or standing)
• Glandular dysfunction
• Difficulties with food digestion
• Difficulties with sexual function

The type of nerve involved determines to a large extent the array of symptoms which may be involved. Symptoms related to specific nerve damage include:

Motor nerve damage

• Muscle wasting
• Fasciculation - uncontrolled muscle contractions or twitching visible under the skin
• Painful muscle cramps
• Bone degeneration

Sensory nerve damage

Symptoms are more complex since sensory nerves have a wider range of function than motor nerves. Symptoms from damage to large fibers differ than those related to small fiber in the following way:

Large fiber damage

• Numbness of hands and/or feet
• Diminished sense of touch
• Diminished sense of vibration
• "Stocking and glove" sensation
• Loss of sense of position in space (proprioception)
• Difficulty coordinating complex movements
• Loss of reflexes
• Pain

Small fiber damage

• Diminished ability to feel pain or notice an injury to an affected limb
• Diminished ability to sense temperature changes
• Pain described as burning, stabbing, prickling, jabbing, or lancinating (piercing)
• Sensation of "broken glass", "burning sand", or "ice pick in the bone"
• Tight band-like pressure
• Insensitivity to heat and cold
• Autonomic dysfunction - related to functioning of the organs.
• Normal electrodiagnostic studies

Autonomic nerve damage

• Impaired ability to regulate body temperature
• Blurred vision
• Reduced sweating
• Dizziness
• Bowel/bladder dysfunction

All of these sensations may occur simultaneously, intermittently, or on a constant basis. They are highly variable from individual to individual. Many patients with peripheral neuropathy also complain of fatigue, mood swings, difficulty with memory, and loss of coordination/balance.

Symptoms according to the distribution of neuropathy include:

Mononeuropathy - pain will be felt along the pathway of a single peripheral nerve.

Mononeuropathy multiplex - pattern of nerve involvement is random. Symptoms often evolve quickly.

Polyneuropathy - symptoms of the most common polyneuropathy (also called chronic axonal neuropathy or chronic distal polyneuropathy) include:

• Toes and soles of the feet affected first
• Dysesthesia (distorted sense of touch so that an innocuous stimulus causes pain or unpleasantness) in the toes or feet
• Symmetrical symptoms
• Symptoms spread up the legs and patients may have trouble walking on their heels resulting in an unsteady gait
• Symptoms may spread to fingertips and up the arms
• Numbness
• Burning
• Paresthesia (abnormal sensations on the skin with no stimuli)
• Muscle weakness in lower legs and feet

Acute polyneuropathy - symptoms are typically symmetrical with rapid progression that may result in paralysis.

Chronic demyelinating polyneuropathy - symptoms vary with the specific condition which includes:

• Charcot-Marie-Tooth symptoms are highly variable and include: ankle weakness, structural deformities of the foot (high arch and hammertoes), muscle wasting resulting in difficulties with walking, running, and balance; and drop foot where patient raises their knees very high to step to avoid tripping.
• Chronic Inflammatory Demyelinating Polyneuropathy - numbness, tingling, pain, progressive muscle weakness, loss of deep tendon reflexes (areflexia), fatigue, and abnormal sensations. This condition usually presents with predominantly motor involvement and typically follows a course of gradual progression.
• Multifocal motor neuropathy - early symptoms include weakness and muscle atrophy in the forearms and hands.

Neuropathic pain tends to be worse at night which results in disrupted sleeping and subsequent fatigue. Depression is not uncommon in patients with peripheral neuropathy due to the significant impact of symptoms on activities of daily living and general quality of life.