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Altered sensation, numbness and tingling

Medicine > Neurosciences

Differential Diagnosis Schema 🧠

Neurological Causes

  • Peripheral neuropathy: Often presents with glove and stocking distribution, common in diabetes, alcoholism, B12 deficiency, and certain drug toxicities.
  • Multiple sclerosis: May present with asymmetric sensory loss, optic neuritis, or Lhermitte’s sign.
  • Spinal cord compression: Look for sensory level, hyperreflexia below the lesion, and urinary retention.
  • Stroke: Sudden onset, usually unilateral, associated with other neurological deficits such as weakness or speech difficulties.
  • Carpal tunnel syndrome: Numbness in the thumb, index, and middle fingers, often worse at night.
  • Ulnar nerve entrapment: Tingling in the ring and little fingers, often associated with prolonged elbow flexion.

Vascular Causes

  • Peripheral arterial disease: Intermittent claudication, reduced pulses, cold extremities.
  • Raynaud’s phenomenon: Episodic color change in fingers and toes, triggered by cold or stress.
  • Thromboangiitis obliterans (Buerger’s disease): Often in young male smokers, presents with claudication, ulcers, and gangrene.

Metabolic and Endocrine Causes

  • Diabetic neuropathy: Most common cause of peripheral neuropathy, often with a symmetrical glove and stocking distribution.
  • Hypothyroidism: Can cause generalized slowing of thought and reflexes, and may present with carpal tunnel syndrome.
  • Vitamin B12 deficiency: Leads to subacute combined degeneration of the cord, peripheral neuropathy, and cognitive changes.

Infectious Causes

  • Herpes zoster (shingles): Dermatomal distribution, painful vesicular rash followed by postherpetic neuralgia.
  • HIV neuropathy: Can present in various ways, including painful sensory neuropathy.
  • Lyme disease: May present with a radiculopathy, cranial nerve palsies, or mono/oligoarticular arthritis.
  • Leprosy: Hypopigmented or reddish skin lesions with loss of sensation, commonly in endemic areas.

Key Points in History 🥼

Onset and Duration

  • Acute onset: Consider stroke, transient ischemic attack (TIA), or acute nerve compression.
  • Subacute onset: Could suggest a demyelinating condition like multiple sclerosis or Guillain-Barré syndrome.
  • Chronic onset: More likely to be peripheral neuropathy or a compressive neuropathy.

Location of Symptoms

  • Symmetrical or asymmetrical: Symmetrical symptoms are more common in metabolic or toxic causes, while asymmetrical may suggest a focal neurological lesion.
  • Proximal or distal: Distal symptoms suggest peripheral neuropathy, whereas proximal weakness may indicate a myopathy.
  • Specific dermatomes: May point towards radiculopathy or shingles.

Precipitating and Relieving Factors

  • Worse with activity: Vascular claudication or carpal tunnel syndrome.
  • Improvement with rest: Neurogenic claudication often improves with rest or sitting.
  • Positional change: Symptoms related to nerve compression may change with body position.
  • Triggered by cold or stress: Raynaud’s phenomenon.

Associated Symptoms

  • Weakness: Suggests a more severe neurological involvement such as in a stroke or Guillain-Barré syndrome.
  • Autonomic symptoms: Consider diabetic autonomic neuropathy or Guillain-Barré syndrome.
  • Visual disturbances: May indicate multiple sclerosis.
  • Rash: Look for shingles, lupus, or systemic vasculitis.

Background

  • Past medical history: Diabetes, autoimmune diseases, history of stroke, or previous neurological conditions.
  • Drug history: Chemotherapy, isoniazid, or antiretroviral drugs.
  • Family history: Hereditary neuropathies, multiple sclerosis, or other neurological disorders.
  • Social history: Alcohol consumption, occupational hazards, or exposure to toxins.

Possible Investigations 🌡️

Blood Tests

  • Full blood count (FBC): To check for anemia or infection.
  • Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP): Raised in inflammatory or infectious conditions.
  • Blood glucose and HbA1c: To screen for diabetes.
  • Vitamin B12 and folate levels: To assess for deficiency as a cause of neuropathy.
  • Thyroid function tests: To screen for hypothyroidism.
  • Urea and electrolytes: To check for renal function and electrolyte imbalances.

Imaging

  • MRI of the brain and/or spine: Indicated if central causes such as multiple sclerosis or spinal cord compression are suspected.
  • CT scan: Used in acute settings to rule out stroke or significant trauma.
  • Ultrasound: Can be used to assess for vascular causes such as peripheral arterial disease.

Electrophysiological Studies

  • Nerve conduction studies (NCS) and electromyography (EMG): Helpful in diagnosing peripheral neuropathies, carpal tunnel syndrome, and other nerve entrapment syndromes.
  • Evoked potentials: Useful in diagnosing multiple sclerosis.

Lumbar Puncture

  • Used to assess for central nervous system infections, multiple sclerosis (oligoclonal bands), or elevated protein levels in Guillain-Barré syndrome.

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Neurosciences