Neurologic signs and symptoms:

  • Numbness—tingling
  • Weakness of legs, arms, trunk
  • Impaired vibration—position sense
  • Abnormal reflexes
  • Unsteady or abnormal gait
  • Balance problems
  • Difficulty ambulating
  • Dizziness
  • Tremor
  • Restless legs
  • Visual disturbances
  • Forgetfulness, memory loss
  • Dementia
  • Impotence
  • Urinary or fecal incontinence

Psychiatric symptoms:

  • Depression   
  • Irritability
  • Paranoia
  • Mania
  • Hallucinations
  • Psychosis
  • Violent behavior
  • Personality changes

Hematologic signs and symptoms:

  • Anemia
  • Macrocytosis (enlarged red-blood cells)
  • Generalized weakness
  • Fatigue
  • Shortness of breath
  • Pallor

Signs & symptoms in infants and children:

  • Developmental delay or regression
  • Apathy—Irritability
  • Hypotonia
  • Weakness
  • Tremor
  • Involuntary movements
  • Seizures        
  • Ataxia
  • Anorexia
  • Failure to thrive
  • Poor weight gain
  • Poor head growth
  • Poor socialization
  • Poor motor skills
  • Language delay
  • Speech problems
  • Lower IQ—Mental retardation
  • Anemia
  • Macrocytosis