From the Guidelines
Numbness and tingling are definitive reasons to check for vitamin B12 deficiency, as these sensations are common neurological symptoms of B12 deficiency. These symptoms, particularly in the hands and feet, occur because vitamin B12 is essential for maintaining healthy nerve function and producing myelin, the protective coating around nerves. When B12 levels are low, nerve damage can occur, leading to these uncomfortable sensations along with other symptoms like weakness, balance problems, memory issues, and fatigue. According to the most recent guidelines, if neurological involvement is suspected, such as unexplained sensory and/or motor and gait symptoms, urgent specialist advice from a neurologist and haematologist should be sought 1. Testing for B12 deficiency typically involves a simple blood test measuring serum B12 levels, with values below 200 pg/mL generally indicating deficiency. Some key points to consider include:
- The importance of not giving folic acid first as it may mask underlying vitamin B12 deficiency and precipitate subacute combined degeneration of the spinal cord 1.
- The need for periodic blood tests to identify postoperative deficiencies, which should be carried out every 6 mo and interpreted with caution 1.
- The potential for neuromuscular symptoms, such as paraesthesia, and numbness in the trunk, muscle weakness, abnormal reflexes, tendon jerks, spasticity, gait ataxia, myelopathies and myelo-neuropathies, to become more severe as deficiency progresses 1. If diagnosed, treatment usually involves B12 supplementation, either orally or via injections, for those with severe deficiency or absorption issues. The underlying cause should also be identified, as deficiency can result from inadequate dietary intake, malabsorption conditions, or certain medications. Hydroxocobalamin 1 mg intramuscularly on alternate days until there is no further improvement, then administer hydroxocobalamin 1 mg intramuscularly every 2 months is recommended for people with neurological involvement 1.
From the FDA Drug Label
Vitamin B12 deficiency that is allowed to progress for longer than 3 months may produce permanent degenerative lesions of the spinal cord. Neurologic manifestations will not be prevented with folic acid, and if not treated with vitamin B12, irreversible damage will result.
Yes, numbness and tingling can be a reason to check for vitamin B12 deficiency, as vitamin B12 deficiency can cause neurologic manifestations, including permanent degenerative lesions of the spinal cord if left untreated 2 3.
From the Research
Numbness and Tingling as a Reason for B12 Check
- Numbness and tingling can be symptoms of vitamin B12 deficiency, as seen in patients with pernicious anemia 4.
- These symptoms can be accompanied by other neurological findings such as weakness, clumsiness, and ataxia 4, 5.
- Vitamin B12 deficiency can cause a range of neurological symptoms, including sensory deficits, loss of deep tendon reflexes, movement disorders, and neuropsychiatric changes 5.
- Early diagnosis and treatment of vitamin B12 deficiency are crucial to prevent long-term neurological damage 6, 7.
Underlying Causes of B12 Deficiency
- Pernicious anemia, caused by an intrinsic factor deficiency or autoantibodies against intrinsic factor, can lead to vitamin B12 deficiency 4.
- Intestinal tuberculosis can also cause vitamin B12 deficiency by involving the terminal ileum 5.
- Celiac disease can lead to vitamin B12 deficiency, especially if left untreated 8.
- A vegetarian or vegan diet can also increase the risk of vitamin B12 deficiency due to limited dietary intake 7.
Importance of B12 Check
- A B12 check is essential in patients presenting with neurological symptoms such as numbness, tingling, and weakness 4, 6, 5, 7.
- Early suspicion and detection of vitamin B12 deficiency can prevent serious and permanent neurological damage 4.
- Treatment of vitamin B12 deficiency can lead to significant improvement or resolution of neurological symptoms 4, 6, 7, 8.