From the Guidelines
Vitamin B12 deficiency can cause weakness, and it is essential to treat it promptly to prevent permanent nerve damage and other complications. This is a common symptom that occurs because B12 is essential for proper nerve function and red blood cell formation. When B12 levels are low, your body cannot produce enough healthy red blood cells to carry oxygen throughout your body, resulting in fatigue and weakness. Additionally, B12 deficiency can damage the protective coating around nerves (myelin sheath), leading to neurological symptoms including muscle weakness 1.
The treatment for vitamin B12 deficiency typically involves B12 supplementation, either orally or by injection. For severe deficiency, doctors often prescribe B12 injections (hydroxocobalamin) at 1 mg intramuscularly on alternate days until there is no further improvement, then 1 mg intramuscularly every 2 months 1. For people with no neurological involvement, hydroxocobalamin 1 mg intramuscularly should be administered three times a week for 2 weeks, followed by maintenance treatment with 1 mg intramuscularly every 2–3 months for life 1.
Some key points to consider:
- Vitamin B12 deficiency can cause weakness, fatigue, and neurological symptoms including muscle weakness and gait disturbances 1
- Treatment should be initiated promptly to prevent permanent nerve damage and other complications
- B12 supplementation, either orally or by injection, is the typical treatment for vitamin B12 deficiency
- People with certain conditions like pernicious anemia, those who've had gastric surgery, or strict vegans are at higher risk and may need lifelong supplementation 1
- It is essential to seek urgent specialist advice from a neurologist and haematologist if there is possible neurological involvement, such as unexplained sensory and/or motor and gait symptoms 1
From the FDA Drug Label
Doses of folic acid greater than 0. 1 mg per day may result in hematologic remission in patients with vitamin B12 deficiency. Neurologic manifestations will not be prevented with folic acid, and if not treated with vitamin B12, irreversible damage will result. Failure to do so will result in return of the anemia and in development of incapacitating and irreversible damage to the nerves of the spinal cord The answer is: Yes, B12 deficiency can cause weakness, as it can lead to incapacitating and irreversible damage to the nerves of the spinal cord and anemia if left untreated 2.
- Key points:
- Neurologic manifestations will not be prevented with folic acid.
- Irreversible damage will result if not treated with vitamin B12.
From the Research
Vitamin B12 Deficiency and Weakness
- Vitamin B12 deficiency can cause variable symptoms, which may be irreversible if not diagnosed and treated in a timely manner 3.
- The symptoms of vitamin B12 deficiency can masquerade as a multitude of illnesses, presenting different perspectives from the point of view of the hematologist, neurologist, gastroenterologist, general physician, or dietician 4.
- Clinical B12 deficiency with classic haematological and neurological manifestations, including weakness, is relatively uncommon, but subclinical deficiency affects between 2.5% and 26% of the general population depending on the definition used 5.
Causes and Diagnosis of Vitamin B12 Deficiency
- Vitamin B12 deficiency can be caused by either inadequate intake, inadequate bioavailability, or malabsorption 5.
- Diagnostic biomarkers for B12 status include decreased levels of circulating total B12 and transcobalamin-bound B12, and abnormally increased levels of homocysteine and methylmalonic acid 5.
- Recognition of clinical symptoms, including weakness, should receive the highest priority in establishing the diagnosis of B12 deficiency 3.