Symptoms Of A Vitamin B12 Deficiency Other Than Anemia

Vitamin B12, which is also known as cobalamin, is needed for a multitude of biochemical processes throughout the body. Deficiency of B12 can develop as a result of decreased absorption or insufficient dietary intake, which most often occurs in vegans, the elderly and alcoholics. Aside from anemia, B12 deficiency can damage the nervous system. There are several typical patterns in which this damage occurs.

Spinal Cord Degeneration

Nerve cells are covered by a myelin sheath. If this sheath is damaged, normal transmission of nerve signals is disrupted. In subacute combined degeneration (SCD) of the spinal cord, the myelin covering nerves in the spinal cord is damaged. Most affected are nerves that carry motor signals from the brain, and nerves that transmit the sense of vibration and position from the body to the central nervous system. Symptoms develop gradually over the course of several months. Patients lose the sense of position and vibration in the extremities. As a result, gait becomes clumsy and awkward. Muscle weakness develops, especially in the lower limbs. Muscles develop spasticity, which means they are stiff and unable to relax.

Peripheral Neuropathy

B12 deficiency can damage the nerves leading from the spinal cord to the limbs. Patients may experience sensations of pins and needles in their legs, and lose their ability to sense pain and temperature. The pattern of sensory deficit depends on whether the spinal cord or the peripheral nerves are the more affected. Sensory changes start at the end of the longest nerves, and often occur in what's known as a "stocking and gloves" distribution, starting in the feet and later on appearing in the hands.

Psychiatric Symptoms

Psychiatric symptoms may be the first sign of B12 deficiency. People can become irritable and suspicious, and their personality can undergo significant changes. Behavior can change drastically, with elderly people becoming aggressive and disinhibited. Memory impairment may occur, and can develop into full-blown dementia. Psychosis may also occur, meaning patients may lose their sense of reality and develop delusions, which are beliefs that are patently false.

Optic Neuropathy

The optic nerve can be damaged by insufficient amounts of B12. Symptoms can include loss of central vision in both eyes. Though visual damage is relatively rare, it can lead to permanent blindness if not treated in time; hence, the importance of early detection.