Spina bifida occulta is a mild and often hidden form of spina bifida, a birth defect where the bones of the spine do not fully close during early fetal development. Unlike more severe types, spina bifida occulta usually does not involve exposed spinal cord or nerves, and the skin over the defect remains intact. Because of this, many people with spina bifida occulta may not show obvious symptoms or even know they have it. However, there are some subtle signs and clues that can suggest its presence.
One of the most common signs of spina bifida occulta is a small patch of hair growing unusually over the lower back, often called a “tuft of hair.” This hairy patch is sometimes accompanied by other skin changes such as a small dimple, a birthmark, or a tiny lump or fatty swelling (lipoma) on the skin over the spine. These skin markers are important clues because the underlying vertebrae may not have fused properly, leaving a hidden gap in the spinal bones.
In some cases, spina bifida occulta can cause mild neurological symptoms, although many individuals remain asymptomatic. These symptoms might include:
– Occasional lower back pain or discomfort, especially after physical activity or prolonged sitting.
– Mild weakness or numbness in the legs or feet, though this is rare.
– Changes in bladder or bowel control, such as occasional incontinence or difficulty emptying the bladder fully.
– Abnormal reflexes or muscle tone in the lower limbs, detected during a neurological exam.
Sometimes, spina bifida occulta is discovered incidentally during imaging tests like X-rays, MRI, or CT scans performed for unrelated reasons, such as after an injury or for back pain evaluation.
In very rare cases, spina bifida occulta may be associated with tethered spinal cord syndrome, where the spinal cord is abnormally attached within the spinal canal. This can lead to progressive neurological symptoms including worsening leg weakness, sensory changes, and bladder or bowel dysfunction. Early detection and treatment of tethered cord are important to prevent permanent damage.
It is important to note that many people with spina bifida occulta live normal lives without any symptoms or complications. The condition is often called “hidden” because the defect is covered by skin and does not cause the severe disabilities seen in other forms of spina bifida.
In summary, the signs of spina bifida occulta can be very subtle and include:
– A tuft of hair, dimple, birthmark, or small lump on the lower back skin.
– Occasional lower back pain or mild neurological symptoms.
– Rarely, bladder or bowel control issues.
– Incidental findings on spinal imaging.
Because these signs can be mild or absent, spina bifida occulta often goes unnoticed unless specifically looked for during medical evaluation. When symptoms do occur, they usually warrant further neurological assessment and imaging to guide appropriate management.
