All levels of the spinal cord may be involved, although a thoracolumbar distribution is most common. This disorder typically produces symptoms within the first 30 minutes after diving, and the first symptom is usually bilateral sensory change, which often ascends from distal to proximal, shortly followed by weakness producing ascending paraplegia. This is usually associated with a loss of bladder sensation and tone and a loss of anal tone. Cervical involvement may also produce sensory change and weakness in the upper limb. Examination findings are typically consistent with loss of upper motor neuron function under any circumstances, but in DCS there may be patchy involvement of different regions of the spinal cord, and detailed examination to delineate the location and extent of lesions is usually not necessary or helpful, especially at first presentation. Once the approximate extent of spinal involvement is understood, timely instigation of recompression treatment is the priority.
The natural history of spinal DCS is variable. In cases that progress to weakness, spontaneous recovery is possible, especially with surface oxygen administration. However, permanent sequelae are common even after treatment with recompression and hyperbaric oxygen. This makes spinal DCS the most feared and debilitating of the dysbaric diseases.