Ischemic myelopathy is a condition where the blood supply to a portion of the spinal cord is suddenly interrupted. This deprives the spinal cord of the oxygen and nutrients it needs to function. It is often compared to a “stroke” but occurs in the spinal cord rather than the brain, leading to rapid onset of neurological issues.
Understanding Ischemic Myelopathy
The spinal cord relies on a network of arteries for its blood supply, including a single anterior spinal artery and two posterior spinal arteries. The anterior spinal artery supplies the front two-thirds of the spinal cord, while the paired posterior spinal arteries supply the back one-third.
These main arteries receive blood from smaller feeder vessels called radicular arteries, which branch off from the aorta and other arteries along the spinal column. The lower thoracic region of the spinal cord is susceptible to ischemia due to a narrower diameter of the anterior spinal artery in this area and less consistent blood supply from segmental arteries.
Causes and Contributing Factors
Ischemic myelopathy can arise from various factors that disrupt blood flow to the spinal cord. A common cause involves an embolism, where a fragment of material blocks a small artery supplying the spinal cord. One specific type is a fibrocartilaginous embolism (FCE), where a piece of disc material from the spine enters the bloodstream and obstructs a spinal artery.
Other causes of compromised blood flow include aortic dissection, where the inner layers of the aorta tear, impacting blood supply to spinal arteries. Vasculitis, an inflammation of blood vessels, can also narrow or block spinal arteries. Severe hypotension, or abnormally low blood pressure, can reduce overall perfusion to the spinal cord, leading to ischemia. Conditions like atherosclerosis, which involves plaque buildup in arteries, and hypercoagulable states, where blood clots more easily, can also contribute to blockages.
Recognizing the Symptoms
The symptoms of ischemic myelopathy appear suddenly and vary depending on the specific area of the spinal cord affected. Patients may experience weakness or paralysis in one or more limbs, ranging from mild incoordination to a complete inability to walk. This weakness can be symmetrical, affecting both sides of the body equally, or asymmetrical, with one side more severely impacted.
Sensory changes are common, including numbness, tingling, or a loss of sensation, particularly for pain and temperature. Bowel or bladder dysfunction, such as difficulty controlling urination or defecation, can also occur. Though often non-painful, some individuals experience sudden, severe back pain at the onset, which can radiate around the torso. Neurological signs do not worsen after the initial 24 hours.
Diagnosis and Management
Diagnosing ischemic myelopathy involves a thorough medical history, a comprehensive neurological examination, and advanced imaging studies to rule out other conditions. Magnetic Resonance Imaging (MRI) of the spinal cord is the preferred imaging technique. MRI provides detailed views of soft tissues, identifies areas of spinal cord injury, and helps exclude other causes of sudden neurological deficits, such as disc herniations or spinal fractures that might require different treatments.
Management primarily focuses on supportive care and addressing any identifiable underlying causes. While there is no specific treatment to reverse spinal cord damage, maintaining adequate blood pressure and oxygenation is important to prevent further injury. Supportive nursing care, including proper positioning to prevent bed sores and managing bladder function, is also provided. Physical therapy and other rehabilitative measures are initiated to maximize functional recovery.
Prognosis and Rehabilitation
The outlook for individuals with ischemic myelopathy varies, depending largely on the initial severity and location of the spinal cord injury. Factors such as the extent of motor weakness and the preservation of sensation below the injury level can influence recovery. Patients with more severe deficits, such as complete paralysis and loss of pain sensation in the affected limbs, may have a less favorable prognosis for full recovery.
Rehabilitation plays a significant role in improving functional outcomes and quality of life for those affected. This includes physical therapy to regain strength and mobility, occupational therapy to improve daily living skills, and other supportive measures. While significant recovery can occur over weeks to months, some individuals may experience residual weakness or other neurological deficits long-term.