A spinal stroke, also known as a spinal cord infarction, occurs when the blood supply to the spinal cord is disrupted, leading to damage or death of spinal cord tissue. Though much less common than brain strokes, accounting for less than 1% of all strokes, it can lead to severe disability or be fatal.
Understanding Spinal Stroke
A spinal stroke involves the spinal cord, a long, tube-like structure extending from the brainstem down the back. The spinal cord acts as a communication pathway, transmitting nerve impulses between the brain and the rest of the body, controlling movement, sensation, and organ function. To perform these functions, the spinal cord requires a continuous supply of oxygen and nutrients, which it receives through a network of arteries and veins.
The main blood vessels supplying the spinal cord are the anterior spinal artery, which nourishes the front two-thirds of the cord, and the paired posterior spinal arteries, which supply the back third. When blood flow to any part of the spinal cord is reduced or completely cut off, the affected tissue experiences ischemia, a lack of oxygen and nutrients. Prolonged ischemia can lead to infarction, the death of spinal cord tissue, resulting in neurological deficits.
The Mechanisms of Spinal Stroke
Spinal strokes primarily occur through two distinct mechanisms: ischemic and hemorrhagic. The vast majority, around 86%, are ischemic spinal strokes.
Ischemic Spinal Stroke
An ischemic spinal stroke happens when there is a blockage in the arteries supplying the spinal cord. This blockage prevents oxygen-rich blood from reaching the spinal cord tissue, leading to tissue damage and death. The most frequent cause is a blood clot that forms directly within a spinal artery or travels from another part of the body, such as the heart or aorta, and lodges in a spinal vessel. This can also occur due to narrowing of the arteries from plaque buildup, known as atherosclerosis.
Hemorrhagic Spinal Stroke
A hemorrhagic spinal stroke involves bleeding into or around the spinal cord. This bleeding occurs when a blood vessel supplying the spinal cord ruptures. The accumulation of blood then compresses the spinal cord, disrupting its normal function and blood flow, leading to tissue damage and infarction. Hemorrhagic spinal strokes are less common but can be severe.
Common Causes and Risk Factors
Spinal strokes arise from various underlying conditions and risk factors that compromise the spinal cord’s blood supply. Direct causes often involve issues with major blood vessels or surgical complications. For instance, an aortic dissection, a tear in the aorta, can disrupt blood flow to the spinal arteries. Complications during spinal or aortic surgery, such as cross-clamping of the aorta, are also recognized causes. Severe atherosclerosis can narrow the spinal arteries directly, reducing blood flow.
Certain medical conditions and lifestyle choices increase an individual’s susceptibility to a spinal stroke. High blood pressure, or hypertension, damages and weakens arteries over time, making them more prone to blockages or ruptures. High cholesterol contributes to atherosclerosis. Diabetes, smoking, and advanced age also predispose individuals to vascular damage. Less common causes include certain types of vasculitis (inflammation of blood vessels), spinal tumors, aneurysms, and abnormal tangles of blood vessels called arteriovenous malformations (AVMs).
Recognizing the Signs
The symptoms of a spinal stroke appear suddenly and can progress rapidly, often within minutes or a few hours. The specific signs depend on which part of the spinal cord is affected and the extent of the damage.
A common initial symptom is sudden, intense pain in the back or neck, which may spread into the arms or legs. This pain can sometimes feel like a tight band around the body. Individuals may experience sudden weakness or paralysis in the legs. Numbness, tingling, or a loss of sensation are also frequent. Additionally, difficulty with bladder or bowel control is a neurological deficit.
Diagnosis and Immediate Steps
Diagnosing a spinal stroke requires prompt medical evaluation due to the sudden onset of symptoms. Healthcare providers begin with a detailed neurological examination to assess motor and sensory function. This helps identify specific patterns of weakness or sensation loss that point to spinal cord involvement.
Magnetic Resonance Imaging (MRI) is the imaging test used to confirm a spinal stroke. An MRI provides detailed images of the spinal cord, allowing doctors to identify areas of tissue damage caused by disrupted blood flow or bleeding. Sometimes, a lumbar puncture, or spinal tap, may be performed to rule out other conditions like infections or inflammation that can mimic spinal stroke symptoms. Seeking immediate emergency medical care is necessary if a spinal stroke is suspected, as timely intervention helps stabilize the patient and manage symptoms.