Thalamic syndrome is an unusual neurological condition resulting from a cerebral stroke. It affects the thalamus of the brain. The condition most often occurs in older people. Lesions that are usually present in one hemisphere of the brain most often cause an initial lack of sensation and tingling on the opposite side of the body. Weeks and months later, numbness can develop into severe and chronic pain.
Definition
The thalamus is a part of the midbrain that acts as a relay for sensations such as touch, pain and temperature carried by different parts of the spinal cord. The thalamus, having received these sensations, integrates them and transmits them to the corresponding part of the cerebral cortex. Bleeding or a blood clot in the blood vessels can lead to a stroke, which is the main cause of thalamic syndrome. People with irregular heart rhythms, high blood pressure and high cholesterolare at risk of developing this condition.
History
In 1906, Joseph Jules Dejerine and Gustave Roussy presented a description of central post-stroke pain (CPS) in their paper titled "The Thalamic Syndrome". The name of the Dejerine-Roussy syndrome was coined after their death. It included "severe, persistent, paroxysmal, often unbearable pain on the hemiplegic side, not amenable to any pain medication."
In 1911, it was found that patients often develop pain and hypersensitivity to stimuli during recovery of function. The pain associated with a stroke was thought to be part of it. It is now accepted that thalamic syndrome is a condition that has developed due to damage that interferes with the sensory process. This prompted the start of pharmaceutical research and stimulation research. The last 50 years have been filled with refractory surveys. As of the early 2000s, longer procedures lasting months to years were being explored in an ongoing search for removal of abnormal pain.
Signs
Signs and symptoms of thalamic syndrome can range from numbness and tingling to loss of sensation or hypersensitivity to external stimuli, involuntary movements and paralysis. Severe and prolonged pain may also occur. Stroke survivors reporting pain or abnormal sensations are evaluated for confirmationdiagnosis. The cause of the pain is established through a process of elimination. Brain imaging may be required to rule out tumors or blockages in blood vessels.
The prognosis of thalamic pain syndrome depends on the severity of the stroke. Lifelong pain management through medication may often be necessary.
Development Risk
The following are some risk factors for thalamic pain syndrome:
- High blood pressure (hypertension).
- High cholesterol levels in the blood (hypercholesterolemia).
- Old age.
- Blood clotting disorders.
- Irregular heart rhythm.
It is important to note that a risk factor increases the chances of developing the condition. Some of them are more important than others. The absence of a risk factor does not mean that a person will not get the syndrome.
Causes and pathophysiology
Although there are many factors and risks associated with strokes, very few are associated with Dejerine-Roussy thalamic syndrome. In general, strokes damage one hemisphere of the brain, which may include the thalamus. Sensory information from environmental stimuli enters it for processing. Then to the somatosensory cortex for interpretation. The end product of this is the ability to see, hear or feel. Thalamic syndrome after a stroke most often affects tactile sensations. Therefore, damage to the thalamus causes a violationinteractions between the afferent pathway and the cerebral cortex, changing what or how a person feels. The change may be a wrong feeling, an intensification or a dulling of it.
Symptoms
Signs and symptoms associated with thalamic syndrome may include:
- Severe pain in the limbs (may be permanent).
- The reaction can be exaggerated: even a pinprick can cause severe pain.
- Surface touch, emotional stress, and a sudden change in air temperature can cause severe pain.
- Weakness or paralysis of affected limbs.
- Loss of sense of position: the inability to determine the position of a limb or the development of the illusion that it is not there when the eyes are closed.
- Abnormal involuntary movements.
How it is diagnosed
Thalamic syndrome is diagnosed using the following methods:
- Careful physical examination and assessment of the victim's symptoms.
- Evaluation of medical history.
- Careful neurological examination.
- Treat other causes of pain through the use of imaging techniques.
- Computed tomography of the head and neck.
- MRI of the brain.
- Angiogram of the brain.
How it is treated
Treatment for thalamic syndrome is aimed at relieving pain. For this there may bethe following measures are considered:
- Use of opioids. Despite their effectiveness, relief lasts from 4 to 24 hours. They also pose a high risk for addiction.
- Tricyclic antidepressants and selective serotonin reuptake inhibitors. They are effective for a short time.
- Use of anticonvulsants.
- Relevant local anesthesia.
- Stimulation of the thalamus and spinal cord through electrode implantation.
Thalamic syndrome is usually not treated with commonly available pain medications. Pain medicine is usually required for the remainder of life.
Epidemiology
Of the millions of stroke survivors worldwide, more than 30,000 have acquired some form of Dejerine-Roussy syndrome. 8% of all patients experience central pain syndrome, 5% - moderate pain. The risk of developing the syndrome is higher in older stroke patients. Approximately 11% of stroke patients are older than 80.
