What are the other Names for this Condition? (Also known as/Synonyms)

• Central Thalamic Post-Stroke Syndrome
• Dejerine-Roussy Syndrome
• Thalamic Pain Syndrome

What is Thalamic Syndrome? (Definition/Background Information)

• Thalamic Syndrome is an uncommon neurological condition that results from a brain stroke. It affects the thalamus of the brain. The condition generally occurs in older individuals
• The thalamus is a part of mid-brain that acts as a relay station for sensations, such as touch, pain, and temperature, which are carried by the different tracts of the spinal cord. The thalamus, after receiving these sensations, integrates and transmits them to the appropriate part of the cortex of the brain.
• Bleeding or blood clot in the blood vessels of the thalamus can result in stroke, which is the main cause of Thalamic Syndrome. Individuals with irregular heart rhythms, high blood pressure, and high cholesterol levels are at risk for developing the condition
• The signs and symptoms of Thalamic Syndrome can vary from numbness and tingling sensation, to loss of sensation, or hypersensitivity to environmental stimuli, involuntary movements, and paralysis. Extreme and prolonged pain has also been reported
• Individuals, affected by a stroke and reporting pain or abnormal sensations, are evaluated to confirm a diagnosis. The cause of pain is established through a process of elimination, to arrive at a diagnosis of Thalamic Syndrome. Imaging studies of the brain may be additionally required, to rule out the presence of tumors or blood vessel blockages
• The symptoms of Thalamic Syndrome are treated using opoids, anti-depressants, anti-convulsants and topical medicines for pain. The use of implanted electrodes to stimulate the affected brain region is currently under investigation. Also under study is spinal cord stimulation to alleviate the symptoms
• There are no effective methods available to prevent Thalamic Syndrome. Effective management of predisposing health conditions, such as high blood pressure and cholesterol levels, may help minimize susceptibility to the condition
• The prognosis of Thalamic Syndrome depends upon the severity of the condition, and more importantly on the extent of the brain stroke. Often, lifelong management of pain through medications may be required

Who gets Thalamic Syndrome? (Age and Sex Distribution)

• Thalamic Syndrome occurs in older individuals, who are at risk for, or have already had a brain stroke
• There is no sexual predilection with respect to occurrence of the condition
• Individuals of all races and ethnic groups may be affected

What are the Risk Factors for Thalamic Syndrome? (Predisposing Factors)

The following are some risk factors for Thalamic Syndrome:

• Increased blood pressure (hypertension)
• Elevated blood cholesterol levels (hypercholesterolemia)
• Old age
• Blood clotting disorders
• Irregular heart rhythm: This can cause formation of blood clots in the heart, which may travel to the brain resulting in a stroke

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Thalamic Syndrome? (Etiology)

The cause of Thalamic Syndrome is predominantly related to stroke in the region of the thalamus (a part of the brain). 

• The causative factor could either be a bleeding episode (hemorrhagic stroke), or a blood clot (ischemic stroke) in the thalamic blood vessels
• When there is a damage to the thalamus, usually involving deeper small vessels (such as the thalamogeniculate artery), there is an altered response to the sensations received by it. This is mostly manifested as a severe pain in the extremities and loss of ‘position sense’
• If the side of brain area affected by stroke is large, it may cause a weakness or paralysis of the body, on the opposite side

What are the Signs and Symptoms of Thalamic Syndrome?

The signs and symptoms associated with Thalamic Syndrome may include:

• Extreme pain in the limbs (extremities):
  • The pain can be continuous
  • The reaction to pain may be exaggerated such that even a pinprick can cause extreme pain
  • Superficial touch, emotional stress, and hot and cold temperatures can trigger extreme pain as well
• Weakness or paralysis of the affected limbs
• Loss of position sense: Inability to locate the position of a limb, or developing an illusion that the limb is lost when the eyes are closed
• Abnormal involuntary movements

How is Thalamic Syndrome Diagnosed?

The diagnosis of Thalamic Syndrome is performed by using the following methods:

• A thorough physical examination and assessment of symptoms of the affected individual
• Medical history assessment
• A thorough neurological evaluation
• Eliminating other causes for the pain, by clincal evaluation and use of imaging techniques. Some such causes can be tumors or blockages in blood vessels in the brain
• CT scan of the head and neck
• MRI of the brain
• Angiogram of the brain

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Thalamic Syndrome?

Some potential complications associated with Thalamic Syndrome include:

• Chronic pain and reduced quality of life
• Hypersensitivity to touch or other external stimulii

How is Thalamic Syndrome Treated?

The treatment for Thalamic Syndrome is geared towards pain-relief, for which the following measures may be considered:

• Administration of opioids: Although effective, the relief lasts only for 4-24hrs; as a result, they pose a high risk for addiction
• Tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRI) antidepressants are effective for short durations
• Use of anticonvulsants
• Topical local anaesthetic patches
• Stimulation treatment: It involves stimulating the thalamus and spinal cord through the implantation of electrodes. This procedure is under study
• Physical therapy

Treatment of the underlying factors, such as arrhythmia, hypertension, and hypercholesterolemia are often necessary.

Note:

• Thalamic Syndrome is generally not treated with commonly available analgesic medications
• Medication for pain is generally required for the remainder of the lives

How can Thalamic Syndrome be Prevented?

Currently, there are no effective methods available to prevent Thalamic Syndrome

• Managing the risk factors, such as hypertension and heart problems, may help minimize susceptibility to the condition
• This may be achieved by bringing about certain lifestyle modification and the use of suitable medications

What is the Prognosis of Thalamic Syndrome? (Outcomes/Resolutions)

• The prognosis of Thalamic Syndrome depends on the ‘pain severity’ experienced by the individual. The prognosis also depends on the extent of the brain stroke
• The pain can persist throughout the remainder of life and may need to be managed with a combination of pain medications and therapies

Additional and Relevant Useful Information for Thalamic Syndrome:

The following DoveMed website link (on Brain & Nerve Health Center) is a useful resource for additional information:

http://www.dovemed.com/health-topics/neurological-institute/