Thalamic stroke is one of the most dangerous or life threatening form of intracerebral hemorrhage. Thalamic stroke is caused by bleeding in the brain tissue causing severe damage. Usually, thalamic stroke occurs when there is restricted supply of blood and oxygen to the lower part of the brain known as thalamus. Thalamic stroke is caused by bleeding in the section of brain known as thalamus. The bleeding causes severe injury of thalamus. Thalamic stroke occurs when the blood flow to thalamus is obstructed by blood clot known as embolism. Thalamic stroke can also be caused following profuse bleeding from ruptured artery which would be supplying oxygen and nourishment to the section of brain includes thalamus.
Where is the Thalamus Located Anatomically?
Word thalamus has been derived from a Greek word meaning chamber or room, it is a symmetrical structure present in vertebrates (including human beings) brain. Word thalamus has been derived from a Greek work meaning chamber or room, it is a symmetrical structure present in vertebrates (including human beings) brain. Thalamus is situated in the hindbrain right above the midbrain and very close to the central brain. From thalamus numerous nerve fibers are projected in all directions through cerebral cortex. The forebrain and hindbrain (thalamus) is enclosed within cerebral cortex or brain. From thalamus numerous nerve fibers are projected in all directions through cerebral cortex. Most of the sensory and motor signals to and from brain passes through thalamus. Thalamus influences the sleep pattern, level of consciousness as well as coordination of activities during emergency situation.
Is the Thalamus in the Brain Stem?
Thalamus is not a part of brain stem. It is located in between the midbrain and cerebral cortex. Common functions of thalamus includes inducing sensation, responsible for partial sense, and passing motor signals to cerebral cortex, which helps in regulating sleep, alertness and sleep. Thalamus closely and firmly surround the third ventricle and yes it also a crucial part of embryonic diencephalon. Brain stem is formed by midbrain. Medulla oblongata and pons. Thalamus is not a part of brain stem, but anatomically closely connected to brainstem since it lies superior to brain stem. Thalamus is located in between the midbrain and cerebral cortex. Sensory and motor fibers from brain and midbrain relays in thalamus and exchanges information. Thalamus receives and diverts the traffic of impulses to selected part of brain and midbrain. Thalamus closely and firmly surround the third ventricle and yes it also a crucial part of embryonic diencephalon.
What is the Function of the Thalamus in the Brain?
Thalamus perform multiple functions in brain, in simple words it is called as hub of information. Thalamus acts a relay between cerebral cortex and various subcortical areas. Sensory systems comprise of thalamic nerves that receives sensory signals and spread it to all the primary cortical area associated. The thalamus process both sensory information and also replay the same.
Sensory impulses from peripheral tissue passes through spinal cord and midbrain to thalamus. These impulses are then forwarded to appropriate section of the brain. Thalamus also plays a key role in regulating different states of mind and controls the sleep pattern and consciousness. Any damage to thalamus can actually take a person to a state of coma. Different functions of sensory and motor coordination are closely linked with different areas of thalamus. Different sensory systems controlled by thalamus are as follows:
- Visual Systems.
- Somatic Systems.
- Gustatory Systems.
- Auditory Systems.
- Visceral Systems.
What is Bilateral Thalamus Stroke?
Bilateral thalamus stroke is a very rare form of thalamic stroke. The situation occurs when a complex combination is formed between risk factors and prejudicing vessel distribution. It is very serious and can even cause fatal outcome. Bilateral thalamus stroke can lead to prolonged unconsciousness. Bilateral stroke is observed when main artery supplying both the lobe of thalamus is blocked and ruptured resulting in relatively severe intracerebral bleeding.
Causes of Thalamic Stroke
- High blood pressure is a cause of thalamic stroke.
- Excess deposition of protein in brain.
- Bleeding in brain tissues because of injury.
- Aneurysms may cause thalamic stroke.
- Restricted flow of oxygen in brain.
- Restricted flow of Blood in brain causes thalamic stroke.
Causes of Restriction of Thalamic Blood Flow-
- Thalamic or Intracerebral Arterial Aneurysms- Aneurysms of thalamic or surrounding blood vessel may cause pressure obstruction of thalamic artery or rupture of thalamic artery aneurysm can cause severe obstruction of blood flow to thalamus resulting in thalamic stroke.
- Atherosclerotic Stenosis of Basilar Artery- Basilar artery supplies oxygenated blood and nutrition to thalamus. Obstruction of basilar artery by stenosis causes restriction of blood supply resulting in thalamic stroke.
- Hypoxia- Low oxygen saturation to brain or low blood pressure can restrict the oxygen flow to thalamus and cause thalamic stroke.
- Stenosis of Major Artery- Carotid artery stenosis or narrowing of branch of carotid artery which supplies blood to thalamus can induce thalamic stroke.
Symptoms of Thalamic Stroke
Symptoms and signs following thalamic stroke and infarction of thalamic tissue depends on extent of thalamic and surrounding brain tissue injury. In most cases thalamic stroke is associated with midbrain infarction. Bilateral thalamic stroke involving midbrain infarction can cause unconsciousness and respiratory failure resulting in fatal outcome. Most of the thalamic stroke are partial and causes following sensory and motor malfunction. Thalamus integrates incoming sensory impulses like taste, peripheral somatosensory sensation, visual and auditory with the brain. The thalamic stroke in most cases affects taste, visual and auditory function.1 The sensory abnormalities like, tingling, numbness and stingling sensation are wide spread in entire body.
Some of the frequent symptoms of thalamic stroke includes:
- Lack of balance or coordination is a major symptom of thalamic stroke.
- Facial paralysis is also a sign of thalamic stroke.
- Difficulty in droop eyelids.
- Severe headache.
- Frequent feeling of nausea or vomiting.
- Interruption in speaking or difficult to speak.
- Swelling in body.
- Stinging sensation.
- Numbness in body.
Treatment for Thalamic Stroke
If the problem of thalamic stroke is identified at an early stage then it can be treated with medicines. Doctors try different combination of medicines on patients to see recovery prospect. However, in majority of cases of thalamic stroke surgery is the only treatment option available. The surgery is not an easy one, instead; it has various complications associated. Before the surgery doctors perform a series of tests to ensure to know the exact condition of brain. Through surgery doctors remove all the damaged blood vessels that have actually caused the brain hemorrhage.
After the thalamic stroke surgery, the patients are asked to take extra care and follow all the instructions and precautions so as to ensure fast recovery. After experiencing thalamic stroke, patient may need to take speech therapy, physical therapy, or at times even occupational therapy. Acupuncture has been tried in acute moderate thalamic hemorrhage.1
Surgical Treatment for Thalamic Stroke-
- Thalamic Hematoma Drainage2- The blood clot accumulated around thalamus often causes pressure over smaller arteries of thalamus resulting in obstruction of blood supply to thalamus. Such cases are treated by invasive surgical procedure. MRI, CT scan and ultrasound studies are performed to locate the hematoma. The endoscopy tube is placed in the hematoma structure and blood clot is aspirated. In few cases external drainage tube is left in hematoma space to drain further clot and blood.
- Thrombectomy and Dilatation of Atherosclerotic Occlusion3- Throbectomy surgical procedure is performed when basilar artery is blocked by emboli or thrombi. The catheter is passed into basilar artery and clot is removed using net. Dilatation of basilar artery is performed by placing the stent in the arterial lumen.
Recovery Period/Healing Time for Thalamic Stroke
As it is brain related problem, hence; recovery is slow. Although, the recovery period or healing time for thalamic stroke is completely based on the severity of disease or treatment opted. Both in case of medication and surgery the time required for complete recovery is decently long. Patients need to keep patience and should strictly follow all the instructions provided by doctors, any leniency can have adverse effect on the patient.
Prevention of Thalamic Stroke
As such there are no preventive measures known for avoiding thalamic stroke, but people who have already suffered the problem once can take precautions to avoid facing the similar situation later. Preventive measures varies with the actual mechanism of the disease. In majority of cases, doctors prepare a tailored preventive mechanism for patient to ensure they never face the thalamic stroke again or even if they face the intensity should be very low.
Risk Factors for Thalamic Stroke
As thalamic stroke is a brain related problem, hence there are numerous risk factors associated with the same. Brain controls the entire human body and thalamus play a crucial role in controlling various important functioning of body. Ruptured tissues can have adverse impact on different sensory organs such as smelling power, touch, vision problem and so on leading to partial or permanent damage of sensory organs.
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Acupuncture for acute moderate thalamic hemorrhage: randomized controlled trial study protocol.
Wang C1, You C2, Ma L2, Liu M1, Tian M2, Li N3., BMC Complement Altern Med. 2017 Feb 15;17(1):112.
Clinical Features of Thalamic Stroke.
Chen XY1, Wang Q2, Wang X3, Wong KS4., Curr Treat Options Neurol. 2017 Feb;19(2):5. Minimally invasive thalamic hematoma drainage can improve the six-month outcome of thalamichemorrhage. Liu WM1, Zhang XG2, Zhang ZL1, Li G3, Huang QB1., J Geriatr Cardiol. 2017 Apr;14(4):266-273.
Acute Basilar Artery Occlusion: Differences in Characteristics and Outcomes after Endovascular Therapy between Patients with and without Underlying Severe Atherosclerotic Stenosis.
Lee YY1, Yoon W2, Kim SK1, Baek BH1, Kim GS1, Kim JT3, Park MS3., AJNR Am J Neuroradiol. 2017 Aug;38(8):1600-1604.