Moyamoya disease - Clinicals, Diagnosis, and Management

Neurology

Clinicals - History

Fact Explanation
Introduction Moyamoya disease is a progressive chronic vasculopathy leading to stenosis of the main intracranial arteries. It has unknown eatiology. Mainly affecting the supraclinoid internal carotid arteries and the circle of Willis. This will causes formation of extensive arterial collaterals at the base of the brain. The term Moyamoya came from Japanese with the meaning of “puff of smoke” which is angiographic appearance of these fine basal collaterals. Clinically this disease may presents as ischaemic, haemorrhagic and epileptic type.
The disease is most common among Asian population. The disease is more frequent among children and adolescents and also among the women.
Introduction
Moyamoya disease is a progressive chronic vasculopathy leading to stenosis of the main intracranial arteries. It has unknown eatiology. Mainly affecting the supraclinoid internal carotid arteries and the circle of Willis. This will causes formation of extensive arterial collaterals at the base of the brain. The term Moyamoya came from Japanese with the meaning of “puff of smoke” which is angiographic appearance of these fine basal collaterals. Clinically this disease may presents as ischaemic, haemorrhagic and epileptic type.
The disease is most common among Asian population. The disease is more frequent among children and adolescents and also among the women.
Symptoms of transient Ischaemic attacks (TIA): sudden onset of visual problems, limb weakness lasting less than 24 hours According to the World Health Organization criteria proposed in 1988, transient ischemic attack (TIA) is defined as rapidly developed clinical signs of focal or global disturbance of cerebral function, lasting less than 24 hours, with no apparent non-vascular cause.
Symptoms of the disease usually preceded by TIAs. Disease causes stenosis and occlusions of large arteries of the anterior part of the Willis circle, and may involve the collateral vasculature. This may cause reduction of the blood supply for certain areas of brain causing these symptoms.
Symptoms of transient Ischaemic attacks (TIA): sudden onset of visual problems, limb weakness lasting less than 24 hours
According to the World Health Organization criteria proposed in 1988, transient ischemic attack (TIA) is defined as rapidly developed clinical signs of focal or global disturbance of cerebral function, lasting less than 24 hours, with no apparent non-vascular cause.
Symptoms of the disease usually preceded by TIAs. Disease causes stenosis and occlusions of large arteries of the anterior part of the Willis circle, and may involve the collateral vasculature. This may cause reduction of the blood supply for certain areas of brain causing these symptoms.
Sudden onset of unilateral limb weakness In paediatric cases most common presentation is ischaemic events. It commomnly manifest as hemiplagia. Vascular oclusion, stenosis and thrombosis causes iscahemia of the particular areas of the brain, and haemorrhages may result due to the rupture of microaneurysms. Once the motor cotex is affected, it can cause contralateral weakness of the limb. Sudden onset of unilateral limb weakness
In paediatric cases most common presentation is ischaemic events. It commomnly manifest as hemiplagia. Vascular oclusion, stenosis and thrombosis causes iscahemia of the particular areas of the brain, and haemorrhages may result due to the rupture of microaneurysms. Once the motor cotex is affected, it can cause contralateral weakness of the limb.
Sensation Disturbance Ischaemia and haemorrhagic lesions affecting the sensory cortex may cause sensory disturbances. Sensation Disturbance
Ischaemia and haemorrhagic lesions affecting the sensory cortex may cause sensory disturbances.
Aphasia As a common symptom due to ischaemia to speech area of the brain. Dysarthria is common with the involvement of the posterior circulation. Aphasia
As a common symptom due to ischaemia to speech area of the brain. Dysarthria is common with the involvement of the posterior circulation.
Headache, nausea, vomiting,Vertigo, decreased consciousness In adults common presentation is haemorrage rather than ischemia. It can cause intravenricular and periventricular haemorrhage is common. Rupture of the aneurysm may also contributes. But also those symptoms can appear with the ischaemic infarction also which cannot differentiate clinically. Headache, nausea, vomiting,Vertigo, decreased consciousness
In adults common presentation is haemorrage rather than ischemia. It can cause intravenricular and periventricular haemorrhage is common. Rupture of the aneurysm may also contributes. But also those symptoms can appear with the ischaemic infarction also which cannot differentiate clinically.
Seizures This is a common presentation in the paediatric patients due to insult to the brain due to infarction and damaging the neuronal cells. Seizures
This is a common presentation in the paediatric patients due to insult to the brain due to infarction and damaging the neuronal cells.
Involuntary movements This also a common presentation among paediatric patients. Involuntary movements
This also a common presentation among paediatric patients.
Cognitive dysfunction Atypical presentation of the disease.
This is usually a complication of the disease due to neuronal damage cause by ischaemia rather than the true association.
Cognitive dysfunction
Atypical presentation of the disease.
This is usually a complication of the disease due to neuronal damage cause by ischaemia rather than the true association.
Visual Disturbances and hemianopia Hemianopia commonly seen in adults due to involvement of occipital region of the brain . Also Bálint's syndrome: inability to perceive the visual field as a whole , making it difficulty in fixating the eye, and inability to move the hand to a specific object by using vision is a rare presentation of this disease. Visual Disturbances and hemianopia
Hemianopia commonly seen in adults due to involvement of occipital region of the brain . Also Bálint's syndrome: inability to perceive the visual field as a whole , making it difficulty in fixating the eye, and inability to move the hand to a specific object by using vision is a rare presentation of this disease.

Clinicals - Examination

Fact Explanation
Hemiplagic gait, reduced power on upper and lower limbs of contralateral side Moyamoya disease can cause ischemia from occlusion of the carotid vessels or hemorrhage of the vulnerable collateral vasculature. Ischemic stroke may cause contralateral meakness of the limbs depending on the area of brain involvement. Hemiplagic gait, reduced power on upper and lower limbs of contralateral side
Moyamoya disease can cause ischemia from occlusion of the carotid vessels or hemorrhage of the vulnerable collateral vasculature. Ischemic stroke may cause contralateral meakness of the limbs depending on the area of brain involvement.
Hemianopia and other visual disturbances Anterior, middle, and posterior cerebral artery territories are susceptible to infarction involving the frontal, parietal, and temporal lobes. Scintillating scotoma is a rare presentation of the disease causing visual disturbance. Hemianopia and other visual disturbances
Anterior, middle, and posterior cerebral artery territories are susceptible to infarction involving the frontal, parietal, and temporal lobes. Scintillating scotoma is a rare presentation of the disease causing visual disturbance.
Sensory defects Thrombotic changes, are the usual cause of ischaemic events. Presence of microaneurysms and increased blood flow through thin collateral walls during stress can be the cause for the of intracranial haemorrhages. Involvement of the parietal lobe by these lesions may cause sensory cortex impairment. Sensory defects
Thrombotic changes, are the usual cause of ischaemic events. Presence of microaneurysms and increased blood flow through thin collateral walls during stress can be the cause for the of intracranial haemorrhages. Involvement of the parietal lobe by these lesions may cause sensory cortex impairment.
Dysarthria, aphasia Speech problems are a common manifestation in moyamoya disease in both adults and children. Due to the involvement of the of the posterior circulation of the brain. Dysarthria, aphasia
Speech problems are a common manifestation in moyamoya disease in both adults and children. Due to the involvement of the of the posterior circulation of the brain.
Altered behaviour Disease causes stenosis and occlusions of large arteries of the anterior part of the Willis circle, and may involve the collateral vasculature. Altered behaviour
Disease causes stenosis and occlusions of large arteries of the anterior part of the Willis circle, and may involve the collateral vasculature.
Increased tone, exagerated reflexes and upgoing plantar response These signs indicate the spasticity of the limbs and is due to either haemorrhagic space occupying lesions or ischaemic lesions. Increased tone, exagerated reflexes and upgoing plantar response
These signs indicate the spasticity of the limbs and is due to either haemorrhagic space occupying lesions or ischaemic lesions.
Cognitive impairment Ischaemia may damage the neuronal cells causing impaired cognitive functions. Cognitive impairment
Ischaemia may damage the neuronal cells causing impaired cognitive functions.

Investigations - Diagnosis

Fact Explanation
Angiography Disease causes stenosis and occlusions of large arteries of the anterior part of the Willis circle, and may involve the collateral vasculature giving the appearance of ‘clouds of smoke’ or ‘puff of cigarette smoke’ on angiography.
Angiographic criteria of the diagnosis of moyamoya disease include stenosis or occlusion of the distal parts of intracranial internal carotid arteries and proximal parts of anterior and middle arteries, involvement of collateral vasculature in the regions of the brain base, without no other causative disease.
Bilaterality of the described findings is more common, but there can be unilateral cases as well. Magnetic resonance angiography (MRA) is usually followed by other conventional angiographic studies.
Angiography
Disease causes stenosis and occlusions of large arteries of the anterior part of the Willis circle, and may involve the collateral vasculature giving the appearance of ‘clouds of smoke’ or ‘puff of cigarette smoke’ on angiography.
Angiographic criteria of the diagnosis of moyamoya disease include stenosis or occlusion of the distal parts of intracranial internal carotid arteries and proximal parts of anterior and middle arteries, involvement of collateral vasculature in the regions of the brain base, without no other causative disease.
Bilaterality of the described findings is more common, but there can be unilateral cases as well. Magnetic resonance angiography (MRA) is usually followed by other conventional angiographic studies.
CT scan of the brain There can be ischaemic or haemorrhagic stroke in the course of the disease that will be evaluated by CT scan. Ischaemic areas may be present in basal ganglia and in the white matter in periventricularly and subcortically. CT scan of the brain
There can be ischaemic or haemorrhagic stroke in the course of the disease that will be evaluated by CT scan. Ischaemic areas may be present in basal ganglia and in the white matter in periventricularly and subcortically.
Magnetic Resonance Imaging Diagnosis is possible with MRI as it visualizes the FLAIR sequence is helpful to diagnose the ‘ivy sign’ which is an increase in signal intensity along the fissures and gyri of cerebral hemispheres,due to the reduction of the cortical flow Sensitivity of findings can be enhanced with diffusion techniques. Magnetic Resonance Imaging
Diagnosis is possible with MRI as it visualizes the FLAIR sequence is helpful to diagnose the ‘ivy sign’ which is an increase in signal intensity along the fissures and gyri of cerebral hemispheres,due to the reduction of the cortical flow Sensitivity of findings can be enhanced with diffusion techniques.

Investigations - Management

Fact Explanation
Perfusion imaging: CT perfusion, MRI and PET scan Perfusion examinations are helpful to evaluate the effectiveness of the procedure. It can also be used to improve haemodynamic parameters such as increasing cerebrovascular reserve and decreasing cerebral blood volume (CBV) and O2 extraction fraction (OEF). Perfusion imaging: CT perfusion, MRI and PET scan
Perfusion examinations are helpful to evaluate the effectiveness of the procedure. It can also be used to improve haemodynamic parameters such as increasing cerebrovascular reserve and decreasing cerebral blood volume (CBV) and O2 extraction fraction (OEF).
Thyroid function and thyroid autoantibody levels Elevated in some patients with moyamoya disease and is better to monitor during follow up. Moyamoya disease have autoimmune mechanisms of pathogenesis and may be associate dwith Graves disease. Thyroid function and thyroid autoantibody levels
Elevated in some patients with moyamoya disease and is better to monitor during follow up. Moyamoya disease have autoimmune mechanisms of pathogenesis and may be associate dwith Graves disease.
Perfusion imaging Surgical options for the moyamoya disease are direct anastomoses, indirect procedures, and combined therapies. Before any kind of procedure to be done it is important to evaluate the cerebrovascular reserve. This is done using CT perfusion, MRI or Positron Emmision Tomography. Perfusion imaging
Surgical options for the moyamoya disease are direct anastomoses, indirect procedures, and combined therapies. Before any kind of procedure to be done it is important to evaluate the cerebrovascular reserve. This is done using CT perfusion, MRI or Positron Emmision Tomography.
SPECT examination with acetazolamide test This is the test that assess the qualification for surgery and need to be done before the procedure. SPECT examination with acetazolamide test
This is the test that assess the qualification for surgery and need to be done before the procedure.
Full blood count As a routine test before surgery to identify aneamia, as it should be corrected prior to surgery. Full blood count
As a routine test before surgery to identify aneamia, as it should be corrected prior to surgery.
Prothrombin time and International normalized ratio To detect any bleeding diathesis before surgery. Prothrombin time and International normalized ratio
To detect any bleeding diathesis before surgery.
Electrocardiogram and electrocardiogram Indicated prior to surgery particularly in patients who have a high risk for the cardiovascular morbidities. Electrocardiogram and electrocardiogram
Indicated prior to surgery particularly in patients who have a high risk for the cardiovascular morbidities.
Serum electrolytes and Creatinine These are particularly important in patients with co-morbities like diabetes mellitus or hypertension. Serum electrolytes and Creatinine
These are particularly important in patients with co-morbities like diabetes mellitus or hypertension.
Random blood sugar If patient is diabetic, blood sugar should be repeated on the day of surgery. Random blood sugar
If patient is diabetic, blood sugar should be repeated on the day of surgery.
Angiography The Suzuki grading system divides the moyamoya disease into 6 degrees according to the severity of vascular changes in angiography. First degree is only stenosis of the carotid artery, second and third degree, the collateral vasculature of moyamoya type develops and in the fourth and fifth degree, vessels start to disappear, sixth degree where they totaly invisible. Angiography
The Suzuki grading system divides the moyamoya disease into 6 degrees according to the severity of vascular changes in angiography. First degree is only stenosis of the carotid artery, second and third degree, the collateral vasculature of moyamoya type develops and in the fourth and fifth degree, vessels start to disappear, sixth degree where they totaly invisible.
CT scan of the brain CT scan can be used to visualize the complications of the disease such as haemorrhagic and ischaemic stroke, intracranial haemorrhages and brain atrophy. Thrombotic changes, are the usual cause of ischaemic symptoms. Presence of microaneurysms and increased blood flow through thin collateral walls during stress can be the cause for the of intracranial haemorrhages. CT scan of the brain
CT scan can be used to visualize the complications of the disease such as haemorrhagic and ischaemic stroke, intracranial haemorrhages and brain atrophy. Thrombotic changes, are the usual cause of ischaemic symptoms. Presence of microaneurysms and increased blood flow through thin collateral walls during stress can be the cause for the of intracranial haemorrhages.
Magnetic Resonance Imaging The MRI will also demonstrate the late sequelae of the previous strokes like brain atrophy and widening of the ventricular system and of the pericerebral fluid spaces. Magnetic Resonance Imaging
The MRI will also demonstrate the late sequelae of the previous strokes like brain atrophy and widening of the ventricular system and of the pericerebral fluid spaces.
Levels of protein C, protein S, antithrombin III, homocysteine and factor V Leiden Moyamoya disease is known to cause ischemic, if any stroke that treated with antiplatelet agents or anticoagulants is not responding to therapy,moyamoya disease has to be considered. Evaluation the other risk factors for the ischaemic stroke is also important in these situations. Levels of protein C, protein S, antithrombin III, homocysteine and factor V Leiden
Moyamoya disease is known to cause ischemic, if any stroke that treated with antiplatelet agents or anticoagulants is not responding to therapy,moyamoya disease has to be considered. Evaluation the other risk factors for the ischaemic stroke is also important in these situations.

Management - Supportive

Fact Explanation
Patient education Patient should be educated on the nature of the disease as a chronic occlusive vasculopathy of unknown etiology, complications, treatment options and side effects of the treatments. Its course is typically indolent but may be progressive. Proper counselling about the complications of the surgery is required. Patient education
Patient should be educated on the nature of the disease as a chronic occlusive vasculopathy of unknown etiology, complications, treatment options and side effects of the treatments. Its course is typically indolent but may be progressive. Proper counselling about the complications of the surgery is required.
Management of co-morbidities If intracerebral hemorrhage is occurred, hypertension management becomes more important. They need specific management. Intensive treatment including hypervolemia, hemodilution, keeping moderate hypertension and administration of a free radical scavenger without hyperosmotic agents are useful as hypotension and dehydration can cause lethal consequences in moyamoya disease. Management of co-morbidities
If intracerebral hemorrhage is occurred, hypertension management becomes more important. They need specific management. Intensive treatment including hypervolemia, hemodilution, keeping moderate hypertension and administration of a free radical scavenger without hyperosmotic agents are useful as hypotension and dehydration can cause lethal consequences in moyamoya disease.
Management of complications Intracranial haemorrhages, ischemic stroke and haemorrhagic stroke are the complications of the disease. Management of complications
Intracranial haemorrhages, ischemic stroke and haemorrhagic stroke are the complications of the disease.
Follow up Progression of clinical findings, improvement of neurological disability and compliance to pharmacological and non pharmacological treatment are needed to be assessed. Perfusion studies are helpful in follow up. Follow up
Progression of clinical findings, improvement of neurological disability and compliance to pharmacological and non pharmacological treatment are needed to be assessed. Perfusion studies are helpful in follow up.

Management - Specific

Fact Explanation
Conservative management If the symptoms are mild, it can be treated with conservative measures. This can be applied even in the acute stage of severe disease with the plan of revascularization. Therapies hypervolemia, hemodilution, keeping moderate hypertension and administration of a free radical scavenger may be useful in patients with moyamoya disease. Central venous pressure (CVP) and intracranial pressure (ICP) needs to be monitored in order to make sure that the cerebral perfusion and hydration is adequate. Conservative management
If the symptoms are mild, it can be treated with conservative measures. This can be applied even in the acute stage of severe disease with the plan of revascularization. Therapies hypervolemia, hemodilution, keeping moderate hypertension and administration of a free radical scavenger may be useful in patients with moyamoya disease. Central venous pressure (CVP) and intracranial pressure (ICP) needs to be monitored in order to make sure that the cerebral perfusion and hydration is adequate.
Surgery Severe cases need surgical management. Surgery includes direct anastomoses, indirect procedures, and combined therapies. Surgical management is indicated in patients who present with infarction or cerebral hemorrhage found to be in good neurological condition, infarctions are less than 2 cm in maximal diameter on CT scan all previous hemorrhages have completely resolved, angiographic stage of disease is stage II to IV and the timing of operation is at least 2 months after the most recent attack. Surgery
Severe cases need surgical management. Surgery includes direct anastomoses, indirect procedures, and combined therapies. Surgical management is indicated in patients who present with infarction or cerebral hemorrhage found to be in good neurological condition, infarctions are less than 2 cm in maximal diameter on CT scan all previous hemorrhages have completely resolved, angiographic stage of disease is stage II to IV and the timing of operation is at least 2 months after the most recent attack.
Direct anastomoses Direct anastomoses are done between the superficial temporal artery and the middle cerebral artery (STA-MCA). Advantage of this is provision of an immediate increase in cerebral blood flow. Direct anastomoses
Direct anastomoses are done between the superficial temporal artery and the middle cerebral artery (STA-MCA). Advantage of this is provision of an immediate increase in cerebral blood flow.
Indirect anastomoses Placement of vascularised tissue in the brain cortex, to promote neoangiogenesis is an indirect procedures: synangiosis. Eg:- pencephaloduroarteriosynangiosis using dura matter, encephaloduroarteriomyosynangiosis using muscle tissue. Encephaloduroarteriosynangiosis (EDAS) is a procedure that creates an artificial connection between the superficial temporal artery and the surface of the brain through burr holes. Major disadvantage of indirect revascularization is the inherent delay in collateralization. Indirect techniques are advantageous than direct techniques in certain situations. Eg:-bypass is not technically feasible in children due to the small caliber of both the external carotid artery distal branches and the intracranial arterial trunks and difficulty in assessing the hypoperfusion in anterior and posterior cerebral artery regions via a direct arterial bypass in adults. Indirect anastomoses
Placement of vascularised tissue in the brain cortex, to promote neoangiogenesis is an indirect procedures: synangiosis. Eg:- pencephaloduroarteriosynangiosis using dura matter, encephaloduroarteriomyosynangiosis using muscle tissue. Encephaloduroarteriosynangiosis (EDAS) is a procedure that creates an artificial connection between the superficial temporal artery and the surface of the brain through burr holes. Major disadvantage of indirect revascularization is the inherent delay in collateralization. Indirect techniques are advantageous than direct techniques in certain situations. Eg:-bypass is not technically feasible in children due to the small caliber of both the external carotid artery distal branches and the intracranial arterial trunks and difficulty in assessing the hypoperfusion in anterior and posterior cerebral artery regions via a direct arterial bypass in adults.
Combined techniques of surgery Direct and indirect revascularization techniques can be combined to give a better outcome. Combined therapies are practiced as this procedures eliminate the risk of recurrence of ischaemic incidents. Combined techniques have the advantage of the immediate revascularization provided by direct arterial bypass, and maximize the eventual cerebral revascularization to regions outsidethe particular arterial distribution. Combined techniques of surgery
Direct and indirect revascularization techniques can be combined to give a better outcome. Combined therapies are practiced as this procedures eliminate the risk of recurrence of ischaemic incidents. Combined techniques have the advantage of the immediate revascularization provided by direct arterial bypass, and maximize the eventual cerebral revascularization to regions outsidethe particular arterial distribution.
Antiplatelet and anticoagulative therapy There is a risk of getting further ischaemic strokes if the stenosis progreses. Therefore anticoagulation and antiplatelet agents are used for the prevention of further strokes. Daily dose of aspirin may be helpful. Antiplatelet and anticoagulative therapy
There is a risk of getting further ischaemic strokes if the stenosis progreses. Therefore anticoagulation and antiplatelet agents are used for the prevention of further strokes. Daily dose of aspirin may be helpful.
Antihypertensives Maintaining a constant low blood pressure is done by using antihypertensives, calcium channel blockers. Antihypertensives
Maintaining a constant low blood pressure is done by using antihypertensives, calcium channel blockers.

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