Intracranial Dolichoectasias
Encyclopedia
The term dolichoectasia means elongation and distension. It is used to characterize arteries throughout the human body which have shown significant deterioration of their tunica intima
(and occasionally the tunica media), weakening the vessel walls and causing the artery to elongate and distend.
, continued stress on the walls of the artery will degrade the vessel wall by damaging and loosening the collagen and elastin meshwork which comprises the intima. Similarly, hypercholesterolemia or hyperlipidemia can also provide sufficient trauma to the vessel wall resulting in dolichoectasia. As the arrangement of connective tissue is disturbed, the vessel wall is no longer able to hold its original conformation and begins to unravel due to the continued hypertension. High blood pressure mold and force the artery to now take on an elongated, tortuous course to better withstand the higher pressures.
(Vertebral Basilar Dolichoectasia or Vertebrobasillar Dolichoectasia). The Internal Carotid Artery is also at high risk to be affected. Patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD)
are more likely to be subject to dolichoectasias. Dolichoectasias are most common in elderly females.
In cases involving the Basilar Artery (VBD), the pathogenesis arises from direct compression of different cranial nerves.
Additionally, ischemic effects on the brain stem and cerebellar hemispheres as well as symptoms related to hydrocephalus are common. Direct cranial nerve compression can lead to isolated cranial nerve dysfunction, usually associated with a normal-sized basilar artery that is tortuous and elongated. Cranial nerve dysfunction most commonly involves the VII cranial nerve and the V cranial nerve. Multiple cranial nerve dysfunction is far more likely to occur if there is dilation (ectasia) associated with a tortuous and elongated basilar artery. Cranial nerves affected in descending order of frequency include: VII, V, III, VIII, and VI.
Internal Carotid Artery dolichoectasia is particularly interesting because the artery normally already contains one hairpin turn. Seen in an MRI as two individual arteries at this hairpin, a carotid artery dolichoectasia can progress so far as to produce a second hairpin turn and appear as three individual arteries on an MRI. In the case of a dolichoectasia of the Internal Carotid Artery (ICD), the pathogenesis is primarily related to compression of the Optic Nerves at the Optic Chiasma (see Fig. 1 and 2).
ICD
Tunica intima
The tunica intima is the innermost layer of an artery or vein. It is made up of one layer of endothelial cells and is supported by an internal elastic lamina...
(and occasionally the tunica media), weakening the vessel walls and causing the artery to elongate and distend.
Etiology
Most commonly caused by hypertensionHypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
, continued stress on the walls of the artery will degrade the vessel wall by damaging and loosening the collagen and elastin meshwork which comprises the intima. Similarly, hypercholesterolemia or hyperlipidemia can also provide sufficient trauma to the vessel wall resulting in dolichoectasia. As the arrangement of connective tissue is disturbed, the vessel wall is no longer able to hold its original conformation and begins to unravel due to the continued hypertension. High blood pressure mold and force the artery to now take on an elongated, tortuous course to better withstand the higher pressures.
Pathophysiology
Most commonly affected is the Vertebral Basilar ArteryBasilar artery
In human anatomy, the basilar artery is one of the arteries that supplies the brain with oxygen-rich blood.The two vertebral arteries and the basilar artery are sometimes together called the vertebrobasilar system, which supplies blood to the posterior part of circle of Willis and anastomoses with...
(Vertebral Basilar Dolichoectasia or Vertebrobasillar Dolichoectasia). The Internal Carotid Artery is also at high risk to be affected. Patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD)
Polycystic kidney disease
Autosomal dominant polycystic kidney disease is an inherited systemic disorder that predominantly affects the kidneys, but may affect other organs including the liver, pancreas, brain, and arterial blood vessels...
are more likely to be subject to dolichoectasias. Dolichoectasias are most common in elderly females.
In cases involving the Basilar Artery (VBD), the pathogenesis arises from direct compression of different cranial nerves.
Internal Carotid Artery dolichoectasia is particularly interesting because the artery normally already contains one hairpin turn. Seen in an MRI as two individual arteries at this hairpin, a carotid artery dolichoectasia can progress so far as to produce a second hairpin turn and appear as three individual arteries on an MRI. In the case of a dolichoectasia of the Internal Carotid Artery (ICD), the pathogenesis is primarily related to compression of the Optic Nerves at the Optic Chiasma (see Fig. 1 and 2).
Signs and Symptoms
VBD- Hemifacial SpasmHemifacial spasmHemifacial spasm or HFS is a neurological disorder in which blood vessels constrict the seventh cranial nerve and cause varying degrees of facial spasm, typically originating around the eye of the afflicted side of the face...
- ParesisParesisParesis is a condition typified by partial loss of voluntary movement or by impaired movement. When used without qualifiers, it usually refers to the limbs, but it also can be used to describe the muscles of the eyes , the stomach , and also the vocal cords...
- Trigeminal neuralgiaTrigeminal neuralgiaTrigeminal neuralgia , tic douloureux is a neuropathic disorder characterized by episodes of intense pain in the face, originating from the trigeminal nerve. It has been described as among the most painful conditions known...
ICD
- Progressive Visual Field Defect
Treatment
A combination of lifestyle modifications and medications can be used for the treatment of dolichoectasias.- Antihypertensive medications such as Thiazides, Beta BlockerBeta blockerBeta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
, ACE InhibitorACE inhibitorACE inhibitors or angiotensin-converting enzyme inhibitors are a group of drugs used primarily for the treatment of hypertension and congestive heart failure... - Trental or other Pentoxifylline drugs
- Dietary changes
- Weight loss
- Regular exercise