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Open Collection of Student Writing (OCSW)

Blood Pathology Report

Internal Carotid Agenesis is when one or both of the blood vessels that supply blood to the brain do not develop. The carotid artery can be missing from either side of the body. Agenesis of the ICA is a developmental anomaly that occurs before the 24-mm stage of embryonic growth. Agenesis of the internal carotid artery (ICA) is defined as a congenital absence of the carotid canal and occurs in less than 0.01% of the population. The absence of an ICA was first described in 1787 after being discovered during a postmortem examination. This developmental defect may be asymptomatic, or it can also lead to cerebrovascular lesions. Some of the symptoms include headaches, blurred vision, paralysis of some of the nerves in the head, recurrent seizures, or muscle weakness on one side of the body. When these symptoms are present it may be a result from compression of the brain by vessels that dilate to compensate for the absence of the ICA or the presence of an aneurysm. The term agenesis is used when both the ICA and its bony canal are absent. Some of the most frequent signs and symptoms are cerebral ischemia (present in 30% to 79%% of cases), dilation of the cerebral artery (present in 30% to 79% of cases), and subarachnoid hemorrhage (present in 30% to 79% of cases). Some of the more occasional signs and symptoms include headaches (present in 5% to 29% of cases) and arachnoid cyst (present in 5% to 29% of cases). The risk of someone with internal carotid agenesis to develop a brain aneurysm is estimated at 24% to 34%. Being as this can be asymptomatic at times, it is typically diagnosed by accident. It is usually diagnosed using specific imaging tests. These tests may include angiography, computerized tomography scanning (CT scan), magnetic resonance imaging (MRI), and sometimes a magnetic resonance angiogram (MRA). With these tests you are avaible to visualize the blood vessels and the surrounding bones. Considering how there are times when symptoms are not present, then there is no need for treatment. There are some cases where surgery would be an option due to the blood being rerouted through other smaller blood vessels to supply blood to the brain because those blood vessels may develop problems due to the extra blood flow. The long-term outlook for those who are affected by internal carotid agenesis is typically good. If it is associated with other syndromes or diseases, then the outlook depends on what those syndromes or diseases would be. One thing that is important for those people who have internal carotid agenesis is for them to let their doctors or surgeons about their diagnoses because they are more likely to suffer from complications during certain types of surgeries. This malformation is not known to run in families due to finding that mutations in a specific gene have not been associated with internal carotid agenesis. It is possible for the malformation to ne inherited or passed on to future generations if internal carotid agenesis is a sign of another disease or syndrome. For those who suffer from internal carotid agenesis it is recommended to have frequent screenings for aneurysms due to them being in greater risk of having an aneurysm. Having internal carotid agenesis is malformation that will not affect the way you do things, nor will it be a barrier for you to do certain things. There are many cases where people go undiagnosed with malformation until they go to the doctors for a different health concern and that is when they find out about their diagnoses. Although this condition is rare and may seem like it is something that should not be concerning sue to it being asymptomatic at times it should be taken seriously because it does make you have a greater chance of getting an aneurysm.

Brain scan image, two scans side by side

When I first began to research this malformation, I thought it would be something that was common, and it just went undiagnosed. I also thought that it would be something that was not be worried about seeing that the people who suffered from this rare case could have it, yet they would have no symptoms of it. Now after learning more about this I have learned that just because it can be asymptomatic for some it is still dangerous. Also, the symptoms like a headache or dizziness are things that happen so often that when they do occur people tend to brush them off thinking its just something minimal and it will go away. I thought it was really interesting how there where cases where people would go in to get a headache, blurred vison, and many other small things like that and find out that they had this malformation. After learning more about internal carotid agenesis, I think that this is a malformation that should be studied more closely because of the high risk that people are to having an aneurysm. I also think that it would be helpful to know what diseases and syndromes this could be a sign of.

Work Cited

Dinç, Hasan, et al. “Agenesis of the Internal Carotid Artery Associated with Aortic Arch Anomaly in a Patient with Congenital Horner’s Syndrome.” American Journal of Neuroradiology, American Journal of Neuroradiology, 1 June 2002,

Oliveira, Giuliano da Paz, et al. “Bilateral internal carotid artery agenesis: a case report.” Jornal Vascular Brasileiro, Sociedade Brasileira de Angiologia e de Cirurgia Vascular,

Okawa, Masakazu, et al. “Left internal carotid artery agenesis with trans-Sellar collateral and a right aortic arch: Case report.” Interventional Neuroradiology, SAGE Publications, Dec. 2015,;year=2015;volume=5;issue=1;spage=7;epage=7;aulast=Kumaresh





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