What causes benign enlargement of the subarachnoid space?
The causes of a large head include hydrocephalus (an excess volume of CSF intracranially), megalencephaly (enlargement of the brain), thickening of the skull and hemorrhage or non-bloody fluid into the subdural or epidural spaces (1, 2).
What is bessi?
Benign enlargement of the subarachnoid spaces in infancy (BESS or BESSI) also known as benign external hydrocephalus (BEH) is, as per the name, a benign enlargement of the subarachnoid spaces in infants.
What is mild prominence of the subarachnoid spaces?
MRI usually reveals normal or mild prominence of all the ventricles (mild communicating hydrocephalus) with enlarged, usually symmetric, subarachnoid spaces along the anterior aspect of the brain. The sub-arachnoid spaces along the posterior aspect of the brain are usually normal.
What causes benign external hydrocephalus?
As most reported cases of external hydrocephalus seem to be idiopathic, various theories regarding the underlying pathophysiology have been presented. The most common theory suggests that external hydrocephalus is caused by immature arachnoid villi not able to absorb the CSF that is produced continuously .
What is benign Macrocrania?
Benign Macrocrania of Infancy (BMI) is a clinical entity of relative frequency in the first years of life. While usually self-limited, it may lead to clinical complications that go beyond an increased head circumference, such as a higher incidence of sudural hematomas resulting from incidental, low-energy head trauma.
What is the purpose of subarachnoid space?
The structural components of the subarachnoid space, such as the arachnoid trabeculae, also function to provide support and stabilization to the brain and spinal cord. The subarachnoid space also provides an expanse for important neurovascular structures to pass through as they supply the brain and spinal cord.
Why is the subarachnoid space important?
The subarachnoid space is the cerebrospinal fluid-filled space that exists between the arachnoid and the pia. The primary functions of the CSF are to cushion the brain and spinal cord from trauma and to supply them with nutrients and remove waste.
What does Macrocephaly mean?
Macrocephaly (or “big head”) is a very common reason for referral to a pediatric neurosurgeon. Children with macrocephaly have a head circumference (the measurement around the widest part of the head) that is greater than the 98th percentile.
What is the significance of the subarachnoid space?
Subarachnoid Space The primary functions of the CSF are to cushion the brain and spinal cord from trauma and to supply them with nutrients and remove waste. In addition to the CSF, the major arteries of the brain run through the subarachnoid space.
What is the content of subarachnoid space what is the clinical importance of this space?
Can a subdural effusion be a hygroma?
SHMs usually resolve spontaneously but a number of these may become a hygroma, a type of external hydrocephalus and precursor of chronic subdural hematoma (CSHM) . Subdural fluid collections (SFCs) may be either a hygroma (i.e. CSF accumulation communicating freely with the subarachnoid space-SAS) , or an effusion.
What causes CSF to enter the subdural space?
The most commonly encountered explanation is a tear in the arachnoid layer forming a ball-valve opening allowing CSF one way passage into the subdural space. Although this explanation has the benefit of simplicity, it does not necessarily represent a true description of the underlying mechanisms.
Is there subdural space in the human brain?
The subdural space does not exist under normal circumstances and is appreciable only when there is underlying pathology 2. Bridging veins drain from the underlying brain to the dura mater and the superior sagittal sinus. They have a relatively straight course and do not allow for much movement of the underlying brain tissue.
What kind of fluid is in a subdural effusion?
Subdural effusions (SEs) contain xanthochromic fluid due to extravasation of plasma from these capillaries . SEs usually resolve spontaneously and only a small percentage may evolve into CSHM .