Now, ‘Intracranial’ literally means ‘within the skull’ while hypertension refers to high fluid pressure. Therefore, intracranial hypertension (IH) is a condition produced when CSF pressure within the skull rises beyond acceptable limits.
What Is Intracranial Hypertension ( IH )?
The human skull provides a finite space to the components contained within it. Therefore, the three components i.e. the brain, CSF and blood supply have to maintain a delicate balance among them. If one component fails to do so, then it will affect the functioning of the other two.
Typically, 400-500ml of CSF is produced, circulated and absorbed into the system every day. If for some reason, this fluid cannot be drained out effectively, then it will automatically result in intracranial pressurization. Since the skull is solid and cannot grow to accommodate the change, the increased intracranial pressure is felt by the brain and connecting blood supply components. Medically, the CSF pressure has to be 250mmH20 or more to be defined as intracranial hypertension.
Intracranial hypertension may be divided into two primary categories – acute IH and chronic IH. Often times, severe head injuries, strokes or even bleeding within the scull due to aneurysm lead to chronic IH.
On the other hand, chronic IH is considered as a neurological disorder where the cerebrospinal fluid pressure rises and then remains in the elevated state for a long period of time. If the reason for the CSF rise is undetectable, then it is called idiopathic IH. And if the intracranial pressure rise can be connected to an instigating element such as a disease, injury, blood clot in the brain or medication, then the condition is termed as secondary IH.
Chronic intracranial hypertension tends to affect overweight women who are of childbearing age. While the reasons for this are still unclear, it is seen that when such women decrease their weight, the symptoms of IH also recede. However, chronic IH especially secondary IH can be developed by just about anybody irrespective of their gender, ethnicity, race, age or body type.
Symptoms Of Intracranial Hypertension
The primary consequences of chronic IH include vision symptoms, headache and pulse-synchronous Tinnitus. Let’s look at them more closely:
Vision Symptoms: Normally, grey spots begin to appear briefly in front of the eyes owing to elevated intracranial pressure. Yet, other patients may complain of blurred or double visions, temporary loss of vision in one or both eyes and/or total blindness.
Headache: Seen in almost 90% of IH cases, the headaches are quite unbearable and even migraine, or general pain relieving medications prove insufficient in such cases. However, these headaches, while severe like those felt when suffering from migraine, are either be accompanied by visual symptoms or a whooshing sound felt in the ears (pulse-synchronous tinnitus).
Pulse-Synchronous Tinnitus: It is defined as a characteristic noise heard in one or both ears. This noise can be of a whistling, whooshing, marching or humming nature further characterized by a cycle of highs and lows that matches with your pulse.
Diagnosis And Treatment Of IH
Apart from brain scans, doctors depend on a diagnostic technique called spinal tap to measure the pressure of the CSF circulating within the brain and the spinal cord. A high initial pressure reading confirms IH.
Depending on the severity of the condition, a doctor may either prescribe special medications or surgery. Medications include the likes of carbonic anhydrase inhibitors, which are prescribed in high doses.
Conversely, surgery can be of two types; one where the optical nerve sheath is given a small opening to relax the swelling and the other where tubes are inserted and connected to the abdomen to drain the excess CSF.