Head Injuries and Intracranial Pressure Flashcards
(51 cards)
What is the rigid structure that contains non-compressible components in the head?
The skull
What are the three components that maintain intracranial pressure (ICP)?
- The Brain
- Cerebrospinal fluid
- Blood
What is the normal range for intracranial pressure (ICP)?
5 - 15 mmHg.
What is considered an abnormal ICP level that requires treatment?
Greater than 20 mmHg
What can cause transient rises in intracranial pressure?
Activities such as coughing, sneezing etc.
What happens to the volume of the components maintaining ICP if there is an alteration in one of them?
An alteration in the volume of any one of the components will result in changes in the other two components to maintain ICP.
What is the physiological significance of maintaining a uniform intracranial pressure?
Crucial for protecting the brain ensuring adequate blood flow and fostering normal neurological function.
How does the body respond to an increase in volume of one of the components of ICP?
The body responds to an increase in the volume of one of the components by decreasing the volume of the other two components to keep the ICP within a normal range.
What can cause raised intracranial pressure (ICP)?
- Brain tumours
- Haematomas
- Increases in cerebral blood flow due to hypercapnia or hypoxia
- Increased production of cerebrospinal fluid
- Decreased absorption of CSF
- Blockages in the CSF pathways.
What is cerebral perfusion pressure (CPP)?
A critical measure that indicates the adequacy of blood flow to the brain.
How is CPP calculated?
Mean arterial pressure (MAP) minus the intracranial pressure (ICP)
What is the normal range for cerebral perfusion pressure (CPP)?
70 - 100 mmHg.
What may happen to CPP following a head injury?
Can fall below 60 mmHg which indicates inadequate blood flow to the brain and can lead to further brain injury.
What are common signs and symptoms of raised ICP?
- Headache
- Nausea and vomiting
- Visual disturbances
- Alterations in pupil reaction and size
- Depressed consciousness
- Late signs include hypertension bradycardia and respiratory irregularities.
What is the difference between primary and secondary traumatic brain injury?
Primary traumatic brain injury occurs at the moment of impact and is considered irreversible. Secondary traumatic brain injury occurs after the initial injury and is a result of processes related to the initial injury; it may be prevented or reduced.
What is hypercapnia and how does it affect cerebral blood flow?
Hypercapnia is a condition characterized by an increase in carbon dioxide (CO2) levels in the blood. It can cause increases in cerebral blood flow which may contribute to raised ICP.
What is hypoxia and its effect on cerebral blood flow?
Hypoxia is a deficiency in the amount of oxygen reaching tissues. It can lead to increased cerebral blood flow which can be one of the factors causing raised intracranial pressure.
How does increased production of cerebrospinal fluid (CSF) lead to raised ICP?
By adding volume within the cranial cavity leading to pressure increases against intracranial structures.
What role does decreased absorption of CSF play in raised ICP?
Can result in an accumulation of CSF within the cranial cavity contributing to increases in intracranial pressure.
What are potential late signs of raised ICP to be aware of?
- Hypertension
- Bradycardia
- Irregular respiratory patterns.
What is the primary goal of management in traumatic brain injury (TBI)?
To prevent secondary injury to the brain.
What are the different types of head injury?
- Concussion
- Contusion
- Extradural haemorrhage
- Subdural haemorrhage
- Intracerebral haemorrhage
What is an extradural haematoma?
A collection of blood that occurs in the ‘potential’ space between the skull and the outer protective lining covering the brain known as the dura mater.
What is a subdural haematoma (SDH)?
A type of bleeding where a collection of blood gathers between the inner layer of the dura mater and the arachnoid mater of the meninges surrounding the brain. It typically results from tears in bridging veins that cross the subdural space.