neuro quick fire Flashcards
What is intracranial pressure (ICP)?
ICP is important as it affects cerebral perfusion pressure and cerebral blood flow. Normal ICP is between 5 and 13 mmHg.
What are the constituents within the skull?
- Brain (80%/1400 ml)
- Blood (10%/150 ml)
- Cerebrospinal fluid (CSF 10%/150 ml)
What is the Monro-Kellie hypothesis?
If one of the three components in the skull increases in volume, there must be compensation by a decrease in the volume of one or more of the remaining components to prevent increased ICP.
What is primary brain injury?
Primary brain injury occurs at the time of the head injury and is unavoidable except through preventative measures.
What causes secondary brain injury?
Secondary brain injury is caused by:
* Reduction in oxygen delivery due to hypoxaemia or anaemia
* Reduction in cerebral blood flow due to hypotension or reduced cardiac output
* Factors causing raised ICP and reduced CPP.
What are the initial management needs for brain injury?
- Airway and cervical spine protection
- Ventilation and adequate oxygenation
- Adequate blood pressure and cerebral perfusion pressure (CPP).
What are the techniques to reduce intracranial pressure (ICP)?
- Reduce brain tissue volume
- Reduce blood volume
- Reduce CSF volume.
What techniques can be employed to reduce brain tissue volume?
- Tumour resection or abscess removal
- Steroids (especially dexamethasone) to reduce cerebral oedema
- Mannitol/furosemide or hypertonic saline to reduce intracellular volume
- Decompressive craniectomy to increase intracranial volume.
What techniques can be employed to reduce blood volume?
- Evacuation of haematomas
- Barbiturate coma to reduce cerebral metabolic rate and oxygen consumption
- Avoiding hypoxaemia, hypercarbia, hyperthermia, and vasodilatory drugs
- Patient positioning with 30° head up, avoiding neck compression, PEEP, and airway obstruction.
What techniques can be employed to reduce CSF volume?
- Insertion of external ventricular drain
- Ventriculoperitoneal shunt.
True or False: Secondary brain injury is preventable through appropriate management.
True
Fill in the blank: Normal ICP is between _______.
5 and 13 mmHg
effect of volatiles and sux on ICP
Effects of thiopentone on IVP
effects of urea on ICP
volatiles and sux can cause a small rise in ICP
thiopentone causes cerebral vasoconstriction which reduces cerebral blood flow and therefore reduces ICP
thiopentone also reduces cerebral metabolic oxygen requirement which can reduce ICP
urea is an osmotic diuretic which can reduce cerebral oedema and therefore reduce ICP
anticonvulsants like carbamazapine have beneficial effects on IC{ by terminating seizures, but have no intrinsic ICP reducing effects
what are the symptoms of anterior spinal artery infarct and why
loss of motor function below level of infarct due to disruption in corticospinal tract. Also loss of pain, and temp sensation
-proprioception and vibration are maintained as these are the dorsal side of spinal column
symptoms of central cord syndrome at c7
greater loss of motor function to upper limbs than lower limbs, with variable sensory sparing because lower limb supply is more peripheral.
Also get dysfunction of bladder and bowels which are supplied more centrally/
sacral tracts are positioned more peripherally and usually spared from injury
This injury is more associated with hyperextension in middle age, and cervical spondylosis and extension in elderly
tell me about artery of Adamkiewicz occlusion
SPARES PROPRICEPTION & VIBRATION
The largest anterior medullary artery, the great anterior medullary artery of Adamkiewicz, which is susceptible to occlusion with neurologic deficit, is located at the lumbar enlargement, usually at L2 on the left side (but may be at any point from T8 to L2).
The Artery of Adamkiewicz (also called the great anterior radiculomedullary artery) is the major blood supply to the lower spinal cord, typically arising from T9–L2. Its occlusion can lead to anterior spinal artery syndrome, causing spinal cord ischemia.
Key Symptoms:
Acute Onset Paraplegia/Paraparesis (Bilateral Weakness)
Sudden weakness or paralysis of both legs.
Reflexes may be absent initially (spinal shock), then become hyperreflexic later.
Loss of Pain & Temperature Sensation (Spinothalamic Tract Dysfunction)
Bilateral loss below the level of injury.
Touch, vibration, and proprioception remain intact (posterior columns spared).
Bladder & Bowel Dysfunction
Urinary retention or incontinence.
Loss of voluntary control over bowel movements.
Sexual Dysfunction
Erectile dysfunction due to autonomic involvement.
“Watershed” Infarction Pattern
Often affects the mid-thoracic region (T8–L1), where blood supply is most vulnerable.
what is brown-sequard syndrome?
“MVP on the SAME side, Pain & Temp on the OPPOSITE side”
M = Motor loss (ipsilateral).
V = Vibration & proprioception loss (ipsilateral).
P = Pain & temperature loss (contralateral).
Brown-Sequard syndrome is a hemicord lesion resulting in assymetrical neuro deficits due to damage to both sensory and motor pathways on one side.
-ipsilateral upper motor neurone paralysis and loss of proprioception & vibration
-contralateral loss of pain and temperature sensation.
Causes include trauma, neoplasm and multiple sclerosis.
what level does spinal cord terminate in adults and children?
At birth, the spinal cord extends lower (L2–L3).
With growth, the vertebral column elongates more than the spinal cord, pulling the termination level higher (L1–L2 in adults).
Clinical Relevance
✅ Lumbar Puncture Site:
Adults: L3–L4 or L4–L5 (to avoid spinal cord injury).
Children: L4–L5 or L5–S1 (as the cord terminates lower).
