General NSx Flashcards
What examination findings are consistent with cauda equina?
- Saddle anaesthesia (S2-4)
- Urinary retention
- Faecal incontinence/lack of anal tone on exam
- Bilateral lower limb weakness
- Bilateral paraesthesia
- LL hyporeflexia
- Absent bulbocavernosus reflex
What should you document/look for with a spinal cord injury exam?
Motor weakness level
Sensory loss types and level
Evidence of sacral sparing (bulbocavernosus reflex, anal tone and sensation)
Signs of spinal shock (areflexia, priapism)
When does a Hangmans fracture actually occur with Hangings?
If the drop is greater than the persons height and the knot is put in front of the chin
How does the SAH Fisher grading scale work?
The most well known and used system, purely radiological and also used to predict risk of vasospasm
Grade I - No SAH visualised (but still present), vasospasm risk 21%
Grade II - thin <1mm SAH with no clots, risk 25%
Grade III - Localised clots and/or thicker SAH >1mm, risk 37%
Grade IV - IVH or ICH present, risk 31%
How does the SAH WFNS (World federation of neurological societies) grading scale work?
The most well known clinical based scale
Grade I - GCS 15, no motor deficit
Grade II - 13-14, no motor deficit
Grade III - 13-14, motor deficit
Grade IV - 7-12
Grade V - 3-6
What are the main complications with VP shunts?
Obstruction
- 75%
- Kinking, disconnection, migration
- Valve defect
- Clogging from debris
Infection
- 15%
- S. epidermidis most common
- Also S. aures, E. coli, Corynbacterium
Overdrainage
- 5%
- Slit ventricle, low ICP
Intracranial bleed
- Local irritation
- Most common is SDH
Abdominal issues
- Bowel perforation
- Migration into other structures including the pelvis/scrotum
What is the mortality and morbidity of haemorrhagic stroke?
- 30% of patients die
- rises to 80% if warfarinised
- Most deaths occur in the first 48hrs
- The likeliness of discharge to home is 33%
- Only 30% of patients survive the 1st year
Which ICH’s are amenable to surgery?
- Cerebellar haemorrhages >3cm
- Haemorrhages within 1cm of the cerebral surface, but not commonly done
- If >1cm from the cerebral surface then tend to do worse from surgery
- IVH is associated with much higher rates of mortality from obstructive hydrocephalus
What are the risk factors for ICH?
- Excess ETOH
- HTN (specifically DBP >95mmHg)
- Men 2:1 women
- 10-15% of all strokes
- More common in Asians
What are the risk factors for SAH?
- Previous SAH (biggest risk)
- PCKD
- Smoking (3-10x)
- HTN
- 1st or 2nd degree relative (4x)
- Being female
- Amphetamine use
- Connective tissue disorders ie Marfans, Ehlers-Danlos
- Alpha 1 antitrypsin deficiency
What are the general features of aneurysms?
- Larger aneurysms grow faster than smaller ones
- Risk begins to increase when >7mm
- The most commonly affected site is the anterior COW
In a patient with a C-spine injury, what does paradoxical abdominal breathing suggest?
- Loss of intercostal muscles but at least partial sparing of the diaphragm
- Thus the lesion must be below C3 as if it was at C3 or above the diaphragm would be lost as well
What are the highest risk sites in the spine for injury?
Junctions
- C7-T1, T12-L1, L5-S1
Congenital fusions
Surgical/Inflammatory fusions
Any area with known structural abnormalities (ie lytic mets)
What are the typical and atypical presentations of central cord syndrome?
- Typically cause by hyperextension injury to neck in the elderly
- Upper limb weakness > lower limb weakness, bladder dysfunction and paraesthesias (upper > lower)
- Less common variant is from central cord pathology such as slow growing intramedullary tumours and syringomyelia
- Loss of pain/temp sensation at the site of lesion and just around it
- Levels above and below are typically spared
- Get hyporeflexia at these levels
- Overall the prognosis is good
What causes spinal shock?
- After an acute injury there is loss of all spinal cord function caudal to the lesion (may spare the sacral region)
- This can occur in the absence of any MRI finding of spinal cord damage
- Thought to be due to acute neuronal dysfunction from potassium leak from the cells
- As the potassium corrects itself the symptoms variably improve
- This transient state is highly variable and can last hours to weeks
What is the most common site of spinal cord injury in younger kids?
High C-spine injury C1-3
Due to the relatively large head size of children
These injuries are often fatal
What is SCIWORA?
Spinal Cord Injury Without Obvious Radiological Abnormality
- Absence of pathology on CT and Xray
- Occurs in younger children
- Due to ligamentous laxity
- Usually has poor outcomes as affects the upper C-spine C1-3
- Diagnosed with MRI
How does dorsal (posterior) cord syndrome present?
Dorsal columns
- Ataxia, loss of proprioception and paraesthesias
Corticospinal tracts
- Weakness, urinary incontinence
Causes
- MS, tabes dorsalis, Friedrich ataxia, atlantoaxial subluxation, tumours and AVM’s
- Subcacute combined degeneration
What are the general neuroprotective strategies post traumatic brain injury/ICH?
- Elevate head to 30 degrees
- Avoid tight tapes/ties
- CPP >60 but avoid hypertension ie <160 SBP and <110 DBP
- Adequate sedation/analgesia titrated to HR/BP/Tearing
- Aim sats 92-95, avoid hypo and hyperoxia
- Aim sodium 145-150, prevent hyponatraemia
- Low normal ETCO2 35-40
- Normothermia, normoglycaemia
- IDC, NG
- +/- Nimodipine 60mg NG Q4hr
At what rate should BP be lowered in in hypertensive encephalopathy?
- 10-20% within 60mins
- No more than 25% in the first 24hrs
- For ICH aim BP 120-140 if initial SBP <220, if >220 then aim 140-160
What blood pressure lowering meds are relatively contraindicated in SAH aneurysmal bleeding?
GTN and SNP
Can cause cerebral vasodilation potentially worsening both bleeding and ICP
What are the causes of an isolated area of altered sensory function (ie L) upper limb numbness)?
Central
- Stroke/TIA
- Tumour
- AVM/Aneurysm
- MS
- Has to effect the pre-central gyrus or cortical tracts
- Syringomyelia
-
Peripheral
- Demyelination (MS, GBS)
- Infections (Leprosy, lyme, HIV, HSV, VZV, TB)
- Toxins (mercury, platinum, lead)
- Trauma (Norve root or peripheral plexus/nerve compression)
- Vascular (PVD, vasculitis, Raynauds)
What measures can be done to lower ICP in an awake patient?
- Mannitol and HTS
- Analgesia
- Antiemetics
- Head up to 30 degrees
- Tap shunt if VP shunt in situ
What are the potential non-traumatic causes of acute spinal cord compression and what are their risk factors?
Iatrogenic
- Recent spinal procedure (ie LP)
- Bleeding diathesis
