Neurosurg. ~ Short Answer

Question 1.

A 10 year old boy is brought to hospital by his parents after falling off his skateboard and hitting his head.

 

A.) List 3 evidence based clinical decision rules that can be used to decide whether to perform a CT scan on this child?

Show Answer

  • NEXUS II
  • CHALICE
  • PECARN

(3 marks)

 

B.) How sensitive and specific are these clinical decision rules over all?

Show Answer

  • High Se e.g. PECARN 96.8% > 2 y.o.; 100% < 2 y.o.; NEXUS II 98.6%
  • low Sp e.g. NEXUS II 15.1%

(2 marks)

 

C.) List 8 historical factors according to the clinical decision rules that would make you more likely to order a CT scan on this child?

Show Answer

  • NEXUS II
    • Persistent vomiting
    • Abnormal behaviour
    • Coagulopathy
  • CHALICE
    • Witnessed LOC > 5 mins
    • Amnesia > 5 mins
    • 3 or more episodes of vomiting
    • Traumatic seizure
    • Suspicion of NAI
    • Drowsiness
    • MVA > 40 kph
    • Fall > 3 m
    • High-velocity projectile
  • PECARN
    • Loss of conscious ness > 5 s
    • Severe mechanisms (MVA with ejection, rollover, death of passenger, pedestrian or bicyclist with no helmet struck by motorised vehicle, fall > 2 m (age > 2) or 1m (age < 2), head struck on high-impact object)
    • Abnormal behaviour if < 2 y.o.
    • Severe headache > 2 y.o.

(8 marks)

 

D.) List 6 features of physical examination according to the clinical decision rules that would make you more likely to order a CT scan on this child?

Show Answer

  • NEXUS II
    • Significant skull fracture
    • Altered LOC
    • Neurological deficit
    • Scalp haematoma
    • Abnormal behaviours
  • CHALICE
    • GCS < 15 if < 1 y.o.
    • GSC < 14 if > 1 y.o.
    • Depressed or basilar skull fracture
    • Penetrating injury
    • Tense fontanelle
    • Focal neurological deficit
    • Bruising, swelling, laceration > 5 cm if < 1yo
  • PECARN
    • Scalp haematoma except frontal
    • ALOC
    • Skull fracture
    • Abnormal behaviour
    • Signs of basilar skull fracture if > 2 y.o.

(6 marks)

 

E.) What advice will you give on discharge in regards to coming back to the emergency department?

Show Answer

Go back to your doctor or hospital immediately if your child has:

  • Unusual or confused behavior.
  • Severe or persistent headache which is not relieved by paracetamol (irritability in a baby).
  • Frequent vomiting.
  • Bleeding or discharge from the ear or nose.
  • A fit or convulsion, or spasm of the face or arms or legs.
  • Difficulty in waking up.
  • Difficulty in staying awake.
  • If you are worried for any reason.

(6 marks)

 

F.) What is your discharge advice regarding concussion symptoms?

Show Answer

  • The suspected diagnosis of concussion can include one or more of the following concussion complaints:
    • there was loss of consciousness or
    • inability to remember the event (amnesia)
    • symptoms of headache or feeling like in a fog
    • being irritable
    • slowed reaction times
    • sleep disturbances or drowsiness
  • see doctor if these occur

(4 marks)

 

G.) What advice would you give regarding returning to sport if the child does show evidence of concussion?

Show Answer

  • Need rest from physical activity and those that require concentration e.g. video games, school work
  • Graded return to activity
  • g.:
  • Instructions:
    • Each step takes at least 24 hours (a minimum of seven days total).
    • Your child should only move to the next step if they have no concussion complaints.
    • If concussion complaints occur, go back to the previous step.
    • If your child cannot advance to the next step without concussion complaints, you should see your doctor before returning to play.

Neuro & Radio Table 1 Short Answer

(4 marks; detail not needed)

Author: J Haire

Ref: Tintinalli p. 888-92 + RCH guidelines


 

Question 2.

A 19 year old woman is brought to the emergency department by her concerned parents with a two day history of irritability and headache.  She has a history of developmental delay and a ventriculoperitoneal shunt for congenital hydrocephalus.

Her Glasgow Coma Score is 15.  Her vital signs are normal.

A.) List 4 causes of shunt malfunction

Show Answer

  • Obstruction
  • Mechanical failure e.g. Fracture, disconnection, migration, misplacement
  • Slit ventricle syndrome or overdrainage
  • Loculation
  • Abdominal complications e.g. pseudocyst formation

(4 marks)

 

B.) Describe how you would examine the valve chamber for obstruction.

Show Answer

  • Gently compress chamber and observe for refill
  • Difficulty compressing chamber – distal obstruction
  • Slow refill (> 3s after compression) – proximal obstruction

(3 marks)

 

C.) How sensitive is this examination for shunt obstruction?

Show Answer

  • Not very sensitive
  • 40% obstructed shunts compress and refill normally

(1 mark)

 

D.) What imaging should be ordered for and ventriculoperitoneal shunt and what for?

Show Answer

  • Shunt series
    • AP & lateral skull
    • AP chest and abdomen
    • For mechanical failure
  • CT brain
    • For raised ICP/low pressure

(4 marks)

 

E.) How sensitive are these tests?

Show Answer

  • Poor sensitivity
  • Still need neurosurgical opinion

(1 mark)

 

F.) Which populations are at the most risk for shunt infection?

Show Answer

  • Very young
  • Very old
  • Recently placed shunts

(2 marks)

 

G.) When do shunt infections occur most commonly?

Show Answer

  • After initial placement
  • 70% in first 2 months
  • 80% in first 6 months

(2 marks)

 

H.) How do patients with infected shunts present?

Show Answer

  • Symptoms of:
    • Meningitis
    • Obstruction
    • Fever
    • Abdominal pain

(4 marks)

 

I.) What is the definitive investigation needed to diagnose shunt infection and how is it performed?

Show Answer

  • Shunt tap
  • Shaved and sterilise skin over reservoir
  • 23G butterfly attached to a manometer
  • Measure opening pressure
    • Should be 12 +/- 2 cmH2O
    • > 20 cm H2O – distal obstruction
    • < normal – proximal obstruction
  • Removed CXF and send for analysis

(4 marks)

Author: J Haire

Ref: Tintinalli P 1180-83


 

Question 3.

A 55 year old man has just undergone endotracheal intubation for severe asthma. Immediately post intubation, his systolic blood pressure falls to 80 mmHg.

 

A.) What are the likely causes of this patient’s hypotension?

Show Answer

  • Dynamic hyperinflation (gas-trapping) leading to raised intra-thoracic pressure and decreased venous return
  • hypovolaemia secondary to dehydration
  • induction drugs causing myocardial depression and vasodilatation
  • tension pneumothorax secondary to barotrauma
  • hypoxia secondary to barotrauma, mucous plugging, ETT migration/misplacement, disconnection from ventilator

(5 marks)

 

 B.) What actions would you take to address this situation?

Show Answer

  • Disconnect the patient from the ventilator and move to BMV
  • Long expiration time and can compress chest to exclude gas-trapping
  • Check tube in right place
    • Attach CO2 monitoring
  • Fluid bolus
  • Push-dose pressor e.g. metaraminol
  • Check for pneumothorax clinically and decompress emergently

(6 marks)

 

 C.) Describe your ventilation strategy in asthmatic patients.

Show Answer

  • Long expiration times to avoid gas-trapping & barotrauma and permissive hypercarbia
  • Will need heavy sedation (uncomfortable)
  • High flow rate to reduce inspiratory time 80-100- l/min
  • TV 8 ml/kg
  • Low RR i.e. 10 bpm
  • High I:E ratio i.e. 1:5
  • PEEP 0 mmHg
  • Initial settings
  • Aim is for adequate oxygenation but tolerate high CO2 as long as pH > 7.25

(8 marks)

Author: J Haire

Ref: Tintinalli p. 520; Roberts and Hedges 5th Ed 144 & experience


 

Question 4.

A 23 year old man is brought in to the emergency department by ambulance with an isolated stab wound to his left anterior chest. He is alert, sweaty and taking shallow breaths. The weapon is not in situ upon his arrival in the emergency department.

 

His examination findings are:

HR 105 /min

BP 95/60 mmHg supine

RR 30 /min

O2 Saturation 93 % on room air

 

 A.) What are the main issues in this patient?

Show Answer

  • Penetrating life-threatening trauma
  • Haemorrhagic shock
  • Hypoxia

(3 marks)

 

 B.) What are the potential injuries causing this?

Show Answer

  • Tension pneumothorax
  • Cardiac tamponade secondary to puncture heart or great vessels
  • Haemothorax secondary to laceration of intra-thoracic vessels

(3 marks)

 

C.) What are the essential investigations in this patient?

Show Answer

  • CXM
  • CXR or US
  • FAST scan

(3 marks)

 

 D.) What are the indications for emergency department thoracotomy?

Show Answer

  • Penetrating injury
  • Patients have signs of life in field or ED but then deteriorate

(2 marks)

 

E.) Briefly describe how you would perform an left anterolateral thoracotomy

Show Answer

  • Incision in left 4th or 5th intercostal space (space below nipple in man and in infra-mammary fold in woman)
  • Incision from sternum to the posterior axillary line along that intercostal space through skin, s/c fat, superficial muscle
  • Cut remaining muscles with scissors along top of rib
  • Spread ribs
  • Apply retractor handle down

(4 marks)

 

 F.) List 3 options for control of haemorrhage cardiac wounds?

Show Answer

  • Finger occlusion
  • Staples
  • Horizontal mattress sutures
  • Foley catheter
  • Occlude the SVC and IVC

(3marks)

Author: J Haire

Ref: Tintinalli p. 1761; Roberts and Hedges 5thEd P. 319-20


 

Question 5.

A 45 year old man presents to your emergency department with vertigo and ataxia.

Neuro & Radio Photo 1 Short Answer

 

A.) What are the main abnormalities in this CT?

Show Answer

  • Multiple areas of low attenuation in the cerebellum
  • Bilateral

(2 marks)

 

B.) What is your differential diagnosis?

Show Answer

  • Ischaemic CVA
  • Metastases
  • Abscesses

(2 marks)

 

C.) What further investigations would help to establish the diagnosis?

Show Answer

  • Contrast CT
  • MRI
  • CVA look for source
    • US carotids
    • Echo
  • Mets look for source
    • CT head/chest/abdo
    • Biopsy lesion

(4 marks)

Author: J Haire

 


Question 6.

A head CT scan of an 83 year old woman has been performed, who has presented with a 3 day history of increasing confusion and unsteady gait following a fall. Her GCS is 12 (M5, V3, E4).

Neuro & Radio Photo 2 Short Answer

 

A.) Describe the abnormalities seen in this CT.

Show Answer

  • Large right frontotemperoparietal subdural haematoma
  • Heterogeneous – acute on chronic
  • Significant mass effect with movement of midline at least 2 cm
  • Effacement of superior horns of lateral ventricles
  • Effacement of sulci
  • Blood in posterior horn on right and tracking along falx cerebri

(4 marks)

 

B.) What is the diagnosis?

Show Answer

  • Massive acute on chronic subdural with significant mass effect

(2 marks)

 

C.) What is the prognosis?

Show Answer

  • Guarded/poor

(1 mark)

 

D.) What factors would you take into account in deciding whether operative therapy was appropriate?

Show Answer

  • Previous wishes of patient if articulated
  • Pre-morbid function
  • Co-morbidities
  • Neurosurgical opinion re prognosis/futility

(3 marks)

 

E.) Who would you consult in making this decision?

Show Answer

  • Neurosurgeons
  • GP
  • Family/NOK

(3 marks)

Author: J Haire

 


 

 

 

 

 

 

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