Interpretation Flashcards
CT Head - Process
Demographics
Non-contrast // Contrast (only for vascular)
Work from OUT -> IN
- Soft Tissue swelling? asymmetry?
- Bone fracture
- Periphery? bleed, atrophy
- Paranchyma? hypo/hyperdense
- Ventricles? Symmetry
- Mid line shift??
What does atrophy look like on CT?
Obvious, pronounced sulci and gyri
Symmetrical left to right
May not be symmetrical front to back
e.g. fronto-temporal dementia only anterior
Who is at risk of subdural and why?
Elderly, alcholics
- More likely to fall
- Atrophied brain, cortical bridging veins are more stretched and easier to severe
Subdural: Appearance
Concave ‘sliver’ on brain periphery
May be hyperdense (acute bleed) or hypodense (chronic)
OR acute on chronic (hyper and hypo dense)
Subdural: Hx
Repeated falls
Fluctuating consciousness
Who gets extradurals and why?
Often younger patients
Trauma related as middle meningeal artery bleed
Extradural: Appearance
Convex ‘eggtradural’ on periphery
Hyperdense, acute blood (high pressure bleed)
Within suture lines (between skull and dura)
May be midline shift
Extradual Hx
Traumatic incident with lucid interval
Then LOC, decreased GCS
e.g. rugby player took blow to head, carried on playing, dropped dead in changing room after match.
Extradural Mx
A to E, senior, refer neurosurgeons
SAH Mx
A to E, senior, refer neurosurgeons
Hypodense Brain Tissue: Causes
Ischaemia
Oedema
Old bleed
Hyperdense Brain Tissue: Causes
Acute bleed
Tumour
Calcification (often choroid plexus in ventricles)
SAH Risk Factors
Family history
HTN
PCKD
How to tell if old blood OR ischaemia/oedema on CT?
Old bleed will be much more defined than ischamia/oedema
SAH on CT
Could be central area of hyperdensity in the circle of willis area
May be midline shift
What anticoagulant?
Arterial vs Venous clot
Arterial e.g stroke, MI
- Due to platelet aggregation
- Give antiplatelets: aspirin, clopidogrel, ticagrelor
Venous e.g. DVT, AF clots
- More to do with clotting factors and cascade
- Give warfarin, DOAC
Ischaemic Stroke on CT
Initial CT Head may be normal
— Primarly to rule out haemorrhage
CT head 2-3 days later will show ischamia
- Hypodense area in parenchyma
- Asymmetrical
- May be midline shift
Initial Ischaemic Stroke Management
A to E
NBM until pass swallow assessment
CT Head to rule out haemorrhage
Aspirin 300mg Oral/600mg PR if unsafe swallow
CALL STROKE TEAM
- Consultant will make decision RE thrombolysis
Stroke Medical Management
Aspirin 300mg for 14 days
then
Clopidogrel 75mg for life
Mx If CT head shows haemorrhagic stroke?
A to E
Swallow assessment and NBM
Refer neurosurgeons
DO NOT GIVE ASPIRIN
Definitive rx for Ischaemic stroke
Thrombolysis if <4.5 hours (Stroke consultant to decide)
NEW Rx:
<4 hours, possibly PCI for brain
= mechanical thromolectomy
- discuss with stroke
When is midline shift significant?
ALWAYS
there is no such thing as a minor midline shift!!!
Why would you do an AXR?
Obstruction (main)
Perf - but probably would do erect CXR, abdo CT instead
Good Xray?
Diagphragm -> hernial orifices
Should be able to see psoas muscle
- if not, ? AAA rupture
SBO?
Dilation <3cm Valvular coniventes (all the way across)
3, 6, 9 rule for bowel size
Small < 3cm
Trans. colon <6 cm
Caecum <9cm
LBO?
Haustra not all the way across
Signs of inflammation in LB
Usual cause?
Thumprinting
- thickened bowel wall
Lead pipe colon
- smooth, featureless
TMC
- Smooth, featureless, +++ size
- risk of perf
Cause = IBD
Cause of concurrent LBO and SBO?
Incompetent ileocaecal valve
Volvulus?
Sigmoid
- towards RUQ, coffee bean sign
- Common, elderly, rx with flatus tube
Caecal
- toward LUQ, rarer
Signs of perf?
Wrigler’s sign
- double wall sign, gas on inside and out of bowel
Common surgical clips?
RUQ, cholystectomy clips
ECG placement
4th intercostal space for V1
Ride Your Green Bike
R = RA, Y = LA, G = LF, B = RF
Rate?
Count complexes on rhythm strip
Rhythm?
Irregular = likely AF!
P waves
- Absent?
- Shape?
Absent = AF
Triangular + tall = p pulmonale
- indicative of large right atrium
- usually due to lung disease causing pulm. hypertension
Bifid = p mitrale
- indicative of large left atrium
- usually mitral valve regurg/stenosis
Axis?
Look at V1 and V3
LAD = leaving: +ve in V1, -ve in V3
RAD = reaching: -ve in V1, +ve in V3
PR interval?
- Normal?
- What does length indicate?
should be 3-5 small sq
< 3 = accessory pathway e.g. WPW
> 5 = heart block
3 Features of WPW on ECG
Delta wave (slurred upstroke)
Short PR
Broad QRS
Mnemonic for Reciprocal changes
PAILS
ST depression in the area after
e.g. Posterior STEMI = ST depression in ant. leads
Narrow QRS?
< 3 sqs - ALSO NORMAL!
usually atrial problem if tachy
Broad QRS?
> 3 sqs, never normal
ventricular cause // pathway obstruction
To work out if LV Hypertrophy?
Count the squares of the deepest S wave in V1
Tallest R wave in V5 or V6
If total = >35 then the pt has LVH
Causes of small voltage QRS?
Tamponade, pericardial effusion?
OBESITY!!
Cause of QRS Alternans?
Pericardial effusion
Heart is mobile in fluid filled sack
Height of QRS alternates from smaller to larger regularly
Causes of Broad QRS?
VT, VF
BBB
Hyperkalaemia
Drug OD
Pacemaker (see pacemaking spikes, talk to senior)
VT w/ a pulse?
Unstable = DC shock, need anaesthetist
Stable = amiodarone
- 300mg over 20 mins
- 900mg over 24 hours (infusion)
Signs of instability in arrhythmia?
Shock
MI
HF
Syncope
MUST BE DUE TO THE ARRHYTHMIA
Unstable Tachy?
DC shock (need anaesthetist)
Broad complex Stable Tachy?
Reg: VT w/pulse
- amiodarone 300mg
Irreg: AF with block, need senior
Shockable Rhythms
Pulseless VT
VF
Non-shockable rhythms
Aystole
PEA
Risk of Amiodarone
Prolongs QT, be wary if patient already has long QT
Narrow Complex Stable Tachy?
Reg: SVT
- carotid sinus massage,
- blow syringe,
- adenosine 6mg, 12 mg, 12mg
Irreg: AF
- Beta blocker (caution: asthma)
- Digoxin (caution: HF)
Cautions in asthmatics?
Beta-blockers = ABSOLUTELY NOT
Adenosine = DON’T YOU DARE
high risk of bronchospasm
J wave
Osborne wave, usually in hypothermia
Homeless, old with long lie
May have shivering artifact (e.g. tremors)
ST Elevation: Causes
INFARCT!
- SAH (due to raised ICP)
- LBBB
- Pericarditis (saddle shaped)
- Brugades (v1-v3: sudden death)
- ventricular pacemakers
ST Depression: Causes
Hypokalaemia Digoxin (dali reverse tick sign) RBBB Reciprocal change in infarct (PAILS) Vent. pacemaker
LBBB on ECG
With LAD = likely LBBB
Need to check old ECG
- If new, rx as STEMI
Leads and areas?
V1-V4 = anterior
V5-V6, I and AvL = lateral
II, III, avF = inferior
LBBB vs RBBB
LBBB = WiLLiaM (look at V1 and V6)
- Pathological
RBBB = MaRRow (look at V1 and V6)
- may be a normal varient
Bad lead to have in ST elevation?
aVR - means very proximal infarct, not a good prognostic sign
LAD + RBBB
Bifasicular block
Most likely STEMI to cause arrhythmia?
Inferior - NEED telemetry
Hyperacute T waves
Pre-ischaemic change in early MI
Tall and broad
Asymmetrical
Usually follows lead pattern of infarct e.g. inferior = I, II, avF
Tall-tented T waves
High K+
Tall and symmetrical
Biphasic T waves
Ischamia (STEMI) =
- up then down
Hypokalemia
- down then up (U wave)
Risk in Long QT?
Causes?
Cardiac arrest
- due to torsades de pointes
Low temp, low K+, low Ca2+, drug overdose
Prolonged QT
Male: >440
Female: >460
Risk in short QT?
Causes?
Sudden death
Congenital, hypercalcaemia
Bradycardia Unstable
Shock, MI, syncope, HF
Atropine
Pacing
Bradycardia Stable
Rx
Risk of asystole
- Treat as unstable
- Atropine
- Pacing
Low Risk
- Observe
Low Risk
First degree
Mobitz type 1
High Risk of Aystole
> 3 seconds ventricular pause
Mobitz Type 2
Complete Heart Block
Mobitz Type 1 (Wenkebach)
Clumping of QRS complexes
PR increases until 1 is dropped
If asymptomatic = observe
Symptomatic (rare) = atropine and pacing
Mobitz Type 2
Ratio e.g. 2:1
No lengthening of PR
When to do an ABG?
ONLY if worried about ventilation
e.g. high RR, low O2 sats
otherwise DO A VBG!
When to do an ABG in asthma?
ONLY if life threatening or deterioration
Don’t want to stop people coming back to A&E as scared of ABG
Process for ABG interpretation
pH
does CO2 account for pH?
HCO3
O2 - check amount of o2 patient is using
Lactate
Hb
Electrolytes
Metabolic Acidosis with low Bicarb cause?
ABG?
Renal Failure // AKI
Very low bicarb
Low CO2 to try and compensate
(due to increased HCO3- excretion)
Raised anion gap
Chronic Resp acidosis?
e.g. COPD
pH low, or may be compensation
High CO2
high bicarb to comp
Lactic Acidosis Causes
ABG?
Seizure
Bowel ischameia
Sepsis
Metformin
- due to anaerobic resp
low pH, norm CO2 + bicarb, high lactate
Metabolic Acidosis
ABG
e.g. DKA
low pH, low CO2 (comp), low bicarb
Normal anion gap
AKI Staging and meaning
I = risk
II = intermediate
III = failure
Drugs to omit in AKI
ACEi/ARB
NSAIDs
Metformin
Diuretics
Drugs to Keep in AKI
Aspirin 75mg (not damaging to kidneys)
Drugs to dose review in AKI
ALL
Abx, opiates, insulin, digoxin, benzos, lithium
How to assess Fluid Balance
Inspection: vomit bowls, stoma, catheter, blood loss
- Is the patient drowsy, well?
Hands: temp, perfused, CRT, turgor
Pulse: high HR?
BP: both arms lying and standing
- postural drop indicates poor fluid status before lying BP will drop
Face: mucous membranes?
Neck: Raised JVP?
Chest: Central cap refill, listen to bases of lungs for overload
Sacrum and legs: Check for fluid overload
Process for AKI?
ABCCDD
Assess fluid balance Bloods Catheter (monitor fluid balance) Cannula (push oral or give IV fluids) Drugs: REVIEW Dialysis? senior decision
Bloods in AKI?
Daily U+Es
- creatinine
- K+
VBG
- Check bicarb
Calcium and phosphate
FBC
- Check Hb (norm. anaemia, not acute change)
ALT:ALP ratio
Is it hepatic or biliary tree?
ALT ++++ in damage to hepatocytes
ALP ++++ in damage to CBD e.g. obstructive pathology
- also raised in bone conditions e.g. paget’s
- also high in pregnancy
READ Hx
Why is ALT not a good marker of function?
Produced by destruction of hepatocytes
If you have no hepatocytes left e.g. cirrhosis than ALT may be decievingly low even if function is bad
How to measure liver function?
Synthetic function
- Low albumin
- Clotting - high PT (>30 secs) = bad
- BM: low if non-functioning liver
What else is AST found in?
Muscles
- Will be high in rhabdomyolysis
Acute inflammatory markers?
Positive
- CRP, WCC, platelets, Iron
Negative
- Albumin
Don’t do ESR acutely - ONLY RHEUM!
Hypocalcaemia?
CATs go Numb on a LONG QT
Convulsions
Arrythmias
Tetany
Numbness
Long QT
