Standardised Case Based Discussion Flashcards
What are the typical tasks for OSCE CBD’s?
Outline your approach to the clinical situation, with rationale
Outline your priorities in the investigation and management of the patient.
Answer the examiner’s further questions as the case evolves.
What have candidates done well in the past for OSCE CBD’s?
had a structured approach to the station and expressed themselves clearly.
were able to synthesise the clinical information and consider the patient’s medical history and medications and how these would impact the patient’s current presentation.
were able to outline priorities in their initial assessment and resuscitation and to then modify and justify their approach to ongoing resuscitation based on further case information.
recognised the critical nature of the presentation and the urgency to act with a need for resuscitation and potential airway management
gave specific details of the actions they would take in assessment and management of the patient as opposed to generic resuscitation responses.
correctly identified the ECG findings, escalated their management without prompting.
What is the LIPSSS mnemonic for approaching SCBD’s?
L: Label the case ie
- 3 month old in status epilepcticus
- critically unwell septic obese man in hypoxic respiratory failure
- Unstable but already intubated polytrauma patient
I: Issues
- Rural location, ongoing pathology, need for MTP, no IV access, predicted difficult intubation etc
P: Priorities
- MTP, treat hyperK, treat low BSL, early antibiotics, NIV for delayed sequence intubation etc
S: Staff
- Resus team, specialties, retrieval services
S: Space
- resus vs theatre vs transfer etc
S: Stuff
- equipment needed (ie intubation stuff)
Approach to adult and paediatric hyperkalaemia?
Main Causes
- Too much K in (ie overdose)
- Release from cells (ie rhabdo)
- Not enough out (ie AKI, addisons)
- Pseudohyperkalaemia (usually from RBC lysis with difficult blood draw)
Adult top differentials
- Renal failure
- Rhabdomyolysis
- TLS
- DKA and HHS
- Addisons disease
- Beta blockers
- Metabolic acidosis
Paediatric
- Tumour lysis syndrome
- Rhabdomyolysis
- Accidental overdose
- Acute renal failure
- Acidosis (ie from acute sepsis)
Paediatric Doses
- Salbutamol 2.5-5mg Neb (fastest, 0.5-1mmol drop)
- Calcium gluconate 10% 0.5ml/kg (reduces ECG changes, doesnt alter serum K+)
- Sodium bicarbonate 8.4% 0.5-1ml/kg
- 5ml/kg 10% dextrose with 0.1U/Kg of insulin short acting
- Calcium resonium
- IV frusemide for hypervolaemic and non-anuric patients
- Haemodialysis
How should a rash be approached?
Non-blanching
- Palpable: Meningococcaemia, HSP, endocarditis
- Non-palpable: ITP, TTP, HUS
- Either: Leukaemia, sepsis with DIC, NAI/mechanical
Blanching
- SSSS, scarlet fever, anaphylaxis, measles, viral exanthem, Kawasakis
Sloughing
- Nikolsky +ve: TEN/SJS and pemphigus vulgaris
- Nikolsky -ve: Pemphigoid
Shock and Rash
- Anaphylaxis
- SJS/TEN
- Toxic shock syndrome (usually staph but can be strept)
- Meningococcal septicaemia and Gram Negative sepsis
- Measles (worse in adults)
- DRESS syndrome
- Heat stroke
- Others (Idiopathic Erythroderma, Leptospirosis and rocky mountain spotted fever)
Shock and Rash in children
- As for adults
- SSSS
- Kawasakis
- PIMS TS/MIS-C
- Bad viral illness with exanthem
- Scarlett fever
Erythroderma (diffuse redness) DDx
- Toxic shock syndrome (staph and strep)
- Meningiococcaemia (before purpura)
- Heat stroke
- Anaphylaxis
- SSSS
- Adenovirus, scarlet fever and measles
- Kawasakis disease/PIMS TS/MIS-C
- Drug eruptions (SJS, TEN, DRESS)
- Severe sunburn or dermal burns
Hyponatraemia SCBD?
Risk Factors for complications
- Severity of hyponatraemia
- Acuity of onset (seizures/cerebral oedema higher with acute, ODS higher with chronic)
Important points on Hx/Ex
- Volume status!
- Headache/lethargy/confusion
- Unstable gait
- New drugs
- Recent pneumonia or surgery
- GCS, neurological deficits
- Seizures, unexplained loss of time
Complications
- Seizures
- Cerebral oedema
- Osmotic demyelination syndrome aka central pontine myelinolysis
Hypovolaemic
- Acute dehydration (vomiting, diarrhoea, ALOC etc)
- Diuretic induced
- Addisons disease
- Treat intravascular volume loss, CSL has Na+ 128 so lower chance ODS
- This is the main time DDAVP is indicated, as once correcting hypovolaemia a diuresis often occurs
Euvolaemic
- SIADH
- Non-diuretic drug induced (antipsychotics, SSRI’s, amiodarone etc)
- Steroid induced adrenal insufficiency
Hypervolaemic
- CCF, renal failure, liver failure
- Psychogenic polydipsia
- Treat with fluid restriction
SIADH Definition
- Euvolaemia hypo-osmolar
- Urine Na+ >20
- Urine osmolarity >100
- Not explained by other organ disease ie liver/renal/cardiac failure
- Causes: CNS disturbance, pneumonia, surgery, drugs, malignancies, hypothyroidism, exogenous ADH
Treatment of complications
- 3ml/kg of 3% saline titrated to rise in serum Na+ of 4-6mmol (usually 100-150mls with repeat to max 300)
- If no 3% saline then use 1 amp (100mls) sodium bicarbonate
General treatment
- Fluid restriction aiming for rise in 24hrs no greater than 10-12mmol
- Saline lock the IV
- Strict fluid balance, insert IDC
- Aim for UO <100ml/hr
- If UO >100ml/hr then send urine osmolarity
- If Urine osmolarity <100 then give DDAVP 1mcg to concentrate urine
- NO WATER!!!
ODS
- Occurs due to rapid overcorrection
- Can occur up to 7 days post
- Typically the Pons, but also cerebellum and basal ganglia
- Ataxia, quadriplegia, cranial nerve palsies and lock in syndrome
- RF’s elderly, chronic low Na+, malnourished, hypokalaemia
Hypercalcaemia SCBD
Causes
- Malignancy (bone mets, MM, paraneoplastic syndromes ie NSCLC)
- Granulomatous disease (TB and Sarcoid)
- Hyperparathyroidism
- Drugs (Thiazides, lithium)
- Hyperthyroidism, Phaeo, Addisons
- Acromegaly, pagets disease
- Milk-alkali syndrome and parenteral nutrition
- Long term immoblisation
ECG
- Short QT interval
- Tall QRS complexes
- Osborn waves
- PR prolongation
- Broad T waves merging with the QRS (pseudo STE)
- VT and VF can occur
Treatment
- IV fluids 0.9% saline, titrated to normovolaemia + 1-2ml/kg/hr UO
- Bisphosphonate (IV Pamidronate 60- 90mg)
- Calcitonin 4 international units/kg
- IV hydrocortisone 1-200mg QID
- Withhold meds that cause hypercalc (ie thiazides)
- Haemodialysis if other treatments are refractory
Hypokalaemia SCBD?
Causes
- Reduced intake (malnourishment, refeeding syndrome, short gut)
- Intracellular sequestration (catecholamines, excess insulin, alkalosis)
- Increased loss (thiazide diuretics, RTA 1&2, diarrhoea, *severe vomiting, mucous secreting tumours, fistulas, hyperaldosteronism ie Cushings, burns losses and RRT)
* Vomiting doesn’t normally cause hypokalaemia, unless severe and underlying renal failure or thiazide use
ECG
- inverted T waves
- Large U waves
- Prolonged QT (QU)
- Prolonged PR
Complications
- ascending muscle weakness and respiratory failure
- Rhabdoymyolysis > myoglobin induced kidney injury
- Hypomagnesaemia
- Arrhythmias (particularly TdP)
Treatment
- Always correct Magnesium when correcting potassium
- Seek and treat hypovolaemia
- IV vs oral repalcement
- 0.25mmol/kg/hr aiming for K+>4.0
- 0.2mmols/kg bolus magnesium aiming for >1.0
ECG differentials
STEMI mimic (ELAVATION mnemonic)
E- Electrolyte abnormalities (ca+, K+)
L- LBBB
E- Electrical (Early Repolarisation, PPM)
V- ventricular hypertrophy/Aneurysm
A- Arrhythmia (Brugada, VT)
T - Takutsubos
I- Injury (myocardial contusion) and Inflammation (Peri/myocarditis)
O- Osborne waves (hypothermia)
N- Non-atherosclerotic (Coronary vasospasm, PE, TAD, global ischaemia, elevated ICP)
Q waves
- STEMI
- LBBB
- Normal in V1/2, II, III, AVF (Right and inferior facing leads)
- Dexrocardia
- L) pneumothorax
- HOCM (dagger q waves)
- LV and RV hypertrophy
- HyperK
- WPW
TWI
- Ischaemia
- Raised ICP
- Hypokalaemia
- Takutsubos
Peaked T waves
- Hyper acute T waves (ischaemia)
- Hyperkalaemia
- Coronary vasospasm
- BER
- LVH
- LBBB
- Rarely raised ICP and pericarditis
Short QT interval
- Hypercalcaemia
- Digoxin toxicity
- Hyperkalaemia
- Hyperthermia
- Short QT syndrome
- Catecholamine toxicity
- Severe acidosis
- Myocardial ischaemia
Long QT Interval
- Hypo K/Mg/Ca
- Long QT syndrome
- Many drugs
STEMI vs Pericarditis
- 15% of Pericarditis cannot be distinguished from STEMI on ECG
- Reciprocal depression in any leads except aVR and V1
- STE in lead 3 > lead 2 (3 is higher number than 2, and STEMi is higher priority than pericarditis)
- Convex or horizontal (STEMI) vs concave (pericarditis) STE
- Checkmark or RT sign
- New Q waves (not old)
- New TWI (uncommon in pericarditis unless also myocarditis)
STE in AVR causes
- Proximal LAD or LMCA STEMI
- Diffuse subendocardial ischaemia
- Large PE
- Aortic dissection
- Demand ischaemia from poor perfusion (severe sepsis, upper GI bleed, shock, dysrhythmias, severe anaemia etc)
- Na+ channel blockade
- Correlates with poorer prognosis
- Consider NO CLOPIDOGREL if ACS with STE in AVR as strongly correlated with need for CAGS
HHS vs DKA
HHS Basics
- mOsm >320 (normal 275-295)
- Often marked hyperglycaemia
- Unusual to be ketotic
HHS endpoints
- <300mOsm
- BSL <15
- UO >1ml/kg/hr
- GCS 15, neurological baseline
HHS Treatment
- IV fluids aiming for UO >1ml/kg/hr
- Drop in mOsm no greater than 4mOsm per hour
- 0.05U/kg/hr insulin
Toxic Shock Syndrome
Diagnostic criteria
- Fever >38.9
- Diffuse macular erythroderma rash
- Hypotension
- Multisystem involvement (>3 systems)
- Negative results on other microbiological/serological testing (except staph and strep)
- A comfirmed case is all 5 + the rash desquamates 1-2 weeks later
Shock with non-blanching Rash DDx
- TSS
- Sepsis
- Meningococcaemia (can have non-blanching rash first
- Anaphylaxis
- SJS/TENS or DRESS syndrome
- PIMS-TS/MIS C in children
- Kawasakis with shock in children
- Fulminant viral infection (Influenza, adenovirus, measles etc)
- Red Man syndrome (Vanc infusion)
Ventricular tachycardia SCBD?
Definition
- 3 or more VEB at >130bpm
- Sustained is >30secs
Brugada criteria
- Is RS complex present in all precordial leads? No = VT
- Is RS interval >100ms? Yes = VT
- AV dissociation present (ie capture beats and fusion beats)? yes = VT
- Morphology criteria for VT present? yes = VT
Wide Complext Tachy DDx
- Monomorphic VT
- SVT/AF/Aflutter/ST with Aberrancy
- Antidromic WPW
- AF with WPW
- Hyperkalaemia
- TCA/Na+ blocker toxicity
- Polymorphic VT
- Torsades de Pointes
- AIVR
VT Causes
- See picture
- Enhanced automaticity
- Re-entry
- Enhanced trigger acitivity
Tox Causes
- Hydrocarbon induced catecholamine sensitisation
- TCA/Na+ blocker overdose
- Sympathomimetic (speed, cocaine, meth) induced
- Channelopathy (ie brugada) + ethanol or Na+ channel blocker
Risk Factors
- Older age (>35)
- Structurally abnormal heart
- IHD and active ischaemia
- electrolyte abnormalities
- Catecholamine sensitivity (congenital vs tox/acquired)
- Channelopathies (ie Brugada) or FHx of sudden cardiac death
- Hypothermia
LBBB morphology criteria
- Absence of R wave (QS complex) V6
- R/S ratio <1 in V6 (small R wave)
- Josephson sign (notching/slurring of the S wave)
- Very wide QRS complex
RBBB morphology criteria (V1/2)
- Taller left rabbit ear (ie opposite to tox taller right rabbit ear)
- qR complex in V1
- Smooth monophasic R wave
- SVT suggested by RSR pattern
Pericarditis SCBD
Causes
Inflammatory
- Post viral
- Autoimmune
Infectious
- TB, IE
Post MI
- Dresslers syndrome
Injury
- Direct trauma, radiation, post surgery
- Aortic dissection
Medication
- Chemotherapeutics
Systemic Diseases
- Uraemia
- metastatic cancer
- Amyloidosis, sarcoidosis
Risk factors for severe disease
- Large effusion or evidence of tamponade
- Strong anticoagulant use or bleeding diathesis
- Acute trauma
- Immunosuppressed patients
- Elevated trop (suggests concomitant myocarditis)
- Failure to respond to 7 days of appropriate therapy
- Fever and subacute course
Treatment
- NSAID’s 1st line
- Colchicine 2nd line
- Glucocorticoids 3rd line
- Anti-immune agents 4th line
Pericarditis vs BER
- Both have concave STE in multiple leads
- Both can have spodicks sign
ST/T wave ratio
- Measured in V6
- STE measured from the end of the PR segment to the start of J point
- STE measurement normally relative to the TP segment, so different to normal
- Ratio <0.25 = BER
- Ratio >0.25 = pericarditis
Fish hook sign
- Notching or irregularity at the j point, suggestive of BER
Hypertension evaluation and emergenices SCBD
Life Threats
Subarachnoid Haemorrhage
- Aim SBP <160mmHg
- GTN and BB’s, Hydralazine as well
- ANALGESIA!!!
Ischaemic Stroke
- Aim SBP <180 if fibrinolysing or if evidence of other end organ damage (no need to lower otherwise as may worsen ischaemia
- BB’s +/- Clevidipine
- SNP may worsen ischaemia due to shunt
*Hypertensive Encephalopathy
- Aim 20% reduction in MAP in 1-2hrs
- BB’s +/- GTN/Hydralazine
Eclampsia
- Aim SBP <160 and DBP <100
- Labetalol, Hydralazine, Magnesium
Aortic Dissection
- Aim SBP <120
- Esmolol/Labetalol + GTN/SNP
- ANALGESIA!!!
- If aortic regurge present BB’s may worsen this
STEMI
- Aim MAP 20% reduction
- GTN +/- BB’s
- BB’s controversial as may worsen acute heart failure
- Aspirin, antiplatelet, heparin, PCI
- Acute Heart Failure
- GTN and Frusemide, NIV with PPV
- Clevidipine as CCB, BB’s are relatively contraindicated
Secondary Hypertension Causes
- Head down approach
- Raised ICP (SOL)
- Inctracranial bleed/stroke
- Amphetamine/stimulant use
- Hyperthyroid
- Cushings syndrome
- HOCM/Aortic coarctation
- Phaechromocytoma
- Reno-vascular hypertension
Antihypertensive dosing
Esmolol
- 500mcg/kg load then 50mcg/kg/min infusion
Labetalol
- 20mg bolus then 2mg/min
GTN
- 5mcg/min
Hydralazine
- 5mg bolus
Pacemaker Problems SCBD
Under-sensing
- When the PPM doesn’t sense underlying rhythms and attempts to pace over an intrinsic rhythm
- Programming issues
- Lead displacement
- New bundle branch block
- Stimulation threshold too high
ECG findings
- Pacemaker spikes within native QRS complexes
Over-sensing
- PPM interprets inappropriate signals as QRS’s and doesn’t pace
- Very large P or T waves
- Lead contact issues
- Significant skeletal muscle activity
ECG Findings
- Native rhythm with intermittent or no pacemaker spikes
Failure to Pace
- When no paced stimulus is generated
- Battery low
- Oversensing
- Lead misplacement/fracture
- Interference
ECG
- No or less than normal pacing spikes, native rhythm revealed
Failure to Capture
-When a paced stimulus reaches the myocardium but does not cause depolarisation
- Acidaemia and electrolyte abnormalities
- ischaemia
- lead displacement/fracture
- exit block
ECG
- Pacing spikes present but no P or QRS immediately post this
Twiddlers Syndrome
- When the leads are miss placed due to accidental or intentional movement of the generator by the patient
- leads to output failure, sometimes pacing of innapropriate structures (ie diaphragm and sometimes lead dysplacement arrythmias
ECG Findings
- Native rhythm +/- intermittent ventricular ectopics or VT
Pacemaker mediated tachycardia
- Usually starts with retrograde conduction of a PVC with a dual chamber system in situ
- This sets up a circus movement tachycardia using the dual chamber PPM as the accessory pathway
- Maximum rate is usually 140-150
- Can be terminated either by magnet or AV blockade (as still need AV node for circus movement)
- Occasionally it is due to a physiologic response (ie underlying sinus tach), this can only occur if the PPM is rate responsive in its programmin (ie DDDR)
Recent Pacemaker insertion
- Tension pneumo/haemothorax
- Cardiac tamponade
- Large or infected haematoma
- New VSD/ASD from pacemaker erosion
- Ischaemia
- PPM/cardiac infection
- Pulmonary embolism
Unstable
- Pacing/defibrillation pads in the AP position away from the generator
- Standard ACLS protocol
- Magnet on PPM will default it to VOO or DOO (depending on PPM) and ICD will turn off defibrillation
- Magnet can be used to check for low battery and oversensing
- May need multiple magnets in obese patients
Stable
- Interrogate using wand
- CXR, electrolytes, ECG +/- inflammatory markers, trop and thyroid function tests
STEMI SCBD
STEMI Mimics
Ischaemia
- Prinzmetals angina
- Cocaine/amphetamines
- Aortic dissection
- Myocardial contusion
- Myocarditis
- Emboli to coronaries (infective endocarditis, air embolism etc)
- Coronary vasculitis
- Congenital (ie ALCAPA)
ST elevation
- Takutsubo’s cardiomyopathy
- LVH/HCOM
- Hypercalcaemia
STEMI Equivalents
- Right sided MI
- Posterior MI
- AVR STE with widespread STD
- Sgarbossa criteria in LBBB and new onset LBBB
New onset bifascicular block
- Specifically LAFB + RBBB + ischaemic sounding chest pain
- Associated with prox LAD occlusion
Inferior wall MI
- STE of any degree in 2 of leads II/III/AVF
- STD in lead AVL +/- other leads
- Doesn’t meet normal STEMI criteria but represents and OMI
De Winters T waves
- A true STEMI equivalent, indication for both thrombolysis and cath lab
- ST/J depression that upslopes into a large T wave, often accompanied by STE in AVR
- Different from hyper acute T waves as this often persists whereas hyperacute changes to typical STEMI pattern within minutes
- Represents proximal LAD occlusion
- By definition the patient had acute angina that has now resolved and are (mostly) asymptomatic
Wellens Syndrome
- Represents a very high risk for proximal LAD occlusion in the next 24-48hrs
- Is an indication for acute but not neccesarily immediate PCI (unless symptomatic), it is NOT an indication for thrombolysis on its own
- Deep and symmetric TWI or biphasic TWI with terminal negativtity in leads V1-6
Sgarbossa criteria LBBB
- 3 or more points is 98% specific and 20% sensitive
- Concordant STE >1mm in any lead = 5 points
- Concordant STD >1mm in leads V1- V3 = 3 points
- Discordant STE > 25% of the S wave in leads with dominant S = 2 points
Sgarbossa modified for RV pacing
- No points, any of the 3 in isolation or combined are of equal value
- Approx 80% sensitive and specific
- Concordant STE >1mm in any lead
- Concordant STD >1mm in V1-V6
- Discordant STE >25% in the lead with the greatest STE/S wave ratio
COVID SCBD
Life threats
- PIMS-TS in children
- ARDS
- Secondary bacterial Sepsis
- PE and myocarditis
Differentials
- CAP/HAP
- Other viruses
- Autoimmune disease
- COPD/Asthma
Severity Grading
Mild
- Viral symptoms
- No SOBOE, no dyspnoea at rest
- Normal imaging, normal sats
Moderate
- Evidence of LRTI clinically or on imaging
- Sats >94% on room air
Severe
- Sats <94% on RA, RR >30, lung infiltrates >50% or Pa02/Fi02 <300mmHg
Life Threatening
- ARDS, septic shock, cardiogenic shock, severe VTE
- Usually intubated
High risk groups
- Immunocompromised
- Age >75
- Age >65 and unvaccinated
- Poorly controlled diabetes
- Renal/cardiac/liver failure
Treatment
Mild
- Simple analgesics and supportive care, monitor for deterioration
Moderate Outpatient
- As above, also for mild but at risk of deterioration
- Paxlovid (oral 5 day course) and Remdesevir (IV 3 day course) 1st line
- Molnupiravir 2nd line (oral 5 days)
Severe Inpatient
- Remdesevir 1st line
- Dexamethasone if needing 02
- Prophylactic vs therapeutic anticoagulation based on VTE risk
Critical
- As above
- Add PO baracitinibb if can swallow
- Add IV Tocilizumab if intubated or cant swallow