Emergency Medicine Flashcards
What strength of adrenaline in anaphylaxis?
+ Doses
1:1000
- <6y: 150 micrograms
- 6-12y: 300 micrograms
- >12y: 500 micrograms
Presentation of anaphylaxis
Mins after exposure
- Urticaria, angioedema
- Upper airway obstruction
- Abdominal cramping / diarrhoea
- Shock
What are the phases of bone healing?
- Inflammatory phase (hours-days): Inflammation, formation of haematoma –> primary calculus
- Reparative phase (days-weeks): Thick callus forms around bone.
- Remodelling phase (months-years): Osteoblastic / osteoclastic activity
May need to repeat xray - see callus formation
Types of shock
- Hypovolaemic - haemorrhage
- Distributive - Sepsis, anaphylaxis
- Cardiogenic - Arrhythmia
- Dissociative - Profound anaemia
- Obstructive - PE, tamponade, pneumothorax
What is pre-load?
Tension in ventricular wall at end of diastole (“Stretch”)
What is afterload?
Tension in left ventricular wall required to push blood into aorta (“Squeeze”)
What is myocardial contractility?
The ability of the heart to react to pre-load and after-load
Noradrenaline/ adrenaline mechanism of action
- Alpha-1 receptors
- Increased vasc. resistance (increased HR / SV / CO)
Dopamine mechanism of action
- Alpha-1, Dopamine-1 receptors
- Increased vascular resistance
- Selective vasodilation: renal, cerebral, coronary, mesentry
Dobutamine mechanism of action
- Beta-1/2 receptors
- Increased HR and CO
Vasopressin mechanism of action
- V1/2 receptors
- Increased vasc. resistance due to reduced UO and vasoconstriction
What are the reversible causes of cardiac arrest?
4 H’s: Hypotension, Hypoxia, Hypothermia, Hypo/hyperkalaemia
4 T’s: Tamponade, toxins, tension pneumothorax, Thrombus
How is cardiac output calculated?
CO = HR x SV
How is BP calculated?
BP = SV x Vascular resistance
Description of superficial (simple erythema) burns
Erythema. No blistering. +/- peeling
Epidermis only
1 week healing.
Description of Superficial partial thickness burn
Wet erythema and blistering. Painful. Usually no scarring. 2w to heal.
Epidermis and upper 1/3 dermis.
Description of Deep partial thickness burn
Yellow / white. Blistering. Less painful that superficial. Risk scarring. Takes 8 weeks to heal.
Deeper layers of dermis
Description of full thickness burn
White/ brown. Painless. Scarring / contractures.
All layers of skin.
How to calculate fluid resus in burns
4 x body weight x % area of burn
In 24 hours
50% in 1st 8 hours, maintenance fluid given on top of this.
Burns criteria for referral to a specialist centre
- > 5% total SA
Burns to face, hands, feet, genitalia, perineum - Full thickness
- Electrical / chemical burns
- Inhalation
- Circumferential burns
- Suspicious
What is Cushing’s Reflex?
Result of raised ICP
- Irregular respirations
- Bradycardia
- Hypertension
Presentation raised ICP
- Cushing’s response
- Reduced GCS
- Headache - morning / coughing / sneezing
- Focal neurology
- Retinal haemorrhage
- Sunset sign - downward looking pupils
- Papilloedema
Treatment raised ICP
- Elevation of bed 30 degrees (improved venous return)
- Supportive
- Fluid restriction
- Mannitol 20%/ 3% saline
- Surgical decompression
- Strict regulation ventilation / temp
Indications for CT Head
- Suspicion NAI
- Post-traumatic seizure
- GCS <14 on arrival, <15 2 after injury
- Open, depressed, basal skull fracture
- Focal neuro deficit
- Bruise / swelling >5cm in <1 y/o
>1 of: LOC >5 mins, drowsiness, amnesia >5mins, >2 x vomits, dangerous mechanism
Presentation spinal cord injury
Loss of motor / sensation function
Unopposed parasympathetic response –> bradycardia / hypotension
Pathophysiology drowning
- Submersion / immersion in liquid
- Asphyxia +/- aspiration
- Hypoxia + ischaemia
- Multisystem failure
What is diving reflex?
Facial contact with cold water –> bradycardia and vasoconstriction to preserve blood supply to vital organs
Describe primary prevention
Removal of circumstances causing injury eg lock on medicine cupboard
Describe secondary prevention
Reduce severity of injury eg bike helmet
Describe tertiary prevention
Optimal treatment eg good first aid
Paracetamol overdose: Mechanism and presentation
Mechanism: NAPQI produced by saturation of life CYP450, unable to conjugate to glutathione
Presentation: Abdo pain, vomiting, liver failure
Paracetamol OD management
N-acetylcysteine
- Over Tx line
- Staggered >1 hour
- >150mg/kg
Presentation and management of ingestion button batteries
Clear history
Abdominal pain +/- perforation
Tx: AXR / CXR, endoscopic removal
Carbon monoxide poisoning: Mechanism and presentation
Mechanism: Binds to Hb –> lower o2 transport
Presentation: Headache, nausea, drowsy, confusion, coma
Worse prognosis in Preg, cardio conditions, (resp conditions)
CO poisoning managment
High flow o2
Salicylate OD: Mechanism and presentation
Mechanism: Stimulates resp. centre, uncouples oxidative phosphorylation
Presentation: Vomiting, tinnitus, resp. alkalosis (acidosis = late), hyperventilation, sweating, diplopia, dizziness
Salicylate OD management
<1 hour - activated charcoal
Urine alkalinisation
Haemodialysis
Symptoms of theophylline OD
Hyperventilation / resp. alkalosis
Vomiting
Agitation
Dilated pupils
Hyperglycaemia
Tachycardia.
TCA OD: Mechanism and presentation
Eg amitriptylline
Mechanism: Interferes with cardiac conduction (blocks Na+ channels)
Presentation: Tachycardia, arrhythmia, drowsy, seizure
TCA OD management
Sodium bicarb
Supportive
Presentation organophosphate poisoning
Miosis - antimuscarinic eye effects
Ethylene glycol poisoning: Mechanism and presentation
Eg antifreeze
Mechanism: Toxic metabolites interfere with cellular energy production
Presentation: Intoxication, tachycardia, severe met. acidosis, renal failure, HTN
Ethylene glycol/ methanol poisoning management
Fomepizole
Alcohol
Competitive inhibitors of alcohol dehydrogenase
Iron OD: Mechanism and presentation
Mechanisms: Corrosive –> disruption of oxidative phosphorylation –> free radicals
Presentation: Vomiting, diarrhoea, GIB, seizures, coma, gut strictures
Iron OD Tx
IV Desferrioxamine (binds to free iron and enhances renal elimination)
Activated charcoal if <1 hour
Amphetamine OD presentation and management
Dilated pupils
Hypertension, tachycardia
Skin pallor
Hyperexcitability, agitation
Hypokalaemia.
Hyperpyrexia
Rhabdomyolysis
Acute renal / liver failure
Tx: beta blockers, BDZ
Treatment of beta-blocker OD
Atropine
Glucagon
How is Anion gap calculated
[(Na+ + K+) - (HCO3- + Cl-)]
Causes of raised anion gap (>16 mmol)
MUDPILES
Methanol
Uraemia
DKA
Propylene Glycol
Iron and Isoniazid
Lactic acidosis
Ethylene glycol
Salicylates
What is Klumpke’s palsy and how does it present?
Damage to T1 SNS chain –> ulnar and median nerves. Excessive abduction of arm.
Can move arm but not hand
Loss of sensation thumb, index and middle finger
How to calculate cerebral perfusion pressure
Cerebral perfusion pressure = MAP - ICP
Presentation of lead poisoning
- Pica eg lead containing products, drinking water from old lead pipes
Nausea
Abdo pain
Constipation
Blue discolourationg of gums
Neuropathy, GDD, impaired cognition
Classification of hypovolaemic shock
I-II: <25%
III: 25-40%
IV: >40%
Which nerve is most likely to be damaged in distal radius fracture?
Median nerve
Describe features of Rheumatic fever
GAS infection
Mainly 4-15 years.
Common middle and east Asia, Eastern Europe and SA.
Fleeting migratory polyarthritis affecting large joints.
What is “pulled elbow” / “Nursemaid’s elbow”?
Radial head subluxation. Presentation = holding arm to side with extended elbow and pronated forearm. Comfortable unless asked to move.
<6y (weak annular ligament). Caused by sudden pull on extended, pronated forearm.
