Emergency

Question 1

2008A Q2

A three-year-old boy is being resuscitated in the community following an immersion injury. What is the currently recommended ratio of external cardiac compressions to exhaled air resuscitations for a two rescuer resuscitation in this patient?

A. 3:1
B. 5:1
C. 15:2
D. 30:2
E. 30:1

Answer 1

C. 15:2

Question 2

2008A Q10

A 16-year-old girl is brought to the Emergency Department after attending a dance party. On presentation, she is extremely confused and agitated, she looks flushed and sweaty, and has dilated pupils. Her heart rate is 120 beats/minute and her blood pressure is 140/90 mmHg. She is complaining of some central chest pain.
Her presentation is most likely due to the ingestion of which of the following drugs?
A. Cannabis (Marijuana).
B. Diamorphine (Heroin).
C. Gamma Hydroxybutyrate (Grievous Bodily Harm, GHB).
D. Ketamine (Special K).
E. 3,4–Methylenedioxymethamphetamine (Ecstasy).

Answer 2

E. 3,4–Methylenedioxymethamphetamine (Ecstasy).

Question 3

2008A Q19

A ten-year-old girl is brought into the Emergency Department after being bitten by an unidentified snake. The snake venom detection kit is positive for brown snake venom from a bite site swab. Which of the following is the most common clinical effect in this envenomation?
A. Cardiotoxicity.
B. Coagulopathy.
C. Nephrotoxicity.
D. Neurotoxicity.
E. Rhabdomyolysis.

Answer 3

B. Coagulopathy.

Question 4

2008A Q30

A patient in the Emergency Department has the laboratory results shown below:

Serum Sodium 130 mmol/L [136 – 146 mmol/L]
Serum Potassium 6.5 mmol/L [3.5 – 5.0 mmol/L]
Serum HCO3 14 mmol/L [22 – 28 mmol/L]
Serum Chloride 115 mmol/L [95 – 107 mmol/L]
Venous pH 7.19 [7.34 – 7.44]
PCO2 42 mmHg [35 – 45 mmHg]
Base excess –10 mmol/L [-3 – + 3 mmol/L]

Which of the following is the most likely cause of the acidosis?

A. Acute renal failure.
B. Diabetic ketoacidosis.
C. Lactic acidosis.
D. Renal tubular acidosis.
E. Salicylate poisoning.

Answer 4

D. Renal tubular acidosis.

The distinguishing feature is the hyperchloremia.

Defect in renal tubules prevents reabsorbtion of all of the filtered bicarbonate or excretion of ammonium ions in the urine. RTA’s characterised by hyperchloremic metabolic acidosis (so normal anion gap). Na+ and H2O are taken with the HCO3.

_K+ _

• T1 (distal) low because K+ excreted instead of H+ during Na+ reabsorption. Can also be high due to voltage defects and hypoaldosteronism.
• T2 (proximal) low because HCO3 takes Na+ and H2O causing volume depletion - stimulates aldosterone which exchange K+ for Na+ (reabsorbed) in distal tubule.

Pt has metabolic acidosis with normal CO2, and low HCO3. Cl- is elevated indicating RTA. K+is high. Anion gap is normal at 7.5 (normal =6-16)

In acute renal failure, ketoacidosis, lacticacidosis and salicylate poisoning the anion gap would be elevated and no hyperchloraemia. (think of MUDILES)

Question 5

What is antidiuretic hormones action on the kidney?

Answer 5

Peptide released by posterior pituitary that promotes water reabsorption in collecting ducts.

Question 6

Describe the renin-angiotensin system and its physiologic role.

Answer 6

Renin is released from the JGA in response to low volume/low Na+ detected at JGA.

Renin is the first step in the angiotensin II pathway.

Angiotensin II acts in three ways

1. Vasoconstriction
2. Stimulates proximal Na+ reabsorption
3. Stimulates secretion of Aldosterone from adrenal cortex which stimulates Na+ reabsorption

Question 7

2008A Q37

In acute paracetamol overdose, which of the following mechanisms may result in hepatotoxicity?
A. Conversion by cytochrome P450.
B. Conversion to glutathione conjugate.
C. Conversion to sulphate conjugate.
D. Direct toxic effect of unchanged drug.
E. Metabolism to phosphate form.

Answer 7

A. Conversion by cytochrome P450

Paracetamol is metabolised in the liver to sulfate and glucoronide conjugates which are both non toxic and excreted in the urine. Of the remaining paracetamol, half is excreted unchanged in the urine. The remaining half is metabolized by cytochrome P450 to hepatotoxic NAPQI. At non toxic paracetamol doses, NAPQI is rapidly conjugated to hepatic glutathione (non toxic) and excreted in the urine. At toxic doses, the glutathione stores are depleted and hepatotoxic NAPQI accumulates.

Question 8

How would you expect a child with transverse myelitis to present?

Answer 8

• Motor and sensory deficitis involving one or both sides of spinal cord
  
  • paraesthesia (1st), weakness and sphincter dysfunction (urinary retention)
• Often associated with severe back pain
• May have partial recovery after 1-3 months.

Question 9

In the following drugs used in the ED setting for sedation, what are the onset/offsets times of the drugs?

1. ketamine
2. propofol
3. PO midazolam
4. chloral hydrate
5. Inhaled serflourane

Answer 9

1. Ketamine - quick onset/offset
2. Propofol - usually used in adults, used in intubation for kids, short onset/offset
3. Midazolam - may not always sedate. Unreliable onset/offset times. Might be long time after dose given.
4. Chloral hydrate - onset variable, long offset
5. Inh seroflourane - quick onset/offset

Question 10

What is mx of paracetamol OD?

Answer 10

• If max possible dose <200mg/kg OR total ingested dose <10g - no levels or intervention needed.
• If max possible dose ingested >200mg/kg OR >10g OR unknown dose
  
  • if tabs/capsules - measure levels at 4 hrs
  • if elixer - measure 2 hr level
    
    • <500mcg/L on graph - no action
    • >500mcg/L on graph - level at 4 hrs
• Activated charcoal if
  
  • presents w/i 1 hr and
  • no co-ingestion likely to decrease LOC and
  • Dose >200mg/kg

Question 11

Salicylate poisoning - acidosis or alkalosis?

Answer 11

Respiratory alkalosis followed by metabolic acidosis.

(remember mudpiles- high anion gap acidosis)

Question 12

What is anion gap likely to look like in ARF, DKA and lactic acidosis?

Answer 12

High anion gap.

Question 13

Best imaging for bleeding suspicious of Meckels?

Answer 13

Radionuclide scan

Question 14

Management of pulseless VT in ED?

Answer 14

Aysnchronous shock

Question 15

Shape of bleed of subdural haematoma?

Answer 15

Crescent

Question 16

Shape of extradural haematoma?

Answer 16

Lenticular

Question 17

What is Mannitol used for?

Answer 17

Cerebral oedema

Question 18

What Rx for hypertensive emergency?

Answer 18

Sodium nitroprusside

Question 19

Investigation for bileous vomiting?

Answer 19

Barium meal to look for volvulus

Question 20

Phases of iron overdose.

Answer 20

Phase 1

0-6 hrs - mucousal irritant. D & V, bleeding.

Phase 2

6-24 hours - seems well

Phase 3

Begins when acidotic. Cyanosed, coma, seizures, shock

Question 21

Ix in iron overdose?

Answer 21

AXR - if present, tablets will be seen.

If few, whole bowel irrigation.

If many together, surgical removal.

Question 22

Management of Iron overdose if symptomatic within 6 hours?

Answer 22

Desferoxamine

Question 23

Symptoms of anticholingergic toxidrome?

Answer 23

Blind as a bat,

mad as a hatter,

red as a beet,

hot as a hare,

dry as a bone,

the bowel and bladder lose their tone,

and the heart runs alone

Question 24

What NV structures affected by supracondylar #?

Answer 24

Median nerve and Brachial artery.

Question 25

What do you test for to determine if unilateral nasal discharge is CSF leak?

Answer 25

ß2-transferrin

Question 26

Treatment of pulseless VF

Answer 26

Shock 4J/kg

CPR 2mins

Shock 4J/kg

Question 27

What increases risk of invasive pneumococcal?

Answer 27

• Age <2, >65
• chronic CV, resp, liver disease, renal failure, nephrotic syndrome
• Diabetes
• asplenia
• immunocompromised for any reason
• CSF leak

Question 28

In the oxygen dissociation curve, a shift to the right decreases affinity for oxygen (easier to unload at tissues).

What conditions shift curve to right?

to left?

Answer 28

To right (decrease affinity)

• decreasing pH/more acidotic
• increasing temp
• increasing CO2
• increasing 2,3 DPG/2,3 BPG

To left (increase affinity)

• increasing pH
• carbon monoxide

NB. affinity of heme to CO is 230times that of oxygen so will preferentially bind CO. The other three of the the four tetramers bind O2 but affinity is so strong it won’t release at tissues. This is how CO poisoning occurs.

Question 29

Describe a subdural haemorrhage

Answer 29

Bleeding from rupture of bridging vessels between dura and arachnoid.

Crescent shaped on CT.

Crosses suture lines but limited by limited by dural attachments (falx cerebri and tentorium cerebelli)

Question 30

Describe an extradural haemorrhage

Answer 30

Between dura and skull

Doesn’t cross suture lines

Lens shaped

Question 31

describe a subarachnoid haemorrhage

Answer 31

Type of stroke

Bleeding into subarachnoid space

assoc c head injury or sudden “thunderclap” headache

Question 32

Describe intracerebral haemorrhage

Answer 32

Haemorrhage within brain tissue caused by trauma or haemorrhagic stroke.

Question 33

Describe intraventricular haemorrhage

Answer 33

• Occurs in subependymal or germinal matrix
• most frequent in
• Other RF include prolonged resus, RDS, chorioamnionitis, no maternal glucocorticoids

Question 34

Describe how CO exerts its toxic effects on inhalation

Answer 34

Reversible binding of CO to cytochrome A3.

CO binds to cytochrome oxidase disrupting cellular respiration. This is the toxic effects exerted.

CO binds to haemoglobin (carboxyhaemoglobin - COHb) and has >200 times the affinity of oxygen. Oxygen is displaced and there is impaired delivery to the cells. COHb does not correlate well with toxic effects.

CO displaces NO from protein (NO is potent vasodilator).

Treatment is high flow oxygen.

If levels >20%, consider intubation for 100% O2 to remove CO 200 times faster than room air.

Question 35

Anion gap is calculated by

(Na+K+)-(Cl-+HCO3-)

Mean anion gap is 8+/-2

What are the causes of a high anion gap metabolic acidosis?

Answer 35

MUDPILES

Methanol,

Uraemia (renal failure),

Diabetic ketoacidosis,

Paraldehyde,

Iron, isoniazid, inborn errors of metabolism,

Lactic acidosis,

Ethanol,

Salicylates

Question 36

When is sycope more likely to be of a cardiac nature?

Answer 36

Syncope is more likely to be of a cardiac nature in the following situations: – Syncopeduringexerciseorexertion

• Sudden onset without prodromal dizziness or awareness
• Complete loss of tone or awareness so that fall leads to injury
• History of preceding palpitations
• Significant tachycardia or bradycardia noted after the event
• Family history of sudden death

Question 37

What is the main treatment for all forms of RTA?

Answer 37

Bicarbonate

Question 38

What is the most common serious complication of etoh ingestion in a child?

Answer 38

Hypoglycemia due to impaired gluconeogenesis.

Infants have even less ability compensate for this with glycogenolysis due to decreased glycogen stores.

Question 39

What is Human Metapneumavirus commonly associated with?

Answer 39

LRTIs ie Bronchiolitis

RSV is in metapneumavirus family

Question 40

What is Erysipelas?

Answer 40

Erysipelas is a rare acute Group A
Streptococcus infection (aka S.pyogenes) involving the deeper layer of the skin and underlying connective tissue.
• Illness onset is abrupt and systemic symptoms are usually present. The most characteristic finding is a rash with a sharply defined slightly elevated border.
• Affected skin is swollen, red and very tender.

Question 41

When is Whole Bowel Irrigation (WBI) indicated in iron overdose?

Answer 41

Whole bowel irrigation is the decontamination treatment of choice in iron poisoning (activated charcoal does not absorb iron). WBI is indicated in children with an abnormal x-ray or those who are currently symptomatic.

Question 42

Describe Ramsay Hunt Syndrome

Answer 42

Ramsay Hunt syndrome (herpes zoster oticus with facial paralysis) may present with herpes vesicles in the ear canal and on the pinna, facial paralysis and pain. Other cranial nerves may be affected e.g. 8th nerve.

Treatment includes systemic antiviral agents e.g. acyclovir and corticosteroids

Up to 50% of patients with Ramsay-Hunt syndrome do not completely recover their facial nerve function.