Enviro. ~ Short Answer

Question 1.

A 5 year old boy is brought to your major referral emergency department by his mother, who states he has been bitten on his ankle by a snake while playing in their back yard one hour previously. He has a pressure immobilization bandage in place. He is currently asymptomatic with the following vital signs:

 

PR 90 per min

BP 95/55 mmHg

RR 20 per min

O2 Sat 99% room air

 

A.) What features on history would indicate envenomation?

Show Answer

  • Collapse
  • Nausea, vomiting
  • Bleeding
  • Weakness
  • Blurred vision
  • Dysarthria

(4 marks)

 

B.) What features on physical examination indicate envenomation?

Show Answer

  • Evidence of bleeding
    • Gingiva
    • IV sites
  • Evidence of descending symmetrical flaccid paralysis
    • Cranial nerve weakness initially
  • Evidence of deteriorating respiratory function
    • Poor effort/PEFR

(3 marks)

 

 C.) What investigations will you perform and why?

Show Answer

  • Coagulation profile – evidence of consumptive coagulopathy or anticoagulation
    • INR
    • APTT
    • D-dimer
    • Fibrinogen
    • FDP
  • CK
    • Evidence of rhabdomyolysis
  • FBC
    • Microangiopathic haemolytic anaemia and thrombocytopaenia (baseline)
  • U&Es
    • Renal dysfunction (baseline)

(5 marks)

 

One hour later the child is asymptomatic. Initial investigations are normal. The pressure

immobilisation bandage is still in place.

 

 D.) What is your management now?

Show Answer

  • Removal of PIB under observation
  • Any sign of deterioration then replace and give antivenom
  • Observation including neuro obs for the nest 12 hours
  • Repeat labs at 1, 6, 12 hours
  • If at any time there is deterioration or evidence of envenomation then give antivenom

(4 hours)

 

 E.) If features or envenomation evolve, how would you determine which type of antivenom to give?

Show Answer

  • Knowledge of snakes in that area
  • Clinical presentation
  • Laboratory findings
  • Snake Venom Detection Kit

(4 marks)

 

F.) Regarding the Snake Venom Detection Kit:

i. What is it used for?

Show Answer

  • Indicating the right monovalent antivenom to use once envenomation has been established

(1 mark)

 

ii. How is the sample taken?

Show Answer

  • Bite-site swab preferably through key hole in PIB
  • Urine second line
  • NOT serum or blood

(1 mark)

 

iii. Who should perform the test?

Show Answer

  • A trained experienced technician

(1 mark)

 

iv. How is a positive test detected?

Show Answer

  • First well to turn blue in 10 minutes

(1 mark)

 

v. How should the result be interpreted?

Show Answer

  • In conjunction with clinical assessment and other investigations

(1 mark)

 

G.) How would antivenom be administered in this patient?

Show Answer

  • Full non-invasive monitoring with one on one nursing
  • Vigilant for anaphylaxis
  • Dose determined by guidelines for that snake
  • Adult dose in 10 ml/kg of NSaline over 20 minutes
  • No premedication

(3 marks)

Author: J Haire

Ref: Tox Handbook p. 36-43 + 470


 

Question 2.

A 35 year old man presents after collapsing during a marathon on a hot day. His vitals are HR 143, BP 92/68, RR 24 bpm, O2 sats 94% 15 L NRB, Temp 40.8°C, GCS 9 E2 V3 M4 .

 

A.) What are the life-threats he is presenting with and what do you think are causing them?

Show Answer

  • Shock
    • Hypotension & tachycardia
    • May be due to dehydration or high-output cardiac failure
  • Altered level of consciousness
    • Airway at risk
    • Due to hyperthermia + shock
  • Respiratory failure
    • Due to ALOC
    • May be pulmonary oedema
  • Severe hyperthermia
    • Due to heat stroke

(4 marks)

 

 B.) What is the likely diagnosis?

Show Answer

  • Heat stroke

(1 mark)

 

 C.) What are your differential diagnoses?

Show Answer

  • Neurological
    • CVA
    • SAH
    • Seizure
  • Infectious
    • Meningitis
    • Encephalitis
  • Toxicological
    • Anticholinergic syndrome
    • Sympathomimetic OD
    • Serotonin syndrome
    • Neuroleptic malignant hyperthermia
  • Endocrine
    • Thyroid storm
    • Pheochromocytoma
    • DKA

 

(6 marks)

 

D.) What is you initial resuscitative management?

Show Answer

  • Resuscitation
    • Airway
      • Intubation
    • Breathing
      • Ventilation
    • Circulation
      • Judicious fluid boluses
      • Assess whether degree of failure
      • Start inotropes (vasopressors may interfere with heat loss and increase afterload)
    • Start to cool

 

(4 marks)

 

E.) What are the potential complications of heat stroke?

Show Answer

  • Hypotension from hypovolaemia or cardiac failure
  • Cardiac
    • High out-put cardiac failure
    • Myocardial damage
  • Respiratory
    • Pulmonary oedema
    • ARDS
  • Renal
    • Failure due to hypovolaemia or rhabdo
  • Muscles
    • Rhabdomyolysis
  • Neuro
    • Delirium
    • Coma
    • Seizures
    • Cerebral oedema
    • Encephalopathy
    • May get permanent neuro deficit
  • Metabolic
    • hypoK and later hyperK
    • HyperNa or HypoNa
    • HypoCa
  • haematological
    • thrombocytopaenia
    • DIC
  • Hypothermia due to overshoot

(10 marks)

 

F.) Describe the options for cooling this patient in order of escalation?

Show Answer

  • Non-invasive
    • Evaporation
      • Tepid water + fan
      • Can cause shivering
    • Ice water immersion
      • Can cause shivering
      • Impractical and unsafe in intubated/sick patient
    • Ice packs in neck, axilla, groin
      • Can cause shivering
      • Limited effect
    • Cooling blankets
      • Limited effect
    • Minimally invasive
      • Cold fluid infusion
        • Not recommended in high volumes due to cardiac failure
      • Invasive
        • Gastric, bladder, rectal lavage with cool fluid
          • Less invasive that other options
          • Easier to do
        • Pleural or peritoneal lavage
          • Very invasive
          • Takes time to do
        • Cardiopulmonary bypass
          • Very effective
          • Hard to do

(10 marks)

Author: J Haire

Ref: Tintinalli p. 1339-44


Question 3.

A 35 year old man is brought to your emergency department after being struck by lightning.

 

His vital signs are:

HR 120 /min

BP 100/60 mmHg supine

RR 18 /min

Temperature 35° Celsius

GCS 9

 

A.) What type of injuries can occur with lightning strike?

Show Answer

  • Directly due to the lightning strike e.g. Keraunoparalysis, cardiac arrest
  • Blunt trauma from being thrown
  • Blast injury e.g. tympanic membrane rupture, organ contusion
  • Thermal burns e.g. from direct hit, contact with metal that has been hit

(4 marks)

 

 B.) What may be the causes of this patient’s reduced GCS?

Show Answer

  • ICH
    • SDH
    • EDH
    • Traumatic SAH
    • Cerebral contusion/diffuse axonal injury
  • Heat-induced coagulation of the cerebral cortex
  • Keraunoparalysis

(3 marks)

 

 C.) What cardiac effects can lightning strike have?

Show Answer

  • Cardiac arrest immediately
    • Asystole usually
    • Can recover with even prolonged CPR
  • Global myocardial depression
  • Coronary artery spasm
  • Pericardial effusion
  • Dysrhythmias

(4 marks)

 

D.) What vascular effects can occur with lightning strike and how are they treated?

Show Answer

  • Vasomotor spasm in extremities can occur
  • Usually recovery spontaneously

(2 marks)

 

 E.) What ocular and auditory injuries can occur with lightning strikes?

Show Answer

  • Cataract formation
  • Tympanic membrane rupture

(2marks)

 

F.) List & describe 4 dermatological manifestations of lightning strike

Show Answer

  • Lichtenberg figures
    • Fine fern-like pattern on skin
    • Due to electron showering and not true burns
  • Flash burns
    • Mild erythema or corneal damage
  • Punctate burns
    • < 1 cm full-thickness burns
    • Look like cigarette burns
  • Contact burns
    • From metal close to skin that is heated when lighten strikes
  • Thermal burns
    • Superficial epidermal and superficial dermal burns
  • Linear burns
    • < 5 cm wide in skin folds e.g. axilla

 

(4 marks)

Author: J Haire

Ref: Tintinalli p. 1391-4


Question 4

A 55 year old man collapses on emerging from the water after snorkelling on a Queensland beach. He is rapidly transported to the emergency department.

 

 A.) List your differential for this man’s condition

Show Answer

  • Marine envenomation
    • Sea snake
    • Box jellyfish
    • Irukandji
    • Blue ringed octopus
    • Stone fish
  • Near drowning
  • Attacked by large marine life
    • Shark
    • Stingray
    • Crocodile
  • Medical causes of collapse
    • Cardiac
      • ACS
      • Dysrhythmia
      • Structural heart disease
      • Pulmonary embolus
    • vasovagal
    • Neurological
      • SAH
      • CVA
      • Seizure
    • Orthostatic hypotension
      • Bleeding
        • AAA
        • Trauma
      • Drugs
      • dehydration

(8 marks)

 

B.) How does Box jellyfish envenomation present?

Show Answer

  • Stings very painful and cause linear welts with crosshatched pattern
  • Systemic envenoming causes collapse or sudden death within few minutes of the sting
  • Cardiac effects
    • Hyper or hypotension
    • Tachycardia
    • Impaired cardiac contraction
    • Arrhythmia
  • Can get delayed hypersensitivity reactions
    • Pruritic erythema at sting site

(3marks)

 

 C.) What is the pre-hospital first aid to a victim of box jellyfish sting or envenomation?

Show Answer

  • If cardiac arrest, prolonged CPR and get to hospital for antivenom
  • Vinegar to sting

(2 marks)

 

 D.) What are the indications and dose of box jellyfish antivenom?

Show Answer

  • Cardiac arrest
    • Undiluted antivenom by IV push
    • Up to 6 ampoules
    • Can also give 10 mmol IV MgSO4
  • Systemic envenomation but not cardiac arrest
    • 3 ampoules in 100 ml NSaline over 20 mins
  • Pain
    • Morphine IV
    • If refractory to opiates then 1 ampoule of antivenom

(6 marks)

 

E.) How does Irukandji syndrome present?

Show Answer

  • Usually do not feel sting and no markings found
  • Systemic symptoms then develop
    • Impending doom
    • Agitation
    • Dysphoria
    • Vomiting
    • Sweating
    • Sever pain back, limbs abdomen
    • Hypertension and tachycardia
  • More severe effects of catecholamine release
    • Toxic cardiomyopathy
    • Cardiogenic shock
    • Pulmonary oedema
    • ICH

(5 marks)

 

 F.) What first aid measures can be done on scene for Irukandji syndrome?

Show Answer

  • Generous vinegar to inactive nematocysts

(1 mark)

 

G.) What is the management of Irukandji syndrome?

Show Answer

  • Supportive
  • Pain
    • IV fentanyl
    • Often need large doses
  • Nausea
    • Promethazine
  • Hypertension refractory to opioid analgesia
    • GTN infusion
  • Severe catecholamine effects
    • ECG for dysrhythmia and treat as per dysrhythmia
    • May need inotropes for cardiomyopathy
    • May need intubation/ventilation for pulmonary oedema
    • May need surgery for ICH
    • MgSo4 and benzodiazepines have been tried

(6 marks)

Author: J Haire

Ref: Tox Handbook 452-6


Question 5.

A 20 year old man presents to your emergency department with central chest pain that commenced after recreational drug use at a party two hours earlier.
His observations are:

HR 108 /min
HR 150/85 mmHg supine
SO2 98 %

 Environmental Pix 1 SA

 

A.) Describe the abnormalities in this x-ray.

Show Answer

  • Air around the cardiac border and upper mediastinum
  • Subcutaneous emphysema in the neck and shoulder
  • Pneumomediastinum

(3 marks)

 

B.) What is the management of this condition?

Show Answer

  • Search for trauma to larynx, trachea, major bronchi, pharynx or oesophagus
  • If those ruled out then supportive management with analgesia

(2 marks)

 

C.) What would be your discharge criteria for this patient?

Show Answer

  • No further abnormality found
  • Tachycardia nad hypertension settled
  • No respiratory distress
  • No longer impaired from drug effect
  • Safe disposition with responsible adult

(4 marks)

Author: J Haire

Ref: Tintinalli p. 1754

 


 

Question 6

A 25 year old man sustains a pelvic injury in a high speed motorcycle accident.

A pelvic X-ray including a retrograde cystogram is performed.

 Environmental Pix 2 SA

A.) Describe the abnormalities in this x-ray

Show Answer

  • Pelvic fractures
    • Superior and inferior pubic rami fractures on left
    • Vertical left sacral fracture
    • Pubic symphysis diastasis
    • Vertical shear fracture left pelvis
  • Cystogram
    • Indistinct superior border of bladder
    • Likely bladder rupture

(6 marks)

 

B.) How are bladder ruptures categorised?

Show Answer

  • Intraperitoneal or extraperitoneal or combination

(3 marks)

 

C.) How does their treatment differ?

Show Answer

  • Intraperitoneal rupture requires surgical exploration and repair
  • Extraperitoneal often is treated conservatively with a urinary catheter and antibiotics except when:
    • the IDC does not drain the bladder properly
    • there is associated rectal or vaginal injury
    • associated injury of bladder neck
    • open fixation of a pelvic fracture (to avoid contamination)

(3 marks)

Author: J Haire

Ref: Tintinalli p. 1776

 


 

Question 7

A 50 year old man presents with shortness of breath and sharp central chest pain of 24 hours duration. He has no past medical history and is on no medication.

Environmental Pix 3 SA

A.) Describe the abnormalities on this ECG

Show Answer

  • Narrow complex tachycardia rate approx. 200 bpm
  • P waves hard to see but can see them in V2
  • Short PR interval 80 s
  • Electrical alternans
  • TWI inferiorly
  • ST depression V2-5

(4 marks)

 

B.) What is the differential diagnosis?

Show Answer

  • Common:
    • Pericardial effusion
    • Conduction abnormalities
      • WPW/accessory pathway
      • Prolonged QT syndrome
      • Bradycardia
      • Paroxysmal tachycardia
    • Hypothermia
  • Less common:
    • Cor pulmonale
    • HTN
    • Electrolytes
    • CA spasm/occlusion
    • Rheumatic HD

(5 marks)

 

C.) What is the diagnosis likely to be in this patient?

Show Answer

  • SVT caused by an accessory pathway

(1 mark)

Author: J Haire

Ref: ECG in Emergency Medicine and Acute Care p. 222

 


 

Question 8

A 78 year old man is brought to your emergency department after collapsing at the local shopping centre that morning. He is now alert with no memory of the event. His observations are normal.

Environmental Pix 4 SA

A.) List the abnormalities in this ECG

Show Answer

  • Intermittently paced rhythm
  • Underlying complete heart block
  • Hard to know if initial beats are sinus or cannot see pacing spikes in limb leads; can see pacing spikes before QRS in precordial leads
  • When paced rate is approx. 65 bpm
  • Ventricular pauses of up to 3s when not paced
  • QRS shows pacing morphology i.e. wide
  • P wave normal morphology and no pacing spike before it

(3 marks)

 

B.) What type of pacemaker could this be?

Show Answer

  • DDD
    • Atrial impulse sensed and pacemaker inhibited
    • Ventricular impulse not sensed so paced

(2 marks)

 

C.) What type of pacemaker failure is this?

Show Answer

  • Failure to pace

(1 mark)

 

D.) What can cause this?

Show Answer

  • Oversensing
  • Pacing lead problems (dislodgment, fracture)
  • Battery or component failure
  • Electromagnetic interference

(3 marks)

 

E.) How can you investigate this?

Show Answer

  • CXR for lead dislodgement, fracture
  • Interrogation for oversensing, battery, component failure

(2 marks)

Author: J Haire

Ref: ECG in Emergency Medicine and Acute Care p. 136-8

 


 

 

 

 

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