Question of the week


Previous weeks’ questions

Dental trauma
Question of the week 5th April 2019:
A) Please describe this 5 year old child’s dental injuries (Use technical terms and number the tooth involved) B) What imaging is required?
C) How can this be treated in ED?
D) Bonus question: At what age do children have their milk teeth replaced by permanent teeth?
Images: Internet open access forum

Prize Winner: Dr. Jeanette Koay
(RMO, Launceston general hospital
Answers in comment section below

Question of the week 24.03.2019:
What is the salient abnormality seen in this chest X-ray of a patient who presents with severe abdominal pain? Please describe 2 other signs that could be seen in this condition. Name 3 broad mechanisms by which this condition can develop. Please post your answers in the comments section below.

Images Courtesy: Dr. Michaele Rawson, ED registrar Launceston hospital.

Prize winner: Katie Scott,
Medical Diagnostic Radiographer,
Launceston General Hospital

Infant ECG 1
Infant’s ECG #1 (on arrival)
Infant’s ECG #3 (post fluid 10 ml/kg bolus)

Question of the week 4th March 2019:
What is the rhythm seen on these 2 ECGs of a 6 month old baby who presents with a few days of febrile illness? Please provide answers in the comments section below. Bonus question: How can this be managed?

Images courtesy: Dr. Jacinta O’Rourke, RMO, and
Dr. Matt Labattaglia FACEM, Launceston general hospital
Prize winner: Dr Svetlana Rivilis,
Emergency registrar, LGH

Question of the week 22.02.2019:
What is the classification of the fracture sustained by this 44 year old lady who fell down sand dunes while running? Please answer in the comments section below 
Clue: Answer starts with ‘SCH…’

Image courtesy: Dr Michaele Rawson, Emergency registrar LGH

Prize winner: Dr. Nicole Kar Ye, LGH

Soft tisssue XR neck

Question of the week 10.02.2019:
What is the salient abnormality in this lateral soft tissue neck X-ray of a child with dysphagia? 

Image courtesy: Dr. Linda Chow FACEM, LGH Emergency department.

Prize winner Dr. Bronte Leonard, Medical intern LGH.


    1. Good job, Nicole. Spoken like a true orthopod. I agree. Turns out, there is also Moore & Hohl Classification of fractures of tibial plateau. Luckily, Type 1 Schatzker is the same as Hohi Type 1 -coronal split fracture.

    2. Great thought team! However, to meet criteria for normal sinus rhythm, each QRS complex must be preceded by a normal P wave. P waves have to be upright in leads II, III and AvF. If P waves inverted in inferior leads, that means P waves traveling retrograde from A low atrial or high junctional pacer.

      1. Mid junctional rhythm- no P waves ( P waves will be within QRS due to simultaneous activation of atria and ventricles.

        In low junctional – P wave occurs after QRS, in ST segment and is inverted in leads II, III, and aVF.

        In Left atrial rhythm, P waves inverted in inferior leads as well as lateral leads.

  1. Good work Nicole. You win this week’s prize.
    The Schatzker classification system divides tibial plateau fractures into six types

    Schatzker I: lateral tibial plateau fracture, with minimal (<4mm) depression or displacement.
    Schatzker II: lateral tibial plateau fracture with fragment depression
    Schatzker III: compression fracture of the lateral (IIIA) or central (IIIB) tibial plateau
    Schatzker IV: medial tibial plateau fracture with split/depressed component
    Schatzker V: bicondylar (lateral and medial) tibial plateau fractures
    Schatzker VI: transverse tibial plateau fracture with metaphyseal-diaphyseal discontinuity (also known as Type C articular fracture in the AO classification)

  2. The ECG shows a narrow, regular complex tachycardia with a heart rate of 204 beats per minute, consistent with supraventricular tachycardia (SVT). There are regular atrial and ventricular beats with 1:1 conduction.
    P waves are present but are buried in the T waves.

    SVT is the most common arrhythmia in children.

    Fever often incites SVT. Infants with SVT often present with findings similar to sepsis.

    Etiology of paroxysmal SVT in infants can be visualized with a circle chart:

    Symptoms: In infants and young children SVT is hard to recognize and be present for longer duration. Whereas older children complain of palpitations and chest discomfort, baby may be in SVT for ≥ 2 days at home with nonspecific symptoms of irritability, poor feeding, pallor, mottled, dyspnea.
    Concurrent work up for sepsis and SVT is challenging in babies but necessary.

    – SVT presents as regular tachycardia with HR 180-300/min
    – Babies in SVT eventually develop CHF and may present in shock.

    • Monitor with continuous ECG and check BP frequently.
    • Apply pediatric defibrillator pads

    If child is shocked (i.e. hypotensive, with poor peripheral perfusion, altered mental status) – Proceed to direct current synchronized cardioversion with sedation if possible.
    -Establish access: IV or IO
    – Give oxygen 10 liters/min by facemask
    -Start with 1 Joule/kg Synchronized shock
    – If 1Joule/kg is not effective, increase to 2 Joule/kg.

    Stable child: – start with Vagal maneuvers (elicit gag reflex, ice pack over eyes/iced water to face for 30 seconds, rectal temperature).
    If child is able to follow instructions, try technique of the Revert trial (Applebee, Lancet 2015):
    1. While sitting at 45 degrees, ask pt. to blow into 10 ml syringe for 15 seconds – with enough force to move the plunger
    2. Immediately, at the end of the strain, lie patient flat and legs are raised to 45 degrees for 15 seconds.
    3. Return to sitting position for 45 seconds.

    If Vagal maneuvers fail, time to proceed to adenosine
    – Dose 0.1 mg/kg rapidly given and followed by 10ml saline flush.

    1. Second ECG demonstrates regular narrow complex rhythm with HR 174/min. P waves present appear different than sinus P waves as they are buried in the T waves. The rhythm is not sinus. Since HR is at the upper limit of normal for 6 month old (100-180/min) and if the child remains hemodynamically stable, he/she might be observed for spontaneous reversion into sinus rhythm.

      Although SVT mostly affects kids with normal hearts, structural heard disease is a risk factor for SVT. If the child is well, outpatient follow up with cardiology and transthoracic echo is appropriate.

      1. Can I ask, discussing with Zac VT, Lewis and Clare today at ALs- if this is SVT how do we explain the aVL lead in sinus with clear conducted P waves? Does that mean it is more likely a sinus tachy which responded to the fluid bolus lowering the rate?

  3. So, presence of P waves in isolated lead (aVL) is not sufficient to meet criteria for NSR. In other 11 leads, P waves are present but appear different from sinus P waves as they are buried in T waves. So, rhythm is still SVT.
    We do not know if the baby 👶 only got IVF, there might have been vagal manoeuvres involved ( or adenosine if vágal manoeuvres failed). We were not told if the patient was stable or not stable…if the pt was hypotensive, had poor peripheral perfusion or altered, the treatin team might have used electricity to treat a shocked child.

  4. A very interesting ECG conundrum. Good points and arguments from all the people who have commented so far.
    Don’t we all wish life was as easy as “p waves present=sinus; p-waves not present =not sinus”?
    Unfortunately that’s not how things always work.

    The major contending differentials in this case are:
    1. Sinus tachycardia
    2. Sinus node re-entrant tachycardia
    3. Atrial tachycardia
    4. AV nodal Re-entrant tachycardias (popularly nicknamed ‘SVT’).

    All these are supra ventricular tachyarrhythmias because they all have origin of electrical impulse above the ventricle.
    The major classification of supraventricular tachyarrhythmia is as follows:
    Atrial tissue origin
    1. Sinus tachycardia
    2. Sinus nodal re-entrant tachycardia
    3. Atrial tachycardia
    a. -Focal
    b. -Multifocal (irregular)
    4. AF (irregular)
    5. A flutter (regular unless variable block)

    AV nodal / junctional origin
    1. AVRT
    a. Retrograde
    b. Antegrade
    2. AVNRT
    a. Slow fast (common) 80-90%; [retrograde p not seen or buried in QRS]
    b. Fast slow (uncommon) 10%; [retrograde p waves clearly seen after QRS]
    c. Slow slow (atypical) 1-5%
    3. Junctional tachycardia

    Some hints that may help differentiate sinus tachycardia from the other regular tachyarrhythmias:
    1. Look at the patient’s presenting complaint. (Distressed or not)
    2. Look for the beginning and/or the end of the tachycardia (gradual in sinus tachycardia, instant in others)
    3. Look for rate variability (highly variable in sinus tachycardia)
    4. Look carefully for p waves (and the morphology of it).

    Discussion re: main differentials:
    • The retrograde P wave is obscured in the corresponding QRS or occurs at the end of the QRS complex as pseudo r’ or S waves
    • P waves are often hidden – being embedded in the QRS complexes.
    • Pseudo R’ wave may be seen in V1 or V2.
    • Pseudo S waves may be seen in leads II, III or aVF.
    • In most cases this results in a ‘typical SVT’ appearance with absent P waves and tachycardia

    • Due to the relatively long ventriculo-atrial interval, the retrograde P wave is more likely to be visible after the corresponding QRS.
    • QRS-P-T complexes.
    • Retrograde P waves are visible between the QRS and T wave.

    • Tachycardia with a P-wave seen in mid-diastole… effectively appearing “before” the QRS complex.
    • Confusing as a P wave appearing before the QRS complex in the face of a tachycardia might be read as a sinus tachycardia.

    Sinus Node Re-entrant Tachycardia (SNRT)
    • Caused by re-entry circuit close to or within the sinus node.
    • Abrupt onset and termination.
    • P wave morphology is normal.
    • Rate usually 100 – 150 bpm in adults. Proportionately higher in children
    • Often terminates with vagal manoeuvres.

    Atrial tachycardia
    Atrial tachycardia is a form of supraventricular tachycardia, originating within the atria but outside of the sinus node
    • Atrial rate > 100 bpm.
    • P wave morphology is abnormal when compared with sinus P wave due to ectopic origin.
    • There is usually an abnormal P-wave axis (e.g. inverted in the inferior leads II, III and aVF)
    • At least three consecutive identical ectopic p waves.
    • QRS complexes usually normal morphology unless pre-existing bundle branch block, accessory pathway, or rate related aberrant conduction.
    • Important to recognise persistent AT and treat to avoid cardiomyopathy and heart failure.

    In clinical practice, such conundrums are best dealt by correlating with the clinical context. In essence, treat the patient, not just the ECG.
    For example, in this particular case, the child had distressing persistent tachycardia ~175/’ even after temperature was lowered and was fluid loaded. Hence, the treating physician performed a vagal manoeuvre (placed an icepack on the infant’s face for 25 seconds) with instant (and persistent) reduction of the heart rate to 130s, with concurrent resolution of the infant’s irritable state.

    Here’s the ECG post vagal manoeuvre:

    Luckily in this case we have the fortune of favourable hind sight. After detailed discussions (in- house and with an expert cardiologist), the most feasible explanation of the child’s initial arrhythmia was that it was a Sinus re-entrant tachycardia. The next closest differential is the elusive and rare slow-slow AVNRT. Atrial tachycardia with impulse origin near the SA node is a close differential. It is also reasonable to think that this was a sinus tachycardia which resolved with a vagal manoeuvre, yet the response was too fast.
    Based on discussions with our cardiologist, if the child had not responded to temperature lowering, fluid loading, vagal manoeuvres etc., the next logical step would be to trial Adenosine, which is deemed safe and effective in such tachyarrhythmias. This is best done in conjunction with expert consults and adequate referrals would be essential for follow up.

    For all the hard work done by Dr. Rivilis on answering in detail why she felt it was a SVT and the amount of reading she has done to compile the responses, she is the most suitable prize winner of this week.

    References/ consults: The Heart, LITFL,, Amal Mattu ECG companion, Cardiology unit LGH.

  5. That is too kind, but it is not me who deserves the prize this week. I really appreciated learning and I learned a lot just now from last post. Thank you, Dr, Mohan! It is you, who deserves the prize this week. Are you a fellow “mattuian”?

    On a completely different topic, do you think we should link post a link for the FREE Livestream UMEM Emergency cardiology symposium on site? I sent you an email invite via

  6. The salient abnormality in the chest xray above is sub diaphragmatic air indicating pneumoperitoneum.

    Other signs that could be seen in this condition are continuous diaphragm sign which is shown in the provided CXR and described in the reference below and cupola sign representing gas trapped under the central tendon of the diaphragm on a supine film.

    Pnemoperitoneum is commonly seen in patients post abdominal surgery. Penetrating abdominal trauma can also be a cause but it is not often seen in our department. It can also develop as a result of the perforation of a hollow viscus (usually a perforated ulcer) or from the tracking of gas from the chest. Some examples of intrathoracic causes are: positive pressure ventilation, pneumothorax/pneumomediastinum, pulmonary sepsis, thoracic trauma, CPR and barotrauma.

    Spontaneous pneumoperitoneum can also be caused by the introduction of air through the female genital tract. Gynaecologic causes are not often discussed but are important to consider in the examination to potentially avoid unnessesary laparoscopy. These could be vaginal douching, post-partum exercises, oral-genital insufflation and intercourse. is an excellent resource for learning to recognise the radiographic signs of pneumoperitoneum. This is what it says for the signs I’ve mentioned above.

    ‘The continuous diaphragm sign is a chest radiograph sign of pneumomediastinum or pneumopericardium if lucency is above the diaphragm, or of pneumoperitoneum if lucency is below the diaphragm.

    Normally the central portion of the diaphragm is not discretely visualised on chest radiographs as it merges with the cardiac silhouette. If the diaphragm can be seen continuously across the midline then this is highly suggestive of free gas within the mediastinum, pericardium or peritoneal cavity.’

    Another great article is available on the Medscape website. It goes into a lot of detail about peritoneal gas and how it appears in imaging. You have to sign in to read it but it is free.

    In a nutshell: CT is the gold standard. Ultrasound can be helpful because it is noninvasive, no radation etc and can detect free fluid. Erect CXR is reasonably quick and sensitive but the patient really has to sit up for a minimum of 10 minutes first. TIP: You don’t have to request ‘Erect CXR’. If you write ?free air/free gas/air under diaphragm/pneumoperitoneum in the clinical notes on the request we (radiographers) will do what we can to demonstrate it. Sometimes It may be a decubitus chest or a lateral depending on the patient.

    1. Katie, I totally agree with Dr. Mohan- stellar answer!
      Just to add a factoid – one more NOT COMMON sign on your differential is a Chilaiditi syndrome.
      Chilaiditi syndrome is a mimic of subdiaphragmic air s a rare condition when pain occurs due to transposition of a loop of large intestine (usually transverse colon) in between the diaphragm and the liver. Chilaiditi is not a pneumoperitoneum but is pseudopneumoperitonium.

      As per radiopaedia: features that suggest a Chilaiditi syndrome (i.e. Chilaiditi sign) include:

      – On Plain radiograph:

      1. gas between the liver and diaphragm
      2.haustra within the gas suggesting that it is within the bowel and not free.

      Of course, in the work up of undifferentiated distended abdomen in a patient presenting with abdominal pain one will proceed to CT. Chilaiditi syndrome is treated non operatively e.g.with analgesia

      This is old news, Demitrius Chilaiditi apparently published his description of interposition of the transverse colon between the liver and right diaphragm in 1910 but it has it is more fair to call this sign Cantini sign. According to radiopaedia, Cantini’ s was the first description of interposition of colon between the liver and the right hemi diaphragm was published by Cantini in 1865

  7. A) This child has an extrusion injury of 51, possible subluxation of 52 and 61.
    B) An OPG in ED is required to look for other injuries such as fractured mandible or TMJ injury. Dental x-rays i.e. periapical radiograph is best for looking at the presence of any alveolar fractures or any damage to the underlying permanent tooth bud.
    C) Since this child is only 5, all his teeth would likely be primary teeth so the injured teeth can usually be
    – monitored or
    – temporarily held together with glue and aluminium foil or cemented (if a dental kit is available in ED) until the patient sees the dentist or

    Urgent review by a dentist is required.

    The injured teeth are not usually re-positioned because of close proximity and risk of damage to underlying permanent tooth.

    D) Permanent incisors usually erupt between 6 and 8 years of age. By 14+ years of age, all their milk teeth should have been replaced by permanent teeth.

  8. Blistering hot answer Jeanette !!!

    1. There are several systems worldwide for numbering/ notation of teeth. In Emergency practice we commonly use the ISO system recommended by WHO:

    The pictures below demonstrate the ISO dental notation system.
    (Image courtesy Partinya FDI-Zahnschema Quadranteneinteilung (aus Patientensicht gegen den Uhrzeigersinn; Wikipedia).

    In this child it is the primary tooth # 51 is extruded.
    Blood and gum injury makes it appear like the child may have subluxation of the teeth 52 and 61, however they are structurally intact.

    2. OPJ would be the right test for excluding other fractures or other injuries (including to teeth buds).

    3. Cannot better Jeanette’s answer on this. Monitor, secure or extract.
    The only point to add is that in children there is an existing risk of the loose tooth being ingested or inhaled if it comes loose especially while asleep. Hence monitoring it without securing may be slightly risky in a child.

    4. As per Jeanette.

    Fantastic work, Dr. Jeanette Koay! Your answers are outstanding. You win the prize of the week.

    For more details on dental trauma and know where the dental kit lives in the department, please click here to access the user-friendly dental trauma guide on this website.

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