This Week’s EMCQs – Week 3

QUESTION 1

A 2 year old boy is brought to a Paediatric Emergency Department after parents notice the child having palpitations while running in the park. He has normal physical examination

As part of his work up an ECG was performed. Attached below is his ECG.

ECG

Which one of the following is the most likely diagnosis of this patient?

A: Normal Paediatric ECG

B: Wolf Parkinson white Syndrome (WPW)

C: Right Bundle Branch Block (RBBB)

D: Congenital Short PR interval

A: Normal Paediatric ECG (Correct answer)

B: Wolf Parkinson white Syndrome (WPW)

C: Right Bundle Branch Block (RBBB)

D: Congenital Short PR interval

Commentary

This ECG of a healthy 2-year old boy displays many of the typical features of the paediatric ECG:

  • Heart rate of 110 bpm (normal for age).
  • Dominant R waves in V1-3.
  • RSR’ pattern (partial RBBB morphology) in V1.
  • Juvenile T-wave pattern (T wave inversion in V1-3).

Common normal findings on the Paediatric ECG:

  • Heart rate >100 beats/min
  • Rightward QRS axis > +90°
  • T wave inversions in V1-3 (“juvenile T-wave pattern”)
  • Dominant R wave in V1
  • RSR’ pattern in V1
  • Marked sinus arrhythmia
  • Short PR interval (< 120ms) and QRS duration (<80ms)
  • Slightly peaked P waves (< 3mm in height is normal if ≤ 6 months)
  • Slightly long QTc (≤ 490ms in infants ≤ 6 months)
  • Q waves in the inferior and left precordial leads.

QUESTION 2

A 67 year old heavy smoker man has been diagnosed recently with Small cell carcinoma of lungs.

 

Which ONE of the following paraneoplastic conditions would he get with the above lung cancer?

A: Hypokalaemia

B: Hyperkalaemia

C: Hyponatremia

D: Hypercalcaemia

A: Hypokalaemia

B: Hyperkalaemia

C: Hyponatremia (correct answer)

D: Hypercalcaemia

Commentary

Paraneoplastic syndromes are signs or symptoms that occur as a result of organ or tissue damage at locations remote from the site of the primary tumour or metastases.

Paraneoplastic syndromes associated with lung cancer can impair various organ functions and include neurologic, endocrine, dermatologic, rheumatologic, hematologic, and ophthalmological syndromes, as well as glomerulopathy and coagulopathy (Trousseau’s syndrome).

The histological type of lung cancer is generally dependent on the associated syndrome, the two most common of which are humoral hypercalcemia of malignancy in squamous cell carcinoma and the syndrome of inappropriate antidiuretic hormone secretion in small cell lung cancer that cause hyponatremia.

The symptoms often precede the diagnosis of the associated lung cancer, especially when the symptoms are neurologic or dermatologic.

The proposed mechanisms of paraneoplastic processes include the aberrant release of humoral mediators, such as hormones and hormone-like peptides, cytokines, and antibodies.

Treating the underlying cancer is generally the most effective therapy for paraneoplastic syndromes, and treatment soon after symptom onset appears to offer the best potential for symptom improvement.