Discussion
This case illustrated an unusual ECG pattern of diffuse J-point
elevation which is non-cardiac in aetiology. The authors would like to
specifically mention that there is no ST-segment upsloping, but rather
‘J-point elevation’ with an elevated cardiac troponin level. Such an ECG
pattern can be alarming, as it may suggest early changes of acute
myocardial infarction. Of note, her deterioration during presentation
was without symptoms typical of myocardial infarction and there was a
resolution of ST-segment changes following electrolyte correction and
hydration. These findings strengthen the proposition that electrolyte
imbalance secondary to gastrointestinal loss and the newly diagnosed
hypoparathyroidism was the cause of the global ST-segment elevation. ECG
changes of global ST- segment elevation is well recognized in
hyperkalemia. However, reported cases associated with hypokalemia are
rare. A pseudoinfarction ECG pattern as seen in hyperkalemia was noted
previously in a patient with severe hypokalemia undergoing correction,
and was postulated to be associated with rapid changes in
intracellular/extracellular [K+] ratio6.
Hypocalcemia has been shown to simulate ECG patterns of myocardial
injury with subsequent investigations showing no evidence of
infarction8-9 and it has also been suspected to
provoke coronary vasospasm9. Dehydration, severe
hypotension, congestive heart failure, coronary vasospasm, myocardial
bridging, and hypertensive emergencies have all been linked to provoking
conditions that can cause a mismatch in myocardial oxygen supply (type
II myocardial infarction). An elevated cardiac troponin has been found
in these situations10. Taken together, these facts fit
well in the case of our patient but the exact mechanism and contribution
of these factors to the ECG manifestation remain unknown. According to
earlier case studies, metabolic acidosis associated with DKA may also
result in an elevation in ST-segment2-4. However, our
patient’s pH, serum bicarbonate, or other serum electrolytes did not
notice any noteworthy alterations when the ECG was normalized.
To date, several authors have reported cases of hypoparathyroidism
diagnosed many years after surgery. This phenomenon of delayed onset
hypoparathyroidism has been postulated to be associated with scar
formation as well as progressive atrophy of parathyroid glands. We
report this rare case with the aim of creating awareness about this
potential complication in post thyroidectomy patients. This case adds to
the literature as well the association of hypokalemia and hypocalcemia
with pseudo-ischemic electrographic changes that clinicians should be
aware of.