Could be reduced intake but usually excessive losses –
|Renal tubular acidosis (type 1 or 2)||Vomiting eg pyloric stenosis|
|Bartters or Gitelmans syndrome||Diarrhoea|
|Hyperaldosteronism (CAH, tumour)||Thyrotoxicosis|
|Familial periodic paralysis|
Symptoms depend on severity and how rapidly decrease has happened. Chronic low levels are better tolerated. Since potassium important for membrane potentials, effects are mostly neuromuscular.
- Cramps, weakness, paralysis
- Metabolic acidosis (although underlying cause often produces alkalosis)
- Arrhythmia, heart failure
ECG classically shows U waves, T wave flattening, and ST-segment changes. Can be tall wide P waves, can look like long QT if T and U waves merge.
Do urine and blood electrolytes to look at fractional excretion.[Endocrine connections 2018][Current Treatment Options in Peds 2022]