Could be reduced intake but usually excessive losses –
| Renal | Non-renal |
| Renal tubular acidosis (type 1 or 2) | Vomiting eg pyloric stenosis |
| Bartters or Gitelmans syndrome | Diarrhoea |
| Diuretics | Laxative overuse |
| Hyperaldosteronism (CAH, tumour) | Thyrotoxicosis |
| Salbutamol | |
| Familial periodic paralysis | |
| Pseudo-Bartter’s | |
| Trauma | |
| Diabetic ketoacidosis |
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
- Ileus
- Metabolic acidosis (although underlying cause often produces alkalosis)
- Arrhythmia, heart failure
- Rhabdomyolysis
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]