In this post… The renal regulation of bicarbonate excretion The pathogenesis of proximal RTA The pathophysiology of vomiting How is renal bicarbonate excretion regulated? With respect to bicarbonate reabsorption, there are two key parameters to consider: the Tm = maximal rate of tubular HCO3 reabsoption and the renal bicarbonate threshold = the serum [HCO3] at which the filtered load exceeds Tm, and bicarbonate begins to appear in the urine.

In this post… A summary of our recent salt perspectives paper A few “clinical pearls” relating to salt Introduction We (with Matt Bailey and Bean Dhaun) recently wrote a perspectives article on salt and disease. This was an entertaining and educational process. Here I reflect on what I learned while writing the review, expanding a little on some potentially useful “clinical pearls”. (As the following is discussed in detail and fully referenced in our paper, I have not inserted many references below.

In this post… Why does low Mg cause low K? Distal Na and K transport and the transepithelial voltage Hypomagnesaemia: easy to find if you go looking for it; usually left well alone. (And often caused by a drug.) But sometimes hypomagnesaemia is worth paying attention to if it is contributing to another electrolyte disorder such as hypocalcaemia or hypokalaemia. Any medical student can tell you that Mg deficiency can cause refractory hypokalaemia.

In this post… Electrolyte-free water clearance can help assess disorders of sodium homeostasis Potassium supplementation can help in cases of hyponatraemia What are we made of? What are little girls made of? What are little girls made of? Sugar and spice And all things nice That’s what little girls are made of — Nursery Rhyme Well we are not made of sugar and spice - but what are we made of?