June 1, 2020

Should I stop the furosemide?

In this post… What effect do loop diuretics have on renal free water clearance? Should we stop furosemide in hyponatraemia? Why do we need to restrict water intake when giving furosemide in hyponatraemia? We are mostly water and rapidly run into trouble when we become under- or over-hydrated. We could argue, therefore, that one of the kidney’s most important jobs is that of maintaining water homeostasis. It is surprising that we are able to mess around quite profoundly with this process without running into trouble more frequently than we do.

May 5, 2020

Terlipressin and hyponatraemia

In this post… The evolution of the vasopressin system How can one hormone regulate two physiological parameters (tonicity and blood pressure)? Why does terlipressin not always cause profound hyponatraemia? “Thousands have lived without love, not one without water.” — WH Auden Does terlipressin cause hyponatraemia? We had a patient with hepatorenal syndrome on the unit recently. Her sodium was 125 mM and I found myself wondering - as I always do in such a patient - whether terlipressin could be contributing.

January 12, 2020

Oh Mg (part 1)

In this post… PPIs are associated with hypomagnesaemia PPIs reduce intestinal Mg2+ absorption diuretics, CNIs and anti-cancer agents promote renal Mg2+ loss PPIs and Mg We had a referral recently for a case of persistent hypomagnesaemia “? cause”. As is often the case, the patient had been taking a PPI for some years. There was no obvious alternative explanation and FEMg was low - so we blamed this as the likely culprit.

December 9, 2019

Sugar and spice and all things nice

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?

November 18, 2019

Filtration-reabsorption: the central renal paradox

In this post… How the kidney evolved to filter first and reabsorb later How we came to know how the kidney works in this way It is so obvious! ‘One never notices what has been done; one can only see what remains to be done.’ — Marie Curie As facts become established dogma, it becomes almost impossible to conceive of a time when they were not known. How could we have not known about natural selection before Darwin?

November 4, 2019

Why write a blog?

“Renal physiology has now passed into a quantitative phase where unsupported speculation and empirical description are no longer warranted.” — Homer Smith, 1951 In this post… What are the aims of this blog? Where does the name come from? Why write a blog? I enjoy learning about renal physiology - in particular those aspects that are relevant to clinical disorders of fluid-electrolyte balance. However I have a bad habit of reading up on a topic, understanding it for 10 minutes, and promptly forgetting it again.