class: birds-title <div id="vantajs"></div> <div id="birds-writing"> <h1>Electrolyte disorders | cases</h1> <h3>MBChB Year 5 Teaching 2025/6</h3> </div> <script> VANTA.WAVES({ el: "#vantajs", mouseControls: true, touchControls: true, gyroControls: false, minHeight: 200.00, minWidth: 200.00, scale: 1.00, scaleMobile: 1.00, shininess: 40, waveSpeed: 0.8, zoom: 0.65, color: 0x3273e }); </script> <!-- # Learning intentions --> <!-- - hyponatraemia --> <!-- - hypokalaemia --> <!-- - hypercalcaemia --> <!-- - general approach --> <!-- .RWH_footnote_right[.RWH_footer_style[slides at: https://www.kidneyfish.net/talks/]] --> <!-- --- --> --- class: center, middle, inverse # .white[Hyponatraemia] ??? Remind me: - what has gone wrong here? - which endocrine system is responsible for regulating water homeostasis? --- # Case 1 `79F, two weeks post-op after CABG`: - Na 112 mM (from 135 mM four days ago) - confused for 2 - 3 days - **PMH**: MI, HTN - **Rx**: dalteparin, aspirin, amlodipine, paracetamol, ranitidine, co-amilofruse, sertraline - complaining of headache; cannot recall heart surgery - warm peripheries, no oedema, JVP + 4 ??? What would you do? Options: - 1 = send more tests - 2 = start fluid restriction - 3 = stop diuretic - 4 = call for help - this is an emergency! ---  .RWH_footnote_right[.RWH_footer_style[[Sterns *et al.* (2015)](https://pubmed.ncbi.nlm.nih.gov/25551526/)]] --- # Case 1 `79F, two weeks post-op after CABG`: - Na 112 mM (from 135 mM four days ago) <br> -- - BM 8 - POsm 240 mOsm - UOsm 395 mOsm - UNa 72 mM - TFTs and 9 am cortisol normal ??? UK 47 mM ??? What would you do next? 300 ml 1.8% NaCl ---  ---  ---  ---  ---  ---  ??? Adapted from Spasovski et al. (NDT, 2014). Reasons why kidneys may be unable or unwilling to excrete free water: - no water delivery to kidney (low GFR) - impaired free water generation = thiazides (NB also PG effect on AQP2) - impaired free water generation = loops (NB but also impaired medullary gradient = protective) - water reabsorption on CDs = ADH = volume / nausea / stress / drugs / paraneoplastic <br> <br> So back to our case - what was the diagnosis? Was SIADH from sertraline. Given fluid restriction - Na gradually improved. --- class: center, middle, inverse # .white[Hyperkalaemia] ??? Which organs / hormones regulate K? --- # Case 2 `58M with 8 days of diarrhoea; struggling to walk` - K 7.2 mM - **PMH**: EtOH XS, liver cirrhosis - **Rx**: lactulose, omeprazole, levothyroxine, spironolactone - ABP 94/50; HR 112; SaO2 99% - cool peripheries, JVP only visible lying flat, wrinkled skin over ankles - urea 32 mM, Cr 306 mcM (previously 108), eGFR 8, Na 134 mM ??? What is the cause of his hyperK? How dangerous is this for him? How likely is this to respond to medical Rx? How would you treat him? --- class: black  ??? K 9.2 mM --- class: black  ??? 30 mins after calcium ---  .RWH_footnote_right[.RWH_footer_style[[UKKA (2023)](https://ukkidney.org/health-professionals/guidelines/guidelines-commentaries)]] --- class: black  ??? K 7.2 mM; AKI on atenolol (BRASH) ---  .RWH_footnote_right[.RWH_footer_style[[UKKA (2023)](https://ukkidney.org/health-professionals/guidelines/guidelines-commentaries)]] --- class: center, middle, inverse # .white[Hypercalcaemia] ??? Which hormone(s)? --- # Case 3 `66M thirsty and 'just not right' for a few weeks` - stopped playing golf; thoracic back pain - not sleeping - cCa 3.36 mM - **PMHx**: HTN, gallstones, ex-smoker | **Rx**: enalapril - ABP 159/88, HR 92, SaO2 99% - JVP +1 cm, no oedema, pale - Hb 94, urea 7 mM, Cr 108 mcM, PO₄ 0.9 mM -- - PTH 0.4 pM (1.6 - 6.9) ??? What one test would you do first? What tests would you do now? How would you manage him? ---  .RWH_footnote_right[.RWH_footer_style[[Bernstein (2019)](https://doi.org/10.1053/j.ajkd.2018.06.035) & [Eastell (2014)](https://academic.oup.com/jcem/article/99/10/3570/2836338)]] --- # Management of hypercalcaemia - see guidelines for [hypercalcaemia](https://doi-org.eux.idm.oclc.org/10.1530/ec-16-0055) and [hypercalcaemia of malignancy](https://academic.oup.com/jcem/article/108/3/507/6916871) - IV 0.9% NaCl (typically 4L in 24 hrs and aiming for u/o 100 - 150 ml/hr) - IV bisphosphonate (and / or denosumab) - disease-specific interventions (e.g. glucocorticoids) ??? Two reasons for giving copious NaCl: 1) to correct volume depletion from hyperCa (effect on CaSR in TALH) 2) to encourage [calciuresis](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8889795/) by driving Na-coupled calcium excretion in PCT --- class: center, middle, inverse # .white[Take-home points] --- # Take-home points (1) `HypoNa`: - a water problem - POsm: is this hypotonic (i.e. dangerous)? - UOsm: are the kidneys trying to get rid of the extra water? - UNa: do the kidneys think there is volume depletion? <br> `HyperK`: - urine output = GFR now - don't unleash medical Rx if K < 6 mM; always treat at K > 7 mM - protect heart > shift into cells > eliminate from body .RWH_footnote_right[.RWH_footer_style[slides at: https://www.kidneyfish.net/talks/]] --- # Take-home points (2) `HyperCa`: - polyuria > volume depletion - classify with PTH <br> `General`: - is it an emergency? - drugs, drugs, drugs - think through the physiology .RWH_footnote_right[.RWH_footer_style[slides at: https://www.kidneyfish.net/talks/]] --- class: center, middle, inverse # .white[Supplemental slides] ---  ---  ---  ---  ---  ---