Common electrolyte disorders in primary care
description
Transcript of Common electrolyte disorders in primary care
Common electrolyte disorders Common electrolyte disorders in primary carein primary care
Steve HyerSteve Hyer
ELECTROLYTESELECTROLYTES
ApproachApproachHistoryHistory including including drugsdrugs
Examination Examination including fluid including fluid status, blood status, blood pressurepressure
Screening testsScreening tests
ConfirmatoryConfirmatory teststests
Thinking about electrolytesThinking about electrolytes
Excess/reduced intake
Excess/reduced Loss
Redistribution
Is hyponatraemia important?Is hyponatraemia important?3 reasons……3 reasons……1.1. The wrong The wrong
treatment can be treatment can be disastrousdisastrous
2.2. Rapid correction Rapid correction can be disastrouscan be disastrous
3.3. Acute severe Acute severe hypoNa hypoNa associated with associated with increased increased mortalitymortality
T1: Low density T2: High density
ScopeScope
SodiumSodium
PotassiumPotassium
CalciumCalcium
Case 1Case 169y F69y F Na 121Na 121
Previously Na 139Previously Na 139
Started bendro 10d Started bendro 10d previouslypreviously
Stopped bendro: Stopped bendro: Na 134 10d later.Na 134 10d later.
Diagnosis: Thiazide-induced hyponatraemia
Case 2Case 288y M88y MAcutely unwell with Acutely unwell with sodium 120 mmol/l sodium 120 mmol/l and signs of pleural and signs of pleural effusion. effusion. Chest CT scan showed Chest CT scan showed extensive inoperable extensive inoperable bronchial carcinoma. .bronchial carcinoma. .
Diagnosis: SIADH associated with carcinoma bronchus
Case 3Case 383y F 83y F Na 126–129 mmol/l Na 126–129 mmol/l following AP resection following AP resection and ileostomy. and ileostomy. Urine: maximal Urine: maximal sodium conservation.sodium conservation.Na normalised by Na normalised by reversal of ileostomy .reversal of ileostomy .
Diagnosis: Salt and water loss through high flow stoma
Case 4Case 456y M 56y M 10d diarrhoea and 10d diarrhoea and vomiting. vomiting. Na 108 mmol/l K 5.5 Na 108 mmol/l K 5.5 Subsequent Subsequent investigations investigations confirmed Addison’s confirmed Addison’s disease. .disease. .
Diagnosis: Hyponatraemia due to adrenal insufficiency
2 important hormones….2 important hormones….
No aldosterone! No aldosterone! (Adrenal insufficiency)(Adrenal insufficiency)
ACE-inhibitors effectively lead to low aldosterone; can cause hypoNa
Diagnosis adrenal insufficiencyDiagnosis adrenal insufficiency
SYNACTHEN TEST
Enhanced ADH releaseEnhanced ADH releaseTumours releasing Tumours releasing ADH eg Ca bronchusADH eg Ca bronchus
CNS disorders CNS disorders affecting affecting hypothalamus eg SAHhypothalamus eg SAH
Pain especially Pain especially thoracicthoracic
NauseaNausea
Opiates, SSRIs, CBZPOpiates, SSRIs, CBZP
Atypical pneumoniaAtypical pneumonia
V2 receptorsDilutional hyponatramia
One important bit of the kidney….One important bit of the kidney….
Distal convoluted tubuleDistal convoluted tubuleThis is where the This is where the aldosterone aldosterone worksworks
DrugsDrugs
Renal tubular Renal tubular acidosisacidosis
Chronic Chronic pyelonephritispyelonephritis
Excess water intake with low solutesExcess water intake with low solutes
Low solute intake: Fun runnersLow solute intake: Fun runnersDrinking fluids Drinking fluids every mile every mile
Gain weight after Gain weight after run!run!
Drink 3 litres + in a Drink 3 litres + in a run of 1-2 hrsrun of 1-2 hrs
Severe Severe hyponatraemia hyponatraemia and even deathand even death Non
elite runner
Low solute intake: Beer potomaniaLow solute intake: Beer potomaniaBeerBeer
Very low sodium/ Very low sodium/ potassiumpotassiumMaximum 4-5 litres Maximum 4-5 litres of electrolye free of electrolye free water excretable water excretable per dayper dayIn absence of In absence of solute, >5L beer; solute, >5L beer; severe hypoNasevere hypoNa Tea + toast
old ladies
Primary polydipsiaPrimary polydipsiaLow osmotic Low osmotic threshold to feel threshold to feel thirstythirstyUnable to suppress Unable to suppress thirstthirstExaggerated thirstExaggerated thirst
Hyponatraemia + Hyponatraemia + polydipsia + polydipsia + polyuriapolyuria
Diagnosis……Diagnosis……
Clinical symptomsClinical symptomsPlasma Na+Plasma Na+ SymptomsSymptoms MortalitMortalit
y (%)y (%)>125>125 Usually none. Usually none.
Occasional headache, Occasional headache, nauseanausea
Not Not reportedreported
120 -125120 -125 Headache, nausea, Headache, nausea, cramps, confusioncramps, confusion
2323
115-120115-120 Agitation, drowsy, Agitation, drowsy, stuporstupor
3030
<115<115 Seizures, comaSeizures, coma 4040
Step 1: Assess Volume statusStep 1: Assess Volume status
Mucosal membranes, Mucosal membranes, tongue, skin turgor, urine tongue, skin turgor, urine outputoutput
Step 2: CLASSIFYStep 2: CLASSIFY
HyperHyper-volaemic-volaemic
NormoNormo-volaemic-volaemic
HypoHypo-volaemic-volaemic
Weight: Down OK Up
Step 3: Step 3: Evaluate: Evaluate: ClinicalClinical
Step 4: Step 4: Evaluate: Evaluate:
LaboratoryLaboratory
Conserving sodiumLosing
sodium in urine
Management SIADH Management SIADH Underlying causeUnderlying causeFluid restrict (0.5-Fluid restrict (0.5-1L/d)1L/d)May take days to May take days to come downcome downMaintain Na intakeMaintain Na intake(Demeclocycline-(Demeclocycline-causes NDI)causes NDI)
VAPTANS VAPTANS (e.g.Tolvaptan)(e.g.Tolvaptan)
V2 blocker
TolvaptanTolvaptanOral agentOral agentCurrently only in Currently only in secondary care for secondary care for chronic SIADHchronic SIADHExpensive but could Expensive but could reduce hospital stayreduce hospital stayEspecially where fluid Especially where fluid restriction poorly restriction poorly toleratedtoleratedC/I Hypovolaemic C/I Hypovolaemic hypoNahypoNa?long term?long term
Secondary careSecondary care Special testsSpecial tests
Hypertonic saline Hypertonic saline testtestWater loading testsWater loading testsMeasurement of Measurement of AVPAVPHypertonic saline Hypertonic saline infusions –Na rise infusions –Na rise not >10mmol/dnot >10mmol/dScans, etcScans, etc
DDI: Dipsogenic DI
Summary: HyponatramiaSummary: Hyponatramia
Multitude of causesMultitude of causes
Many patients with chronic mild Many patients with chronic mild hyponatraemia have adapted and hyponatraemia have adapted and apparently very well- may apparently very well- may decompensate in acute illnessdecompensate in acute illness
First do no harm!First do no harm!
Hypernatraemia Na>145Hypernatraemia Na>145HistoryHistory
Thirst/ PolyuriaThirst/ Polyuria
No symptomsNo symptoms
DrugsDrugs
ExaminationExamination
DehydratedDehydrated
Think diabetes insipidus
ExcessivExcessive water e water
lossloss
Algorithm NaAlgorithm Na
Loss of water
Loss of water
HypokalaemiaHypokalaemiaHistoryHistory
Diarrhoea, vomitingDiarrhoea, vomiting
No symptomsNo symptoms
Drugs eg Ventolin, Drugs eg Ventolin, diuretics, insulindiuretics, insulin
ExaminationExamination
Fluid statusFluid status
Blood pressureBlood pressure
Think diuretics
Cola drink hypokalaemiaCola drink hypokalaemiaSugar++++Sugar++++
Caffeine +++Caffeine +++
At least 2 litres/dayAt least 2 litres/day
Hypertension + low KHypertension + low K++
Think ConnThink Conn
(Hyper-(Hyper-aldosteronism)aldosteronism)
Think CushingThink Cushing
Think renal artery Think renal artery stenosisstenosis
Renin: Aldo ratio
Algorithm KAlgorithm K
Gut loss
Renal loss
Hyperkalaemia K>5.0Hyperkalaemia K>5.0
HistoryHistoryRenal Renal No symptomsNo symptomsDrugs eg ACE-I, Drugs eg ACE-I, spiro, amiloridespiro, amiloride
ExaminationExaminationAddisons Addisons RenalRenal
Think renal failure Don’t forget haemolysed samples, old samples
AlgorithmAlgorithm
Input Output
Don’t forget Addison
Hypercalcaemia Ca>2.6Hypercalcaemia Ca>2.6Mild Mild hypercalcaemiahypercalcaemia (Ca <3mmol)(Ca <3mmol)Mostly due to Mostly due to primary primary hyperparathyroidishyperparathyroidismmUsually Usually asymptomaticasymptomaticDiagnosis: Ca Diagnosis: Ca blood/ urine + PTH blood/ urine + PTH
Recommending PTH-ectomyRecommending PTH-ectomy Patient fit for surgeryPatient fit for surgery Significantly reduced Significantly reduced
BMD on DEXA scanBMD on DEXA scan Reduced renal Reduced renal
function (eGFR)function (eGFR) Ca>2.85Ca>2.85 History of stonesHistory of stones Increased Ca Increased Ca
excretionexcretion Frail elderly: consider bisphosphonate infusion
Moderate-severe CaModerate-severe CaConsider Consider malignancy esp malignancy esp older patientolder patient
MyelomaMyeloma
SarcoidosisSarcoidosis
ThyrotoxicosisThyrotoxicosis
FHHFHH
DrugsDrugs
Bisphosphonates
Malignant hypercalcaemiaMalignant hypercalcaemia
Tumour mets Non-metastatic (PTH-RP)
AlgorithmAlgorithm
Low calcium Ca <2.2mmolLow calcium Ca <2.2mmol
Usually Vitamin D Usually Vitamin D deficiency (30% deficiency (30% elderly, 90% elderly, 90% Asians?)Asians?)May be Chronic May be Chronic renal failurerenal failureHypoPTH HypoPTH PseudohypoPTHPseudohypoPTH(Low Mg)(Low Mg)
Lack of sun
Phytate in chipatis
Housebound
High Ca High PTH
High Ca Low PTH
Low Ca High PTH
Low Ca Low PTH
Assessment Ca Assessment Ca
HistoryHistoryDiet/ diarrhoea/ Diet/ diarrhoea/ mal-absorption mal-absorption Thyroid surgeryThyroid surgeryDrugs eg phenytoinDrugs eg phenytoin
ExaminationExaminationTetany, ChvostekTetany, ChvostekRenalRenal
InvestigationsInvestigationsCa/P/ Alk P’ase/ Ca/P/ Alk P’ase/ Vit D/ PTHVit D/ PTH
Treatment Vit D deficiencyTreatment Vit D deficiencyCalciferol (D2)Calciferol (D2)
Ex: Ex: CalciumCalcium & Vit D & Vit D 400u bd400u bd
Colecalciferol (D3)Colecalciferol (D3)Ex: AdEx: Adcalcal-D3 (400) bd-D3 (400) bd
ErgocalciferolErgocalciferol10,000 u (mal-10,000 u (mal-absorption)absorption)
AnaloguesAnaloguesEx: One –Alpha Ex: One –Alpha 0.25mcg (renal 0.25mcg (renal failure)failure)
Pure vitamin D (Boots, Tesco, Holland & Barrets:
*25mcg (1000u) od (treat) *10 mcg (400u) od (maintain)