U&Es - Summary of urea and electrolytes test and results PDF

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Summary

Summary of urea and electrolytes test and results...

Description

Urea and Electrolytes (U&Es): Why: -

To assess kidney function and electrolyte balance Suspected renal failure (acute/chronic) Monitoring of patients receiving intravenous fluids Monitoring of established CKD (chronic kidney disease)

What: - Electrolytes: o Usually measured as part of a renal profile which measures the main electrolytes in the body:  Sodium (Na+) —> 135 - 147 mmol/L  Potassium (K+) —> 3.4 - 5.6 mmol/L o Dietary intake of sodium, potassium and chloride is regulated by renal excretion as a function of hormonal control (ADH, natriuretic peptides, aldosterone) - Creatinine —> 64 - 104 umol/L (M), 49 - 90 umol/L (F) - Urea —> 2.0 - 6.6 mmol/L Sodium: - Most sodium is found in extracellular fluid (ECCF), where it helps regulate the amount of water in the body - High sodium = hypernatraemia o From dehydration due to not drinking enough fluids, diarrhoea, kidney dysfunction, and diuretics - Low sodium = hyponatraemia o From consumption of too many fluids, kidney failure, heart failure, cirrhosis and use of diuretics o Also chronic, severe vomiting or diarrhoea Potassium: - Found mainly inside the cells (ICF), with a small but vital amount is in the plasma - Small changes to potassium level can affect the heart’s rhythm and ability to contract - High potassium = hyperkalaemia o Main causes include acute kidney failure and CKD o Other causes include Addison’s disease (adrenal insufficiency), angiotensin II receptor blockers, ACE inhibitors, beta blockers, dehydration, destruction of RBCs due to severe injury or burns, excessive use of potassium supplements, type 1 diabetes - Low potassium = hypokalaemia o Most common cause is excessive potassium loss in urine due to prescription diuretics (i.e. for those with hypertension or heart disease) o Other causes include excessive alcohol use, CKD, diabetic ketoacidosis, diarrhoea, excessive laxative use, excessive sweating, folic acid deficiency, primary aldosteronism, some antibiotic use, vomiting -

Electrolyte disturbances may reflect hormonal imbalances: o SIADH o Diabetes insipidus o Impaired renal function (e.g. peripheral vascular disease, chronic kidney disease, etc.) o Or may exist as sequelae to other primary conditions such as liver cirrhosis or congestive cardiac failure (CCF)

Creatinine: - Almost completely filtered by the kidneys - Increasing serum concentrations correspond with a worsening of the glomerular filtration rate as a function of encroaching kidney failure Urea: - Serum urea correlates with catabolic states and increases during tissue/organ trauma - Whilst circulating levels are a good indication of a patient’s overall hydration status and/or kidney function...