Interpreting U and Es Flashcards
What are the causes of increased urea?
Caused by increased protein breakdown so dehydration, GI bleeding, trauma, infection, malignancy, high protein intake
What investigations do all patients with AKI require?
Urine dipstick
Bloods - FBC, U and E, CRP, Calcium, Phosphate, PTH
VBG - look for low bicarb/metabolic acidosis and hyperkalaemia
Accurate fluid balance chart
Stopping renally excreeted and nephrotoxic drugs
What are the causes of pre-renal AKI?
Hypovolaemia/sepsis (most common cause), renovascular disease, cardiorenal failure (increased venous pressure reduces renal perfusion pressure)
What are the main investigations and treatment for pre-renal AKI?
Investigate with fluid assessment and renal artery doppler
Treat cause e.g. IV fluids in hypotension
What are the causes of intrinsic renal failure?
acute tubular necrosis (ischaemic or nephrotoxic)
Acute interstitial nephritis
Acute glomerulnephitis
What are the main investigations for intrinsic renal failure?
Urine dipstick for blood and protein in glomerulonephritis
Urine protein/creatinine ratio (<15mg/mmol = normal, >300mg/mmol = nephrotic)
Nephritic screen: ANA, ANCA, Anti-GBM, hepatitis
Myeloma - protein electrophoresis and serum free light chains
Creatine kinase if rhabdo suspected
Renal biopsy - if nephritic screen positive or glomerulonephritis suspected
What is the treatment for intrinsic renal failure?
Treat the cause
Stop causative agents for acute interstitial nephritis
Steroids, diuretics and ace inhibitor may be required for glomerulonephritis
What are the causes of post renal failure?
Ureters - stones, stricture, compression
Bladder - neurogenic, bladder calculi, tumour
Urethra - BPH, prostate cancer, stricture
What are the investigations for post renal failure?
Renal tract USS
Bladder scan
What is the treatment for post renal failure?
Relieve obstruction - catheter if urethral, nephrostomy if ureteric
What are the indications for dialysis in AKI?
AEIOU Acidosis Electrolyte abnormalities (Hyperkalaemia) Intoxicants - methanol etc Overload Ureamia - Urea >60 or encephalopathy
What are the common causes of chronic kidney disease?
Diabetes (secondary to glomerular disease)
Chronic hypertension
Chronic glomerulonephritis
Polycycstic kidney disease
What is the management of CKD?
General measures - fluid restriction, dietary protein restriction, ACE inhibitor Treat complications: -hypertension - antihypertensives -Anaemia - ESA + iron supplements -Oedema - fluid restriction -Secondary hyperparathyroidism: --Kidney unable to reabsorb calcium so causes hyperparathyroidism -- GIve active vit D therapy --Dietry phosphate restriction --If calcium low then give supplement tablets -Acidosis - give sodium bicarb -hyperlipidaemia - give statin -Hyperkalaemia - potassium restriction
How does aldosterone effect electrolyte levels?
It causes increased sodium reabsorption and increased pottasium excretion in the distal convoluted tubule
What are the symptoms of hyponatraemia?
Nausea/vomiting
headache
seizures
reduced consciousness
What are the causes of hyponatraemia?
Hypovalaemic - Na+ lost and water follows:
-Urinary sodium >30 - Diuretics, addisons disease (increased K+), kidney injury
-Urinary sodium <30 Na + lost from elsewhere- Dirrhoea/vomiting
Euvolaemic - H2O gained:
-Urinary Na+ >30 - SIADH, Hypothyroidism
-Urinary Na+ <30 - H2O intoxication
Oedematous - retention of water that is disproportionate to the retention of sodium - congestive cardiac failure, hypoalbuminaemia
What investigations should be done for hyponatraemia?
Plasma osmolality to confirm if true hyponatraemia:
-Low=true
-Normal =False (pseudohyponatraemia due to high lipids
-High = dilutional (due to high glucose)
Urine sodium concentration
Specific tests to confirm causes e.g. synacthen for addisons, TFTs for hypothyroidism
What is the management of hyponatraemia?
Treat cause
Correct sodium
-seizures consider 3% hypertonic saline with ICU input
-Hypovolaemia - replace lost fluid with 0.9% saline - slowly if chronic e.g. 1L over 12 hours
-Euvolaemic - correct cause
-If SIADH or oedematous then fluid restrict to 1L/day
What are the symptoms of hypernatraemia?
Thirst
Confusion
Muscle spasms
What are the causes of hypernatraemia?
Euvolaemic - iatrogenic e.g. too much IV sodium containing fluids
Hypovolaemic:
-Small volumes of concentrated urine - dehydration
-Normal urine - diabetes insipidus, osmotic diuresis e.g. DKA
What are the investigations for hypernatraemia?
Urine and serum osmolality
Fluid deprivation test to confirm diabetes indipidus
What is the management of hypernatraemia?
Treat ause
Sodium correction:
-Most patients - 5% dextrose, slowly if chronic
-Signs of volume depletion - replace lost fluid with 0.9% saline
How do insulin and catecholamine increase K+ cellular uptake?
They cause stimulation of the ATPase Na+/K+ pump
What are the symptoms of hypokalaemia?
Arrhythmias
Tremour
Muscle weakness/cramps
Constipation
What are the causes of hypokalaemia?
Increased renal loss:
-Diuretics (except potassium-sparing diuretics)
-Endocrinological (steroids, Cushing’s syndrome, hyperaldosteronism)
-Renal tubular acidosis
Intestinal loss:
-Intestinal fluid loss (vomiting/dirrhoea)
Increased cellular uptake:
-Salbutamol
-Insulin
-Alkalosis
How do you manage hypokalaemia?
> 2.5mmol/L - potassium supplementation e.g. sando K 2 tablets 3/7
<2.5mmol/L - 40mmol/L potassium chloride in 1L 0.9% saline over 4-6 hours (do not give >10mmol/hr outside ITU)
Treat cause
What are the symptoms of hyperkalaemia?
Arrhythmias
Lethargy
Muscle weakness
What are the causes of hyperkalaemia?
Reduced renal excretion: -Acute/chronic kidney injury -Drugs (potassium-sparing diuretics, ACEi, NSAIDs) -Aldosterone deficiency (addisons) Increased K+ load: -Iatrogenic -Massive transfusion Celluar release: -Acidosis -Tissue breakdown e.g. rhabdo, haemolysis
What is the management of hyperkalaemia?
ECG an 3 lead cardiac monitor
-changes flat P waves, wide QRS, tall T waves
Calcium gluconate - 10ml 10% IV over 10 mins
-Lasts 30-60 mins
Actarapid insulin - 10 units in 250ml 10% dextrose IV over 30 mins
Calcium resonium - only treatment that actually removes potassium from body - give with lactulose as causes constipation
Treat cause
What is the physiology behind calcium levels in the body?
Vitamin D is required for calcium absorption from the gut
Parathyroid hormone causes reabsorption of calcium in the kidneys and reabsorption from bone
What are the causes of Hypocalcaemia?
Increased renal excretion (Increased phosphate and increased PTH)
-Drugs (loop diuretics)
-Chornic kidney disease
-Rhabdo/tumour lysis syndrome (free phosphate binds calcium)
PTH related (High phosphate, low PTH)
-Hypoparathyroidism
-Hypomagnesaemia
-Pseudohypoparathyroidism (resistant to PTH)
Increased deposition/reduced uptake
-Bisphosphonates
-Vit D deficiency
What is the management of hypocalcaemia?
In severe cases (<1.9mmol/L or symptomatic) give 10ml 10% calcium gluconate over 30 mins diluted
Mild - calcium supplements
Treat cause e.g. vit D deficiency replace, calcium and vit D deficiency give Adcal-D3
What are the causes of hypercalcaemia?
Decreased renal excretion -Drugs - thiazide diuretics Increased release from bones -Bony mets (Increased ALP) -Myeloma (normal ALP) -Sarcoidosis -Thyrotoxicosis Excess PTH: -Primary hyperparathyroidism or tertiary hyperparathryroidism Excess Vit D intake Dehydration is also common cause
What are the investigations for hypercalcaemia?
Initial: - Renal function, ALP, PTH, Phosphate
Myeloma screen - bence jones proteins
Serum ACE - if suspect sarcoidosis
Isotope bone scan if thinking bony mets
What is the management of hypercalcaemia?
Treat cause
Rehydrate - continous 0.9% saline at 1L/4-6hrs
If severe >3.5 or symptomatic - medical emergency - also give bisphosphonates e.g. pamindronate 30-90mg IV depending on severity
