Electrolyte Imbalances Flashcards
What population is most affected by hyponatremai
Hospitalized patients (ICU especially)
What are risk factors for hyponatremia
CHF Cirrhosis Nephrotic Syndrome Pneumonia ICU Old
What are the two main regulatory systems for serum osmolarity
ADH
thirst
What are non-osmotic stimuli for ADH release
Baroreceptors Nausea Hypoxia Pain Medications (opiates, SSRIs) Pregnancy
What does hyponatremia primarily result fromt
Increases in TBW and less from changes of total body sodium
When does acute hyponatremia become chronic hyponatremia
at the 48 hr mark
How is the diagnosis of SIADH made
Dx of exclusion. Must rule out cortisol deficiency, hypothyroidism, and other causes
What is the most common cause of SIADH
Small cell lung cancer
What drugs are associated with SIADH
Antidepressants Anticonvulsants Antipsychotics Cyclophosphamide Opiates MDMA
What is the goal when replacing the sodium of symptomatic hyponatremic patients
Decrease symptoms (3%) saline
if over corrected give 5% dextrose, DDVAP, or both
What are some complications of hyponatremia
Osteoporosis Falls Seizures Coma Death Osmotic Demylenation Syndrome
What occurs in osmotic demylenation syndrome
2-6 days after rapid correction, demyelination occurs in the pontine and extrapontine neurons
In which populations is hypernatremia seen
Infants and the elderly
What are the risk factors for developing hypernatremia
Trauma Burns ICU Dementia uncontrolled DM
What is the most common cause of hypernatremia
Unreplaced water loss
sodium overload is less common
What is the goal correction rate in chronic hypernatremia
10-12 mEq/day
What are the two steps in treating hypernatremia
replace water deficit
Correct underlying cause leading to water loss
What organ is the primary regulator of renal potassium
kidney
Which part of the kidney works in potassium excretion
distal part of nephron
What defines hyperkalemia
> 5.0 or 5.5 mEq/L
What are the risk factors that are associated with developing hyperkalemia
AKI CKD DM MEdications Malignancy Rhabdo Old
What are the main, life threatening categories of hyperkalemia complication
Cardiac Arrhythmia
Skeletal muscle weakness
Metabolic acidosis
What are the two main reasons for hyperkalemia
Transcellular shift
Decreased renal K secretion
What is pseudo hyperkalemia
artificial increase of serum K due to cell lysis
ie leukocytosis
in decreased renal K secretion what are the pathologies that lead to hyperkalemia
low aldosterone secretion/resistance
AKI or CKD
What classes of drugs are liable to induce hyperkalemia
Anything that hurts RAAS
ACEi
ARB
Renin inhibitors
What test do we NOT order to diagnose hyperkalemia
Transtubular Potassium Gradient
What is the treatment of hyperkalemia when you have peaked T waves
Calcium gluconate to stabilize cardiac membrane
What is the treatment of hyperkalemia if the etiology is transcellular shift
Insulin
B-2 Agonist
What is the treatment if potassium removal is the goal
Loop diuretic or thiazide
Exchange resins
- -Sodium polystyrene
- -Zirconium cyclosilicate
- -Patiromer
What are the clinical manifestations and complications associated with hypokalemia
Cardiac Arrhythmias (PAC, PVC, Tachy, brady) Weakness Rhabdo Alkalosis Nephrogenic diabetes insipidus
What are the three main reasons for hypokalemia
Transcellular shift (Insulin and B2 agonist most common)
Extrarenal loss
Renal loss
What amount are you looking for in hypokalemia in a 24 hour urine collection to confirm potassium wasting
> 25-30 mEq/day
Urine K/Cr ratio normally <13
–higher values indicate wasting
What are the treatment steps for hypokalemia
Treat underlying cause
Replace potassium (.1 mEq/L for every 10 mEq of KCl)
Replace Magnesium if low
Repeat K to ensure normalization
