Electrolytes - UW Flashcards
Hypoventilation is a/w what kind of A-a gradient and which metabolic/respiratory acidosis/alkalsosi?
Normal A-a gradient and respiratory acidosis.
What agents are used to shift potassium intracellularly?
Insulin, glucose, sodium bicarbonate, and beta-2 agonists.
Hyponatremia can be classified into what categories?
According to the volume status of patient - hypovolemic, euvolemic or hypervolemic.
Normally, ADH secretion is regulated primarily by?
Plasma osmolarity.
How does hypovolemia affect hyponatremia?
Potent hypovolemia activates the renin-aldosterone-angiotensin-sympathetic nervous systems, and stimulates ADH release from the pituitary. This leads to volume retention to cause hyponatremia. Hyponatremia normally suppresses ADH release but persistent hypovolemia overrides this and releases ADH in an attempt to correct the hypovolemia.
Management of hyperkalemia is dependent on?
Severity, acuity, and rapidity of onset of the hyperkalemia.
What are athe most important steps in the management of lactic acidosis from septic shock?
IV normal saline (IV 0.9% saline) with or without vasopressor to maintain intravascular pressure and antibiotics to correct underlying infection.
What is normal anion gap?
6-12 mEq/L
Diuretic abuse leads to what sodium and potassium findings in the serum and urine?
Serum sodium and potassium levels are low, urine sodium and potassium levels are low.
What is the clinical presentation of diuretic abuse?
Weight loss, dehydration, confusion, orthostatic hypotension, hyponatremia, hypokalemia.
Acute kidney injury can lead to what kind of acidosis?
Non-anion gap metabolic acidosis due to impaired acid excretion or an anion gap acidosis due to retention of unmeasured uremic toxins.
Trimethorpim can cause what kind of electroylyte abnormality? What is the mechanism?
Can cause hyperkalemia. Blocks epithelial sodium channel in the collecting tubules. (similar to the action of amiloride). Can also cause elevated serum creatinine because trimethoprim competitively inhibits tubular creatinine secretion. Does not affect GFR.
Triad of fever, tinnitus and tachypnea after overdose of a medication is highly suggestive of what drug OD?
Aspirin.
Acute salicylate intoxication causes what kind of electorolyte.metabolic disturbance?
Respiratory alkalosis and anion gap metabolic acidosis.
What medications commonly cause hyperkalemia?
ACE inhibitors, nonselective beta adrenergic blockers, ARBs, K+ sparing diuretics, digitalis, NSAIDS, cyclosporine.
How does nephritic glomerulonephritis usually present?
Urinary sediment containing RBCs, occasional WBCs, and red cell or mixed cellular casts.
Edema in patients with neprhitic glomerulonephritis is usually due to?
Decreased GFR and sodium and water retention by kidneys.
Acute nephritic syndrome is ?
Primary glomerular damage due to causes such as poststreptococal glomeruloneprhtiis, IgA nephropathy, lupus nephritis, MPGN and RPGN.
What is a common electrolyte abnormality in patients with Cushing’s (excessive cortisol)
Corticosteroids have some mineralocorticoid activity, and bind receptors in the kidney causing renal potassium wasting. IF severe, the hypokalemia in Cushing’s can be treated with spironolactone - aldosterone antagonist.
Urine of patients with ethylene glycol poisoning (anti-freeze) shows what?
Rectangular, envelope shaped crystals consistent with calcium oxalate crystals.
When anion gap is markedly elevated and frank uremia is not present, what should you do?
Calculate osmola gap for ethanol, methanol and ethylene glycol poisoninng.
Bicarbonate is the conjugate base of?
PaCO2
In any patient what two lab values provide the best picture of acid-base status?
PH and PaCO2
What drugs are common causes of nephrogenic diabetes insipidus?
Lithium.
How is lithium-induced nephrogenic DI treated?
Salt restriction and discontinuation of lithium
A post-seizure anion gap metabolic acidosis is classically the result of?
Lactic acidosis.
What is the typical course of the acid-base disturbance that occurs after a tonic-clonic seizure?
Usually get post-ictal lactic acidosis which is a transient anion gap metabolic acidosis that resolves without treatment within 60-90 minutes following resolution of seizure activity.
What is the most common cause of hypernatremia?
Hypovolemia.
How do you treat 1) mild and 2) severe cases of hypovolemic hypernatremia?
1) 5% dextrose in 0.45% saline 2) 0.9% saline
What kind of acid-base disorder is diabetic ketoacidosis
Anion gap metabolic acidosis
What is Winter’s formula aand what is it used for?
PaCO2 = 1.5 (HCO3-) + 8. Used to calculated the expected PCO2 during respiratory compnesation for a primary metabolic acidosis.
Normal acid base status, bicarbonate ion, and PCO2
pH = 7.35 - 7.45, bicarbonate ion = 22-26 mEq/L, PCO2 = 35-45mmHg
Metabolic alkalosis can be classified as saline-responsive or unresponsive based on?
Urinary chloride levels and ECF volume status
Saline responsive metabolic alkalosis is a/w high or low urinary chlroide and corrects with?
Low urinary chloride excretion and corrects with saline infusion alone.
What are the classic causes of metabolic acidosis?
MUDPILES: methanol, uremia (renal failure), DKA, paraldehyde, INH, lactic acidosis, ethylene glycol, salicylates
What kind of acid-base disturbance does vomiting cause?
Hypovolemic, hypochloremic metabolic alkalsosis
How do you treat metabolic alkalosis caused by vomiting?
Volume resuscitation and treat the hypokalemia
What is succinylcholine? Who is contraindicated for use of succinylcholine?
Depolarizing neuromuscular blocker. Patients who are at high risk for hyperkalemia Patients with crush or burn injuries more than 8 hours old (risk of rhabdomyolysis), demyelinating syndromes such as Guillame Barre, and with tumor lysis syndrome should not get succinylcholine
What electrolyte disturbance can occur immediately after or during surgery in patients underoing major surgery/requiring extensive transfusions?
Hypocalcemia?
What is an initial manifestation of hypocalcemia?
Hyperactive deep tendon reflexes
What are the most common electrolyte deficiences seen in adrenal insufficiency?
Hyponatremia is the most common followed by hyperkalemia.
