Fluids And Electrolyte Flashcards
Who has more water, adults, kids, full-term, pre-term?
Preterm
Mild dehydration sx
poor skin turgor, sunken fontanel, lack of tears and saliva, lethargy, and tachycardia
Moderate dehydration sx
orthostatic hypotension, tachycardia, oliguria, deepening lethary
Severe dehydration sx
shock
Percentage of water loss in infant/child for mild
5% and 3%
Percentage of water loss in infant/child for moderate
10% and 6%
Percentage of water loss in infant/child for severe
15% and 9%
How do you correct for dehydration?
isotonic 20cc/kg to restore blood volume, replete 1st 50% in first 8 hours, remainder in next 16
Oral hydration
5-10cc every 5 to 10 min
Serum osmolality calculation
Na x 2 + K x 2 + glucose/18 + BUN/3
If hyponatremic, what would you check next?
serum osmolality
Hyponatremia, serum osmolality normal; what are the causes
factitious, hyperglycemia, hyperlipidemia
Hyponatremia, serum osmolality low; what is the cause
SIADH
Pattern: anorexia, headache, muscle cramps, seizure, obtundation, coma, cerebral edema
SIADH
What are Na and Posm numbers for SIADH
Na <130mEq/L
Posm <280
What are causes of SIADH
nausea/vomiting, pain/stress, pulmonary disease, surgery, Cytoxan, vincristine, opiates
Pattern: thirsty, doughy skin, irritability, high fever, high pitched cry, convulsions, stupor, paralysis death
hypernatremia
Rx rate for lowering serum sodium
0.5 to 1mEq/hr
What do check next if pt is hypernatremic?
Urine
Hypernatremic + concentrated urine
non-renal
Hypernatremic + diluted urine
renal
What are cause of non-renal hypernatremia?
GI (diarrhea, vomiting) Insensible losses (fever, high ambient temp)
What are causes of renal hypernatremia?
Can’t concentrate urine - central DI or nephrogenic DI
What are causes of central DI?
trauma, CNS infection, pituitary infarction or pit pit/hypothalamic tumors
What are 3 major categories of causes for hyperkalemia?
- Transcellular shift
- Excess
- Decreased renal excretion
What are causes of transcelluar shift to cause hyperkalemia?
B blockers Acidosis Hyperglycemia - insulin insufficiency Succinylcholine Digitalis Arginine and lysine HCl Sodium fluoride
What are cause of excessive K
Tumor lysis Consumption of exogenous Stored blood Hematoma breakdown IV coagulopathy Tissue necrosis GI bleeding Hemolysis
What are causes of decreased renal excretion?
Renal failure, decreased aldosterone, or decreased sensitivity to aldosterone by kidney
What are causes of decreased aldosterone
Addison’s disease
congenital adrenal hyperplasia
ACE inhibitor usage
NSAIDs
What are cause of decreased aldosterone sensitivity?
obstructive uropathy, SCD, SLE, K-sparing diuretics (spironolactone, amiloride, triamterene)
What are signs of skeletal weakness from hypokalemia?
weakness, cramps, rhabdomyolysis, paralysis
What are signs of smooth muscle weakness from hypokalemia?
gastric distension, ileus, constipation, urinary retention
What are causes of transcellular shift to hypokalemia?
Extreme leukocytosis, treatment of severe anemia (make more RBCs), periodic paralysis (post-carb meal)
What are causes of inadequate body stores?
If pt is acidotic
You can lose K in urine - how hi does urine K have to be
> 20mEq/L
If hypokalemic and renal loss is suspected, check serum pH, if acidic what is the cause, if alkalosis what is the cause
acid - RTA
alkalosis - diuretics, Bartter syndrome, Gittelman syndrome
Low bicarbonate, serum <7.4
metabolic acidosis
Low bicarbonate, serum >7.4
respiratory alkalosis
Hi bicarbonate, serum <7.4
respiratory acidosis
Hi bicarbonate, serum >7.4
metabolic alkalosis
pH >7.4, low bicarbonate
respiratory alkalosis
pH >7.4, high bicarbonate
metabolic alkalosis
pH <7.4, low bicarbonate
metabolic acidosis
pH <7.4, high bicarbonate
respiratory acidosis
What are causes of respiratory acidosis?
retain a lot of CO2 - respiratory depression
What are causes of respiratory alkalosis?
Stimulation of respiratory center, anxiety, drugs, fver, gram neg sepsis, liver insufficiency, CNS
If you have metabolic alkalosis what else do you want to check?
Urine Chloride because K is usually lost with metabolic alkalosis and Cl is usually retained to try to save KCl
If in metabolic alkalosis, urine chloride is lo what is the cause
extra-renal
If in metabolic alkalosis, urine chloride is hi, what is the cause?
renal
If renal metabolic alkalosis, what next to check
Blood pressure
Met alk, renal (hi urine cl), normotensive - slightly hypo
pyloric stenosis, CF
Met alk, renal, normotensive where is the problem
loop of Henle
What are some causes, association with met alk, renal normtensive
Loop diuretics, Bartter’s syndrome, gittelman’s syndrome
What are some causes of met alk, renal, hypertensive
excessive aldosterone - CAH, 11B-hydroxylase deficiency) RAS, Liddle’s syndrome
Pattern: polyhydramnios, hypercalciuria, hearing loss
Bartter’s syndrome
If metabolic acidosis then what next
calculate anion gap Na-Cl-HCO3
what is considered anion gap
> 12
What are cause of anion gap
Methanol Uremia DKA Paraldehyde Isoniazid/iron Lactic acidosis (dehydration, sepsis) Ethylene glycol Salicylates
What are causes of non-gap acidosis
GI losses (diarrhea, fistulas) RTA
Pattern: short stature, nephrocalcinosis, rickets
RTA
Pattern: inability of distal tubule to excrete acid
RTAI
Pattern: lowered proximal tubular bicarbonate excretion
RTA2
What is the urinary pH in RTAI/RTA2
pH >5.5 (serum is acidotic)/pH <5.5 (serum is alkalotic)
Pattern: renal wasting of phosphate, amino acids, bicarbonate, urate and glucose, cystinosis, rickets
Fanconi’s syndrome
What drug can cause acquired RTA
Ifosfamide
What is potassium status of RTA’s
HypoK RTAI and 2, hyperK RTAIV
Disorder of distal nephron/inability to excrete acid
RTA IV
Causes of RTAIV
Addison’s disease, obstructive uropathy
