นพ.สกานต์ บุนนาค งานโรคไต รพ.ราชวิถี
นพ.สกานต์ บุนนาคงานโรคไต รพ.ราชวิถี
K+ < 3.5 meq/l
R/O pseudo hypo K+
R/O redistribution • Periodic paralysis• Insulin, B2 agonist• refeeding• Rx neutropenia with G-CSF• Rx anemia with B12, folate• Ba poisoning, acute chloroquine toxic
WC > 100,000
• TTKG > 4 or • 24 hour urine K+ > 20 meq
No• diarrhea • sweating• remote diuretic use
= renal loss
• TTKG < 2 or • 24 hour urine K+ < 10 meq
Renal K+ loss
Metabolic acidosis normal Metabolic alkalosis
High gap• DKA
• ketoacidosis• methanal• ethylene glycol
Normal gap• RTA
• CA inhibitor• glue sniff
• Non-oligulic ATN• Diuretic phase ATN• low serum Mg• high dose PGs• TI disease
Urine Cl-
< 10 meq/l(hypo-volumemia)
>20 meq/l(hyper-volumemia
orCl- losing)
• vomiting• NG suction
Normal BP High BP
R/O HT with diuretic use
• resent diuretic use• Barter• Gitelman
High reninHigh aldosterone
low reninHigh aldosterone
low reninlow aldosterone
• RAS• malignant HT• scleroderma• renin producing tumor
• 1o hyperaldosteronism
• Liddle (mutationof Na channelincrease Na reabsorption)
•Increase mineralocorticoid• Very high cortisol• 11 B-OH def• Licorice• fludocortisone• 17 a-OH def
K+ > 5.5 meq/l
R/O pseudo hyper K+ • Hemolysis
• WC > 70,000• Plt > 1,000,000
If > 6.0 EKG should be done
K+ loadExternal source• diet
• IV fluid• old blood > 5 day
Internal source• intravascular hemolysis
• rhabdomyolysis• tumor lysis syndrome• UGIB• absorb hematoma• major trauma or Sx• severe sepsis
• TTKG > 7 or • 24 hour urine K+ > 200 meq
Redistribution• beta-block (esp.
nonselective beta 1)• metabolic acidosis• periodic paralysis• severe exercise • Digitalis toxic• fluoride toxic
yesno
Defect of renal excretion
Na+
K+
3Na+
2K+
ATP
Collecting tubule
Principal cell
Aldosterone
Aldosterone
Aldosterone+
+
+
lumen basolateral
negative
Cl-
Defect of renal excretion
site cause
Low distal Na delivery
low ECV, low GFR(<15), Gordon syndrome(psudohypoaldosterone type II)
Defect of Na channel (ENAC)
triamterene, amiloride
Defect of Cl-channel
heparin, cyclosporine
Defect of K+ channel (ROMK)
cyclosporine
Defect of aldosterone
ACE-I, ARB, spironolactone, NSAIDs, heparin, cyclosporineDM,1o hypoaldosterone,1o adrenal insuff
Intracellular (Hb, protein)
and Bone Buffering (carbonate)
H+ + HCO3- H2CO3 H2O + CO2
RenalNH4
+ excretion(HCO3- regeneration)
Tritratable acid excretionHCO3
-reclamation
Lung
Fixed AcidA- + H+
Volatile acid(from CO metabo)
GluconeogenesisAnionic Amino acid
Anion gapNa
+- ( Cl
-+ HCO3
-)
Unmeasured anionUnmeasured cation
Measured cationNa+
Measured anionCl-, HCO3
-
K+, Ca2+ , Mg2+ alb , phosphate , sulphate, organic cation ( M protein )
Delta gap in met.acidosis ; due to A-
( HA H+ + A- )
Delta HCO3-◦ 60% H+ buffer in intracellular and bone pure
met.acidosis delta gag/delta HCO3- may be 1:1 to 2:1
◦ Resp.acidosis decrease delta HCO3-
◦ Resp.alk increase delta HCO3-
1-2 pure wide gap acidosis
<1 wide gap + normal gap met.acidosis
wide gap met.acidosis + resp.alk.
>2 wide gap met.acidosis + met.alk.
wide gap met.acidosis + resp.acido.
=Measured osmol – calculated osmol
Calculated osmol
= 2(Na+K) + BUN/2.8 + Glu/18
In wide gap met.acidosis if > 25 suggest methanol or ethylene glycol ingestion
Wide P osmolol gap can be found in lactic or ketoacidosis
Rarely elevated in salicylic acidosis
because toxic level is very low.
Anion gap(Na+ + K+) - Cl-
Unmeasured anion
Unmeasured cation
Measured cationNa+ + K+
Measured anionCl-
NH4+
Urine anion gap (urine net charge)
NH4+ is U unmeasured cation
Urine is neutral.
When acidemia high urine NH4+ high
U unmeasured cation neg urine net charge
=Measured osmol – calculated osmol
Calculated osmol
= 2(Na+K) + UUN/2.8 + Glu/18
More than half of urine osmolol gap is ammonium.
Unmeasured anion are already included in 2(Na+K)
Low serum HCO3-
Met acidosis ?R/O resp. alkalosis
OrMixed acid-base
Serum anion gap (collected with alb)
Wide gap Normal gap
Delta gap/Delta HCO3-
Wide gap met. AcidosisLactic acidosisKetoacidosis (dibetes/starvation/alcoholic)
Toxic (methyl or ethyl alcohol/ethylene glycol/salicylate
ABG
Wide gap met.acidosisWith ?
Normal gap hyperchloremic met. acidosis
Fe HCO3->15 Fe HCO3
-<15
CA-I Proximal RTA (type 2)
Isolated type Fanconi synd.
Fe HCO3- <15
Negative urine net chargeOr
Urine osmolar gap > 100 mmol/lOr
Urine ammonium >50 mmol/day
yes no
High ammonium excretion(diarrhea, acid load) Low ammonium excretion
RTA type 1 (low serum K+) orRTA type 4 (high serum K+)
Generation
Correction
• H+ loss (renal, extrarenal)• H+ shift in to cells• Retention of HCO3-• Contraction Alkalosis
• Increase HCO3- filtration• Decrease HCO3- reabsorption• Decrease HCO3- regeneration
(=decrease NH4+ secretion)• Increase HCO3- secretion
◦ H+loss
GI; vomiting, NG tube suction, antacid
Renal; thiazide or loop diuretic, 1o mineralocorticoidexcess, Bartter or Gitelman synd., post hypercapnia
◦ H+shift in to cell
Hypo K+
◦ HCO3- Gain; administration of NaHCO3, organic
anion(citrate, acetate)
◦ Contraction alkalosis; loss CL- > HCO3-
Cl- losing diarrhea
Generation
Maintenance
Correction
• H+ loss (renal, extrarenal)• H+ shift in to cells• Retention of HCO3-• Contraction Alkalosis
• decrease ECF volume• Cl- depletion• K+ depletion• renal failure