18 terms

Renal concepts

Respiratory acidosis
low pH, high PCo2 + HCO3
pH < 7.4, PCo2 > 40 mmHg, HCO3 > 22.


airway obstruction, acute/chronic lung disease, opiods, narcotics, sedatives, weakening of respiratory muscles.
Metabolic acidosis with compensation

low pH, PCO2 + HCO3.
pH < 7.4, PCo2 < 40 mmHg

check anion gap = Na - (Cl + HCO3)
inc anion gap (> 12)
met acidosis (pH<7.4, PCo2 < 40 mmHg)

Methanol (formic acid)
Diabetic ketoacidosis
Paraldehyde or Phenformin
Iron tables or INH
Lactic acidosis
Ethylene glycol (oxalic acid)
Respiratory alkalosis
high pH, low pCo2, low HCO3
pH > 7.4, PCo2 < 40 mmHg


early high altitude exposure, aspirin ingestion early.
Metabolic alkalosis with compensation

high pH, pCO2, HCO3.
pH > 7.4, PCo2 > 40mmHg.

diuretic use (loop + thiazides), vomiting, antacid, hyperaldosteronism
aspirin overdose
mixed disorder

Low pH, HCO3 and PCo2

1. respiratory alkalosis from hyperventilation --> PCo2 < 40
2. metabolic acidosis due to accumulation of organic acid -- low HCO3 < 22.
RBC casts in urine
glomerulonephritis, ischemia, or malignant hypertension.

presence of casts indicates that hematuria/pyuria is of renal origin
WBC casts
tubulointerstitial inflammation, acute pyelonephritis, transplant rejection.
granular "muddy brown" casts
acute tubular necrosis
waxy casts
advanced renal disease, chronic renal failure
hyaline casts
RBCs, no casts
bladder cancer, kidney stones
WBCs, no casts
acute cystitis.
sedative overdose
mixed. metabolic and respiratory acidosis.

low pH, high pCO2, low HCO3.
metabolic acidosis normal anion gap
Normal anion gap (8-12 mEq/L)

Diarrhea, glue sniffing, renal tubular acidosis, hyperchloremia
RTA type 1 "distal"
Defect in CT ability to excrete H. Assoc with hypokalemia, and risk for Ca containing kidney stones
RTA type 2 "proximal"
Defect in proximal tubule HCO3 reabsorption. Assoc with hypokalemia and hypophosphatemic rickets
RTA type 3 "hyperkalemic"
Hypoaldosteronism or lack of CT response to aldosterone --> hyperkalemia --> inh of ammonia excretion in proximal tubule. Leads to dec urine pH (acid!) due to dec buffering capacity (lack of base)