Renal Control Of Acid-base Balance Flashcards
Is there a higher [H+] intracellularly or extracellularly?
Intracellularly
What is the pKa for carbonic acid?
6.1
Where is bicarbonate primarily reabsorbed?
In the PCT
Where does the NKCC transporter reside in the nephron?
In the TAL
How does ammonia get excreted?
It exists as ammonium in the tubular fluid and gets secreted into the interstitium by the NKCC transporter in place of K+
In the interstitium it gets converted into ammonia, gets pumped into the collecting duct and excreted
If there is acidic blood, what do the alpha intercalated cells do?
They secrete H+ and reabsorb HCO3-
If there is alkalotic blood, what do the beta-intercalated cells do?
They reabsorb H+ and secrete HCO3-
What is a titratable acid?
Salts that are primarily phosphate and have a pKa are lower than 7.4
Account for ~1/3 of net acid excretion
What is net acid excretion?
It must be equal to nonvolatile acid production each day in order to maintain acid-base balance
What accounts for 2/3 of NAE?
Ammonium
What is normal anion gap?
8-16 mEq/L
What are causes of high anion gap metabolic acidosis?
M ethanol U remia D KA P araldehyde I soniazid (treats TB) L actic acidosis E tOH
What are causes of non-anion gap acidosis?
H yperalimentation A cetazolamide R enal tubular acidosis D iarrhea U retero-pelvic shunt P ost-hypocapnia S pironolactone
How do you diagnose renal tubular acidosis?
Acidemia + normal anion gap + normal serum creatinine+ no diarrhea
What is the most common type of RTA?
Type 4
Where is the location of defect for RTA type 1?
Distal tubules
Where is the location of defect for RTA type 2?
Proximal tubules
Where is the location of defect for RTA type 4?
Adrenal gland
Which RTA types have hypokalemia?
Type 1 and type 2
What is the pathophysiology of RTA type 1?
H+ secretion by alpha-intercalated cells is impaired
What is the pathophysiology of RTA type 2?
Failed HCO3- reabsorption from the urine by the proximal tubular cells
What is the pathophysiology of RTA type 4?
Low aldosterone or a failure to respond to it
Why is RTA type 4 the most common form?
It is most common because ACE inhibitors block RAAS and if it is blocking aldosterone, it would result in this presentation
What are some causes of metabolic alkalosis?
C ontraction L icorice E ndo: (Conn, Cushing, Bartter) V omiting E xcess alkali R efeeding alkalosis
P ost-hypercapnia
Causes of respiratory acidosis?
C NS depression
A irway obstruction
N euromuscular disorders
S evere pneumonia, embolism, edema
Causes of respiratory alkalosis
C NS disease H ypoxia A nxiety M echanical ventilators P rogesterone S alicylates/sepsis
