Acid/Base Disturbances Flashcards
What are volatile acids?
Some examples?
Form bicarbonate and H+ which can be eliminated
Glucose (under aerobic respiration)
Fat (under aerobic respiration)
What are fixed acids?
Some examples?
An acid produced in the body from sources other than carbon dioxide, and is not excreted by the lungs.
Glucose (under aerobic respiration) forming Lactate
Cysteine forming sulfate
Phosphoprotein forming phosphate
What change in pH will double or halve the concentration?
0.3
pH values of the following:
Arterial blood
Venous bloods and interstitial fluid
ICF
Urine
Gastric HCL
- 4
- 4
6 to 7.4
- 5 to 8
- 8
What are the buffer systems of the human body, and what are their pKa values.
Bicarbonate = 6.1
Plasma proteins = 6.7
Phosphate = 6.8
Hemoglubin = 7.3
BP pH
Breathing fast will result in what changes to CO2 and pH?
CO2 low = pH high
What is the Henderson Hasselbach equation?
What is the absorption of bicrbonate in the following regions of the nephron:
Proximal tubule
Thick scending limb
Collecting Duct
85%
10%
5%
How is bicarbonate transferred across the luminal cell’s basolateral membrane?
Na+/HCO3- cotransporter - Moves 3 HCO3- out with one Na+
HCO3-/Cl- antiporter
What are the secondary causes of H+ secretion in the proximal tubule?
Increase in filtered load of HCO3-
Decrease in ECF volume
Increase in angiotensin II
Hypokalemia
What are the secondary causes of H+ secretion in the collecting duct?
Increase in aldosterone
What is the primary cause of decrease [H+] secretion?
Increase in plasma HCO3- concentration
Decrease in partial pressure of O2
What acts as a bufffering agent in the tubular lumen?
NaHPO4- / NaH2PO4
What cells secrete bicarbonate?
Beta-intercalated cells
How is new bicarbonate synthesized.
H+ is bound to NH3+ and secreted as NH4.
Bicarbonate is reabsorbed
What is the net acid excretion equation?
What type of acid production should it be equal to in a normal healthy adult?
TA = titratable acids
Nonvolatile or fixed
What are the normal levels of pH?
H+
PCO2
HCO3-?
7.4
40nEq/L
40 mm Hg
24 mEq/L
Why do greater changes occur during acute respiratory acidosis/alkalosis in camparison to chronic respiratory acidosis/alkalosis?
The kidneys have more tie to respond, retaining more H+ or HCO3- depending on the situation.
How do the kidneys correct for metabolic acidosis?
What about the lungs?
Kidneys = Increased generation of NH3+ or HPO4-.
Lungs = Hyperventalation
How is anion gap calculated?
What is the normal?
Na+ - (Cl + Bicarbonate)
8-16 mEq/LCL
What are causes of high metabilic acidosis?
MUDPILERS
Methanol
Uremia
DKA/Alchoholic KA
Paradehyde
Isoniazid - used to treat tuberculosis
Lactic Acidosis
EtOH / Ethylene Glycol
Rhabdomycin/Renal failure
Salicylates
What are causes of non-anion gap acidosis?
HARDUPS
Hyperalimentation
Acetazolamide
Renal Tubular Acidosis
Diarrhea
Utero-pelvic shunt
Post-hypnocapnia
Spirolactone
What are the causes of metabolic alkalosis?
Clever PD
Contraction
Licorice
Endo: Conn, Cushing, Bartter
Vomiting
Excess Alkali
Referring Alkalosis
Post-hypercapnia
Diuretics
What causes acute respiratory acidosis?
CAANS
CNS depression
AIrway obstruction
Acute respiratory distress syndrome
Neuromuscular disorders
Severe pneumonia, embolism, or pulmonary edema
What causes chronic respiratory acidosis?
COPD and anything that can lead to impaired ventalilation.
What causes respiratory alkalosis?
CHAMPS
CNS disease
Hypoxia
Anxiety
Mechanical ventilation
Progesterone
Salicylates/Sepsis
What is the equation for metabolic acidosis?
PaCO2 = 40 - (1.2 x 24 - [HCO3])
What is the equation for metabolic alkalosis?
PaCO2 = 40 - (0.7 x 24 - [HCO3])
What diseases feature metabolic acidosis with urine Cl- > 20 mEq/L?
Chloride resistant, hyperaldosterism, K+ loosing diuretics
What are the equations fro respiratory acidosis?
Acute = 24 + (0.1 x (PaCO2 - 40))
Chronic = 24 + (0.4 x (PaCO2 -40))
What are the equations fro respiratory alkalosis?
Acute = 24 - (0.2 x (40 - PaCO2))
Chronic = 24 - (0.5 x (40 - PaCO2))
What is the mechanism behind Renal Tubular Acidosis Type 1?
What are the highlighted causes?
Where is it effecting?
Intercalated cells cannot secrete H+ by alpha intercalated cells
Urinary stone formation due to hypercalciuria with low urinary citrate and alkaline urine; bone deminieralization
The distal tubule
What is the mechanism behind Renal Tubular Acidosis Type 2?
What are the highlighted causes?
Failed reabsorbtion of HCO3- by the proximal tubule.
Most often seen associated with Faconi syndrome
What is the mechanism behind Renal Tubular Acidosis Type 4?
What are the highlighted causes?
Where is it effecting?
Deficiency of aldosterone (primary or hyporeninemic), or a resistance to its effects due to pseudomypoaldosteronism or drugs
NSAIDs, ACE inhibitors/ARB, and spironolactone or eplerenone
Adrenal Gland
Which form of Renal Tubular Acidosis presents with hyperkalemia?
Type 4
What is the most rare to most common renal tubular acidosis?
2 → 1 → 4
