Nephrology: Acid Base Disturbances

Question 1

Increased serum bicarb

Answer 1

• means you have a metabolic alkalosis
• H+ loss: exogenous steroids, GI loss, Renal loss, decreased chloride intake, diuretics
• HCO3- retention: bicarbonate administration, contraction alkalosis (aldosterone release), milk-alkali syndrome (now we have H2 blockers and PPI)
• H+ movement into cells: hypokalemia

Question 2

Respiratory Alkalosis

Answer 2

• hyperventilation of any kind: anemia, pulmonary embolus, sarcoidosis, anxiety and pain, progesterone, catecholamines, salicylates, hypoxia, cirrhosis

Question 3

Anion gap

Answer 3

Anion gap = (Na+ + K+ ) - (HCO3- + Cl-)

normal is 8-14

• low anion gap: myeloma, low albumin, lithium
• increased anion gap is something there that wasn’t there before: alcohol, lactate, aspirin, methanol, uremia, diabetic ketoacidosis, ethylene glycol, paraldehyde, isopropyl alcohol, INH - these are not measured, so that is why there is increased anion gap
• the only normal anion gap metabolic acidosis is RTA and diarrhea (distinguish these with urine anion gap)

Question 4

Respiratory Acidosis

Answer 4

• hypoventilation of any cause:
• COPD
• Pickwickian syndrome
• Obesity
• Suffocations
• Opiates
• Sleep apnea
• Kyphoscoliosis
• Myopathies
• Neuropathy
• Effusion

increase PCO2