Renal physiology Flashcards
What are the 4 causes of metabolic acidosis with a normal anion gap?
Renal tubular acidosis
Diarrhoea
Ammonium chloride ingestion
Adrenal insufficiency
What are the 4 causes of metabolic acidosis with a raised anion gap?
Lactic acidosis (hypoxia, sepsis, infarction)
Ketoacidosis (DM, starvation, alcohol)
Renal failure
Poisoning (late stages aspirin OD, methanol, ethylene glycol)
Give 5 causes of metabolic alkalosis.
Vomiting
Cardiac arrest
Multi-organ failure
CF
Potassium depletion (diuretics)
Cushing’s syndrome
Conn’s syndrome
Give 5 causes of respiratory alkalosis.
Hyperventilation
PE
Pneumothorax
CNS disorders (CVA, SAH, encephalitis)
High altitude
Pregnancy
Early stages of aspirin OD
Give 5 causes of respiratory acidosis.
COPD
Life-threatening asthma
Pulmonary oedema
Respiratory depression (Opiates, BDZs)
Neuromuscular disease (GBS, muscular dystrophy)
Incorrect ventilatory settings (hypoventilation)
Obesity
What doe/s the anion gap represent
The concentration of all the unmeasured anions in the plasma.
How do you calculate the anion gap?
Na - Cl - HCO3
What are the causes of a high anion gap metabolic acidosis?
Mnemonic CAT MUD PILES:
Carbon monoxide
Alcoholic ketoacidosis
Toluene
Metformin/ Methanol
Uraemia
Diabetic Ketoacidosis
Propylene glycol
Iron/ Isoniazid
Lactic acidosis
Ethylene glycol
Salicylates
What are the causes of a normal anion gap metabolic acidosis?
Mnemonic CAGE:
Chloride excess
Acetazolomide/ Addison’s disease
GI causes (diarrhoea, vomiting, fistulae)
Extra (renal tubular acidosis)
A high anion gap metabolic acidosis normally occurs due to what?
Accumulation of organic acid or impaired excrete of H+.
A normal anion gap metabolic acidosis normally occurs due to what?
Loss of HCO3 from extracellular fluid.
How is lactic acidosis defined?
pH <7.35
AND
lactate >5
What happens to the anion gap in lactic acidosis?
It is raised
What is type A lactic acidosis due to?
Tissue hypoxia
What is type B lactic acidosis due to?
Non-hypoxic processed affecting production and elimination of lactate.
Give some causes of type A lactic acidosis.
Shock (sepsis)
LV failure
Severe anaemia
Asphyxia
Cardiac arrest
CO poisoning
Respiratory failure
Severe asthma
COPD
Regional hypoperfusion
Give some causes of type B lactic acidosis.
Renal failure
Liver failure
Sepsis (non-hypoxic sepsis)
Thiamine deficiency
Alcoholic ketoacidosis
Diabetic ketoacidosis
Cyanide poisoning
Methanol poisoning
Biguanide poisoning
What is the RAAS system responsible for?
Regulation of arterial BP
Concentration of sodium in the plasma
Where is renin released from?
Juxtaglomerular cells
Where are juxtaglomerular cells located?
Afferent arterioles of the kidney
Which 3 things can cause renin to be released?
Decreased arterial BP (reduced renal perfusion)
Decreased sodium load delivered to the DCT
Sympathetic nervous system stimulation
Where is angiotensinogen produced?
Liver
What 4 factors cause an increase of angiotensinogen?
Increased corticosteroid levels
Increased thyroid hormone levels
Increased oestrogen levels
Increased angiotensin II levels
What is the function of renin?
Cleaves the peptide bond between leucine and valine on angiotensinogen, converting it to angiotensin I.