FA Flashcards
Renal tubular defects - types
- Fanconi syndrome
- Bartter syndrome
- Gitelman syndrome
- Liddle syndrome
- Syndrome of apparent minelocorticoid excess
Fanconi syndrome - pathophysiology / results in
Generalized reabsorptive defect in early proximal convoluted tubule –> increased amino acids, glucose, HCO3- and PO4- – Metabolic acidosis (proximal renal tubular acidosis)
causes of Fanconi syndrome
- hereditary defects (Wilson disease, tyrosinemia, glycogen storage disease, cystinosis)
- iscemia
- multiple myeloma
- nephrotoxins/drugs (expired tetracyclines, ifosfamide, cisplatin, tenofovir, lead poisoning)
Bartter syndrome - pathophysiology (and result in)
Reabsorptive defect in thick ascending loop oh Henle
–> affects Na+/K+/2CL- cotransporter –>
1. hypokalemia
2. metabolic alkalosis
3. hypercalciuria
LIKE LOOP DIURETICS
Gitelman syndrome - pathophysiology (results in)
Reabsosptive defect in Distal convoluted tubule LIKE THIAZIDE 1. hypokalemia 2. hypomagnesia 3. metabolic alkalosis 4. hypocalciuria
Gitelman syndrome vs Barrter syndrome according to severity
Barrter is more severe
Liddle syndrome - pathophysiology
Gain of function mutation –> increased Na+ reabsorption in collecting tubules (high activity of epithelial channel)
situation that mimics Liddle syndrome
hyperaldosternism (but aldosterone is nearly undetectable)
Liddle syndrome –> ….. (result in)
- hypertension
- hypokalemia
- metabolic alkalosis
- low aldosterone
Liddle syndrome - mode of inheritance / treatment
AD
amiloride
Syndrome of Apparent Mineralocorticoid excess - pathophysiology
hereditary deficiency of 11β-hydroxysteroid dehydrogenase which normally converts cortisol (can activate mineralocorticoid receptors) to cortizone (inactivate on mineralocorticoid receptors) in cell containing mineralocorticoid receptors –> increased mineralocorticoid activity
Syndrome of Apparent Mineralocorticoid excess - manifestations
- hypertension
- hypokalemia
- metabolic alkalosis
- low serum aldosterone levels
P02, PCO2, HCO3-, ph - normal ranges
PO2: 75-105 mm Hg
PCO2: 33-44 mm Hg
HCO3-: 22-28 mEq/L
pH: 7.35-7.45
Winters formula?? is a formula used to evaluate
respiratory compensation in a metabolic acidosis
PCO2=1.5 (HCO3-) + 8 +/- 2
Winters formula - explanation
If measured PCO2 is bigger than predicted PCO2 –> concominant respiratory acidosis
If measured PCO2 is smaller than predicted –> concomitant respiratory alkalosis
Metabolic alkalosis - DDx
- loop diuretics
- vomiting
- antiacids
- hyperaldosteronism
- thiazide use
- Hypokalemia
- several renal tubular defects
Respiratory alkalosis - DDx
Hyperventilation:
- Hysteria
- Hypoxemia (eg. high altitude)
- Pulmoary embolism
- Tumor
- salicylates (early)
Respiratory acidosis - DDx
Hypoventilation:
- Airway obstruction
- Acute lung disease
- Chronic lung disease
- Opioids/sedatives
- weakening of respiratory muscles
Metabolic acidosis - next step
Check anion gap = Na+ - (CL+HCO3-):
more than 12 –> anion gap metabolic acidosis
8-12 –> normal anion gap metabolic acidosis
anion gap metabolic acidosis - DDx
- Methanol (formic acid)
- Uremia
- Diabetic ketoacidosis
- Propylene glycol
- Iron tablets
- ISONIAZIDE
- Lactic acidosis
- Ethylene glycol (–> oxalic acid)
- Salicilates (late)
normal anion gap metabolic acidosis - DDx
- Hyperalimentation (artificial supply of nutrients, typically intravenously)
- Addison disease
- Renal tubular acidosis
- Diarrhea
- Acetazolamide
- Spironolactone
- saline infusion
Renal tubular acidosis - types
- Distal tubular acidosis (type 1)
- Proximal renal tubular acidosis (type 2)
- Combined proximal and distal renal tubular acidosis (type 3)
- Hyperkalemic renal tubular acidosis (type 4)
Metabolic acidosis - predicted compensatory response
1 meq/L decrease in HCO3- –> 1.3 mmHg decrease in PCO2
Metabolic alkalosis - predicted compensatory response
1 meq/L increase in HCO3- –> 0.7 mmHg increase in PCO2
Respiratory acidosis - predicted compensatory response
acute: 1 mmHg increase in PCO2 –> 0.1 meg/L increase in HCO3-
chronic: 1 mmHg increase in PCO2 –> 0.4 meq/L increase in HCO3-
Respiratory alkalosis - predicted compensatory response
acute: 1 mmHg decrease in PCO2 –> 0.2 meq/L decrease in HCO3-
chronic: 1mmHg decrease in PCO2 –> 0.4 meg/L decrease in HCO3-
Renal cell carcinoma - risk factors
- Smoking
- obesity
- gene deletion of chromosome 3 (sporadic or inheritance as von Hippel-Lindau
von Hippel-Lindau disease - manifestations
- hemangioblastomas in retina, brain stem, cerebellum, spine
- angiomatosis (cavernous hemangiomas in skin, mucosa, orgnas)
- bilateral renal cell carcinoma
- pheochromocytomas