8. Tubulointerstitial and cystic kidney diseases Flashcards
What are the causes of acute tubular necrosis?
- Prolonged ischemia,
- nephrotoxins,
- sepsis,
- radio-contrast material,
- drugs such as aminoglycosides, vancomycin, mTOR-inhibitors, amphotericin B
What is the site of injury in acute tubular necrosis (ATN)?
The site of injury is the proximal tubule and medullary TAL.
What are the causes of acute tubular necrosis?
Hemodynamic factors, endothelial injury, tubular epithelial injury, and inflammatory factors.
What is the differential diagnosis for acute tubular necrosis?
- High urine Na (> 40-50 mmol/L)
- Low urine osm (<350 mOsm/L)
- BUN / creat 10:1
- High FeNa (fraction excretion of Na)
- Granular, muddy brown casts
What are the prevention and treatment options for acute tubular necrosis?
- Avoid prolonged ischemia/nephrotoxic agents,
- monitor volume status,
- diuretics in case of volume overload,
- renal replacement therapy if needed.
Prognosis of ATN?
Spontaneous recovery in 1-3 weeks (can use dialysis in the meantime)
Pathomechanism of radiocontrast induced nepthropathy?
prolonged vasoconstriction -> medullary hypoxia -> tubular epithelial cell toxicity
Clinical picture of radiocontrast induced nephropathy?
Non-oliguric ATN, 2-3 days after contrast administration
What is the recommended prevention for radiocontrast-induced nephropathy?
- Cautious if GFR < 30 mL/min
- adequate hydration and loop diuretics
What is the pathomechanism of aminoglycoside-type nephrotoxin-induced ATN?
The drug accumulates in proximal tubular cell lysosomes, interferes with cellular energetics, and induces oxidative stress.
What is the clinical picture of aminoglycoside-type nephrotoxin-induced ATN?
Non-oliguric ATN.
What is the pathomechanism of ethylene glycol-type nephrotoxin induced ATN?
Ethylene glycol is metabolized to toxic products. This leads to tubular precipitation and obstruction.
What is the clinical picture of nephrotoxin-induced ATN caused by ethylene glycol?
ATN with severe anion gap metabolic acidosis and calcium oxalate crystals in urine.
What is the recommended management for ethylene glycol-induced ATN?
Intravenous ethanol or alcohol dehydrogenase inhibitor
What is the clinical picture of heme pigment nephropathy?
Oliguric ATN with elevated plasma CK and LDH.
What are the risk factors for heme pigment nephropathy?
- Rhabdomyolysis (muscle trauma, seizures, statin use, McArdle disease),
- massive hemolysis.
What is the management of heme pigment nephropathy?
- Correct metabolic abnormalities (hyperkalemia, hyperuricemia),
- maintain fluid balance,
- initiate renal replacement therapy if needed.
What is the etiology of acute tubulo-interstitial nephritis?
- Drugs (>75%),
- infection-related (5-10%).
- ATIN associated with systemic diseases
What is the clinical picture of ATIN?
- Oliguria
- Leukocyturia / eosinophiluria
- Hematuria
- Joint and lumbar pain
- Weakness
- Weight loss
What are the clinical triad of acute tubulo-interstitial nephritis?
fever ± eosinophilia ± skin rash
How is the diagnosis of acute tubulo-interstitial nephritis made?
- clinical picture,
- renal biopsy
What is the treatment for ATIN?
- Discontinuation of the drug (in case of immune checkpoint inhibitors, temporary drug withdrawal)
- Treat infection if infection related
- Corticosteroids if immune or idiopathic
What is the most common renal injury in multiple myeloma?
Myeloma cast nephropathy
What is the clinical picture of myeloma cast nephropathy?
- Acute kidney injury,
- mild proteinuria (<2-3 g/day),
- monoclonal light chains in urine (NOT DETECTED BY DIPSTICK),
- hypercalcemia,
- anemia.
What is the treatment for myeloma cast nephropathy?
- Hydration
- treatment of hypercalcemia,
- urine alkalization (pH >7),
- avoidance of NSAIDs, furosemide,
- plasma exchange/hemodialysis
What are the clinical features of chronic interstitial nephritis and isolated tubulopathies?
- Mild symptoms and signs, slowly progressing renal failure with insidious onset,
- renal anemia at relatively early stage,
- hypertension.
What is Fanconi syndrome?
Fanconi syndrome is a rare disorder characterized by proximal tubular dysfunction.
What are the types Fanconi syndrome?
- Acquired Fanconi syndrome
- Hereditary (storage diseases)
- idiopathic
What is the treatment for Fanconi syndrome?
- bicarbonate
- phosphate
- potassium
- vitamin D3 supplementation.
What are the signs and symptoms of proximal tubular dysfunction?
Tiredness, muscle weakness, bone pain, and in hereditary forms, excessive thirst, polydipsia, and polyuria.
What is Type 2 renal tubular acidosis (RTA)?
Decreased HCO3-reabsorption in the proximal tubules, leading to ion disturbances such as hypokalaemia + hyperchloraemia + acidosis and normal anion gap (12 ±4mmol/ L).
What is the therapy for Type 2 renal tubular acidosis (RTA)?
- bicarbonate supplementation
- thiazide diuretics to decrease bicarbonate loss,
- K-supplementation / K-sparing diuretics.
What are the signs and symptoms of hypokalaemic nephropathy?
- Polyuria / polydipsia
- Decreased renal concentrating capacity
- Hypochloremia
- Metabolic alkalosis.
What is the therapy and prognosis for hypokalaemic nephropathy?
It is reversible with potassium replacement.
When should rare diseases affecting the loop of Henle / distal tubules be considered?
In young patients with tiredness, muscle cramps, polydipsia, excessive thirst
What is the laboratory finding in rare diseases affecting the loop of Henle / distal tubules?
Hypokalaemia, hypochloraemia, metabolic alkalosis.
What are some inherited hypokalemic salt-losing tubulopathies?
- Bartter syndrome
- Gitelman syndrome
What are some cystic kidney diseases?
- Polycystic kidney disease
- Simple / complex renal cysts
- Medullary sponge kidney
What are the consequences of ADPKD?
- Cysts can develop along the entire length of the nephron, leading to renal failure.
- Additionally, multiple liver, pancreatic, and ovarian cysts can occur, and there is a risk of subarachnoid hemorrhage due to intracerebral aneurysms.
What is the clinical presentation of ADPKD?
- ADPKD can be asymptomatic or have few symptoms for a long time.
- It can cause loin pain, macroscopic hematuria, hypertension, kidney stones, frequent UTIs, polyuria, and polydipsia.
What is the treatment for ADPKD?
- increased fluid intake (>3 L/day),
- optimal blood pressure control (ACEI/ARB),
- V2R antagonists in case of rapid progression.
What are Bosniak categories for complex renal cysts?
Bosniak categories are used to classify complex renal cysts on CT scans
