fanconi syndrome

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22

Fanconi syndrome is essentially dysfunction of which nephron segment?

PCT → generalized proximal tubular dysfunction.

23

What are important inherited causes of Fanconi syndrome?

Cystinosis, galactosemia, Wilson disease.

24

Most common inherited cause of Fanconi syndrome in children from these notes?

Cystinosis.

25

Important Fanconi cause in adolescents?

Wilson disease.

26

Important acquired causes of Fanconi syndrome in adults?

Ifosfamide, tenofovir, valproate, outdated tetracyclines, cisplatin; multiple myeloma.

27

What is the classic glycosuria finding in Fanconi syndrome?

Euglycemic glycosuria due to impaired proximal glucose reabsorption.

28

Why does Fanconi syndrome cause renal rickets?

Phosphate wasting → hypophosphatemia → renal rickets.

29

What happens to amino acids in Fanconi syndrome?

Aminoaciduria.

30

What acid-base disorder occurs in Fanconi syndrome?

Type II (proximal) RTA → normal anion gap metabolic acidosis.

31

Why does Fanconi syndrome cause hyperchloremic metabolic acidosis?

HCO₃⁻ is lost in urine → NAGMA/hyperchloremic acidosis.

32

Can the distal nephron still acidify urine in proximal RTA?

Yes. Distal acidification is intact.

33

What can urine pH become in proximal RTA once plasma HCO₃⁻ has fallen?

Can fall to ~4–4.5, because distal acidification is intact.

34

Why is severe systemic acidosis less typical in isolated proximal RTA?

Because once plasma HCO₃⁻ falls sufficiently, filtered bicarbonate load decreases, allowing the distal nephron to maintain a lower urine pH.

35

What happens to uric acid in Fanconi syndrome?

Hypouricemia due to proximal tubular wasting.

36

What happens to carnitine in Fanconi syndrome?

Hypocarnitinemia.

37

What happens to potassium in Fanconi syndrome?