HDMTX induced ARF

 Q; 32 years old female who was started on high dose methotrexate (HDMTX) 2 weeks ago for  hematologic malignancy  presented with nausea and vomiting. Patient was found to be in acute renal failure (ARF). MTX induced ARF tends to be? (select one)

A) reversible

B) irreversible

Answer: A

MTX induced nephropathy usually occurs in high dose administration referred as HDMTX. Methotrexate precipitates in the renal tubules and directly induce tubular injury. This can be avoided by hydration and alkalinization of the urine. It is advisable to keep urine's PH above 7. Moreover, MTX causes transient compromise of glomerular filtration rate (GFR) after each dose due to afferent arteriolar or mesangial cell constriction. 

Fortunately, HDMTX-induced ARF is usually non-oliguric and kidneys recover their function in two weeks once the MTX is stopped. Patient should be watched for MTX toxicity during this period due to decrease clearance and high plasma level. 

#nephrology

#pharmacology

#toxicology

References:

1. Widemann BC, Adamson PC. Understanding and managing methotrexate nephrotoxicity. Oncologist 2006; 11:694. 

2. Amitai I, Rozovski U, El-Saleh R, et al. Risk factors for high-dose methotrexate associated acute kidney injury in patients with hematological malignancies. Hematol Oncol 2020; 38:584.

3.  Garneau AP, Riopel J, Isenring P. Acute Methotrexate-Induced Crystal Nephropathy. N Engl J Med. 2015 Dec 31;373(27):2691-3. doi: 10.1056/NEJMc1507547. PMID: 26716929.