Interstitial Nephritis in a Patient Taking Creatine

A NEJM CASE

A previously healthy 20-year-old man presented with a four-day history of nausea, vomiting, and bilateral flank pain that began approximately four weeks after he started taking 5 g of creatine (pure creatine monohydrate, ProPerformance Laboratories, Pittsburgh) orally four times a day. He had stopped the creatine and had not taken any medications or other food supplements. His blood pressure was 140/90 mm Hg. Physical examination revealed dehydration and diffuse abdominal tenderness. His serum creatinine concentration was 1.4 mg per deciliter (124 µmol per liter). A complete blood count and measurements of antistreptolysin O, antinuclear antibodies, and plasma complement C3 and C4 concentrations were normal. Urinalysis revealed 4+ protein and 1+ blood; the urine sediment contained dysmorphic red cells and white-cell casts. A spiral computed tomographic scan revealed no abnormalities in the kidneys or the collecting systems.

The patient was hospitalized and treated with intravenous fluid and pain medication. During hospitalization, his blood pressure rose to 160/100 mm Hg and his serum creatinine concentration rose to a peak value of 2.3 mg per deciliter (203 µmol per liter). Urinary protein excretion was 472 mg per day. A renal biopsy revealed acute focal interstitial nephritis and focal tubular injury; electron microscopy revealed effacement of glomerular foot processes and focal thickening of the basement membrane. The patient's blood pressure, serum creatinine concentration, and urinalysis subsequently became normal.

Shown are a proximal tubule with flattened epithelium (arrowhead) and an interstitial mononuclear infiltrate with interspersed eosinophils (arrows).






DISCUSSION

Creatine intake has been used for all athletes since about 1980's. The indicated use consist of two phases: a loading and maintenance phase. The loading phase is for 5-6 days and consist of 9 grams and a quarter of grape juice (or sugar) in any beverage, one fasting and the other after do the exercise. The maintenance phase consist of 4 grams and the grape juice but only after do the exrecise, not fasting. Hence, one person intaking creatine do the load phase the first week, the maintenance phase between the second and the fourth week, rest 3 weeks and start again. After the fourth month the rest phase could long two weeks. In this case, this young take 20 grams daily but for a month, so he should had stop the first week; this is very usual because some people want to see fast results no matter what the consequences are.