CLINICAL CASE 18, ANSWER and SUMMARY

Which of the following is a known cause of granulomatous interstitial nephritis?

Sarcoidosis	3 (37%)
Fungal	0 (0%)
BCG vaccination	0 (0%)
Heroin abuse	1 (12%)
Atheroembolic Disease	0 (0%)
All of the Above	4 (50%)
None of the Above	0 (0%)

Most of you got this one. As we commonly associated granulomatous interstitial nephritis with sarcoidosis, that is one of the correct answers but the right answer is all of the above.  Drugs such as b lactam antibiotics, nsaids and diuretics have been associated with it.  Wegener GN, infections such as TB, fungal and bacterial infections, BCG vaccine, jejunal ileal bypass, heroin abuse, paraproteinemias and atheroembolic(chronic) are also causes of it.  Think of these causes when you see such biopsy findings.