Diphtheritic tubulo-interstitial nephropathy

This code signifies kidney damage, specifically affecting the tubules and interstitial tissue, that is a direct consequence of diphtheria infection. It represents a serious complication where the toxins produced by Corynebacterium diphtheriae lead to inflammation and dysfunction within the renal structures. This condition can impair the kidneys' ability to filter waste and regulate fluid balance.

Apply this code when documentation clearly links tubulo-interstitial nephropathy to a confirmed or suspected diphtheria infection. This typically occurs in patients presenting with acute kidney injury or chronic kidney disease in the context of a recent or active diphtheria diagnosis. Supporting documentation should include laboratory confirmation of diphtheria and evidence of renal involvement.

• Always code the underlying diphtheria infection first, followed by this code to show the causal relationship.
• Ensure documentation specifies "diphtheritic" to differentiate from other causes of tubulo-interstitial nephropathy.
• Do not use this code for general kidney involvement in diphtheria; it specifically refers to tubulo-interstitial damage.