Cystitis in diseases classified elsewhere

This code signifies cystitis that arises as a manifestation or complication of another underlying disease process. It indicates that the bladder inflammation is secondary to a condition classified elsewhere in the ICD-9-CM system, rather than being a primary or idiopathic cystitis.

Use this code when the medical record clearly links cystitis to an underlying systemic disease, such as lupus, diabetes, or an autoimmune disorder. Documentation should explicitly state the causal relationship, for example, "cystitis secondary to systemic lupus erythematosus" or "diabetic cystopathy with superimposed cystitis."

• Always code the underlying systemic disease first, followed by this code to show the causal link.
• Do not use this code for infectious cystitis unless the infection itself is a complication of a disease classified elsewhere.
• Ensure documentation specifies the "due to" or "secondary to" relationship; otherwise, a more general cystitis code may be appropriate.