I88.0 vs R59
I88.0 and R59 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on R59
mesenteric (acute) (chronic) lymphadenitis (I88.0)
I88.0
Nonspecific mesenteric lymphadenitis
Billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I80-I89
Use when the record says
- Mesenteric lymphadenitis (acute)(chronic)
Indexed under
- Brennemann's syndrome
- Adenitis › mesenteric
- Infection, infected, infective › mesenteric lymph nodes or glands NEC (opportunistic)
- Lymphadenitis › mesenteric
- Abscess › lymph, lymphatic, gland or node › mesentery (connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
R59
Enlarged lymph nodes
Not billable
- Chapter 18
- Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
- Section
- R50-R69
Use when the record says
- swollen glands
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027