Pneumococcal arthritis, unspecified knee

This code signifies an inflammatory condition of the knee joint caused by Streptococcus pneumoniae bacteria, where the specific knee affected (right or left) is not documented. It represents a bacterial infection leading to joint pain, swelling, and restricted movement.

Use this code when documentation confirms a diagnosis of pneumococcal arthritis affecting the knee, but the laterality (right or left) is not specified. This typically occurs when laboratory tests identify S. pneumoniae from synovial fluid or blood cultures in a patient presenting with acute knee monoarthritis.

• Always attempt to clarify laterality with the provider if possible to use a more specific code (M00.161 or M00.162).
• Do not use this code if the infection is due to a different bacterial organism; refer to other codes within the M00 category.
• Sequence this code as the primary diagnosis when the pneumococcal arthritis is the reason for the encounter.