M46.21
BillableOsteomyelitis of vertebra, occipito-atlanto-axial region
HCC Category Mapping
V28HCC 92 — Bone/Joint/Muscle Infections/Necrosis
0.209V24HCC 39 — Bone/Joint/Muscle Infections/Necrosis
0.482ESRDHCC 39 — Bone/Joint/Muscle Infections/Necrosis
0.000What This Code Means
A bone infection (osteomyelitis) affecting the vertebrae in the upper neck region where the skull connects to the spine (occipito-atlanto-axial region).
Coding Tips
- •This rare location involves the C0-C2 vertebrae; ensure documentation clearly specifies this upper cervical region
- •Infections in this region can be serious due to proximity to vital structures; verify if additional codes for complications are needed
Clinical Significance
Osteomyelitis in the upper cervical spine is particularly dangerous due to proximity to the brainstem and potential for neurological complications. This location requires urgent treatment and careful monitoring for spinal instability and neurological deterioration.
Documentation Requirements
- ✓Documentation of bone infection specifically in occipito-atlanto-axial region
- ✓Clinical presentation consistent with upper cervical osteomyelitis
- ✓Imaging studies confirming infection in C1-C2 region
- ✓Neurological assessment for cranial nerve or brainstem involvement
- ✓Laboratory confirmation of infectious process
- ✓Assessment for spinal instability
- ✓Documentation of antimicrobial treatment plan
- ✓Monitoring for complications including abscess or neurological changes
Commonly Confused Codes
M4622 — Cervical osteomyelitis affects lower cervical vertebraeG04.91 — Myelitis is spinal cord inflammation, not bone infectionM50.00 — Cervical disc disorder is degenerative, not infectiousA39.82 — Meningococcal arthritis affects joints, not vertebral boneM46.30 — Disc infection affects intervertebral disc, not vertebral body
Code Hierarchy
└M46Other inflammatory spondylopathies└M46.2Osteomyelitis of vertebra└M46.21Osteomyelitis of vertebra, occipito-atlanto-axial region
└M46.21Osteomyelitis of vertebra, occipito-atlanto-axial region