ICD-10-CM · Spine

M46.49

Discitis at multiple spinal levels where the causative organism has not been identified or specified in the clinical documentation.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 9
Region: Spine

Drawn from CDCicd10data.com —AAPCCMS

Documentation tips

What should appear in the chart to support M46.49.

Source · Editorial brief grounded in 5 cited references ↓

Name every spinal region affected (e.g., cervical and lumbar) — 'multiple sites' must be supported by explicit documentation of more than one region, not inferred.
Record MRI findings by level: T2 hyperintensity within the disc, endplate erosion, and any paraspinal or epidural extension; imaging is the primary clinical validator for discitis.
Document culture and lab results (ESR, CRP, blood cultures, biopsy results) and note when an organism has NOT been identified — this justifies the 'unspecified' qualifier over M46.5x.
Include symptom onset and duration, constitutional symptoms (fever, weight loss), and any prior spinal procedures or risk factors (immunosuppression, IV drug use) to support medical necessity.
If organism is later identified on culture, update the diagnosis code on subsequent encounters — do not continue to use M46.49 once etiology is confirmed.

Related CPT procedures

Procedure codes commonly billed with M46.49. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

72148 $191.72

Non-contrast MRI of the lumbar spine used to evaluate disc pathology, spinal stenosis, nerve root compression, and other structural abnormalities without administration of contrast material.

72141 $190.72

MRI of the cervical spinal canal and its contents performed without contrast material.

72158 $318.31

MRI of the lumbar spinal canal and its contents performed first without contrast, then repeated after contrast administration for enhanced visualization.

99213 $95.19

Established patient office or outpatient visit requiring 20–29 minutes of total time or low-complexity medical decision-making.

99214 $135.61

Office visit for an established patient requiring moderate-complexity medical decision making (MDM), or 30–39 minutes of total provider time on the date of service.

72100 $40.42

Radiologic examination of the lumbosacral spine capturing two or three views, used to evaluate the lumbar vertebrae and sacrum for injury, degeneration, or structural abnormality.

72110 $53.44

Radiologic examination of the lumbar spine (lumbosacral) with a minimum of four views, including oblique and/or bending views.

72157 View procedure details

97032 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M46.49 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

Assigning M46.49 when only one spinal region is documented — single-site discitis of unknown etiology requires M46.41–M46.48, not M46.49.
Using M46.49 after a causative organism has been confirmed — once etiology is established, M46.5x (other infective spondylopathies) or the appropriate organism-specific code applies.
Defaulting to M46.40 (site unspecified) when the record clearly names multiple regions — M46.49 is the more specific and correct code in that scenario.
Failing to distinguish discitis (M46.4x) from pyogenic vertebral osteomyelitis (M46.2x) or spondylitis (M45.x, M46.1) — the affected tissue and confirmed etiology drive the parent category selection.
Omitting a secondary code for the underlying infectious organism when one is documented — ICD-10-CM guidelines call for dual coding when etiology is known.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M46.49 applies when discitis — inflammation of one or more intervertebral discs — is documented at more than one spinal region and no specific infectious agent or pyogenic etiology has been identified. Use this code only when the clinical record explicitly references multiple spinal sites; if the disease is confined to a single region, select the site-specific M46.4x code (e.g., M46.46 for lumbar, M46.42 for cervical).

The 'unspecified' qualifier means the organism driving the inflammation is not documented — not that the diagnosis itself is uncertain. If a causative organism is confirmed (e.g., Staphylococcus aureus, Mycobacterium tuberculosis), step across to M46.5x (Other infective spondylopathies) at the appropriate site, or the relevant infectious disease code with an additional musculoskeletal manifestation code. If pyogenic spondylitis is confirmed, M46.2x is the correct parent category.

M46.49 maps to MS-DRG 551 (Medical back problems with MCC) or 552 (Medical back problems without MCC) under MS-DRG v43.0. This code has been stable since its introduction in FY2016 with no changes through FY2026 (CDC ICD-10-CM Tabular List 2026).

Sibling codes

Other billable codes under M46.4 (laterality / anatomic variants).

M46.42

Discitis, unspecified, cervical region

M46.47

Discitis, unspecified, lumbosacral region

M46.40

Discitis, unspecified, site unspecified

M46.41

Discitis, unspecified, occipito-atlanto-axial region

M46.48

Discitis, unspecified, sacral and sacrococcygeal region

M46.44

Discitis, unspecified, thoracic region

M46.43

Discitis, unspecified, cervicothoracic region

M46.46

Discitis, unspecified, lumbar region

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01When does discitis at multiple spinal levels warrant M46.49 versus separate site-specific codes?

Use M46.49 as a single code when the documentation describes discitis at more than one named spinal region without identifying the organism. ICD-10-CM's multiple-site convention at the 6th-character level (digit 9) is designed for this scenario — you do not need to stack individual site codes.

02What changes the code from M46.49 to M46.5x?

Organism identification. Once culture, biopsy, or clinical confirmation names the infectious agent, the correct parent category shifts to M46.5 (Other infective spondylopathies) at the appropriate site. If multiple sites are still involved, use M46.59.

03Is M46.49 appropriate for a patient with post-procedural discitis at two levels after lumbar surgery?

Potentially, but post-procedural infections have specific complication codes. Review whether a complication-of-care code (e.g., T84.6x or M96.x series) should be sequenced first, with M46.49 as an additional code describing the disc-level manifestation.

04What imaging documentation is required to support M46.49?

MRI is the standard: document T2 hyperintensity within the affected discs, endplate erosion or irregularity, and any epidural or paraspinal involvement. Note each spinal level evaluated. Lab markers (elevated ESR and CRP) corroborate the diagnosis but imaging findings are the primary clinical anchor.

05Can M46.49 be used as a primary diagnosis on a Medicare claim?

Yes — M46.49 is a billable, specific FY2026 code accepted by CMS. It groups to MS-DRG 551 or 552 depending on the presence of MCCs. Ensure the claim includes supporting lab and imaging documentation to withstand medical review.

06What is the difference between M46.40 and M46.49?

M46.40 is used when the site of discitis is unspecified — meaning the documentation does not name any spinal region. M46.49 is used when multiple named spinal regions are explicitly documented. If the record names two or more regions, M46.49 is the correct and more specific code.

07Does M46.49 require a 7th-character extension?

No. M46.49 is an M-code (musculoskeletal chapter) and does not use 7th-character extensions. Those extensions (A, D, S) apply to injury codes in the S-code range.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

01CDC ICD-10-CM Tabular List 2026 — https://www.cdc.gov/nchs/icd/icd-10-cm.htm
02icd10data.com — 2026 ICD-10-CM Diagnosis Code M46.49
03icd10data.com — 2026 ICD-10-CM Diagnosis Code M46.46
04AAPC Codify — ICD-10-CM Code M46.49
05CMS Medicare Coverage Database — Article 53057 (Home Health Occupational Therapy, CPT 97032)

Mira AI Scribe

The Mira AI Scribe captures spinal region involvement by name (cervical, thoracic, lumbar, etc.), MRI findings per level (T2 signal change, endplate erosion, disc height loss), lab values (ESR, CRP, culture results), and whether a causative organism was identified. This prevents downcoding to M46.40 (site unspecified) when multiple regions are documented, and flags encounters where organism confirmation would require a code change to M46.5x.

See how Mira captures M46.49 documentation