🧬 ICD-10 CM G83.5 — Locked-in State
Billable Code Confirmed
Non-Billable Parent Codes
G83 “Other paralytic syndromes” is a non-billable category header that lacks the specificity required for reimbursement, since it does not indicate which specific paralytic presentation is present^1. G80-G83 “Cerebral palsy and other paralytic syndromes” is a block-level grouping and cannot be reported on any claim^1.
Clinical Context
Locked-in state is distinguished clinically by preserved consciousness and vertical eye movement despite complete quadriplegia and anarthria, which differentiates it from coma or vegetative state^2.
Code Classification
This is a diagnosis code used to report a neurological syndrome, not a procedure or symptom code^1.
🔍 Code Description
Locked-in state, classified under G83.5, describes a rare neurological condition in which a patient retains full cognitive awareness and consciousness but is unable to move or speak due to complete paralysis of nearly all voluntary muscles except those controlling vertical eye movement and blinking^2. The condition most commonly results from a lesion or infarction at the level of the pons, typically caused by basilar artery occlusion, which severs the corticospinal and corticobulbar pathways while sparing the reticular activating system responsible for consciousness^2. This is why coders should also review the medical record for an underlying cerebrovascular cause, such as I63.9 “Cerebral infarction, unspecified,” when the etiology is documented in the same encounter.
The syndrome falls under the broader “Other paralytic syndromes” category G83, which groups conditions distinguished by their distribution and severity of paralysis rather than a single unifying etiology. Unlike G82.5- quadriplegia codes, which classify by limb involvement and severity level, G83.5 is unique in that it is defined entirely by the clinical/functional presentation of preserved consciousness with total motor loss. Documentation must explicitly state “locked-in state” or “locked-in syndrome” since terms like “unresponsive” or “comatose” would misdirect coding toward an altered consciousness code instead.
🌳 Code Tree / Hierarchy
G83 Other paralytic syndromes ❌ Non-billable
│
├── G83.0 Diplegia of upper limbs ✅ Billable
├── G83.4 Cauda equina syndrome ✅ Billable
├── G83.5 Locked-in state ◀ THIS CODE ✅ Billable
│
├── G83.8 Other specified paralytic syndromes ❌ Non-billable
│ │
│ ├── G83.81 Brown-Séquard syndrome ✅ Billable
│ └── G83.83 Posterior cord syndrome ✅ Billable
│
└── G83.9 Paralytic syndrome, unspecified ✅ Billable
Specificity Insight
Tip
✅ Includes
- Locked-in syndrome — a synonymous clinical term for the same condition G83.5.
- Pseudocoma — describes the outward comatose appearance despite intact consciousness G83.5.
- De-efferented state — a term emphasizing loss of motor output pathways while sensory/cognitive input remains intact G83.5.
❌ Excludes
Excludes 1
- G82.5- Quadriplegia — this represents a distinct motor classification code set and cannot be reported alongside G83.5 for the same paralysis, even though locked-in patients are functionally quadriplegic, because the classification systems are mutually exclusive by definition^1.
Danger
The most common Excludes 1 error is coders defaulting to a quadriplegia code from habit when the chart documents locked-in state, missing the more specific and HCC-relevant G83.5.
Excludes 2
- I63.9 Cerebral infarction, unspecified — the underlying vascular cause can and should be coded separately alongside G83.5 when documented, since one code captures etiology and the other captures the resulting syndrome.
📋 Clinical Overview
Locked-in State vs Related Consciousness/Paralysis Codes
Distinguishing locked-in state from other severe neurological presentations hinges on the preservation of consciousness and specific eye-movement communication, which is not present in coma or vegetative states. This table contrasts G83.5 against a true consciousness disorder code and a quadriplegia code to highlight documentation triggers coders should watch for.
| Feature | G83.5 | R40.20 | G82.54 |
|---|---|---|---|
| Consciousness level | Fully alert and aware; patient can track and comprehend surroundings despite paralysis | Unconscious or minimally responsive with no reliable purposeful communication | Variable; consciousness itself is not the defining feature of this code |
| Motor function | Near-total paralysis of limbs, face, and speech muscles except vertical eye movement/blinking | Motor exam is not the classifying factor for a coma code | Quadriplegia specifically classified by completeness (incomplete) and cause |
| Typical HCC/RAF impact | Maps to HCC 254, a payment HCC requiring annual recapture | Coma codes generally are not standalone payment HCCs without further specification | Quadriplegia codes may map to different HCC categories depending on completeness |
Important
A CDI trigger should fire whenever a chart uses “unresponsive” or “vegetative” alongside documentation of intact eye tracking or blink-based communication, since this pattern strongly suggests undercoded locked-in state.
Manifestations & Symptom Burden
- Complete quadriplegia sparing only vertical eye movement and blinking, which becomes the patient’s sole communication method.
- Anarthria (inability to speak) due to paralysis of the bulbar muscles controlling the tongue, lips, and jaw.
- Preserved cognition, hearing, and comprehension, distinguishing it sharply from disorders of consciousness.
- Dysphagia requiring feeding tube placement, since swallowing muscles are also paralyzed.
- Respiratory failure often requiring long-term ventilator dependence due to diaphragmatic and chest wall paralysis.
Tip
Each manifestation above (dysphagia, ventilator dependence, neurogenic bladder) should be captured with its own separate code when documented, since these conditions frequently qualify as CC/MCC and substantially increase DRG weight for these typically long, resource-intensive admissions.
💰 HCC Risk Adjustment
ICD-10 CM G83.5 maps to HCC 254 (Other Severe Neurological Disorders) under the CMS-HCC V28 model, which reached 100% payment phase-in for risk adjustment year 2026^4. Because locked-in state is a stable, non-resolving condition rather than an acute event, capturing it at least once per calendar year through a qualifying encounter is essential to prevent a drop in the patient’s calculated RAF score in the following payment year. Health plans and CDI teams frequently target long-term care and neuro-rehab patients with this diagnosis for annual wellness visit or encounter-based recapture programs given the significant RAF weight attached to HCC 254.
🏥 MS-DRG Assignment
As a principal diagnosis, G83.5 groups to MDC 01 (Nervous System) under DRGs 052-054, with final DRG assignment dependent on whether qualifying CC or MCC conditions are also documented and coded. Common concurrent conditions like ventilator-associated pneumonia, sepsis, or stage 3-4 pressure ulcers frequently elevate the encounter to DRG 052 (w MCC), substantially increasing the DRG weight and expected reimbursement. When the underlying etiology, such as a basilar artery infarction, is identified in the same encounter, coding guidelines generally direct sequencing that cause code first, with G83.5 as a secondary diagnosis reflecting the resulting neurological deficit. A frequent inpatient coding pitfall is failing to code all secondary manifestations (dysphagia, neurogenic bladder, respiratory failure) individually, which artificially suppresses the DRG weight for these resource-intensive, long-length-of-stay admissions.
🔗 Related ICD-10-CM Codes
Etiology/Cause Codes: I63.9 Cerebral infarction unspecified, I63.02 Cerebral infarction due to embolism of basilar artery, I67.1 Cerebral aneurysm nonruptured, S06.9X9S Unspecified intracranial injury sequela.
Related Paralytic Syndrome Codes: G82.54 Quadriplegia unspecified, G82.50 Quadriplegia unspecified complete, G83.81 Brown-Séquard syndrome, G83.83 Posterior cord syndrome, G83.9 Paralytic syndrome unspecified, R40.20 Unspecified coma.
🛠️ Commonly Associated CPT Codes
99291 Critical care, first 60 minutes — commonly reported for the acute management of locked-in state patients during ICU stabilization when qualifying critical care time thresholds are met. 92610 Evaluation of oral and pharyngeal swallowing function — frequently billed given the near-universal dysphagia these patients experience, supporting feeding tube decisions. 31600 Tracheostomy, planned — often required due to prolonged ventilator dependence from respiratory muscle paralysis. 97165 Occupational therapy evaluation — used to establish adaptive communication strategies (e.g., eye-tracking devices) given the patient’s intact cognition. 95992 Canalith repositioning is not typically relevant here; instead 96125 Standardized cognitive performance testing may be billed to document preserved cognitive function for care planning.
NCCI Bundling Considerations
Critical care codes like 99291 generally bundle routine ventilator management and are not separately billable alongside certain evaluation and management services performed during the same time block. Swallowing evaluations (92610) and cognitive assessments (96125) are typically separately payable from critical care time as long as documentation clearly delineates distinct, non-overlapping time and medical necessity for each service.
🔬 ICD-10-PCS Crosswalk
0BH17EZ Insertion of endotracheal airway into trachea, via natural or artificial opening — reflects the ventilator support commonly required for these patients. 0DH60UZ Insertion of feeding device into stomach, percutaneous approach — reflects PEG tube placement for the dysphagia component of the syndrome. 0F798DZ is not applicable here; instead B030ZZZ Plain radiography of brain — may be used to support diagnostic workup confirming the pontine lesion.
💊 Coding Scenarios and Examples
Scenario 1: A 58-year-old male is admitted following acute onset of quadriplegia and inability to speak after a witnessed basilar artery occlusion confirmed on CT angiography; neurology documents “locked-in syndrome” with preserved eye movement and cognition. Correct coding: I63.02 (Cerebral infarction due to embolism of basilar artery), G83.5 (Locked-in state). Sequencing explanation: The cerebrovascular etiology is sequenced first as the underlying cause, with G83.5 reported secondarily to capture the resulting neurological syndrome. CDI note: Query the physician to confirm “locked-in state” terminology if only “quadriplegia” and “aphasia” are documented, since this changes both DRG and HCC capture.
Scenario 2: A long-term care patient with chronic, stable locked-in state from a remote pontine stroke three years ago presents for an annual wellness visit; the physician re-documents “chronic locked-in syndrome, stable” in the assessment. Correct coding: G83.5 (Locked-in state) as the sole diagnosis for this encounter. Sequencing explanation: Since the acute stroke has fully resolved into a chronic residual state, only the chronic syndrome code is reported, not a stroke sequela code, unless documentation specifically states otherwise. CDI note: This annual re-documentation is essential for continued HCC 254 recapture and RAF continuity for the following payment year.
Scenario 3: A patient admitted with locked-in state develops aspiration pneumonia and respiratory failure requiring prolonged mechanical ventilation during the inpatient stay. Correct coding: G83.5 (Locked-in state), J69.0 (Pneumonitis due to inhalation of food and vomit), J96.00 (Acute respiratory failure, unspecified), J96.10 (Chronic respiratory failure) if applicable. Sequencing explanation: Depending on the reason for admission, either the acute complication or the underlying syndrome may be sequenced as principal, but all conditions must be captured to support MCC-level DRG assignment. CDI note: Confirm documentation links the pneumonia and respiratory failure to the underlying paralytic dysphagia to support medical necessity and accurate severity of illness scoring.
⚠️ Coding Pitfalls and Tips
- Do not default to G82.5- quadriplegia codes when the chart specifically documents “locked-in state,” since these code sets are Excludes 1 and mutually exclusive.
- Always attempt to capture the underlying etiology (e.g., I63.02) separately when documented, since G83.5 alone does not convey the vascular cause.
- Confirm annual re-documentation of G83.5 for chronic patients in risk-adjusted plans, since missing this recapture directly lowers the following year’s RAF score.
- Individually code all associated manifestations like dysphagia, neurogenic bladder, and respiratory failure, since bundling them into the syndrome code alone suppresses DRG weight.
- Do not confuse locked-in state with disorders of consciousness like coma (R40.20) or vegetative state, since the defining feature of G83.5 is preserved awareness, not its absence.
Sources: ¹ ICD10Data.com, 2026 ICD-10-CM Diagnosis Code G83.5 · ² gesund.bund.de, ICD-10 code G83.5 Locked-in syndrome · ³ AAPC.com, ICD-10-CM Code for Locked-in state G83.5 · ⁴ HCC Buddy, G83: Other paralytic syndromes — HCC 254