ICD-10 Code for Recrudescence of Old Stroke
The appropriate ICD-10 code for recrudescence of an old stroke is I69.3xx (Sequelae of cerebral infarction) with additional codes to specify the specific deficit that has recrudesced, NOT a code for acute stroke (I63.x).
Understanding Recrudescence vs. Recurrent Stroke
Recrudescence refers to the temporary reemergence of previous stroke-related deficits without new brain injury, which is fundamentally different from a recurrent stroke 1.
Key Distinguishing Features of Recrudescence:
- Transient worsening of residual or prior stroke-related focal neurologic deficits 1
- No acute infarct or hemorrhage on admission MRI 1
- No new lesion on diffusion-weighted imaging 1
- Typically occurs years after the original stroke (mean 3.9 years) 1
- Deficits resolve relatively quickly (mean 18.4 hours; 69% resolved by day 1) 1
- NIHSS score worsens by only a mean of 2.5 points during the episode 1
Appropriate ICD-10 Coding Strategy
Primary Code Selection:
Use I69.3xx series (Sequelae of cerebral infarction) as the principal diagnosis, with the specific fourth and fifth digits indicating the particular deficit that has recrudesced 1, 2:
- I69.351 - Hemiplegia and hemiparesis following cerebral infarction affecting right dominant side
- I69.352 - Hemiplegia and hemiparesis following cerebral infarction affecting left dominant side
- I69.320 - Aphasia following cerebral infarction
- I69.398 - Other sequelae of cerebral infarction
Secondary Codes for Triggers:
Document the precipitating factor that triggered the recrudescence 1:
- Infection codes (e.g., J18.9 for pneumonia, N39.0 for UTI)
- I95.9 for hypotension
- E87.1 for hyponatremia
- F51.0 for insomnia/stress-related factors
- T42.4X5A for adverse effect of benzodiazepines
Critical Coding Pitfalls to Avoid
Do NOT Use Acute Stroke Codes (I63.x):
The ICD-10 codes I63.x are specifically for acute ischemic stroke with new brain injury 2, 3. Using these codes for recrudescence is incorrect because:
- No new infarct is present on imaging 1
- The PPV for recurrent stroke using I63.x codes is only 72%, and this includes true recurrent strokes, not recrudescence 2
- Misclassification can lead to inappropriate acute stroke treatment, including potentially harmful thrombolysis 1
Do NOT Use TIA Codes (G45.x):
While recrudescence may superficially resemble TIA due to transient symptoms, it is mechanistically distinct 1:
- TIA involves new ischemia (even if transient)
- Recrudescence involves no new ischemia, only temporary dysfunction of chronically damaged tissue
- ICD-9 and ICD-10 coding studies show frequent disagreements between ischemic stroke and TIA records, highlighting the importance of accurate differentiation 3
Documentation Requirements for Accurate Coding
To ensure proper ICD-10 code assignment, clinical documentation should explicitly state 1, 4:
- "Recrudescence of prior stroke deficits" or similar terminology
- Timing and characteristics of the original stroke
- Absence of new acute findings on neuroimaging
- Identification of precipitating factors (infection, metabolic derangement, etc.)
- Timeline of symptom resolution
Imaging Documentation:
- MRI showing chronic stroke only without acute infarct 1
- Negative diffusion-weighted imaging for acute lesions 1
- Documentation that underlying chronic strokes predominantly affect white matter tracts (73% involve MCA territory) 1
Clinical Context for Coders
Understanding the clinical presentation helps ensure accurate coding 1:
- Deficits are typically abrupt and mild
- Most commonly affect motor-sensory or language function
- Isolated gaze paresis, hemianopia, or neglect are not typical of recrudescence
- 38% of episodes involve deficits limited to a single NIHSS item
Risk Factors Associated with Recrudescence
While not directly affecting ICD-10 code selection, awareness of these factors supports accurate diagnosis 1:
- Female sex
- African American race
- Diabetes mellitus
- Dyslipidemia
- Smoking history
- Infarcts from small-vessel disease
- Higher initial NIHSS scores at time of original stroke