The ICD-10 code for cerebral venous sinus thrombosis (CVST) is I67.6, Nonpyogenic thrombosis of intracranial venous system, a billable code used when the clot has not caused a brain infarction and is not infected. If the thrombosis has caused a venous infarction, code I63.6 instead; if it is septic, use G08; in pregnancy use O22.5-; and after delivery use O87.3.
The right code depends on the clinical scenario, so the quick-reference table below comes first. The clinical background on dural venous sinus thrombosis follows, because good documentation is what makes the correct code possible.
CVST ICD-10 Code Selection Table
Codes below follow ICD-10-CM, the US clinical modification. The WHO version of ICD-10 uses the same core codes (I67.6, I63.6, G08, O22.5, O87.3) but without the trimester subdivisions.
| Code | Official descriptor | When to use it | Key notes |
|---|---|---|---|
| I67.6 | Nonpyogenic thrombosis of intracranial venous system | Non-infected CVST or cortical vein thrombosis without infarction | Billable. Excludes1: I63.6 (thrombosis causing infarction). Excludes2 at category I67: sequelae (I69.8-) |
| I63.6 | Cerebral infarction due to cerebral venous thrombosis, nonpyogenic | Non-infected CVST that has caused a venous infarction (including hemorrhagic venous infarction) | Billable. Replaces I67.6; do not report both |
| G08 | Intracranial and intraspinal phlebitis and thrombophlebitis | Septic (pyogenic) thrombosis, for example from mastoiditis, sinusitis or facial infection | Billable. Excludes1: nonpyogenic thrombosis (I67.6) and pregnancy/puerperal cases (O22.5-, O87.3) |
| O22.50–O22.53 | Cerebral venous thrombosis in pregnancy (unspecified, first, second, third trimester) | CVST during pregnancy | O22.5 itself is not billable; a trimester character is required |
| O87.3 | Cerebral venous thrombosis in the puerperium | CVST after delivery, during the puerperium | Billable. Excludes2 at category O87: obstetric embolism (O88.-), puerperal septic thrombophlebitis (O86.81), venous complications in pregnancy (O22.-) |
| I69.8- | Sequelae of other cerebrovascular diseases | Lasting deficits after I67.6-type CVST, seen after the acute episode | Category only; needs further characters that name the deficit |
| I69.3- | Sequelae of cerebral infarction | Lasting deficits after a venous infarction (I63.6) | Category only; needs further characters |
How to Choose Between the CVST Codes
Work through the scenario in this order. Each question narrows the choice to one code family.
- Is the patient pregnant or postpartum? Obstetric codes take priority. Use O22.5- with the trimester during pregnancy, or O87.3 in the puerperium.
- Is the thrombosis infected? Septic or pyogenic thrombophlebitis, usually spreading from a nearby infection, goes to G08.
- Has it caused an infarction? If imaging and the physician’s documentation describe a venous infarct, use I63.6.
- None of the above? Use I67.6 for acute, non-infected CVST without infarction.
- Is this a later visit for lasting deficits? Use the matching sequelae code (I69.8- or I69.3-), not the acute code.
Inclusion terms under I67.6
ICD-10-CM lists these synonyms under I67.6, so a chart that uses either wording still points to this code:
- Nonpyogenic thrombosis of cerebral vein
- Nonpyogenic thrombosis of intracranial venous sinus
Clinicians also call the condition cerebral venous thrombosis (CVT), venous sinus thrombosis or dural venous sinus thrombosis. The ICD index treats all of them the same way, provided the documentation doesn’t mention infection, infarction or pregnancy.
What the Excludes notes mean
An Excludes1 note means “not coded here”: the two conditions can’t be reported together. That’s why I67.6 and I63.6 are mutually exclusive. An Excludes2 note means “not included here”. The patient may have both conditions, and both codes can be reported if both are documented.
Obstetric CVST Coding
Pregnancy and the weeks after delivery are well-recognized risk periods for CVST, so obstetric cases come up often. Chapter 15 codes (O00–O9A) are sequenced first whenever a condition occurs during pregnancy, childbirth or the puerperium. Coding guidelines allow a code from another chapter to be added if it gives extra detail.
- O22.50–O22.53: cerebral venous thrombosis in pregnancy. The inclusion term is “cerebrovenous sinus thrombosis in pregnancy”. The final character gives the trimester.
- O87.3: cerebral venous thrombosis in the puerperium. The inclusion term is “cerebrovenous sinus thrombosis in the puerperium”.
- Obstetric embolism (O88.-) and puerperal septic thrombophlebitis (O86.81) sit in separate categories, so check the documentation for either before settling on O87.3.
Sequelae, History and Legacy ICD-9 Codes
Once the acute episode is over, the acute code stops being correct. A patient seen months later with residual weakness, visual loss or cognitive problems after non-infarct CVST is coded under I69.8-, with the characters that describe the specific deficit. If the original event was a venous infarction, the sequelae belong under I69.3-.
For research or older claims data, the approximate ICD-9-CM crosswalk is:
| ICD-10 code | Approximate ICD-9-CM equivalent |
|---|---|
| I67.6 and I63.6 | 437.6 Nonpyogenic thrombosis of intracranial venous sinus |
| G08 | 325 Phlebitis and thrombophlebitis of intracranial venous sinuses |
| O22.5-, O87.3 | 671.5x Other phlebitis and thrombosis in pregnancy and the puerperium |
| I69.8-, I69.3- | 438.x Late effects of cerebrovascular disease |
Crosswalks aren’t one-to-one. ICD-9 had no separate code for venous infarction, which is one reason studies that span the 2015 transition need careful code mapping.
How Reliable Are CVST Codes in Claims Data?
Researchers often use administrative codes to find CVST cases, so coding accuracy matters beyond billing. Validation work that compares codes against medical records has generally found that the specific codes (I67.6, I63.6 and G08) identify true CVST cases well. Vague codes such as unspecified intracranial hemorrhage pick up very few real cases. In practice, a code-based search is only as good as the discharge documentation, so clinicians who write “cerebral venous sinus thrombosis with/without venous infarction” make accurate coding much easier.
What Is Cerebral Venous Sinus Thrombosis?
CVST is a clot in the dural venous sinuses or the cerebral veins, the channels that drain blood out of the brain. When drainage is blocked, pressure builds up behind the clot, causing raised intracranial pressure, brain swelling and, in some patients, venous infarction or bleeding. It is an uncommon form of stroke, and it tends to affect younger adults and women more often than arterial stroke does. The sinus thrombosis overview covers the condition in more depth.
Risk factors
- Inherited thrombophilia: Factor V Leiden, the prothrombin gene mutation, and protein C, protein S or antithrombin deficiency
- Hormonal factors: combined oral contraceptives, pregnancy and the puerperium
- Infection: ear, sinus, face or central nervous system infections (the septic cases coded under G08)
- Cancer, dehydration, head injury and neurosurgery
- Acquired conditions: antiphospholipid syndrome, inflammatory bowel disease and myeloproliferative neoplasms
Symptoms and diagnosis
Headache is the most common symptom and often gets steadily worse over days. Other features include seizures, papilledema (swelling of the optic disc), focal weakness and confusion. Diagnosis rests on imaging: MR venography or CT venography shows the blocked sinus. Blood tests, including a coagulation profile and, in selected patients, a thrombophilia screen, look for an underlying cause.
Treatment
Anticoagulation is the cornerstone of treatment, even when a venous hemorrhage is present, because it stops the clot extending and lets the sinus reopen. Treatment usually starts with heparin and then moves to an oral anticoagulant for a period of months. Endovascular treatment is reserved for patients who deteriorate despite anticoagulation. Seizures, raised pressure and any infection are treated alongside. For the wider picture of clotting disorders, see our blood clotting guide.
Key Takeaways
- I67.6 is the code for non-infected CVST without infarction, and it is billable.
- I63.6 replaces I67.6 when there is a venous infarction. The two are never coded together.
- G08 is for septic thrombosis. O22.5- is for pregnancy and O87.3 for the puerperium.
- Later visits for lasting deficits use the I69.8- or I69.3- sequelae codes.
- Clear documentation of infection, infarction and pregnancy status decides the code.
Frequently Asked Questions
What is the ICD-10 code for cerebral venous sinus thrombosis with infarction?
Use I63.6, Cerebral infarction due to cerebral venous thrombosis, nonpyogenic. It applies when the physician documents a venous infarct caused by the clot. It replaces I67.6 rather than adding to it.
When should G08 be used instead of I67.6?
Use G08 when the thrombosis is septic or pyogenic, meaning it is infected. This usually happens when an infection spreads from the mastoid, sinuses or face. I67.6 is limited to nonpyogenic thrombosis, and each code excludes the other.
What is the ICD-10 code for CVST after delivery?
CVST in the puerperium is coded O87.3, Cerebral venous thrombosis in the puerperium. During pregnancy, use O22.50–O22.53 according to trimester. Obstetric codes are sequenced first.
Can I67.6 and I63.6 be coded together?
No. I67.6 carries an Excludes1 note for I63.6, so when the thrombosis has caused an infarction, report I63.6 alone.
Is I67.6 a billable code?
Yes. I67.6 is a complete, billable ICD-10-CM code that needs no further characters. Its parent category, I67, is not billable on its own.
