Haemorrhagic Infarction (HI)/Transformation
- Following an Ischaemic stroke there can be a form of secondary haemorrhage into the infarcted tissue and this is often termed haemorrhagic infarction or transformation.
- It is more common in embolic strokes, larger stroke and following spontaneous or therapeutically driven recanalisation with thrombolysis (especially intraarterial) and/or thrombectomy.
- Thrombectomy seems to have an increase of asymptomatic HI but symptomatic HI is unaffected. The rate seems to be higher with delayed recanalisation e.g. Alteplase after 3 hours.
- Poorly controlled hypertension is a risk and is one of the reasons to control blood pressure after thrombolysis. Severe hyperglycaemia may also be a risk.
- It tends to happen early within the first few days, but it can be as late as 2 weeks. It is often clinically silent especially as at this time there is rarely any need to do brain imaging.
- Blood is more clearly seen on MRI GRE and T2 star. Often the response is to omit antiplatelets for several days.
- If the patient presents late it can be difficult to distinguish haemorrhagic transformation from a primary intracerebral haemorrhage.
- HT is possibly due to the reopening of occluded blood vessels with flow into tissues with a damaged capillary bed due to local ischaemic necrosis.
- It is always a worry in re-establishing flow that haemorrhage will occur.
However, there is a distinct difference between mild to moderate haemorrhage into already damaged brain and de novo haemorrhage into undamaged brain adding to the overall stroke burden.
|Haemorrhagic Infarction Type 1||Small hyperdense petechiae||No change|
|Haemorrhagic Infarction Type 2||Confluent hyperdensity in infarct zone no mass effect||No change|
|Parenchymal haematoma type 1 (PH1)|| Confluent hyperdensity in infarct zone taking up < 30% infarct area with some mass effect||No change|
|Parenchymal haematoma type 2 (PH4)|| Confluent hyperdensity in infarct zone taking up > 30% infarct area and beyond with oedema and mass effect ||Increased|