CAR-T side effects: CRS, ICANS and when to get urgent help

Prepare the contact plan before infusion

Ask the center for written instructions covering symptoms, contact numbers and the place to go outside clinic hours. Save the CAR-T product name, infusion date and treating team's details on your phone and carry the patient alert information you are given.

Your caregiver should know the plan too. Ask how often to check temperature, how close to the center to stay and what to do if you cannot reach the team. The exact monitoring period depends on the product and local protocol. Plan transport so you are not relying on driving yourself when unwell.

Sources and references: [1] [2]

What cytokine release syndrome can look like

CAR-T cells can trigger a large release of immune signaling proteins called cytokines. The resulting cytokine release syndrome, or CRS, often begins with fever and may progress to low blood pressure or reduced oxygen levels. A person may feel shivery, weak, dizzy or short of breath.

The team grades CRS by its effects on the body and the support needed. Mild and severe cases therefore lead to different treatment plans. Report symptoms promptly so the team can assess blood pressure, oxygen and other findings before the illness becomes more difficult to manage.

Sources and references: [3] [1]

Treat fever as a reason to contact the team

Fever after CAR-T needs assessment for infection as well as CRS. Low blood counts and changes in immune function can make infections serious. Follow the temperature threshold and urgent contact instructions given by your center; do not wait for the next planned appointment if that threshold is reached.

Tell the clinician when the fever started, the infusion date and any other symptoms. Mention medicines already taken for the fever. This information helps the team arrange blood tests, cultures or other investigations and decide whether you need hospital treatment.

Sources and references: [1] [3]

Notice changes in thinking, speech and behavior

Immune effector cell-associated neurotoxicity syndrome, usually shortened to ICANS, can cause confusion, difficulty finding words, changes in writing or unusual sleepiness. More serious problems can include seizures or reduced consciousness. A caregiver may notice that a familiar conversation or task suddenly becomes difficult.

Report a new neurological change immediately, even if a previous fever has settled. Neurological effects can occur with CRS, after it or without it. For a seizure, severe confusion, difficulty waking or another major neurological change, seek emergency care and tell the team about the recent CAR-T treatment.

Sources and references: [3] [1]

How the hospital treats these reactions

Treatment depends on the symptoms and severity. The team may use fluids, oxygen and medicines such as tocilizumab for CRS, with corticosteroids in appropriate circumstances. Neurological toxicity has its own assessment and treatment, often including corticosteroids and seizure management when needed.

Some patients require intensive care. Ask who will update the family if you become too unwell to communicate. A useful question for the treating team is what it is monitoring now and what improvement it needs to see before stepping down support or considering discharge.

Sources and references: [3] [1]

Low blood counts and other complications also matter

CAR-T treatment and its preparation can leave blood counts low for a prolonged period. This can increase infection, bleeding or anemia-related symptoms. Report unusual bruising, bleeding, worsening weakness or difficulty breathing. The team may provide transfusions or other support according to the cause.

A less common severe inflammatory syndrome, sometimes described as HLH/MAS or an immune effector cell-associated HLH-like syndrome, can also occur. Persistent or returning illness needs reassessment. You are not expected to distinguish these conditions at home; the practical step is to report the change and follow the urgent care plan.

Sources and references: [1]

Keep watching after the first hospital stay

Going home or moving to nearby accommodation changes where monitoring happens. Keep scheduled reviews and make sure a responsible adult knows how to contact the center. Follow the product-specific restrictions on driving and other activities that require full alertness.

New symptoms can occur later in recovery too. For example, severe or persistent diarrhea, abdominal pain or weight loss after Carvykti warrants prompt assessment because delayed bowel inflammation has been reported. Tell any clinician you see that you received CAR-T, even when the infusion was weeks or months earlier.

Sources and references: [4] [1]

Build the safety arrangements into a Shanghai treatment plan

For overseas care, clarify the hospital's emergency route, interpreter arrangements and caregiver requirements before treatment starts. Ask which hospital to attend if you are staying off site, and make sure the caregiver can explain the product and infusion date in an emergency.

EastMedGo can help organize these practical questions alongside a CAR-T assessment request. When you contact our team, include your caregiver and language needs so they can be considered in appointment and accommodation planning. The treating center should provide the medical monitoring instructions and urgent contact pathway that you will follow.

Common questions