PJIA: The Facts

The facts about PJIA

Diagnosing arthritis in children dates back to the mid-1800s. Today, rheumatologists and other kinds of doctors treat several types of juvenile idiopathic arthritis (JIA), each with its own symptoms. Two forms of the disease include polyarticular JIA, or PJIA, and systemic JIA, or SJIA.

The key to PJIA is the polyarticular. Let’s break it down further: poly means many. So think of polyarticular as many joints (5 or more, according to its medical definition). Juvenile simply describes the age group affected by the disease. While arthritis means inflammation of one or more joints, idiopathic refers to the cause of the disease: it’s unknown.

PJIA: A disease of the immune system

The immune system is complex. It has many different kinds of cells that protect the body by fighting harmful things like bacteria, fungi, and viruses. When the immune system is not working correctly, it can lead to the signs and symptoms of PJIA, such as inflammation, pain, and stiffness.

Signs and symptoms to watch for in your child

  • Pain or limited movement in 5 or more joints
  • Swelling in joints (usually not seen until it’s in larger joints like the knee)
  • Stiffness, especially after waking up, that fades later in the day
  • Limping
  • Not wanting to use an arm or leg
  • Being less active than usual
  • Trouble with “fine motor” activities, such as gripping

PJIA: Different from other forms of JIA

PJIA has things in common with other forms of JIA—joint pain, for example. But PJIA is unique because of that “5 or more joints” feature. Other forms of JIA typically affect a limited number of joints. In addition, a child with PJIA may find it difficult to chew food, because PJIA can affect not just smaller joints like those in fingers or toes, but also larger joints such as those in the jaw or neck. And unlike some forms of JIA, PJIA often affects both sides of the body, not just one side.

Also, PJIA does not include body-wide symptoms such as rashes or high fevers common to another form of JIA called systemic JIA (SJIA). PJIA is also more common than SJIA: about 1 in 4 children with JIA have PJIA, while only 1 in 10 with JIA have SJIA. Girls tend to get PJIA more than boys do, but both may develop SJIA at about the same rate.

Ask your child's doctor how PJIA is different from other forms of JIA.

Please see Important Safety and Side Effect Information. For additional Important Safety Information, please see full Prescribing Information, including Boxed Warning and Medication Guide

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Check out the Creative Corner for infusion center games and activities, and get recipes for easy-to-make after-school treats.

PJIA stories

Meet Hunter. Hear how ACTEMRA has helped him and his family manage life with PJIA.

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Before reading more, please see the Important Side Effect Information for ACTEMRA

This information does not take the place of talking with your healthcare provider about your medical condition or your treatment.

Important Side Effect Information

After reading about ACTEMRA, please talk to your healthcare provider if you have any questions.


  • Available by medical prescription only
  • For adults with moderately to severely active rheumatoid arthritis (RA) who have used one or more disease modifying antirheumatic drugs (DMARDs), such as methotrexate, that did not provide enough relief
  • For adults with giant cell arteritis (GCA)
  • For people with active PJIA ages 2 and above
  • For people with active SJIA ages 2 and above

It is not known if ACTEMRA is safe and effective in children with PJIA or SJIA under 2 years of age or in children with conditions other than PJIA or SJIA.

ACTEMRA can cause serious side effects

Serious infections

ACTEMRA changes the way your immune system works. This can make you more likely to get infections or make any current infection worse. Some people have died from these infections.

Before taking ACTEMRA, tell your healthcare provider if you have:

  • An infection, think you may have an infection, are being treated for an infection, or get a lot of infections that return. Infection signs, with or without a fever, include:
    • Sweating or chills
    • Shortness of breath
    • Warm, red or painful skin or sores on your body
    • Feel very tired
    • Muscle aches
    • Blood in phlegm
    • Diarrhea or stomach pain
    • Cough
    • Weight loss
    • Burning when you urinate or urinating more often than normal
  • Any of the following conditions that may give you a higher chance of getting infections. These include: diabetes, HIV, or a weak immune system
  • Tuberculosis (TB) or have been in close contact with someone who has TB. Your healthcare provider should test you for TB before starting ACTEMRA and during treatment with ACTEMRA
  • Lived in or currently live in parts of the United States known for fungal infections. These parts include the Ohio and Mississippi River Valleys and the Southwest
  • Hepatitis B or have had hepatitis B

Be sure to contact your healthcare provider or nurse if you see any signs of these side effects.

Stomach tears

If you have diverticulitis (inflammation in parts of the large intestine), talk to your healthcare provider before taking ACTEMRA.

Some people taking ACTEMRA may develop a hole in the wall of their stomach or intestines (also known as a perforation). This happens most often in people who also take nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, or methotrexate.

Tell your healthcare provider right away if you see any of these side effects:

  • Fever
  • Stomach-area pain that does not go away
  • Change in your bowel habits

Changes in blood test results

Your healthcare provider should do blood tests before you start receiving ACTEMRA. If you have rheumatoid arthritis (RA) or giant cell arteritis (GCA) your healthcare provider should do blood tests 4 to 8 weeks after you start receiving ACTEMRA and then every 3 months after that. If you have polyarticular juvenile idiopathic arthritis (PJIA) you will have blood tests done every 4 to 8 weeks during treatment. If you have systemic juvenile idiopathic arthritis (SJIA) you will have blood tests done every 2 to 4 weeks during treatment. These blood tests are to check for the following side effects of ACTEMRA:

Low neutrophil count: neutrophils are white blood cells that help the body fight infection
Low platelet count: platelets are blood cells that help with clotting, which stops bleeding
Increase in liver function test levels
Increase in blood cholesterol levels

You should not receive ACTEMRA if your neutrophil and platelet counts are too low or your liver function test levels are too high. These may cause your healthcare provider to stop your ACTEMRA treatment for a time or change your dose. Your cholesterol levels should be checked 4 to 8 weeks after the start of your treatment, and then every 6 months after that.

Increased risk of cancer

ACTEMRA may increase your risk of certain cancers by changing the way your immune system works.

Hepatitis B infection

If you have hepatitis B, a virus that affects the liver, or are a carrier of the virus, ACTEMRA can cause the virus to become active. Your healthcare provider should test you for hepatitis B before starting treatment. Tell your healthcare provider right away if you see any signs of these symptoms:

  • Feeling very tired
  • Vomiting
  • Chills
  • Dark urine
  • Skin or eyes look yellow
  • Clay-colored bowel movements
  • Stomach discomfort
  • Skin rash
  • Little or no appetite
  • Fevers
  • Muscle aches

Serious allergic reactions

Serious allergic reactions, including death, can happen with ACTEMRA infusions or injections, even if they did not occur with an earlier infusion or injection. If you had hives, a rash, or experienced flushing after injecting, you should tell your healthcare provider or nurse before your next injection.

Contact 911 immediately, as well as your healthcare provider or nurse, if you experience any of these reactions:

  • Shortness of breath or trouble breathing
  • Swelling of lips, tongue, or face
  • Chest pain
  • Feeling dizzy or faint
  • Moderate or severe abdominal pain or vomiting

Nervous system problems

While rare, multiple sclerosis has been diagnosed in some people taking ACTEMRA.

Most common side effects

Tell your healthcare provider if you have these or any other side effect that bothers you or does not go away:

Upper respiratory tract infections (like common cold and sinus infections)


Increased blood pressure (also called hypertension)

Injection site reactions

ACTEMRA & pregnancy

Tell your healthcare provider if you are planning to become pregnant, are pregnant, plan to breast-feed, or are breast-feeding. You and your healthcare provider should decide if you will take ACTEMRA or breast-feed. You should not do both. If you are pregnant and taking ACTEMRA, join the pregnancy registry. The purpose of this registry is to check the health of the pregnant mother and her baby. To learn more, call 1-877-311-8972 or talk to your healthcare provider to register.

Reporting side effects

Tell your healthcare provider right away if you are experiencing any side effects. You may report side effects to the FDA at 1-800-FDA-1088 or You may also call Genentech at 1-888-835-2555.

For more Important Safety Information, please see full Prescribing Information and Medication Guide, including Serious Side Effects.