PIMS (Pediatric Inflammatory Multisystem Syndrome)

Lisa Vogel studied departmental journalism with a focus on medicine and biosciences at Ansbach University and deepened her journalistic knowledge in the master's degree in multimedia information and communication. This was followed by a traineeship in the editorial team. Since September 2020 she has been writing as a freelance journalist for

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PIMS (Pediatric Inflammatory Multisystem Syndrome), also known as PIMS syndrome, is a multi-inflammatory disease that affects children. Among other things, she has severe abdominal pain, persistent fever and PIMS is suspected of occurring as a late consequence of a coronavirus infection in children. But what is PIMS? What do parents have to pay attention to and how do you recognize PIMS in children? Get information here!

Brief overview

Definition: PIMS (Pediatric Inflammatory Multisystem Syndrome), also known as Multisystem Inflammatory Syndrome in Children (MIS-C), is an inflammatory disease that affects various organs. PIMS is suspected to be a long-term consequence of the coronavirus infection in children.

Cause: So far unclear; Doctors suspect that an excessive immune reaction after a coronavirus infection causes inflammatory processes in internal organs, skin and mucous membranes.

Symptoms: fever (> 48 hours), rash, inflamed mucous membranes, itchy eyes, nausea and vomiting, diarrhea, circulatory problems, (severe) abdominal pain, up to suspicion of appendicitis

Frequency: Increase since the end of 2020, in winter 2020/2021 up to 18 cases per week in hospitals in Germany and Austria, 7 to 10-year-olds make up a third of those affected, boys more frequently affected

Course of the disease: fever sets in two to four weeks after the coronavirus infection; good prognosis under medical treatment; seven percent of the children affected develop consequential damage, especially to the cardiovascular system

Treatment: Intensive care treatment, immunomodulatory therapy, partly systemic antibiotic therapy

What is PIMS?

PIMS is a multi-inflammatory syndrome in children. The cause of the violent inflammatory processes is probably an overreaction of the immune system to viruses. So far, however, little is known about the disease.

The PIMS disease is suspected to occur as a result of a coronavirus infection, as most of those affected carry antibodies against Sars-CoV-2. So far there is no evidence that the Sars-CoV-2 infection later causes the rare inflammatory disease in children.

Since it is a novel clinical picture, there is still no uniform name. So far, two terms have become established for inflammatory diseases: Pediatric Inflammatory Multisystem Syndrome (PIMS) and Multisystem Inflammatory Syndrome in Children (MIS-C).

The virus enters the deep respiratory tract via the throat and multiplies there. This activates the immune system. The immune cells then produce so-called proinflammatory cytokines and chemokines. In most patients, the body already has the infection under control at this point.

In some patients, however, the release of these cytokines seems to be uncontrolled, so that a so-called cytokine storm develops. The result is inflammatory reactions. In addition, the tendency of the blood to clot increases. In the worst case, there is a risk of multiple organ failure.

Scientists have been able to observe damage to the inner walls of the blood vessels during examinations. How this is related to the inflammatory processes of the organs is still unclear.

When is PIMS available?

All children and adolescents (up to 19 years of age) who had previously been treated with PIMS in hospital had a fever that lasted for over 48 hours. In addition, they were either acutely infected with Sars-CoV-2 or had had a coronavirus infection in the past. The direct detection of the virus is negative in many patients, but doctors found antibodies against Sars-CoV-2 in most of those affected.

According to the World Health Organization, PIMS is present if the following criteria of the case definition are met:

Children and adolescents up to 19 years of age with fever (> 48h)

and at least two of the following criteria:

Skin rash (exanthema) or bilateral non-purulent conjunctivitis (conjunctivitis) or inflammation of the skin or mucous membrane
Low blood pressure (arterial hypotension) or shock
Myocardial dysfunction, inflammation of the pericardium (pericarditis), inflammation of the heart valves (valvulitis) or coronary artery disease (CHD; coronary pathologies)
Bleeding disorder (coagulopathy)
Acute digestive tract problems (diarrhea, vomiting, abdominal pain, suspected appendicitis)
Abnormalities in the blood count

and

increased inflammation values (CRP, PCT, ESR)
if there is no other clear explanation for the complaint

If PIMS is suspected, doctors should rule out other serious conditions that cause similar symptoms. These include, for example, blood poisoning (sepsis), intestinal infection or severe heart or lung diseases.

Frequency of PIMS

So far there have been a total of 255 reported PIMS diseases in Germany and Austria (as of March 21, 2021). More than half of the children affected were four to ten years old. Boys make up 65 percent of the cases and are therefore more often affected than girls. The majority (82 percent) of the children with the disease had no previous illness.

As early as 2020, during the early phase of the coronavirus pandemic, rare but severe inflammatory diseases occurred in severely affected countries in children after a coronavirus infection. In Germany alone, around 50 cases were documented last year.

In the winter of 2020/2021, when the corona numbers rose significantly in the second wave, the numbers of PIMS cases also increased. From the end of November 2020 to the beginning of February 2021, German and Austrian hospitals treated up to 18 children with PIMS per week. The number of cases fell again in February and March.

Affected organs

PIM syndrome affects various organs and body structures. According to the data available so far, the inflammatory processes take place in the following organs and tissues:

Cardiovascular system (in 82% of reported cases)
Gastrointestinal tract (77%)
Skin (73%)
Mucous membrane, including conjunctivitis (69%)
Lower respiratory tract (55%)
Blood, clotting, hematopoietic organs (42%)
Upper respiratory tract, ENT (30%)
Nerve tissue, neuromuscular inflammation (24%)
Liver (21%)
Kidneys (21%)
Skeletal muscles (13%)

PIMS or Kawasaki Syndrome?

The inflammatory disease PIMS is very similar to the so-called Kawasaki syndrome. This also leads to an overreaction of the child's immune system after infection with viruses or bacteria. Toddlers between the ages of two and five are most likely to develop Kawasaki syndrome. The illness begins with a high fever that lasts for more than five days.

There are five main symptoms that are typical of Kawasaki syndrome. They are also called the Kawasaki criteria:

Fever over 39 ° C without bacteria / viruses being the trigger
Redness of the lining of the mouth, tongue and lips
Rash on the chest, stomach and back, and later peeling of the skin
Bilateral conjunctivitis (conjunctivitis) without pus formation
swollen lymph nodes on the neck

The symptoms of the two diseases are very similar. Nevertheless, there are two different clinical pictures. However, Kawasaki patients can also develop PIMS.

Forms of disease

Doctors differentiate between these forms of the disease:

Sars-CoV-2 non-Kawasaki PIMS (non-KS-PIMS): pure PIMS cases according to the above-mentioned case definition and assessment, with a maximum of one Kawasaki criterion
Sars-CoV-2 Kawasaki syndrome (KS): Kawasaki syndrome cases where at least two of the five Kawasaki criteria are met
Sars-CoV-2 PIMS plus Kawasaki Syndrome (KS-PIMS): PIMS cases that also meet at least 2 of the 5 Kawasaki criteria

About two-thirds of PIMS patients meet the Kawasaki criteria. In addition, other symptoms such as neurological complaints, severe abdominal pain or digestive disorders occur with PIMS. These are rarer at Kawasaki.

PIMS: symptoms

PIMS in children initially manifests itself more with unspecific complaints. For most of those affected, the doctors initially diagnosed a different cause for the symptoms when they were admitted to the clinic.

The main symptom of the inflammatory disease is fever. All affected children suffered from elevated temperatures for more than 48 hours. The following list shows the possible symptoms of PIMS in children:

Fever (> 48 hours)
skin rash
inflamed or changed mucous membranes
Swelling of the lymph nodes
itchy eyes (conjunctivitis)
Nausea and vomiting
diarrhea
(severe) abdominal pain
Circulatory problems up to circulatory failure
Cardiac arrhythmias

If your child develops the listed symptoms after a coronavirus infection, you should consult a doctor immediately.

Treatment of PIMS in children

Although it is a serious condition, parents needn't panic. PIMS is easy to handle. Since there are hardly any studies on the treatment of PIMS so far, the therapy is carried out under intensive medical supervision.

Intravenous immunoglobulins (IVIG) helped most of the patients in a small case study in Liverpool. They were given a dose or two of the drug.Six of 28 patients were already free of fever after the first dose. In combination with intravenous methylprednisolone (IVMP), the fever decreased a little faster. Clinical studies must show whether treatment with immunoglobulins is necessary at all.

A patient with suspected hyperinflammation after a suspected Sars-CoV-2 infection was successfully treated with high-dose anakinra. This is an immunosuppressive drug. The drug suppresses the body's immune response and is usually used in rheumatoid arthritis. The patient was discharged from the clinic after eight days.

Most of the children are also given systemic antibiotics.

Course of the disease and prognosis

The inflammatory disease PIMS can appear around two to four weeks after infection. If left untreated, the inflammatory processes are dangerous and in the worst case scenario can be fatal. However, since doctors can treat PIMS well, there has been no confirmed death in Germany so far. Critical courses of the disease occurred occasionally.

The prognosis for the patient is favorable. Slightly more than 45 percent of the children treated in the hospital have recovered after discharge. 43 percent leave the clinic with residual symptoms. However, consequential damage occurs in around seven percent of those affected. As a result of the inflammatory disease, cardiovascular complaints occur.

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