Our study presents 2 neonates; that following the manifestation of systemic disease; skin rashes appeared in different parts of the body. The standard treatments did not work for the rash and the systemic disease. We noticed that in both cases, mothers were affected by COVID-19. IgM and IgG titers in the neonates confirmed the passage of antibodies. When steroids were added to the treatment, the symptoms subsided. Neonates’ follow-up was normal after they were discharged.
There are more cases of MIS in children and infants (
4) than there are in newborns (
5). A study further reported multisystem inflammatory syndrome in fetus (MIS-F) during the fetal period, where the infection starts during the fetal period, and symptoms appear after birth (
6), as in the cases of this study.
The serum IgG concentration was 10 g/L in case I and 40 in case II, above normal level 5. The levels could rise over time at subsequent titrations, but we could not check them because we didn’t want to inject the baby again for unnecessary lab data. The serologic test results for 20 neonates were positive in India (
3). Since the immune system is immature and non-developed in newborns, positive IgM results are unexpected, though positive maternal IgGs and a history of positive PCR results can be a criterion for detecting MIS-N in newborns (
3).
In case II, the mother confirmed infection with COVID-19 on her 30th week of pregnancy. This history is important during the last few weeks of a pregnant woman’s life (
3). In cases with no history of maternal infections, mothers must undergo serologic tests to find any clues of infection in newborns, as in case I. In these cases, positive IgM and IgG results are a criterion for MIS-N diagnosis. The neonate’s infections can occur two months after relatives’ infections (
7). When there is no evidence of a history of disease and/or positive serologic test results while the infant develops symptoms in the second or third week, infection through carriers who are in contact with the infant can be expected.
The diagnosis criteria for MIS-C are the same in all studies. MIS-C is diagnosed with positive PCR test results and/or a history of contact with those infected or carrying infections and positive serologic test results.
Various case series show the involvement of multiple systems (e.g., skin involvements), spanning children from multi-form to maculopapular rashes and severe lesions such as allergic lesions, urticaria, and even gangrene infection (
4). In both cases, the lesions were mild and disappeared after corticosteroid treatment. There are some criteria for MIS in children (
8). We can’t use MIS-C criteria for neonates as fever is less common than in children, and neonates have mild symptoms. Exposure to COVID-19 and systemic symptoms with increased inflammatory lab data is enough for neonates.
The Coronavirus disease’s active phase does not include MIS-C. Symptoms of an inflamed system appear two to three weeks after a cytokine storm (
9). The first-line treatment, in this case, is corticosteroid pulse therapy (e.g., using methylprednisolone). This technique has been successful in older babies (
8) and, thereby, can treat newborns. In case I, we did not start treatment because of alleviated fever and CRP concentrations, but inflammation was not controlled given the fever recurrence and increased CRP levels. Corticosteroid pulse therapy was used to suppress inflammation. The advantages of corticosteroid pulse therapy are diminished hospitalization period, rapid inflammatory reaction alleviation in the inflammatory phase, and no need for the simultaneous use of non-steroidal anti-inflammatory drugs. In this condition, methylprednisolone is a potent medication for suppressing inflammation (
10).
In many places, intravenous immunoglobulin therapy (IVIG) (
11), used for cardiogenic shocks in patients infected with COVID, is not well accepted because of high expenses, limited availability, and fluid restriction during shocks. The Iranian national guideline recommends the implementation of IVIG in cases when corticosteroids don’t work, and vital organs or coronaries are affected. The standard dose of methylprednisolone in children is 10 to 30 mg/kg as a 2- to -3-hour infusion for three days (and five days in severe cases) (
8). In case I, 30 mg/kg was administered for one day and followed by 1 mg/kg of oral prednisolone for three days because of the patient’s limited stay in the hospital.
Studies have reported up to 90% cardiac involvement, myocardial involvement as a cardiac block, or even cardiogenic shock in patients with MIS-C. For this, both cases underwent echocardiography. With cardiac involvement, proper interventions and regular cardiac follow-ups are required, especially at lower ages (
12), establishing at least two follow-up sessions and checking inflammatory markers within two weeks to two months (
3).
In case I, the neonate had a high D-dimer level but decreased in subsequent tests without anticoagulation medication. Anticoagulants, such as enoxaparin (in urgent cases for patients admitted to the intensive care unit) and aspirin (dosage: 3 - 5 mg per kg of weight, for less severe conditions and patients not admitted to the intensive care unit), have been advised for COVID infection with a high risk of thrombosis and coagulopathy. Such medications are administered depending on the infant’s condition because the risk of thrombosis is low at lower ages and newborns (
3).
Persistent pulmonary hypertension (PPHN) can be related to MIS-N, but we didn’t find it. Dexamethasone is used to alleviate persistent pulmonary hypertension in neonates, which is reported by McCarty et al. (
6). Some studies used the DART (dexamethasone: A randomized trial) protocol for dexamethasone (
13). Dexamethasone varies from methylprednisolone in the drug’s efficacy. The former is a long-action drug, and the latter a short-action medication. High doses of methylprednisolone suppress and restart the immune system by rapid and short-term operating, while dexamethasone’s half-life in blood is longer and can cause long-term immune system suppression implications (
14).
3.1. Limitations and Recommendations
Neonatal multisystem inflammatory syndrome is a term that was added to neonatal literature recently. A delay follows the issue in diagnosis. Suggested criteria for MIS-N are applicable when we think about it. Besides, many suggested inflammatory markers, are not checked routinely in neonates as Ferritin. We believe it may be better to revise or define the suggested markers as a key for diagnosing the titer of COVID-19 antibodies.
3.2. Conclusions
For the similarity of symptoms to sepsis, we should consider this syndrome in infants with sepsis-like symptoms and a positive history of COVID in parents or relatives. Neonatal multisystem inflammatory syndrome does not appear to fill the MIS-C criteria as they do in children with sepsis symptoms. We suggest that combination criteria such as exposure to COVID-19 and systemic symptoms with increased inflammatory lab data are enough for neonates, but more studies are needed. If we consider proper and on-time interventions, it is possible to diminish morbidity and mortality caused by inflammation. Additional trials are required for the use of corticosteroids in newborns.