Pediatric Viral Infection With Rash- Measles

The measles virus, also known as the Rubeola virus, is a virus that primarily affects children.

Etiological Evidence 

The measles virus, which is of the genus Morbillivirus and family Paramyxovirus, is the cause of measles infection. The measles virus is referred to as an enveloped single-stranded RNA virus because it is a single-stranded RNA virus.

Mode of Infection

Because there is no carrier state for the measles, the droplet route is the source of infection only through instances of the disease. The droplet route is the primary mechanism of infection. The only common infection in which there is no carrier state involved is measles.

Secondary Attack Rate

It is a very contagious illness; standard literature has a secondary attack rate of 80–95%. As a result, the rate of secondary attacks is significant.

Period of Infectivity

The measles virus is contagious between 4 and 6 days prior to and following the rash's emergence.

The two measles structural proteins that are most significant are involved in the immune response's induction and, as a result, help shield patients from contracting the infection.

The measles virus consists of two proteins: The fusion (F) protein and the haemagglutinin (H) protein. Neutralizing antibodies target the haemagglutinin (H) protein, while those directed against the fusion (F) protein restrict the virus's ability to multiply within the tissues of the host cell during infection.

Pathology of Infection     

A virus that enters the host through the droplet route can infect both the respiratory tract and non-respiratory tissues. If it infects the respiratory tract, it can cause necrosis, inflammation of the respiratory tract epithelium, and lymphocytic infiltrate. It can also cause a presentation that resembles small vessel vasculitis, with Multinucleated Giant Cells serving as its pathological hallmark. Another name for these multinucleated giant cells is Warthin-Finkeldey cells.

High Yield Point

Two types of receptors are present on the measle cells.

CD150: The receptor found in non-pulmonary tissues is called CD150. For instance, lymphocytes, CNS, and alveolar macrophages. PVRL-4/Nectin-4 . In respiratory epithelial cells, PVRL-4 or Nectin-4 is thought to be the measles receptor.

 The measles takes 10–14 days to incubate.. Due to active or passive immunization, people who already have a partial immunity to the measles can almost always contract modified measles, a moderate infection.

Pregnancy-related measles infections can occur, but congenital abnormalities are not present. It can, however, be more severe than in women who are not pregnant, and there is always a chance of termination.

The measles has a seasonal pattern. Every two to three years, community measles infections rise, according to epidemiological studies.  The World Health Organization has a measles elimination plan known as Catch-up/Keep-up/Follow-up.

Clinical Features

The onset of fever and prodromal symptoms, starting on Day 1, is the first presenting sign of measles. Cough, coryza, and conjunctivitis are prodromal symptoms that are observed in Cs. Enanthem, an eruption that happens at the mucous membrane, occurs between Day 2 and Day 3. Koplik's spot is the name of the usual measles hymn.

According to the book's description, Koplik's spots are bluish-white lesions that resemble grains of sand with surrounding erythema. Koplik's spots typically occur on the buccal mucosa, specifically in the front of the lower 2nd molars. Later on, it may appear on the lips, tongue, or buccal mucosa in other places.

 The start of a Rash will occur about Day 4. These kids have an erythematous maculopapular rash, as seen in the pictures. It generally shows up on the forehead and behind the ear when it first occurs on the face. Following this, it will proceed to the limbs and trunk.

After the rash appears, it will go away in seven to eight days, or roughly one week, leaving pigmentation behind. There will therefore be hyperpigmentation following the rash.

Q. Which is the most consistent feature of prodrome symptoms among the three Cs?

Ans. Conjunctivitis.

Complications in Measles

Acute otitis media is the most frequent measles virus complication. Subacute Sclerosing Panencephalitis (SSPE), a rare and severe symptom, manifests itself years after the initial illness.
Pneumonia is the most prevalent cause of death in cases of measles. There are two types of pneumonia in measles: primary measles pneumonia, which is caused by the virus itself. Pneumonia secondary to bacterial infections is another name for it, meaning pneumonia will develop as a result of a bacterial infection. It is also known as Primary Giant Cell Pneumonia or Hecht's Pneumonia. This covers both Haemophilus influenzae and Pneumococcus.

The rate of measles complications rises in children with protein energy malnutrition (PEM) and vitamin A deficiency.  Other common complications may include myocarditis, encephalitis, black measles (also known as hemorrhagic measles, where there are erythematous, hemorrhagic, and Red-Black bullae forms on the skin), and diarrhea.

Q. Which is more common among the two types of pneumonia in measles?

Ans. Secondary Pneumonia is more common as compared to primary pneumonia.

Measles Virus Induces Immunosuppression. How?

The measles virus incites immunosuppression through two distinct mechanisms: (1) it infects CD4+ T cells, thereby suppressing the immune response of helper T cells; (2) it enters alveolar macrophages, dendritic cells, and circulating lymphocytes through the CD150 receptor; and (3) the combination of these two causes a state that increases the risk of secondary infections, especially pneumonia.

Diagnosis and Treatment

Serum immunoglobulin M antibody (IgM) is the most widely used diagnostic modality for measles. Four-fold rise in IgG antibody titres at intervals of 2-4 weeks is another diagnostic procedure.
• PCR and virus isolation are theoretically possible as well.
• Supportive care is the mainstay of measles treatment; in the event of a complication, you must monitor nutritional status and hydration.
•In vitro studies have shown that ribavirin, an antiviral medication, is also effective against measles infection. Ribavirin is frequently effective against RSV infection. It is not, however, FDA-approved for usage with minors.

Nelson states that vitamin A therapy is recommended for all measles patients. For children 12 months and up, vitamin A should be given once day for two days at a dose of 200,000 IU, 100,000 IU for infants 6 months to 11 months, and 50,000 IU for infants under 6 months.

Q. Which agent is used against in vitro measles infection?

Ans. Ribavirin.

Prevention

 Vaccination against measles specifically to avoid measles.  There are two choices for preventing damage after exposure.  The terms "measles vaccine" and "rubeola" (MR) are interchangeable; the measles vaccine is most effective when administered between 24 and 72 hours following exposure.

Measles-specific vaccines are recommended for high-risk groups such as pregnant women, immunocompromised individuals, and infants younger than six months of age.  Measles-specific immunoglobulins can be used and are effective if administered intramuscularly at a dose of 0.5 ml/Kg up to 6-7 days after exposure.

 The measles virus is the cause of the uncommon, chronic, progressive demyelinating condition known as subacute sclerosing panencephalitis (SSPE).According to Harrison's 20th edition, 85% of patients are in the age range of 5 to 15.

SSPE instances can manifest up to 7–13 years following a measles infection.Once symptoms start, there is a significant mortality rate and it is always fatal within 1-3 years.

Stages of SSPE

• In stage 1, there are subtle behavioural changes.
• In stage 2, there will be the onset of Myoclonic jerks.
• In stage 3, it has been observed that children develop involuntary movements, which are known as choreoathetoid movements; these children will also develop rigidity, and they will have a progressive fall in the sensorium.
• In stage 4, the patient reaches a vegetative state where there is a failure of vital centres of the body, and this is the stage where death occurs.

Diagnosis of SSPE

They use a set of standards called Dyken's Modified Criteria to diagnose SSPE. There are Major and Minor criteria in Dyken's Modified Criteria.
The two major criteria are an appropriate clinical history of measles and elevated CSF antibody against measles. The other minor criteria are brain biopsy, increased CSF immunoglobulin G, EEG changes suggestive of SSPE, and a specific molecular test to identify the mutated genome of the measles virus. A patient is considered to have an SSPE diagnosis when there are two main criteria and one minor criteria.

The EEG of SSPE appears like this (as depicted in the figure).
The Classical Rader Maker Complexes are present in the EEG of SSPE.
Rader maker complexes, as shown in the illustration, are high voltage repeating polyspike sharp end slow wave complexes. These polyspikes happen every 4–16 seconds, with a frequency of 0.5–3 hertz during each interval. In clinical situations, these radar maker complexes are thought to be indicative of SSPE.

Management of SSPE 

Patients experiencing myoclonic jerks present challenges for the management of SSPE; as a result, medications such as carbamazepine are used.  Intrathecal interferon alpha (IFN-alpha) and isoprinosine make up the new therapy regimen now offered for SSPE.

Hope you found this blog helpful for your NEET SS Pediatrics Infections preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.