Measles is a typical childhood disease. It is caused by the measles virus (Morbillivirus), which is an RNA virus that can be transmitted by airborne droplets. The disease is highly contagious and infectious. People who are not vaccinated are at risk of contracting the disease.
The virus infects the lymphatic tissue of the upper respiratory tract (prodromal stage) before viremia occurs with the spread of the measles rash (exanthem stage).
Pathology of measles
After an incubation period of approximately 2 weeks, a typical prodrome occurs in the form of high temperature, pharyngitis, rhinitis, bronchitis, conjunctivitis, and photophobia. At this point, patients are already infectious. By the end of the prodromal stage, which lasts for 2—3 days, the characteristic Koplik’s spots on the buccal mucosa (opposite the lower 1st & 2nd molars) occur.
The temperature decreases initially but reaches another peak with the occurrence of the measles exanthem (twin-peaked increase in fever). The extensive brownish exanthem characteristically starts behind the ears and spreads from this point over the whole body. The exanthem (rash) stage lasts 7—10 days.
Complications of measles
The measles virus is a lymphotropic virus that causes a weakening of the immune system. This has notable implications in immunocompromised patients. Apart from bacterial superinfections (otitis media, pneumonia, and laryngotracheitis), the virus itself can cause serious complications, including measles pneumonia and measles encephalitis. The latter is one of the most important complications and can be divided into 3 forms according to its occurrence and course of the disease:
Post-infectious measles encephalitis occurs approximately 1 week after the start of the rash and presents with neurological symptoms, disturbed consciousness, and seizures amongst others. The lethality of the disease is very high at a rate of approximately 25%.
Subacute sclerosing panencephalitis (SSPE) is a late complication of measles, and it is rarely lethal. It occurs typically 6–8 years after a measles infection.
Measles inclusion body encephalitis (MIBE) is a measles complication that only occurs in the case of immunocompromised patients and has a 30% mortality rate.
Diagnosis of measles
The diagnosis is made via clinical evaluation and virus-specific immunoglobulin M (IgM) antibodies in serum.
Therapy and prevention of measles
As no specific therapy is available, the prevention of measles in early childhood is crucial. The Standing Vaccination Committee at the Robert Koch Institute (STIKO), recommends a basic immunization against measles (live vaccine) from the 11th month of life, which should be followed by a 2nd vaccine during the second year of life (15th–23rd month).
Vaccines against mumps, rubella, and varicella, are administered as part of most countries’ vaccine schedules. Combination vaccines are available for which STIKO has the following recommendation:
Vaccination date: 11–14th month: combination vaccine against mumps, measles, and rubella (MMR) + varicella vaccination on another body part (contralateral arm). If both vaccinations are not given on the same date, a minimal period of 4 weeks until the next vaccination should be maintained.
Vaccination date: 15th–23rd month: combination vaccine (MMR-V).
Post-exposure prevention: After the exposure of unvaccinated persons, immunization within the first 3 days after the initial contact is appropriate. In the case of a person at risk (pregnant women, immunocompromised patients, infants < 6 months old), passive immunization with human Ig within a period of 2–6 days can be considered following post-exposure.
Rubella (German Measles)
Rubella is a viral childhood disease that is communicated via droplet infection. The disease is especially dangerous for pregnant women as placental transmission to the unborn child can occur with grave organ complications (rubella embryopathy).
Pathology of rubella
The first symptoms occur after an incubation period of 2–3 weeks. As the virus initially spreads in the lymph nodes, painful lymphomas occur in the cervical, retro-auricular, and occipital lymph nodes.
Headache and a general feeling of malaise can occur but are not obligatory. Five to seven days after the first symptoms (lymph node disease), a rubella exanthem appears behind the ears, which starts out like measles, and spreads from this point over the whole body.
Complications of rubella
Complications arise for the unborn child if the mother contracts rubella for the first time during the pregnancy. The danger of malformations is especially high in early pregnancy (the first 2 months). Typical organ damages are summarized as Gregg-Trias: labyrinthine deafness, cataract, and heart defects (septal defects, etc.).
For those who contact rubella in the postnatal stage, self-limiting arthritis can occur. Complications of the nervous system, such as encephalitis or encephalomyelitis, or hematopoietic system, such as thrombocytopenic purpura, are very rare.
Diagnosis of rubella
The diagnosis of rubella infection is based on the detection of rubella IgM in blood samples taken at two different points in time. An increase in titer is considered positive. Methods include the hemagglutination-inhibition test (method of choice) or ELISA.
For pregnant women, diagnosis can be via direct pathogen detection in maternal blood, in the amniotic fluid by amniocentesis, or in the fetal blood by cordocentesis.
Therapy and prevention of rubella
There is no treatment for rubella. STIKO recommends the vaccination of all infants. The general immunization takes place as an injection of the attenuated live vaccine which is done twice from the 11th month of life at the same time as the measles and mumps vaccinations (see measles).
If the vaccination is not successful in infancy, it should be given again for girls and child-bearing women. If the second vaccination dose is not administered, it can be given until the age of 18 according to the STIKO recommendation. For child-bearing women, a catch-up is generally possible at a later point in time as well.
In the course of pregnancy, the rubella titer is part of the initial examination. Demonstrable immunity exists at a rubella IgM titer of > 1:32 in the hemagglutination-inhibition test but is also assumed at a titer of 1:16.
The causative organism of chickenpox is the varicella-zoster virus (VZV), also known as human herpesviruses (HHV3). Infection can be airborne or via contact with the infectious content of blisters. Just like the measles virus, VZV is highly contagious.
Pathology of varicella
The typical varicella skin eruptions, which show a stage-like development of reddish papules and/or blisters filled with pathogens and pustules, occur after an incubation period of about 14 days. The blisters eventually scab and heal by crust formation. As new efflorescences occur, there is a ‘colorful picture’ of efflorescences of different ages (so-called Heubnersche-Sternenkarte).
The exanthem is accompanied by prominent itching and affects the skin as well as the hairy scalp. Additionally, there is an enanthem of the mucosae, and high temperature can occur. There usually is no dominant feeling of malaise.
Complications of varicella
There is a danger of bacterial superinfections which primarily affect the skin and result from the scratching of the blisters. Bacterial inflammations of the middle ear (otitis media) and pneumonia can occur.
Viral complications are rare. Pneumonia is as depicted as meningitides and encephalitides. The chickenpox disease is marked with complications during pregnancy as the virus can be communicated via the placenta to the fetus. If the mother falls ill within the 1st and 2nd trimester, a serious infection of the fetus with malformations of the limbs (extremity hypoplasia), as well as damage to the skin and the organs, can occur (varicella syndrome). Newborns can fall severely ill if the mother falls ill 5 days before until 2 days after the birth (neonatal varicella).
The typical varicella skin eruptions, which show a stage-like development of reddish papules and/or blisters filled with pathogens and pustules, occur after an incubation period.
VZV persists after a previous infection within the spinal ganglions and can be reactivated by transient (e.g. stress) or continuous immune impairment.
The clinical appearance is similar to that of chickenpox but symptoms are restricted to the dermatome of the affected nerves. Neuralgiform pain is typical which precedes the efflorescences and can continue after the exanthem subsides (post-zoster neuralgia). Occasionally, high temperature and a general feeling of malaise arise.
Diagnostics for varicella
Chickenpox is typically a visual finding, and a definitive diagnosis is usually not necessary. However, intrauterine varicella infection in early pregnancy is an exception (until the 21st week of pregnancy), and it is crucial to identify the virus (via PCR) in the amniotic fluid (via amniocentesis).
Therapy for varicella
Zinc mixtures, combined with systemically effective antihistamines, are applied to the skin to reduce the itching. Acyclovir is indicated for neonatal varicella infection.
Birth should generally not take place if a mother is in the exanthem stage. Per the exposition of pathogens, early delivery should be sought.
For shingles, taking into account the severity of the presentation, the administration of acyclovir can be considered. Pain management, according to the World Health Organization (WHO) level scheme, is to be introduced for the treatment of neuralgia.
Prevention of varicella
The varicella vaccination is administered at the same time as the measles and rubella vaccinations (see above) in the form of an attenuated live vaccine. The STIKO recommends that the first varicella vaccination be separate from the triple vaccination (MMR). For the second vaccination, the available 4-fold combination vaccine (MMR-V) can be used.
General immunization should be given if vaccination did not take place in infancy. For unvaccinated persons, vaccination can take place after contact with infected persons.
Passive immunization with varicella-zoster immunoglobulin (VZIG) should take place within 96 hours after contact with an infected person for at-risk patients. These include:
- Unvaccinated pregnant women without a history of chickenpox
- Immunodeficient people
- Newborn babies without symptoms if the mother falls ill within the critical period around the birth (5 days before until 2 days after the birth)