Are You Confident of the Diagnosis?
What you should be alert for in the history
Rubella is characterized by a prodrome of fever, headache, and upper respiratory symptoms, followed 1 to 5 days later by an exanthem that spreads cephalocaudally. The rash resolves in 2-3 days in the direction in which it started.
Characteristic findings on physical examination
These include pink macules and papules appearing on face first and spreading caudally to involve the trunk and extremities. Tender lymphadenopathy of the occipital, cervical, and posterior auricluar areas are common. Petechiae of the soft palate (Forchheimer’s spots) may be seen.
Expected results of diagnostic studies
Histopathologic findings include a superficial perivascular infiltrate with mild spongiosis. Atypical lymphocytes called Turk cells have been seen in the skin and in peripheral blood.
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Diagnosis confirmation
Since the exanthem of rubella can mimic other viral exanthems, diagnostic confirmation is achieved by the detection of IgM antibodies, or a four-fold increase in IgG. Differential diagnoses of an exanthematous rash include adenovirus, enterovirus, measles, EBV, and toxin-mediated eruptions such as scarlet fever.
Who is at Risk for Developing this Disease?
Unvaccinated children and adults and the fetus of a non-immune pregnant woman. Infections are most common in the spring months.
What is the Cause of the Disease?
Pathophysiology
Rubella is caused by an RNA virus of the Togaviridae family. The disease is spread via respiratory droplet, infecting the nasopharynx first, then spreading to lymph nodes, resulting in eventual viremia.
Systemic Implications and Complications
The most common systemic complications are arthralgias and arthritis, seen more commonly in postpubertal women. Other complications seen less frequently include hepatitis, myocarditis and pericarditis, hemolytic anemia, and thrombocytopenic purpura. Encephilitis is rare, and one study reported the frequency to be 1 of 6000 cases.
Congenital rubella occurs when a non-immune woman passes the virus to the fetus in-utero during the first 16 weeks of pregnancy. The birth defects that result constitute the Congenital Rubella Syndrome manifested by deafness, cataracts, CNS defects such as microcephaly and hydrocephaly, and cardiac disease such as patent ductus arteriosus, and ventriculo septal defect. Miscarriage or stillbirth may ensue.
Congenital rubella is a cause of the TORCH syndrome resulting in a ’blueberry muffin baby’ secondary to extramedullary hematopoiesis. Widely disseminated erythematous to violaceous papules and nodules are seen in the neonate with this syndrome.
Treatment Options
The disease is usually self-limited, hence treatment is supportive. Prevention is best accomplished by timely vaccination.
Pre-natal counseling should include an inquiry as to whether or not the mother has been vaccinated.
Optimal Therapeutic Approach for this Disease
The current recommended immunization schedule for the rubella vaccine (given along with the measles and mumps vaccines; MMR) is at 12-15 months, and repeated at 4-6 years.
Patient Management
Supportive care for uncomplicated cases, addressing adequate hydration and anti-pyretics for fevers.
In the TORCH syndrome, spontaneous resolution of the cutaneous lesions occurs after the viremia has resolved.
Unusual Clinical Scenarios to Consider in Patient Management
In a pregnant woman who has been exposed to rubella, if serologic testing reveals anti-rubella IgM, or a diagnostic rise in rubella-specific IgG, the patient should be offered pre-natal counseling.
What is the Evidence?
“Recommended childhood and adolescent immunization schedule: United States, 2005”. Pediatrics. vol. 115. 2005. pp. 182(Provides immunization recommendations for rubella.)
Rosa, C. Rubella and rubeola. Semin Perinatol. vol. 22. 1998. pp. 318-22. (Provides a clinical overview of rubella and rubeola).
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