1. Systemic Viral Infections

What virus causes measles?

Morbillivirus in the Paramyxoviridae family.

What is the basic reproductive number (R₀) of measles?

12–18, making measles one of the most contagious viral diseases.

How is measles transmitted?

Airborne droplet transmission; infectious particles can remain airborne for up to 2 hours.

What is the incubation period of measles?

6–21 days.

When is a patient with measles contagious?

5 days before rash onset to 4 days after rash appears.

What are the prodromal symptoms of measles?

High fever, malaise, anorexia, cough, coryza, conjunctivitis.

What is the pathognomonic finding of measles?

Koplik spots — bluish-white lesions on erythematous buccal mucosa.

Describe the measles rash.

Deep red macular rash starting on the face, spreading cephalocaudally, sparing palms/soles.

What lab abnormality is commonly seen in measles?

Leukopenia (unless secondary bacterial infection).

What are major complications of measles?

Pneumonia (most common cause of death), otitis media, encephalitis, diarrhea, SSPE.

What is Subacute Sclerosing Panencephalitis (SSPE)?

Fatal progressive neurodegeneration occurring 7–10 years after measles infection.

How is measles diagnosed?

Rubeola-specific IgM, PCR from nasopharyngeal/throat swab or urine.

What is the treatment for measles?

Supportive care + Vitamin A; ribavirin for severe/immunocompromised cases.

How effective is measles vaccination?

95–98% immunity after MMR; booster at 4–6 years.

What virus causes rubella?

Rubivirus from the Togaviridae family.

Why is rubella clinically important despite mild symptoms?

Severe teratogenic effects in pregnancy.

What is the incubation period of rubella?

14–18 days.

When is rubella contagious?

1–2 weeks before rash onset; decreases once rash appears.

Describe the rubella rash.

Diffuse punctate maculopapular rash, milder than measles.

What complications occur commonly in adults with rubella?

Arthralgia and arthritis, especially in young women.

What lab findings are seen in rubella?

Leukopenia, thrombocytopenia, positive rubella IgM.

What is Congenital Rubella Syndrome (CRS)?

Fetal malformations including PDA, cataracts, deafness, microcephaly, ID.

When is CRS risk highest?

First trimester (85–90% risk).

What virus most commonly causes roseola?

Human herpesvirus-6 (HHV-6).

What age group is most affected by roseola?

6–36 months, peak at 7–13 months.

What is the classic fever pattern in roseola?

High fever for 3–5 days, then sudden resolution.

When does the roseola rash appear?

12–24 hours after fever resolves.

Describe the roseola rash.

Maculopapular, blanching, non-pruritic, starts on trunk.

Why is roseola associated with febrile seizures?

Rapid temperature elevation in infants.

How is roseola diagnosed?

Clinical diagnosis; labs usually unnecessary.

What is the treatment for roseola?

Supportive care only; no antivirals recommended.

How is CMV transmitted?

Body fluids (saliva, urine, blood, semen, breast milk).

What population is most severely affected by CMV?

Immunocompromised patients and neonates.

What are classic CMV retinitis findings?

White granular retinitis with hemorrhage following vessels.

What congenital findings are seen in CMV?

Microcephaly, ventriculomegaly, hearing loss, petechiae.

What percentage of asymptomatic CMV-infected newborns develop sequelae?

15–25%, most commonly hearing loss.

How is CMV diagnosed?

PCR, antigen detection, viral culture, urine in newborns.

What is the treatment for CMV?

Ganciclovir or valganciclovir; prophylaxis in transplant patients.

What virus causes infectious mononucleosis?

Epstein–Barr virus (EBV).

What is the classic triad of mononucleosis?

Fever, pharyngitis, lymphadenopathy.

Which lymph nodes are classically enlarged in mononucleosis?

Posterior cervical lymph nodes.

What lab finding is characteristic of EBV?

Atypical lymphocytosis (>10%).

What medication causes rash in EBV patients?

Amoxicillin or ampicillin.

What test confirms EBV infection?

Monospot (heterophile antibody test).

Why must contact sports be avoided in EBV?

Risk of splenic rupture.

What is the viral family of Morbillivirus, the cause of measles?

Paramyxoviridae.

What is one reason why measles is considered highly contagious?

Because of its high R₀ of 12–18.

What symptom is common in measles before the rash appears?

Cough.

What laboratory test is specific for diagnosing measles?

Rubeola-specific IgM.

What maculopapular rash characteristic of measles spares which areas?

Palms and soles.

What is a common bacterial complication of measles?

Otitis media.

In which scenario would ribavirin be used for measles treatment?

In severe or immunocompromised cases.

What condition can SSPE lead to after a measles infection?

Progressive neurodegeneration.

During what time frame is a patient with measles most contagious?

5 days before rash to 4 days after rash.

What are Koplik spots observed in?

Measles.

What are the characteristics of a rubella rash?

Diffuse punctate maculopapular rash.

What is the typical age for rubella infection?

In young children.

What is a risky condition that can arise from rubella during pregnancy?

Congenital Rubella Syndrome (CRS).

What are potential effects of CRS on an unborn child?

PDA, cataracts, deafness, microcephaly.

In rubella, when does the contagious period start in relation to the rash?

1–2 weeks before rash onset.

Which gender is more likely affected by arthritis due to rubella?

Young women.

What is the typical presentation of rubella symptoms?

Milder than measles.

What is the main treatment approach for roseola?

Supportive care.

What is the common age of peak incidence for roseola?

7–13 months.

How long does a typical fever last in roseola?

3–5 days.

What typically follows the fever in roseola?

The rash appears.

What features characterize the roseola rash?

Maculopapular, starts on trunk.

What could predispose an infant to febrile seizures in roseola?

Rapid temperature elevation.

How is CMV primarily diagnosed?

PCR, antigen detection, or viral culture.

What demographic should take precautions against CMV?

Immunocompromised patients.

What are significant congenital findings for newborns with CMV?

Hearing loss and microcephaly.

What percentage of infants with CMV may develop complications?

15–25%.

What is the first line treatment for symptomatic CMV infection?

Ganciclovir.

What do you monitor in infants who have been diagnosed with CMV?

Hearing loss.

What is the main risk for EBV patients engaging in sports?

Splenic rupture.

What lab test indicates EBV infection effectively?

Monospot test.

What common symptoms present in infectious mononucleosis?

Fever, sore throat, swollen lymph nodes.

What abnormal blood finding is seen in infectious mononucleosis?

Atypical lymphocytes.

What typically enlarges lymph nodes in EBV infection?

Posterior cervical lymph nodes.

What form of infection does Epstein-Barr virus typically lead to?

Infectious mononucleosis.

What virus belongs to the Togaviridae family?

Rubivirus (causes rubella).

Which virus causes roseola in infants?

Human herpesvirus-6 (HHV-6).

What is the timing of the onset of rash relative to fever resolution in roseola?

12–24 hours after fever resolves.

Which symptom may lead to febrile seizures in infants with roseola?

High fever.

What is the transmission mode for CMV?

Via body fluids.

What diagnostic technique can be used for CMV in newborns?

Urine PCR.

What are the symptoms within the classic triad of mononucleosis?

Fever, pharyngitis, and lymphadenopathy.

What is the illness that results from EBV infection characterized by lymphocytosis?

Infectious mononucleosis.

In terms of common toxicity, which antibiotics are unsafe for EBV patients?

Amoxicillin or ampicillin.

What form of antibody response is indicative of acute EBV infection?

Positive heterophile antibodies (Monospot test).

What is the classic consequence of splenic rupture in EBV infections?

Severe abdominal pain and internal bleeding.

What laboratory finding is seen with significant blood abnormalities in EBV infections?

Atypical lymphocytosis.

What is a common complication in older children and adults with mononucleosis?

Fatigue and prolonged malaise.

What is the risk posed by teratogenic effects during rubella infection?

Developmental disabilities in the fetus.

What are common signs of CRS?

Organ malformations and congenital defects.

What should be considered after an infant's high fever resolves with roseola?

Expect the rash to appear.

What is one hallmark of measles that helps in its diagnosis?

Koplik spots in the mouth.

What treatment options are available for severe CMV cases?

Ganciclovir or valganciclovir.

What warning describes the need to avoid certain activities while suffering from EBV?

Risk of splenic rupture.

What significant concern is associated with middle-school age children contracting rubella?

Possible development of arthralgia.