Common Childhood Infections

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Viral Exanthems I - Red Rash Rumble

  • Measles (Rubeola)
    • Virus: Paramyxovirus
    • Prodrome: Cough, Coryza, Conjunctivitis (📌 3 C's), Koplik spots (pathognomonic).
    • Rash: Cephalocaudal maculopapular, confluent, brick-red.
    • Complications: Pneumonia, SSPE.
  • Rubella (German Measles)
    • Virus: Togavirus
    • Prodrome: Mild fever, postauricular/suboccipital lymphadenopathy. Forchheimer spots.
    • Rash: Cephalocaudal maculopapular, pink, non-confluent, faster spread.
    • Complications: Congenital Rubella Syndrome (CRS).
  • Erythema Infectiosum (Fifth Disease)
    • Virus: Parvovirus B19
    • Rash: "Slapped cheek" → lacy reticular on trunk/limbs.
    • Complications: Aplastic crisis, hydrops fetalis.
  • Roseola Infantum (Exanthem Subitum)
    • Virus: HHV-6 / HHV-7
    • Prodrome: High fever (3-5 days), child often well; then defervescence.
    • Rash: Appears after fever; maculopapular, trunk → outward. Nagayama spots.
    • Complications: Febrile seizures.

⭐ Koplik spots in Measles are bluish-white spots on an erythematous base on the buccal mucosa, appearing 1-2 days before the rash.

Viral Exanthems II - Pox, Pink & Slapped Cheeks

  • Chickenpox (VZV)

    • Rash: Pruritic, pleomorphic ("dew drop on rose petal" vesicles), all stages simultaneously. Centripetal (trunk > limbs).
    • Prodrome: Mild fever, malaise.
    • Complications: Bacterial superinfection, pneumonia, encephalitis, Reye's (aspirin).
    • Prevention: Vaccine. VZIG for high-risk contacts.
  • Rubella (German Measles - Togavirus)

    • Rash: Pink, discrete maculopapular. Face → cranio-caudal spread in 24 hrs. Fades 3 days.
    • Prodrome: Low-grade fever, lymphadenopathy (postauricular, suboccipital). Forchheimer spots.
    • CRS: Deafness, cataracts, cardiac (PDA, PPS). 📌 Mnemonic: "I <3 RUBY EARRINGS".
    • Prevention: MMR vaccine.
  • Erythema Infectiosum (Fifth Disease - Parvovirus B19)

    • Rash (3 stages):
      • 1: "Slapped cheek" erythema, circumoral pallor.
      • 2: Maculopapular rash on trunk & limbs.
      • 3: Lacy, reticular rash on extremities; recurs with heat/sun.
    • Complications: Aplastic crisis (hemolytic anemia), hydrops fetalis (pregnancy).

    ⭐ Parvovirus B19 commonly causes arthralgia/arthritis in adults, especially women.

Key Bacterial Infections - Bacterial Blight Brigade

  • Diphtheria
    • Agent: Corynebacterium diphtheriae (Gram-positive bacillus).
    • Patho: Exotoxin inhibits protein synthesis → myocarditis, neuritis.
    • Clinical: Greyish, adherent pseudomembrane (pharynx, larynx); "Bull neck" (cervical edema/lymphadenopathy).
    • Rx: Diphtheria Antitoxin (DAT) ASAP + Penicillin/Erythromycin.
  • Pertussis (Whooping Cough)
    • Agent: Bordetella pertussis. Highly contagious.
    • Phases: Catarrhal (most infectious) → Paroxysmal (fits of coughs, inspiratory "whoop", post-tussive vomiting, marked lymphocytosis) → Convalescent.
    • Rx: Macrolides (Azithromycin <1 month old, Erythromycin).
  • Tetanus (Lockjaw)
    • Agent: Clostridium tetani (anaerobe, spores in soil).
    • Patho: Tetanospasmin (neurotoxin) blocks GABA/glycine release.
    • Clinical: Trismus, risus sardonicus, opisthotonus, painful spasms. Neonatal: umbilical infection.
    • Rx: Human Tetanus Immunoglobulin (TIG) + Metronidazole + Diazepam.

    ⭐ The Spatula Test: Touching posterior pharyngeal wall with a spatula elicits reflex masseter spasm; highly specific for tetanus.

  • Haemophilus influenzae type b (Hib)
    • Key syndromes: Meningitis, acute epiglottitis (📌 "Thumb sign" on lateral neck X-ray), pneumonia, septic arthritis.
    • Prevention: Hib conjugate vaccine (part of Pentavalent).

Lateral neck X-ray: Thumb sign in acute epiglottitis

High‑Yield Points - ⚡ Biggest Takeaways

  • Measles: Koplik's spots (pathognomonic), cephalocaudal maculopapular rash. Vitamin A reduces morbidity.
  • Mumps: Parotitis is classic; orchitis in post-pubertal males is a significant complication.
  • Rubella: High risk of Congenital Rubella Syndrome (triad: cataracts, deafness, PDA).
  • Diphtheria: Adherent greyish pseudomembrane, bull neck, risk of myocarditis/neuropathy.
  • Pertussis: Paroxysmal cough with inspiratory "whoop", post-tussive emesis, marked lymphocytosis.
  • Scarlet Fever: Strawberry tongue, sandpaper rash (Pastia's lines); caused by Group A Strep exotoxin.

Practice Questions: Common Childhood Infections

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Most common complication of diphtheria is -

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Flashcards: Common Childhood Infections

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The most common etiological agent, in India, of acute epiglottitis in the pediatric age group, now is _____.

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The most common etiological agent, in India, of acute epiglottitis in the pediatric age group, now is _____.

H. influenzae type B

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