MonoApp ER

Infectious mononucleosis

Quick guide to diagnosis, management and follow-up for pediatric emergencies.

Etiology: Mainly caused by the Epstein-Barr virus (EBV) (Herpesvirus type 4). Less common causes (mononucleosis syndrome): Cytomegalovirus (CMV), Toxoplasma gondii, Adenovirus, acute HIV.

Epidemiology:

  • Transmission: Direct contact with oral secretions ("kissing disease").
  • Incubation: Long, 4 to 6 weeks.
  • Age peaks: Young children (often asymptomatic or mild symptoms) and adolescents/young adults (Florida clinic).
  • Contagiousness: Lifelong intermittent viral excretion after infection.

Classic Triad:

  1. Fever (may last 1-2 weeks)
  2. Pharyngotonsillitis (with thick pultaceous/membranous exudate)
  3. Lymphadenopathy (typically posterior cervical, bilateral, painful)
  • General: Intense asthenia, anorexia, myalgia.
  • Abs: Splenomegaly (50-60%, maximum risk of rupture in 2nd-3rd week), Mild hepatomegaly (10-15%).
  • ENT/Skin: Petechiae on the palate (Forchheimer's sign), eyelid edema (Hoagland's sign).
  • Exanthema: Maculopapular, especially if they received Amoxicillin/Ampicillin incorrectly (up to 90% of cases).

Laboratory

  • Hemogram: Leukocytosis with lymphomonocytosis (>50%) and presence of atypical lymphocytes (>10%). Mild thrombocytopenia is common.
  • Biochemistry: Elevation of transaminases (AST/ALT) in 80% of cases (they are usually <500 U/L).
  • Heterophile Antibodies (Paul-Bunnell / Monospot): Useful and fast, but high rate of false negatives in children under 4 years of age (up to 50%) and in the first week of illness.
  • EBV Specific Serology: Acute infection pattern:
    • VCA IgM: Positive (appears quickly, lasts 2-3 months).
    • VCA IgG: Positive (appears quickly, lasts a lifetime).
    • EBNA IgG: Negative (appears 6-12 weeks after infection).

Image

  • Abdominal ultrasound: Not routine. Indicate if severe acute abdominal pain (rule out splenic rupture), doubtful palpable mass, or severe jaundice.
  • Lateral Neck X-ray / CT: Indicate if there is suspicion of airway compromise or peritonsillar/parapharyngeal abscess.

Treatment is mainly symptomatic. There are no effective antivirals.

  • Hydration: Maintain good intake of cold or warm liquids.
  • Repose: Relative during the febrile and acute asthenia phase.
  • Analgesics/Antithermics:
    - Ibuprofen: 5-10 mg/kg/dose every 6-8 hours PO. (Useful for its anti-inflammatory effect in the pharynx).
    - Paracetamol: 10-15 mg/kg/dose every 6-8 hours PO.
  • Avoid Antibiotics: Especially Amoxicillin (risk of severe rash). Only use if there is proven bacterial superinfection (e.g. associated S. pyogenes).

Entry Criteria:

  • Airway compromise ("Kissing tonsils", stridor, distress).
  • Refusal to eat with severe dehydration.
  • Suspected or confirmed splenic rupture.
  • Neurological complications (encephalitis, Guillain-Barré).
  • Severe hepatitis, severe hemolytic anemia or severe thrombocytopenia.

Hospital Therapeutics

Fluid therapy

Glucosalline Serum 1/3 or 1/2: At basal needs (Holliday-Segar) + deficit correction according to dehydration status. IV.

IV Analgesia and Antipyresis

Paracetamol (Perfalgan® vial 10mg/ml): 15 mg/kg/dose IV every 6-8 hours. (Pass in 15 min).

Metamizole (Nolotil® ampoules 2g/5ml): 10-20 mg/kg/dose IV every 6-8 hours. For very resistant fever or intense pain.

Corticosteroids (Restricted Use)

Only indicated in: Imminent airway obstruction, hemolytic anemia, severe thrombocytopenia or neurological complications.

  • Dexamethasone (Fortecortin® ampoule 4mg/1ml): 0.15 - 0.6 mg/kg/day IV/PO divided every 6-12 hours. (Max. 10 mg/day). Short regimen (3-5 days).
  • Methylprednisolone (Urbason® vial 8mg, 20mg, 40mg): 1-2 mg/kg/day IV in 2-3 doses.

Hospital Discharge Criteria

  • Adequate oral tolerance to liquids and analgesia.
  • Patent airway without risk of compromise.
  • Controllable fever at home.
  • Absence of acute abdominal pain.

Recommendations for discharge

CRITICAL!

Absolute prohibition of contact sports or intense physical efforts for at least 3 to 4 weeks from the onset of symptoms, due to the risk of splenic rupture (even without palpable splenomegaly).

  • Consult the emergency room if: Sudden and intense abdominal pain (left upper quadrant or referred to the left shoulder), difficulty swallowing liquids, respiratory difficulty, bleeding or severe jaundice.
  • Frequent hand washing, do not share glasses or cutlery.

Follow-up Guidelines (Primary Care)

  • Clinical Visit: Checkup by your pediatrician in 1-2 weeks.
  • Laboratory: Repeat analysis (transaminases) in 2-4 weeks only if were significantly elevated in the acute phase, until they normalized.
  • Image: Control abdominal ultrasound It is NOT routine. It is reserved for elite athletes who require authorization to return to competition within a month, or if there was initial massive splenomegaly.