Prevention of infectious mononucleosis

Clinical presentation and prevention of diagnostic errors

Timely recognition of symptoms of infectious mononucleosis (IM) is the first step in preventing its adverse outcomes. The disease often presents with nonspecific signs: malaise, weakness, fatigue, decreased appetite, and a sore throat. Body temperature may rise to subfebrile levels (around 37.6°C).

The objective status of patients includes the following manifestations:

• Skin: pallor, sparse roseolopapular rash on the trunk and extremities (medium-sized elements, not prone to coalescence).
• Lymphatic system: moderate lymphadenopathy is characteristic. Cervical, supraclavicular, axillary, and inguinal lymph nodes enlarge (on average up to 1.5 cm or the size of a bean).
• Oropharynx: moderate hyperemia of the mucous membrane, single aphthae. Pharyngeal tonsils hypertrophy up to degree I and become friable. Notably, plaque may be absent, although single purulent follicles are sometimes detected on the medial surface of the tonsils.
• Abdominal organs: a typical sign is hepatosplenomegaly (enlargement of the liver and spleen), sometimes accompanied by the development of hepatitis.

Laboratory and serological profile

To confirm the diagnosis and prevent overdiagnosis of other infections, a thorough analysis of laboratory data is required.

Specific changes are determined in the complete blood count (hemogram):

• Leukocytosis (e.g., 10.5 x 10⁹/L) or a normal leukocyte count (9.5 x 10⁹/L).
• Shift in the leukocyte formula (band neutrophils from 6% to 16%).
• Lymphocytosis (34–44%) and monocytosis (18–30%).
• Presence of atypical mononuclear cells—the main specific marker of the disease (detected in amounts from 8% to 16%).
• Accelerated ESR (from 15 to 35 mm/h).
• In severe cases, anemia (decrease in hemoglobin to 90 g/L) and thrombocytopenia (decrease in platelets to 113 x 10⁹/L) may develop.

Blood chemistry in liver involvement demonstrates cytolysis syndrome: elevated ALT (up to 126 IU/L) and AST (up to 96 IU/L) levels with normal or slightly elevated total and direct bilirubin values.

Serological testing includes the Paul-Bunnell test (which can be either positive or negative) and enzyme-linked immunosorbent assay (ELISA). Typical IM profile: positive anti-VCA IgG and anti-EBNA IgG with negative anti-EBV EA IgG. Exclusion of HIV infection (anti-HIV negative) is a mandatory step, especially in the presence of a burdened epidemiological history (e.g., intravenous drug-using partner).

Differential diagnosis of complications

Prevention of diagnostic errors is relevant in the long-term period after IM. Patients may experience persistent asthenia and low-grade fever for months.

For example, six months after discharge, a symptom complex may persist that requires differential diagnosis with yersiniosis:

1. Prolonged fever (37.0–38.0°C for up to 10 days).
2. Arthralgia (joint pain in the extremities, smoothed contours of the hand and foot joints, pastosity and skin hyperemia over them, restricted movement due to pain).
3. Persistent lymphadenopathy and hepatosplenomegaly.
4. Appearance of bilateral interstitial pneumonia and enlarged mediastinal lymph nodes on a chest X-ray.

Knowledge of these long-term manifestations allows the physician to correctly interpret the patient's condition and avoid prescribing inadequate therapy.

Prevention of emergency surgical complications

The most formidable complication of infectious mononucleosis is spontaneous or traumatic splenic rupture. This condition requires emergency surgical care, and its prevention consists of a strict ban on physical activity (especially sports, track and field) for a prolonged period after discharge.

The clinical presentation of a splenic rupture (acute abdomen) develops rapidly. For example, in a teenage athlete during a cross-country run one month after having IM, the following may appear:

• Severe pain in the left abdomen.
• Symptoms of peritoneal irritation and tension of the anterior abdominal wall.
• Weakness, dizziness, brief loss of consciousness.
• Signs of acute blood loss and shock: sharp pallor, hypothermia (axillary temperature drops to 35.8°C), weak and thready pulse, pronounced tachycardia (up to 124 bpm), and hypotension (blood pressure drops to 60/40 mm Hg).

Instrumental imaging (ultrasound) in such cases reveals free fluid in the abdominal cavity (hemoperitoneum), and laboratory tests confirm severe posthemorrhagic anemia (drop in hemoglobin to 60 g/L and decrease in hematocrit to 26%). Ignoring the rules of the recovery period directly leads to such critical conditions.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Interpretation of hemogram in viral infections
• Differential diagnosis of yersiniosis
• Cytolysis syndrome in viral hepatitis
• Clinic of hemorrhagic shock in hemoperitoneum
• Serological markers of Epstein-Barr virus infection

Other topics in the "Respiratory Infections" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.