Infectious mononucleosis is typically a self-limited viral infection of adolescence and early adulthood that resolves in a period of weeks, causing no major sequelae. We describe a case of a healthy 18-year-old female diagnosed with infectious mononucleosis who also presented with right upper quadrant abdominal pain, moderate transaminitis, and cholestatic biochemistry. An ultrasound revealed acute acalculous cholecystitis, generally a condition seen in the context of critical illness. Further investigating emergency department patients with infectious mononucleosis is often not indicated, but may be important for those who present atypically.

Infectious mononucleosis is a clinical manifestation of primary Epstein–Barr virus infection. It is unknown whether genetic factors contribute to risk. To assess heritability, we compared disease concordance in monozygotic to dizygotic twin pairs from the population-based California Twin Program and assessed the risk to initially unaffected co-twins. One member of 611 and both members of 58 twin pairs reported a history of infectious mononucleosis. Pairwise concordance in monozygotic and dizygotic pairs was respectively 12·1% [standard error (s.e.)=1·9%] and 6·1% (s.e.=1·2%). The relative risk (hazard ratio) of monozygotic compared to dizygotic unaffected co-twins of cases was 1·9 [95% confidence interval (CI) 1·1–3·4, P=0·03], over the follow-up period. When the analysis was restricted to same-sex twin pairs, that estimate was 2·5 (95% CI 1·2–5·3, P=0·02). The results are compatible with a heritable contribution to the risk of infectious mononucleosis.

Infection with Epstein–Barr virus (EBV) followed by infectious mononucleosis (IM) is now considered to be a risk factor for Hodgkin's disease (HD). It is less clear whether EBV infection and IM are associated with an increased risk of cancer generally. We used a longstanding record-linkage dataset in Oxford (years 1963–1998), and a more recent record-linkage dataset covering England (1999–2005), to compare rate ratios for cancer between people admitted to hospital for IM and a reference cohort. In the Oxford cohort, there was an increased risk of subsequent HD [rate ratio (RR) 6·0, 95% confidence interval (CI) 2·4–12·5] but not of other cancers combined (RR 0·85, 95% CI 0·57–1·23). In the England cohort, there were increased risks of HD (RR 3·2, 95% CI 1·2–7·0), non-Hodgkin's lymphoma (RR 5·6, 95% CI 2·9–9·8), and oropharyngeal cancer (RR 5·4, 95% CI 1·1–16·2), but no significant overall risk of cancer when lymphomas were excluded (RR 1·01, 95% CI 0·71–1·41). We confirm an association between IM and lymphoma; but the risk, if any, of cancer more generally is likely to be small.

Infectious mononucleosis causing upper airway obstruction due to tonsillar disease and associated lymphadenopathy in adolescents is well recognized. However, infection with Epstein-Barr virus (EBV) in a young child of six months is rare. The authors present such a case, with massive swelling of the retropharyngeal lymph nodes, that has not been published previously. The patient presented to this department with a short history of an upper respiratory tract infection and mild upper airway obstruction. On examination there was a massive enlargement of the retropharyngeal space with a compromised airway. This was confirmed on X-ray. She made an uneventful recovery following incision and drainage and a short period of endotracheal intubation. Because of the presence of retropharyngeal lymphoid tissue in infancy an alternative site of upper airway obstruction may occur here in this age group.

Epstein-Barr virus (EBV) is a γ-herpesvirus that infects over 90% of the human population worldwide. It is usually transmitted between individuals in saliva, and establishes replicative infection within the oropharynx as well as life-long latent infection of B cells. Primary EBV infection generally occurs during early childhood and is asymptomatic. If delayed until adolescence or later, it can be associated with the clinical syndrome of infectious mononucleosis (also known as glandular fever or ‘mono%rsquo;), an illness characterised by fevers, pharyngitis, lymphadenopathy and malaise. EBV infection is also associated with the development of EBV-associated lymphoid or epithelial cell malignancies in a small proportion of individuals. This review focuses on primary EBV infection in individuals suffering from infectious mononucleosis. It discusses the mechanism by which EBV establishes infection within its human host and the primary immune response that it elicits. It describes the spectrum of clinical disease that can accompany primary infection and summarises studies that are leading to the development of a vaccine designed to prevent infectious mononucleosis.

Peritonsillar abscess formation is an uncommon complication of infectious mononucleosis (IM). Early case reports implicated corticosteroids in the development of such abscesses, however, subsequent studies suggested that these drugs do not promote the formation of abscesses at several sites outside the central nervous system. It has recently been demonstrated that zwitterionic polysaccharides, in bacterial capsules, form complexes with CD4+ T lymphocytes leading to abscess formation. A patient is presented who developed peritonsillar abscess a few days after initiation of corticosteroid therapy for IM; the medical literature was reviewed in respect of this subject. It appears that the occurrence of these abscesses in IM is not strongly linked to corticosteroid treatment. The authors, therefore, recommend that steroids should not be withheld from patients with severe IM on the basis that they may precipitate the development of peritonsillar abscess.

Two hundred and four cases of in-patient admission with isolated, unilateral peritonsillar abscess over the three-year period 1999–2001 were reviewed retrospectively. One hundred and fifty-one patients had been screened for infectious mononucleosis (IM) using the heterophile antibody screening test. Of these 142 (94 per cent) tested negative and nine (six per cent) positive. There were no IM-typical clinical or haematological signs in any of the IM positive patients to facilitate the prediction of the diagnosis. Due to the comparatively high prevalence of positives, the low cost of screening, the lack of predictive signs and the diversity of potential complications of IM, routine screening in all patients presenting with peritonsillar abscess is recommended.

Acute tonsillectomy has been advocated for severe infectious mononucleosis (IM) pharyngotonsillitis with upper airway obstruction (UAO) and not responding to corticosteroids. This paper reviews and rationalizes our management. A five-year chart review was carried out with a follow-up telephone survey. There were 36 admissions. Nine had UAO of whom 89 per cent (eight of nine patients) had a tonsillectomy. The diagnosis of UAO was not standardized. Twenty-seven patients did not have UAO and only a small proportion of these patients, 16 per cent (four of 25) went on to have an elective tonsillectomy. Corticosteroids made no significant difference to the tonsillectomy rate. UAO appears to identify patients with more severe disease who are likely to suffer recurrent tonsillitis. Acute tonsillectomy is an appropriate treatment option for this subgroup. The diagnosis of significant IM UAO is not defined and a schema is proposed. Recurrent tonsillitis is an uncommon sequela of severe IM pharyngotonsillitis without UAO.

Frequently, the clinical picture in the oropharynx alone does not lend itself to a reliable differentiation between acute pharyngotonsillitis in infectious mononucleosis and a streptococcal inflammation. Such a differentiation, however, is essential for the indication of antibiotic therapy. Therefore, it was the aim of the present study to investigate whether or not endoscopic verification of larger-than-normal lymphatic tissue with fibrinous membranes in the nasopharynx would enhance the reliability of diagnosis.

Fifty hospitalized patients exhibiting the clinical picture of acute pharyngotonsillitis were examined for the following parameters: nasopharyngeal endoscopy, determination of glutamine-oxaloacetic transaminase (GOT), glutamine-pyruvic transaminase (GPT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), leucocytes and haemogram, antibodies to viral capsid antigen (VCA)-IgM, Epstein-Barr virus nuclear antigen (EBNA), and cytomegalovirus (CMV).

In 24 patients with acute tonsillitis/peritonsillar abscess, and in 26 patients with infectious mononucleosis, the total leucocyte count in the blood and the blood/erythrocyte sedimentation rate were comparable. Atypical lymphocytes or absolute lymphocytosis were not seen in acute tonsillitis, but were found in 88.5 per cent of patients with infectious mononucleosis. Elevated transaminase levels were noted in 77 (GOT) and 88.5 per cent (GPT) of patients with infectious mononucleosis, and in acute tonsillitis in 4.2 (GOT) and 12.5 per cent (GPT) of patients. The CRP was higher than normal in 91.7 per cent of patients with acute tonsillitis, and in 57.7 of patients with infectious mononucleosis. In none of the patients with acute tonsillitis was lymphatic tissue with fibrinous membranes seen in the nasopharyngeal cavity. In contrast, nasopharyngeal endoscopy in infectious mononucleosis was positive in 24 out of 26 patients. Hence, the sensitivity was 92.3 per cent, the specificity 100 per cent, and the prediction value for a positive test turned out to be 1.

Endoscopy of the nasopharngeal cavity employed as a simple and supplementary procedure adds to the reliability of diagnosis of infectious mononucleosis.

Upper airway obstruction is an uncommon but recognized complication of infectious mononucleosis. The management depends upon the degree of airway compromise. In the case described, severe airway obstruction was treated by securing the airway with awake fibre-optic endoscopic intubation and then proceeding to tonsillectomy. Bilateral inferiorly loculated quinsies were encountered unexpectedly and drained. This is the first report of ‘bilateral’ quinsies, associated with infectious mononucleosis and severe airway obstruction. The association, pathogenesis and significance of this finding are also discussed.

Tonsillar haemorrhage is a rare complication of infectious mononucleosis. We present a case of life-threatening tonsillar haemorrhage secondary to infectious mononucleosis in a young man whose predominant symptoms at presentation were haematemesis and melaena. The origin of the haemorrhage was not obvious until the patient was examined under anaesthesia. The bleeding was controlled by emergency tonsillectomy.

Life-threatening upper airway obstruction can be caused by tonsillopharyngitis secondary to infectious mononucleosis (IM). The administration of corticosteroids, emergency tracheostomy and acute tonsillectomy have been advocated as ways of managing this problem. In a series of 25 patients admitted over a five-year period with IM, 15 were judged to have symptoms severe enough to warrant the administration of corticosteroids. Six of these 15 patients had little improvement in their condition and thus underwent acute tonsillectomy. There were no significant complications of this surgery. A further three patients who received corticosteroids required tonsillectomy for recurrent tonsillitis later in the study period. By contrast, only one of the ten patients who did not receive corticosteroids subsequently required tonsillectomy. Acute tonsillectomy is of value in selected cases of IM tonsillopharyngitis. It may decrease the morbidity of recurrent tonsillitis after IM, in addition to averting the immediate risk of respiratory obstruction.