Clinical Review Lesson of the week

Abdominal pain in acute infectious mononucleosis

BMJ 2002; 324 doi: (Published 16 March 2002) Cite this as: BMJ 2002;324:660
  1. Ann L N Chapman, specialist registrar in infectious diseases (alnchapman{at},
  2. Richard Watkin, senior house physician,
  3. Christopher J Ellis, consultant in infectious diseases
  1. Department of Infection and Tropical Medicine, Heartlands Hospital, Birmingham B9 5SS
  • Accepted 29 August 2001

Abdominal pain in patients with infectious mononucleosis may signal splenic rupture

Abdominal pain and tachycardia are unusual in patients with acute infectious mononucleosis. We present a case in which abdominal pain and tenderness signalled the presence of a potentially fatal complication of infectious mononucleosis.

Case report

A previously fit 20 year old man was admitted with a three day history of fever, sore throat, dyspnoea, and malaise. Ten days before admission he had fallen on to his left side and had attended the casualty department with pain over the left chest wall. A chest radiograph did not show a fracture, but the pain had been sufficiently severe to warrant overnight observation in the casualty department.

On admission he was feverish, with a temperature of 39.7°C, and had generalised lymphadenopathy, non-exudative pharyngitis, mild hepatomegaly, and splenomegaly of 2 cm. He looked pale but well, and his blood pressure was 115/95 mm Hg, with a pulse rate of 96 beats/min. He had mild left and right hypochondrial tenderness without guarding.

Initial investigations showed a haemoglobin concentration of 10.9 g/dl, and a total leukocyte count of 11.2 × 109/l with 70% lymphocytes and numerous “atypical” lymphocytes on the blood film. A Paul-Bunnell test gave a positive result the day after admission, and a clinical diagnosis of infectious mononucleosis was confirmed a week later with positive Epstein-Barr virus serology (positive viral capsid antigen IgG and IgM, negative Epstein-Barr virus nuclear antigen IgG).

The patient was reviewed by the infectious diseases team the morning after admission. He remained haemodynamically stable. In view of the clinical diagnosis of infectious mononucleosis, abdominal pain and tenderness, and history of trauma, he underwent an urgent abdominal ultrasound examination that morning. This showed a complete detachment of the inferolateral portion of the spleen 9 cm from the tip, with subcapsular haematoma but no intraperitoneal free fluid (figure). He underwent an emergency splenectomy, from which he made a full recovery. He remained haemodynamically stable from admission until splenectomy, a period of 18 hours. The excised spleen weighed 588 g (normal 200 g); histology showed massive lymphoid infiltration, with thinning of the trabeculae and capsule.


This case illustrates a rare but potentially fatal complication of acute Epstein-Barr virus infection. Splenic rupture is thought to occur in 0.1-0.5% of cases of infectious mononucleosis and has a mortality of around 30%, generally because of failure to establish the diagnosis at an early stage. 1 2 Rupture invariably occurs in the context of splenomegaly, which is present in half of cases of infectious mononucleosis.3 True spontaneous rupture of the spleen is rare in infectious mononucleosis, most of these patients having a history of trauma in the days before presentation; such “trauma” may be as minor as turning over in bed, coughing, vomiting, or defecating.4 The highest risk is said to occur in the second or third week of illness, when the histological changes in the spleen are at their peak.5 However, splenic rupture has been reported in patients with laboratory evidence of infectious mononucleosis but before development of symptoms.6 It is likely that in this case splenic rupture occurred in the first week of the patient's acute Epstein-Barr virus infection, resulting from a combination of trauma to the left side and developing histological changes in the expanding spleen. Recognition that the spleen had ruptured was delayed because of the patient's stable clinical condition and lack of coexisting symptoms of infectious mononucleosis.

Splenic rupture in infectious mononucleosis invariably presents with abdominal pain and tenderness, with variable signs of peritoneal irritation. 1 7 Abdominal pain is a rare feature of uncomplicated infectious mononucleosis, even in the presence of splenomegaly—occurring in only 1-2% of patients in one report.7 Its occurrence in a patient with a recent diagnosis of (or with clinical or laboratory features suggestive of) infectious mononucleosis should always be investigated with an urgent abdominal ultrasound scan or computed tomography.8 Patients may present with left or right hypochondrial pain, and about half will also have pain referred to the left shoulder (Kehr's sign). 5 9 Tachycardia and hypotension may also be present (and again are rare in uncomplicated infectious mononucleosis), although one salutary feature of this patient was the complete absence of any signs of haemodynamic compromise.7


Ultrasound image of spleen, showing complete detachment of the inferolateral portion of the spleen 9 cm from the tip, with subcapsular haematoma

Patients with splenic rupture in infectious mononucleosis generally undergo emergency splenectomy, although some reports suggest that non-operative management may be appropriate for patients who remain haemodynamically stable and who do not have abdominal rigidity or rebound tenderness.10 Because the spleen remains histologically abnormal for a long time after the symptoms of infectious mononucleosis improve, some sources have recommended that patients with splenomegaly should refrain from physical activity for two to three months after illness, increasing to six months for athletes.5

Our case illustrates the importance of careful assessment and investigation of patients with infectious mononucleosis who present with abdominal pain and the need for a high index of suspicion of splenic rupture in such patients, even in the absence of haemodynamic compromise.


Contributors: All three authors were involved in the diagnosis and management of the case. ALNC performed the literature search and wrote the paper. RW and CJE contributed to the development and revision of the paper. CJE is the guarantor.


  • Competing interests None declared


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