Teaching Case

21-year-old male patient admitted with a history of sharp stabbing left upper quadrant pain of 10 days duration. He was diagnosed with glandular fever eight days previously. On examination there was left upper quadrant tenderness and guarding.

^{Figure 1:-} Ultrasound Abdomen:
The spleen is enlarged measuring 18 cm in length and there is a large subcapsular haematoma of maximum thickness 3 cm covering the entire length of the spleen.
The spleen itself appears intrinsic normal.

^{Figure 2:-} Abdomen and Pelvis (Coronal):
There is almost complete left lower lobe collapse with a surrounding left pleural effusion. The splenic parenchyma looks unremarkable, but there is a very large subcapsular haematoma with evidence of fluid of various densities within this suggesting current haemorrhage.
A small volume of free fluid was seen throughout the abdomen.

^{Figure 3:-} Angiogram Splenic artery: Angiogram showed a short coeliac trunk with steeply angulated trifurcation and tortuous splenic artery. There was no contrast extravasation around the spleen to indicate active bleeding at the time of the examination but the spleen was enlarged and displaced medially by the known large subcapsular haematoma.

Background
Infectious mononucleosis sometimes colloquially referred to kissing disease or simply as glandular fever in the United Kingdom, is an infectious widespread viral disease caused by the Epstein–Barr virus (EBV), to which more than 90% of adults have been exposed [1].

Clinical Perspective
A triad of fever, sore throat and cervical lymphadenopathy occurs. Majority of patients will have asymptomatic splenomegaly. However, spontaneous rupture of the spleen secondary to infectious mononucleosis is rare with an estimation of up to 0.5% [2, 3].

Imaging Perspective
Ultrasound performed by experienced investigators is regarded as a valid and reliable method for diagnosis of splenic lesions [4, 5].
Computed Tomography (CT) examination provides the most ideal noninvasive means for evaluating the spleen.
Several grading systems based on ultrasound and CT have been established for traumatic splenic ruptures and have been shown to be reliable and helpful for therapeutic decisions [6]. Conversely there are no valid data on incidence rates, symptoms, causes, therapy and prognosis of spontaneous splenic rupture.
Numerous case reports have been published, but a comprehensive assessment is still missing [7].

Outcome
Our patient was first investigated with ultrasound. The initial plan was to manage conservatively, however, the patient continued to suffer from pain and there was a slight drop in haemoglobin. A repeat ultrasound was carried out which did not vary significantly from the first. This was followed by a CT abdomen and pelvis which demonstrated signs of fresh bleeding (see figure 2). As the patient was haemodynamically stable, the team decided to proceed to splenic artery angiography (see figure 3).
Although there was no contrast extravasation demonstrated on the angiogram, in view of the CT and clinical findings, a decision was made to try and occlude the proximal splenic artery.
Unfortunately this proved unsuccessful due to the complexity of the vascular tree. A coil placed during this procedure inadvertently migrated to the coeliac trunk.
The decision was then made to perform a splenectomy. This was uneventful and the radiological findings of splenomegaly and subcapsular haematoma were confirmed. Minimal free fluid was found.
Subsequent histological analysis of the splenic specimen demonstrated immunoblastic infiltration and expansion of the red pulp. This was consistent with EBV.


Teaching points
Spontaneous rupture of the spleen occurs as a serious although relatively infrequent complication of infectious mononucleosis [8].
The nature of therapy remains controversial although most authors recommend splenectomy, particularly in cases of expansion of the haematoma on imaging or deterioration of the patient’s vital signs or drop in haemoglobin [9].