Idiopathic spontaneous splenic rupture

Clinical History

Middle-aged woman with unremarkable past medical history, presenting to emergency department with epigastric pain and vomiting. She denied recent trauma or abnormal activities, illnesses, travels and medications intake.
At physical examination she was found apyretic, with marked abdominal tenderness at palpation. Biochemistry revealed anaemia (haemoglobin 11.2 g/dl).

Imaging Findings

At emergency department, a nasogastric tube was positioned to relieve vomiting. Plain abdominal radiographs excluded intraperitoneal free air consistent with clinical suspicion of visceral perforation, abnormal bowel distension and air-fluid levels.
Rapidly worsening clinical conditions with hypotension and tachycardia led to further investigation with multidetector CT. Unenhanced images disclosed the presence of multi-compartmental peritoneal effusion, with hyperattenuating values (50-55 Hounsfield Units, HU) in the left upper abdomen and pelvis, indicating haemoperitoneum. Contrast-enhanced acquisition revealed a normal-sized homogeneous spleen, with a deep parenchymal laceration at its upper pole.
Urgent laparotomic surgery confirmed haemoperitoneum with upper splenic pole rupture and splenectomy was performed. Postoperative hospital stay was uneventful and laboratory tests including serology yielded negative results. Pathology of the surgical specimen reported 210g spleen with reactive changes including diffuse marginal expansion, without signs of acute infectious or malignant lesions, confirming the diagnosis of idiopathic splenic rupture.

Discussion

In the vast majority of cases, splenic injuries results from blunt or penetrating trauma. Spontaneous (non-traumatic) splenic rupture (SR) is an uncommon life-threatening occurrence that is usually pathologic, secondary to infections (malaria, mononucleosis or endocarditis), haematologic malignancies, in sporadic cases to amyloidosis, pancreatitis, in association with anticoagulation, pregnancy, haemodialysis or AIDS [1-4].
Due to its rarity, incidence, treatment and prognosis of spontaneous SR are poorly defined. Symptoms include malaise, fever, vomiting, left upper abdominal pain, variable hypotension and anaemia. Advanced cases present with shock, abdominal distension and peritonism. Without trauma, diagnosis of SR may be unsuspected, delayed or missed [1, 2, 5].
An exceptional (7% of all SR cases) “idiopathic” rupture may involve a normal-appearing spleen, for unclear reasons. The hypothesized mechanisms involve intrasplenic cellular or reticular endothelial hyperplasia and engorgement leading to hyperdistension and infarction, or compression by the abdominal musculature during physiological activities such as sneezing, coughing or defecation. Diagnostic criteria for idiopathic SR include exclusion of trauma or unusual efforts, no coexistent disease affecting the spleen, absent previous traumatic or surgical injury, normal spleen at gross inspection and histology, no abnormal viral antibody titers [1, 3-5].
Sensitive for the detection of intra-abdominal fluid, ultrasound may be helpful as a first-line bedside investigation, particularly in haemodynamically unstable patients, but has limited value to detect and grade splenic lesions [1, 2]. Conversely, CT imaging provides reliable classification of splenic damage according to American Association for the Surgery of Trauma scale, allowing a correct surgical choice. Haemoperitoneum is identified as high-attenuation (30-60 HU according to age of bleeding) peritoneal effusion, often with a fluid-fluid level appearance. The source of bleeding may be identified by an adjacent more hyperdense “sentinel clot”, or by contrast extravasation indicating active haemorrhage. Splenic injuries are graded according to extent of capsular involvement, laceration depth, vessel involvement and devascularisation [2, 5, 6].
In conclusion, the very rare SR should be considered in the differential diagnosis of abdominal pain, hypotension and anaemia, even in patients without known infectious or haematological disorders. Notably, spontaneous SR has a high rate of conservative treatment failure, therefore most cases are treated with early splenectomy and transfusions [1, 2, 4, 5].

Differential Diagnosis List

Final Diagnosis

Idiopathic spontaneous (atraumatic) splenic rupture.

URL:	https://eurorad.org/case/10087
DOI:	10.1594/EURORAD/CASE.10087
ISSN:	1563-4086