Splenic rupture as the presenting symptom in infective endocarditis: a rare and dangerous complication

Discussion

Traditional risk factors for infective endocarditis include artificial heart valves, intracardiac devices, a history of infective endocarditis, poor oral hygiene and coexisting comorbidities especially ones that suppress immunity such as diabetes mellitus and intravenous drug use.1 2 In recent years, the mortality of infective endocarditis has improved due to early diagnosis and the earlier use of antibiotics.1 It, however, remains a dangerous condition and mortality estimates are at around 20%.1 One of the major complications of endocarditis which contributes to this increased mortality is septic or thrombotic emboli.2 Stroke is the most common result, but embolism to any vascular bed is possible, which can cause end-organ infarction.3 Emboli can cause infarcts in the kidneys, bowel and spleen. Emboli have also been reported in the coronary arteries.4 Septic emboli can cause secondary infection in the vascular wall, leading to the formation of mycotic aneurysms. Most emboli occur in the first few weeks after the diagnosis is made: the risk decreases rapidly after antibiotics are given.2 Emboli are more likely when vegetations are larger in size, mobile in nature and located on the mitral valve.

Splenic complications of endocarditis are well recognised in the literature though in clinical practice they can be missed due to their rarity. The most common splenic complication is pronounced splenomegaly.2 Untreated endocarditis can result in septic emboli causing splenic infarcts and abscess formation. The incidence of splenic embolism is reported as between 5% and 12% though this is likely to be an underestimate.5 Splenic infarcts will often present with vague abdominal pain and can be the first clinical sign of endocarditis.1 2 Splenic rupture can be the final outcome in untreated cases and a few different pathophysiological mechanisms have been suggested for this. These include rupture of the mycotic aneurysm, capsular tear due to splenomegaly or haemorrhage into a splenic infarction.6 Asymptomatic splenic infarcts do not require surgery; but if they progress to abscess formation, then splenectomy should be considered due to the high risk of splenic rupture.2 Splenic rupture carries a mortality of approximately 58% and therefore it is imperative that the diagnosis of endocarditis is made early.7

Spontaneous splenic rupture as the first presentation of endocarditis is extremely rare, and our case highlights a case where the diagnosis of endocarditis was delayed by up to 4 months. Traditionally, splenic rupture secondary to trauma is due to direct blunt trauma to the abdomen (often seen in high-impact sports) or due to high-speed accidents such as road traffic accidents. In this case, it was very unlikely for the patient’s minor fall to have been the cause of the splenic rupture and searching for an alternative cause for this during the first admission should ideally have been carried out. The patient also had risk factors for endocarditis such as previous valve surgery which should have prompted further investigations. It is therefore imperative to consider endocarditis in a case of spontaneous splenic rupture particularly in high-risk patients. Clinicians should have a low threshold for investigating patients with signs or symptoms suggesting possible splenic infarction, as early recognition may have a very significant effect on outcome.