90 Transient severe mitral regurgitation caused by an exclusively dopamine secreting paraganglioma

Abstract

Abstract INTRODUCTION A 93 year old woman presented to the hospital because of severe dyspnea with a sudden onset. Her medical history was positive for a sick sinus syndrome for which she received a DDD pacemaker in 2014. Furthermore an intra-abdominal paraganglioma (PGL) was discovered a year earlier which was treated conservatively because of her age and lack of symptoms. On physical examination, a sinus rhythm of 88 bpm (pacemaker rhythm) and oxygen saturation of 80% was noted. Blood pressure was 66/38 mmHg. An urgent blood gas analysis showed an elevated blood lactate concentration of 5.5 mmol/l. Her signs and symptoms were compatible with a cardiogenic shock. Transthoracic echocardiography (TTE) revealed a notable hyperdynamic left ventricular (LV) function and a severe mitral regurgitation (MR) (ERO 0,7 cm2), based on restriction and tenting of both the anterior and posterior mitral leaflet with a systolic pulmonary artery pressure (PAPs) of 70mmHg + CVP. Because of her age and a written declaration of will, only a supportive therapy with oxygen and morphine was given. After 45minutes however, the patient suddenly and completely recuperated. Her vital signs stabilized with a blood pressure of 110/60 mmHg and oxygen saturation of 95%. A second TTE showed only a mild MR without any restriction of the mitral leaflets and a normalized PAPs of 30mmHg +CVP. The patient was hospitalized for further investigation. COURSE DURING HOSPITALIZATION During the next 48 hours, four similar episodes with acute dyspnea and signs and symptoms of cardiogenic shock were documented. Each time, TTE revealed a hyperdynamic LV function with a severe MR, based on tenting of both mitral valve leaflets. These episodes always terminated spontaneously with only a mild residual MR afterwards. An angiography was performed and showed no coronary lesions. DIFFERENTIAL DIAGNOSIS Because of the paroxysmal episodes, documentation of a hyperdynamic LV function with severe hypotension and the known PGL, a 24h urine collection was performed. The results demonstrated a markedly elevated urine dopamine concentration (5300 µg/l) with normal concentrations of adrenaline (3.5 µg/l) and noradrenaline (64.3 µg/l). 3-Methoxytyramine, the metabolite of dopamine, was also highly elevated (4700 µg/l). As such, the diagnosis of a dopamine producing PGL was made. The patient refused any treatment and she went home in a palliative setting. CONCLUSION Dopamine-secreting PGL is a very rare entity without a classic clinical presentation. This is the first case report showing a severe MR with cardiogenic shock, leading to the diagnosis of a dopamine secreting PGL. The mechanism of the MR is still unclear, but strain measurements did show an exacerbation of the RV pacing induced dyssynchrony during the episodes of shock, hypothesizing that dopamine release exacerbated the pacing induced asynchrony of the papillary muscles, leading to a functional MR.