Acute systemic lupus erythematosus on the acute medical take: are we missing anything?

Abstract

A 42-year-old man with a background of systemic lupus erythematosus (SLE) presented acutely to the medical admissions unit (MAU) with pleuritic chest pain, shortness of breath and arthralgia. He was receiving no regular medications and denied any other medical problems, any cough, recent flights, calf pain or immobility. He described the chest pain as sudden onset, right sided and exacerbated by deep inspiration. He rated the pain as 10/10 severity and required opiate analgesia on admission to the MAU. On clinical examination the pain was increased by palpation at the right inferior anterior costal margin. The remainder of systems examinations were unremarkable with no rash, no synovitis and no audible pleural or pericardial rub. Baseline investigationsOn admission he was apyrexial, he had a good blood pressure of 132/78 and normal oxygen saturations at 98% on air. Heart rate and respiratory rate were raised at 88/minute and 24/minute respectively. He had an entirely normal arterial blood gas (ABG) on room air with a PO 2 of 12.1 KPa. His chest X-ray (CXR) was within normal limits and his electrocardiogram (ECG) is illustrated in Fig 1. What is the differential diagnosis and the most likely diagnosis? Acute SLE with serositisThis presentation is highly suggestive of an acute SLE flare resulting in pleuritic chest pain secondary to serositis. This is supported by raised inflammatory markers (Table 1) and saddle shaped ST elevation on ECG (Fig 1) consistent with pericarditis. Pulmonary embolusPatients with SLE are at increased risk of thrombosis and care must be taken not to miss a pulmonary embolus. Despite the presence of a normal PO 2 and a Wells Score of zero 1 suggesting a low pre-test probability, pulmonary embolus must be considered. Lower respiratory tract infectionThis is a common cause of pleuritic chest pain, but very unlikely here. To be able to attribute this degree of pleuritic pain to infection you would expect clinical findings consistent with infection, eg productive cough, coarse crepitations, bronchial breathing, pyrexia or consolidation on CXR. What is the initial management?Paracetamol, naproxen and codeine phosphate were used for analgesia but the pain persisted requiring morphine before it was controlled. A D-dimer was sent urgently which was raised (Table 1). E El li iz za ab be et th h S S P