LAUSR

To the Editor: Systemic capillary leak syndrome (SCLS) is a rare and potentially fatal disorder characterized by episodes of hypotension, hypoalbuminemia, and hemoconcentration as a result of increased vascular permeability [1, 2]. A rarer chronic form of SCLS (cSCLS) has been described with persistent, noncyclical, progressive generalized edema in which patients may also have visceral effusions [3, 4]. The underlying pathogenesis is unknown, but both forms are often associated with a monoclonal gammopathy [5]. Preventive treatment with intravenous immunoglobulin (IVIg) may be effective in reducing SCLS attack frequency [6, 7]. However, there is limited experience of its use in cSCLS and other prophylactic treatments have been administered with variable success [4, 8].We describe a patient who presented with cSCLS, neutropenia, and thymoma where treatment with prednisolone and IVIg resulted in a gradual improvement and sustained remission in her symptoms. A 52-year-old, 65-kg woman presented to hospital in February 2018 with a 2-month history of worsening shortness of breath and progressive generalized swelling. She had two previous episodes of moderate, unexplained swelling of her face and legs in 2017. Medical history included rheumatological assessment in April 2016 for a 3-month history of bilateral shoulder and knee pain with no associated symptoms. She was diagnosed with possible undifferentiated connective tissue disease based on polyarthralgia and positive antinuclear antibody [ANA (1:1280 homogeneous)]. Extractable nuclear antigens and double-stranded DNA were negative. Full blood count and inflammatory markers were normal. Short prednisolone courses resulted in complete resolution of joint symptoms in January 2017. She had a family history of ischemic heart disease. The patient was an ex-smoker (15-pack years) with negligible alcohol intake. Upon admission, she was hemodynamically stable. Evaluation revealed anasarca and bilateral pleural effusions. Her weight was 71 kg. Laboratory findings showed hypoalbuminemia, hypothyroidism, and severe neutropenia (Table 1). A 3-g IgGκ paraprotein was observed. Urinalysis was negative for any proteinuria and casts. Complement studies demonstrated low C4 but normal C1 esterase inhibitor level and function. ANA remained positive at lower titer. Tumor markers were negative apart from transient borderline raised CA 125 (transvaginal and pelvic ultrasound was normal). CT chest, abdomen, and pelvis showed moderate pericardial and left-sided pleural effusions, an anterior mediastinal lesion (Fig. 1a), extensive subcutaneous edema, and a venous thromboembolism of the right internal jugular and brachiocephalic veins (Fig. 1b). Concomitantly, she had triple-positive anti-phospholipid antibodies. PET CT revealed a metabolically active anterior mediastinal nodule. Acetylcholine receptor antibodies were positive but the patient had no symptoms of myasthenia gravis. Echocardiography demonstrated a large pericardial effusion with hemodynamic compromise necessitating a pericardial window. Postprocedure echocardiography showed normal biventricular dimension with ejection fraction of 65% indicating normal cardiac function. Bone marrow biopsy was normocellular with reduction in mature neutrophils; there was no B-cell or T-cell Debasish Pyne and Sofia Grigoriadou share joint senior authorship.