A nephrotic child with deep vein thrombosis after a long-haul flight

Abstract

Sirs, The media has periodically highlighted traveller’s thrombosis, particularly where fatalities have arisen [1]. Several studies recognise the risk factors and incidence of deep vein thrombosis (DVT) after a long-haul flight in the adult population [2, 3]. No cases have been described affecting children. In the case we describe here, a child with the additional risk factors of factor V Leiden deficiency and nephrotic syndrome developed a DVT on return from a transatlantic flight. We report the case of a 13-year-old Caucasian girl diagnosed with biopsy-proven focal segmental glomerulosclerosis (FSGS), who responded to steroids and was in remission and steroid free for 2 years subsequently. Routine urine monitoring was not maintained thereafter and only instituted when clinically indicated. She flew across the Atlantic for a vacation and 2 weeks after her return presented with pain in her left groin. Clinical examination revealed a swollen left calf, which on Doppler ultrasound confirmed a DVT. Urinalysis showed 2+ protein (265 mg/mmol, nephrotic range). Blood biochemistry confirmed a low serum albumin of 19 g/l. There was no evidence of peripheral oedema, but the patient was clearly in relapse of her nephrotic syndrome secondary to FSGS. A history of DVT was noted in the maternal grandfather, secondary to immobilisation. A thrombophilia screen revealed factor V Leiden deficiency. Treatment, on confirmation of the DVT, was low molecular weight heparin, elastic stockings and steroids to treat the nephrotic syndrome, with remission achieved within 2 weeks. Following resolution of her clinical symptoms, she was converted to warfarin. Long-haul flights generate a risk for DVT because of the environment. Combining this with an unrecognised thrombosis risk as well as nephrotic syndrome can only have compounded and significantly increased this risk in our patient. Appreciating that factor V Leiden deficiency is seen in 3% of the population [4], it is perhaps not unreasonable to undertake a thrombophilia screen in all patients that present with nephrotic syndrome. This would aid in immediate management as well as in future relapses and allow for targeted advice. We would consider it good practice to advise all patients with a history of nephrotic syndrome to maintain monitoring of their urine for evidence of relapse prior, during and on return from a long-haul journey. This would also apply to those that have apparently been disease-free for a considerable time and are no longer routinely monitoring their urine. Additionally, the advice would also include the wearing of knee-high stockings, adequate mobility and hydration during a flight [5]. Patients would also be made vigilant of symptoms of a DVT on return. Our patient, now well and off warfarin, will in future inject low molecular weight heparin in the departure lounge before all future flights as well as maintain monitoring for proteinuria.