Repatriated patient with leptospirosis and severe iron deficiency

We write to highlight a case of leptospirosis associated with iron deficiency in a 17-year-old Caucasian male who was air-lifted from Tunisia and admitted to the intensive care unit (ICU) in the UK.

It was thought that he contracted the illness swimming in the Kempford River in Gloucestershire, 10 days prior to his holiday, as demonstrated by a self-limiting diarrheal illness. He then travelled to Tunisia where he presented to a clinic with diarrhoea, myalgia, dyspnoea and haemoptysis. He was sufficiently unwell to require intubation and an ICU admission. Treatment included antibiotics, methylprednisolone, blood product transfusion and renal replacement therapy.

Fourteen days later he was transferred via air ambulance to the UK with progressive respiratory failure. After eight days, leptospirosis IgM returned positive at 1:80 and microscopic agglutination test was positive at 1:640, suggesting a strongly positive result. He had complicating severe hypoxic respiratory failure and multi-organ failure. On day 13, he failed extubation due to weakness. A nutritional screen investigating his weakness showed a severe iron deficiency with a serum iron level of 2.4 µmol/L and transferrin saturation of 5%. Iron was replaced with iron sulphate infusion. Post replacement his serum iron level had recovered to 12.4 µmol/L, transferrin saturation to 33% and his strength recovered sufficiently for successful extubation.

It is recognised that diagnosing iron deficiency in critical illness is problematic due to the regular concurrence of systemic inflammation. Serum iron is an unreliable marker for total body iron stores and alone is not considered diagnostic. ¹ Low serum transferrin levels are also less useful in critical illness but may suggest an underlying iron deficiency. Serum ferritin behaves as an acute phase reactant in severe illness and can be artificially elevated despite low underlying iron levels. Serum transferrin saturation has been found to be 40% specific for iron deficiency but as with other markers, is subject to variation in the presence of inflammation ¹ . Iron deficiency is associated with increased morbidity, mortality and transfusion. ²

While diagnosing the cause of his iron deficiency was problematic, we believe that the leptospirosis was a contributing factor, though his haemolytic screen was negative. In this case, the delayed treatment of iron deficiency may have contributed to his weakness and impaired his respiratory recovery. To our knowledge iron deficiency has not been associated with leptospirosis without haemolysis and is not assessed routinely during the treatment of this illness. This could worsen outcomes in these patients.

Leptospirosis is now recognised as an emerging worldwide infectious disease. ³ Increased global travel and migration have changed its epidemiology and it is no longer confined to tropical regions and marginalised communities. ⁴ The interesting aspect of this patient is that he exported leptospirosis from the UK to Tunisia. This goes against emerging trends in its epidemiology which suggest migration and global travel have increased its transmission from tropical to temperate regions. This unusual scenario delayed his diagnosis whilst in Tunisia.