Introduction: Cytokine Release Storm (CRS) leading to fatal or near fatal hypotension has been reported in association with anti thymocyte globulin (ATG) administration. This is a very rare and unusual manifestation of ATG and early recognition and management of this unexpected manifestation will help save lives. We report  a near fatal case of CRS, during renal transplantation, associated with ATG administration, its diagnosis and management.

Materials and Methods: A 27-year-old, otherwise healthy male with Alport's syndrome was undergoing live related preemptive renal transplant. Patient received morning dose of Solu-Medrol and CellCept and was getting Anti Thymocyte Globulin (ATG) slowly after the test does, as the recipient vascular bed was being prepared. Patient started to become hypotensive which was treated with IV fluids and pressors including norepinephrine, epinephrine and dopamine.There was no bleeding from recipient vascular bed.A stat chest x-ray, EKG and echocardiogram on the OR table were normal with good LV function.  Despite maximum dose pressor support and IV fluids, the mean blood pressure was around 45 - 50 mm Hg and a systolic blood pressure was around 65-70 mm Hg, leading to severe metabolic acidosis and lactate buildup. The transplant was canceled and the donor was closed unharmed and the patient was moved to ICU, intubated. His response to colloids was slightly better, but transient, so he was transfused 4 units of blood as volume expander that does not leak into 3rd space.This brought his blood pressure to about 90 mm Hg. A presumptive diagnosis of ATG induced CRS was made. His inflammatory markers including IL-6, ferritin, D-dimers and CRP were very high. 400 mg of Tocilizumab (Actemra) an IL-6 inhibitor along with broad-spectrum antibiotics  were given. Patient also started to developed disseminated intravascular coagulation (DIC) with deranged coagulation screen and some oozing from the wound which was treated with FFPs. In next 12 hours, the patient started to stabilize and in next 48 hours he was extubated.

Discussion: Cytokine Release Storm (CRS) is a potentially fatal condition unless recognized and treated early and aggressively. In COVID pandemic, much better understanding of CRS along with its symptomatology, easy availability of its lab tests and IL- 6 inhibitors became possible. High index of suspicion is extremely important in making an early diagnosis and for early treatment.  In transplant patients, use of ATG is now standard of care and very few cases of ATG induced CRS are reported.  In our case, early diagnosis of CRS from ATG, use of blood as volume expander, early administration of IL-6 inhibitor and aggressive management of DIC turned out to be the life Saver.

Conclusion: In patients receiving ATG, with unexplained hypotension, nonresponsive to IV fluids and pressors, high index of suspicion of ATG induced CRS with early diagnosis and aggressive management can save lives.