Q: 22 year old male just came out of OR to ICU after uncomplicated peri-operative course of kidney transplant. Patient is extubated and vitals are stable. Patient has good urine output. Patient has been started on protocol of anti-rejection medicines. After 30 minutes patient developed high grade fever, chills and hypotension. Clinical picture appears like septic shock. What could be other differential diagnosis? 

Answer: cytokine release syndrome

Solid organ transplants require immediate post-op infusion of Anti-Thymocyte-Globulin (ATG) infusion. ATG infusion may induce cytokine release syndrome and may causes high grade fevers, chills and rigors during administration. Cytokine infusion syndrome can be controlled/avoided with pre-medication with methylprednisolone, diphenhydramine 25–50 mg, and acetaminophen 650 mg - and by slowing the infusion rate of ATG. Cytokine release syndrome is a common immediate complication particularly after the infusion of first dose of ATG.

The pathogenesis is that the antibodies bind to the T cell receptor, activating the T cells before they are destroyed. The cytokines released by the activated T cells produce a type of systemic inflammatory response (SIRS) manifested by hypotension, fever and rigors.

Severe cases are called cytokine storms.

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