Rigors (Shaking Chills)
Every other week or so, I get a call from a nurse or physician who describes a patient being transfused as having "rigors".
That term is often tossed around by clinical staff without recognizing the significance of rigors to a blood banker. It is very important to educate your staff about this term and what it means, because true rigors should bring the possibility of bacterial contamination of a blood product into your mind.
Rigors are usually confused with chills, where a patient feels cold and may have mild trembling. True rigors, on the other hand, are characterized by a patient who has violent, shaking chills, usually associated with rigidity. Rigors in a transfused patient should always lead to an investigation, in my opinion, which should include gram stain and culture of the transfused unit.
As stated above, rigors are most commonly associated with bacterial contamination. In fact, in a letter to the editor in JAMA in 1997, our institution (in conjunction with the CDC) reported a case of Yersinia enterocolitica contamination of a unit of platelets in which the only clinical manifestation of the reaction was an episode of rigors in the recipient. Acute hemolytic reactions, however, may also be associated with this type of response.