From the Guidelines
Rigors are a medical emergency that requires immediate attention, as they can be a sign of a life-threatening infection, such as catheter-associated urinary tract infections (CA-UTIs), which have a mortality rate of approximately 10% 1.
Causes and Risk Factors
Rigors are intense, uncontrollable shivering episodes often accompanied by a rapid rise in body temperature, typically indicating an underlying infection or inflammatory process. Common causes include bacterial infections (particularly bloodstream infections like sepsis), malaria, urinary tract infections, pneumonia, and occasionally medication reactions or cancer.
- Catheter-associated UTIs are a leading cause of secondary health care–associated bacteremia, with a mortality rate of approximately 10% 1.
- The incidence of bacteriuria associated with indwelling catheterisation is 3–8% per day 1.
- Catheterisation duration is the most important risk factor for CA-UTI development 1.
Management
When experiencing rigors, it's essential to seek medical attention promptly as they often signal a serious condition requiring treatment. Management includes addressing the underlying cause with appropriate antibiotics for bacterial infections, antimalarials for malaria, or other specific treatments based on diagnosis.
- Supportive care involves fever reduction with acetaminophen (500-1000mg every 6 hours) or ibuprofen (400-600mg every 6-8 hours), maintaining hydration, and applying warm blankets during the shivering phase.
- In cases of immunotherapy-related toxicities, such as cytokine release syndrome (CRS), management may involve tocilizumab, dexamethasone, or other therapies, depending on the grade of toxicity 1.
Importance of Prompt Medical Attention
Rigors differ from normal chills in their intensity and association with rapidly rising fever, making them an important clinical sign that shouldn't be ignored, especially in vulnerable populations like the elderly or immunocompromised.
- Prompt medical attention is crucial to prevent serious complications, such as sepsis, organ failure, or even death.
- A systematic review and meta-analysis demonstrated that patients at high risk of CA-UTI were female, had prolonged catheterisation duration, had diabetes, and had longer hospital and intensive care unit stays 1.
From the Research
Rigors
- Rigors are not directly mentioned in the provided studies, however, fever is discussed in relation to infection and treatment options 2.
- Fever is a complex physiologic response triggered by infectious or aseptic stimuli, and elevations in body temperature occur when concentrations of prostaglandin E(2) (PGE(2)) increase within certain areas of the brain 2.
- Antipyretics such as aspirin have been widely used to relieve fever, and they work by inhibiting the enzyme cyclooxygenase and reducing the levels of PGE(2) within the hypothalamus 2.
- The use of antipyretics may not be indicated for all febrile conditions, as they may contribute to patient discomfort, interfere with accurately assessing patients receiving antimicrobials, or predispose patients to adverse effects from other medications 2.
- In the context of urinary tract infections (UTIs), symptomatic treatment with ibuprofen has been compared to antibiotic treatment with ciprofloxacin, and the results suggest that ibuprofen may be a viable alternative for uncomplicated UTIs 3.
- However, it is essential to note that the provided studies do not directly address the topic of rigors, and more research would be needed to fully understand the relationship between rigors and the discussed treatment options 4, 5, 6.