Systemic Physiological Responses to Recurrent Fever and Temperature Dysregulation

Abstract

Recurrent fever and temperature dysregulation syndromes represent a diagnostic and therapeutic challenge in clinical medicine. These disorders can be primary or secondary to systemic inflammatory, infectious, or genetic etiologies. Understanding the underlying systemic physiological responses is crucial for effective management. This review synthesizes current evidence regarding epidemiology, pathophysiology, risk factors, clinical manifestations, diagnostic approach, and therapeutic strategies for recurrent fever and temperature dysregulation, with an emphasis on recent advances and guideline-based recommendations for healthcare professionals.

Introduction

Fever is a cardinal manifestation of systemic inflammatory processes and an adaptive host response to infection or immune activation. When fevers are recurrent or associated with disordered thermoregulation, they may indicate underlying autoinflammatory, infectious, neoplastic, or endocrine disorders. Recurrent fever syndromes, including periodic fever syndromes and temperature dysregulation, pose significant diagnostic complexity. A comprehensive understanding of their pathophysiological mechanisms and clinical implications is imperative for evidence-based patient care.

Epidemiology / Disease Burden

Recurrent fever syndromes are relatively rare but are increasingly recognized due to improved clinical awareness and genetic testing capabilities. Familial Mediterranean Fever (FMF), the most prevalent monogenic periodic fever syndrome, affects up to 1 in 1,000 individuals in certain Mediterranean populations. Other syndromes, such as Tumor Necrosis Factor Receptor-Associated Periodic Syndrome (TRAPS) and Mevalonate Kinase Deficiency (MKD), are less common but clinically significant. Beyond hereditary causes, non-genetic etiologies such as chronic infections, neoplasms, and autoimmune disorders contribute substantially to the burden of temperature dysregulation, particularly among hospitalized and immunocompromised populations. The impact on quality of life, healthcare utilization, and morbidity is considerable, with recurrent fevers often resulting in repeated healthcare visits, extensive diagnostic work-ups, and delays in definitive therapy.

Pathophysiology

Physiologically, fever results from a centrally mediated elevation of the hypothalamic set point, primarily driven by pyrogenic cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). In recurrent fever syndromes, dysregulated activation of the innate immune system, often due to monogenic mutations affecting inflammasome components or cytokine pathways, leads to periodic surges of these mediators. Temperature dysregulation can also arise from autonomic dysfunction, impaired heat dissipation, or hypothalamic-pituitary axis abnormalities. Prolonged or recurrent fever episodes may precipitate systemic physiological responses, including increased metabolic demand, catabolism, dehydration, and in severe cases, organ dysfunction. The repeated activation of acute phase responses and consequent oxidative stress can contribute to secondary tissue damage and chronic morbidity.

Risk Factors

Risk factors for recurrent fever and temperature dysregulation are multifactorial. Genetic predisposition is significant in monogenic periodic fever syndromes, with autosomal recessive or dominant inheritance patterns. Environmental factors, such as recurrent exposure to infectious agents, can trigger episodic fevers in susceptible hosts. Immunodeficiency, chronic inflammatory diseases, and malignancies increase vulnerability to both infectious and non-infectious fever syndromes. Medications, especially those affecting immune regulation, may precipitate temperature dysregulation. In pediatric populations, the risk is heightened in the context of genetic syndromes, while in adults, comorbidities and iatrogenic factors become increasingly relevant.

Clinical Features

Clinically, recurrent fever syndromes are characterized by episodic high-grade fevers, frequently accompanied by constitutional symptoms such as malaise, myalgias, arthralgias, and abdominal pain. Certain syndromes exhibit distinctive features: FMF often presents with serositis, while TRAPS may manifest with migratory erythema and myalgia. In temperature dysregulation disorders, abnormal sweating, chills, and periods of hypothermia may alternate with fever. Chronicity can result in growth retardation (in children), fatigue, and secondary amyloidosis due to sustained inflammation. The absence of a clear infectious source and the periodicity of episodes are key diagnostic clues, yet the protean nature of symptoms often complicates clinical recognition and delays diagnosis.

Diagnosis

The diagnostic approach to recurrent fever and temperature dysregulation is systematic and guided by clinical context. Initial evaluation includes detailed history (onset, duration, periodicity, associated symptoms, family history), physical examination, and targeted laboratory investigations. Inflammatory markers (CRP, ESR), complete blood count, and basic metabolic panels are routinely assessed. Exclusion of infectious, malignant, and autoimmune etiologies is paramount. Genetic testing is increasingly available for suspected hereditary syndromes, with next-generation sequencing panels enabling identification of pathogenic variants. Additional work-up may include imaging (ultrasound, CT, MRI) and, in selected cases, tissue biopsies. Diagnostic criteria for periodic fever syndromes (e.g., Eurofever/PRINTO classification) aid in standardizing diagnosis and guiding management decisions.

Treatment & Management

Management strategies are etiology-specific. For hereditary periodic fever syndromes, colchicine remains the cornerstone of therapy for FMF, effectively reducing attack frequency and preventing amyloidosis. IL-1 inhibitors (anakinra, canakinumab) and TNF inhibitors are indicated for patients with inadequate response or intolerance to first-line agents, particularly in TRAPS and CAPS. Supportive care—antipyretics, hydration, and nutritional support—is essential during febrile episodes. Management of secondary causes targets the underlying condition (e.g., antimicrobial therapy for infections, immunosuppression for autoimmune disorders). Patient education and multidisciplinary care are integral to optimizing outcomes, particularly for those with chronic or complicated courses.

Recent Advances / Emerging Therapies

Recent years have witnessed significant advances in the understanding and management of recurrent fever and temperature dysregulation. Improved molecular diagnostics have facilitated early and accurate identification of genetic syndromes, enabling personalized treatment approaches. Targeted biologics, including inhibitors of IL-1, IL-6, and TNF-α, have transformed outcomes for patients with refractory disease. Emerging therapies under investigation include small molecule inflammasome inhibitors and gene-editing technologies, offering potential for disease modification or cure. Ongoing research into the microbiome, metabolic regulation, and neuroimmune interactions is expected to provide novel insights into disease pathogenesis and innovative therapeutic targets.

Guideline Recommendations

Current consensus guidelines advocate for a structured, stepwise approach to evaluation, with early consideration of genetic testing in populations at risk. The European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) emphasize individualized therapy based on disease phenotype, severity, and response to initial interventions. Colchicine prophylaxis is strongly recommended for FMF, while biologic agents are reserved for refractory or severe cases. Regular monitoring for complications, such as amyloidosis and organ involvement, is critical. Multidisciplinary management involving rheumatology, genetics, infectious diseases, and allied health professionals is advised for complex cases.

Conclusion

Recurrent fever and temperature dysregulation syndromes require heightened clinical vigilance, a thorough understanding of pathophysiological mechanisms, and a personalized, evidence-based management approach. Advances in genetic diagnostics and targeted therapies have improved prognosis, yet challenges remain in timely diagnosis and prevention of long-term complications. Ongoing research and adherence to guideline-based care are essential to optimize outcomes for affected patients, emphasizing the importance of multidisciplinary collaboration and continued education for healthcare professionals.