Understanding Post-Acute Infection Syndromes
These conditions have puzzled clinicians for generations. While diagnostic criteria continue to evolve, research has revealed clear biological mechanisms at work. This collection brings together current knowledge for readers, clinicians, and researchers who want to understand what we know, how we know it, and what remains to be discovered.
Interested Readers
Start with the foundational pieces. They explain concepts in accessible language without assuming medical background.
Healthcare Professionals
The clinical practice articles offer practical guidance on assessment, diagnosis, and patient communication.
Researchers
Research deep dives explore the biological mechanisms and emerging evidence with full citations.
Cornerstone Publications
These papers and guidelines form the foundation of current clinical understanding
Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness
Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management
D-A-CH Consensus Statement on ME/CFS
T-cell exhaustion and immune dysregulation in Long COVID
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What is PAIS?
The story of Post-Acute Infection Syndromes begins with a mystery. Patients present with persistent symptoms long after their initial infection clears, yet standard tests often return normal. This introduction traces how researchers came to understand these conditions as a spectrum with shared biological mechanisms.
The Evolution of ME/CFS Diagnosis
For decades, patients struggled to receive recognition. The Canadian Consensus Criteria emerged from clinician observations in 2003, refined later by the Institute of Medicine in 2015. This guide walks through how diagnostic understanding has shifted from exclusion to positive identification.
Long COVID: A New Chapter
When the pandemic began, no one predicted the wave of persistent symptoms that would follow. This overview examines what clinicians have learned since 2020 about post-COVID conditions and how they connect to existing knowledge of post-viral illness.
When the Immune System Stays Alert
Research has revealed that T-cells in PAIS patients show signs of exhaustion. They express markers like PD-1 and Tim-3 long after the infection resolves. This piece explains what this persistent activation means for understanding the disease process.
The NASA Lean Test in Practice
Developed for astronaut health monitoring, this simple assessment has become a cornerstone of orthostatic intolerance evaluation. Learn how to perform the test and interpret what the results reveal about autonomic function.
Cytokine Signaling in Persistent Illness
The JAK-STAT pathway acts as a communication channel for immune cells. When dysregulated, as seen in PAIS, it creates a cascade of inflammation. This research review explains the science and its clinical implications.
Reading the Rhythm of Recovery
Heart rate variability offers a window into autonomic nervous system function. Reduced HRV has emerged as one of the most consistent objective findings in PAIS. This guide covers measurement, interpretation, and what the numbers actually tell us.
The Complement Cascade
The complement system, part of our innate immune defense, appears overactive in many PAIS patients. This review examines the evidence and explores why this ancient immune mechanism might drive modern post-viral symptoms.
Having the Difficult Conversation
Delivering a PAIS diagnosis requires acknowledging uncertainty while offering validation. This guide draws on clinical experience to suggest approaches for discussing complex, invisible conditions with patients and their families.
Ready to Explore Diagnostic Criteria?
These conditions have puzzled clinicians for generations. While diagnostic criteria continue to evolve, research has revealed clear biological mechanisms at work. This collection brings together current knowledge for readers, clinicians, and researchers who want to understand what we know, how we know it, and what remains to be discovered.