Mononucleosis

Mononucleosis, also known as infectious mononucleosis (IM), mono, or glandular fever is a contagious disease most common in teenagers and young adults. It is most commonly spread through bodily fluids, especially saliva.

Causative agents
Epstein-Barr virus (EBV) is the most common cause of infectious mononucleosis (IM), making up approximately 90% of those diagnosed, but other infectious agents, such as cytomegalovirus, toxoplasmosis gondii parasite, HIV (human immunodeficiency virus), rubella virus, hepatitis A, B, or C viruses, and adenovirus can cause this disease.

Although Epstein-Barr virus is the most common cause of infectious mononucleosis, the majority of people infected with EBV never develop mononucleosis. It is estimated that 80% - 90% of the worldwide population is infected with the EBV.

Symptomology
Illness duration can vary from several weeks to several months and may include the following symptoms:
 * extreme fatigue and malaise
 * fever, sweating and chills
 * sore throat
 * head and body aches
 * swollen lymph nodes in the neck and armpits
 * swollen liver or spleen or both
 * rash, usually resolving in several days

Treatment
Treatment is mainly supportive: rest, plenty of fluids, analgesics, and antipyretics. A vaccine for the prevention of Epstein-Barr virus is being explored.

Trigger for Chronic Fatigue Syndrome
A minority of infectious mononucleosis patients develop postviral fatigue syndrome and meet the criteria for chronic fatigue syndrome (CFS). Research studies cite figures from 12% to 24%. A study in 2014 by Jason and Katz looked at numerous medical, demographic, and psychological factors in an effort to find predictors of which infectious mononucleosis patients would develop chronic fatigue syndrome. They found the best predictor was illness severity.

Studies relating to infectious mononucleosis and CFS

 * 2017, A Prospective Study of Infectious Mononucleosis in College Students"'Abstract - Background: The present study aims to prospectively investigate possible biological and psychological factors present in college students who will go on to develop chronic fatigue syndrome (CFS) following Infectious Mononucleosis (IM). Identification of risk factors predisposing patients towards developing CFS may help to understand the underlying mechanisms and ultimately prevent its occurrence. Our study is enrolling healthy college students over the age of 18. Enrollment began in March of 2013 and is ongoing. Methods: Biological and psychological data are collected when students are well (Stage 1), when they develop IM (Stage 2), and approximately 6 months after IM diagnosis (Stage 3). Results: Two case studies demonstrate the progression of student symptomology across all three stages. Conclusion: The Case Studies presented illustrate the usefulness of a prospective research design that tracks healthy.'"
 * 2016, Tracking post-infectious fatigue in clinic using routine Lab tests."ABSTRACT:'BACKGROUND: While biomarkers for chronic fatigue syndrome (CFS) are beginning to emerge they typically require a highly specialized clinical laboratory. We hypothesized that subsets of commonly measured laboratory markers used in combination could support the diagnosis of post-infectious CFS (PI-CFS) in adolescents following infectious mononucleosis (IM) and help determine who might develop persistence of symptoms. METHODS: Routine clinical laboratory markers were collected prospectively in 301 mono-spot positive adolescents, 4 % of whom developed CFS (n = 13). At 6, 12, and 24 months post-diagnosis with IM, 59 standard tests were performed including metabolic profiling, liver enzyme panel, hormone profiles, complete blood count (CBC), differential white blood count (WBC), salivary cortisol, and urinalysis....RESULTS: Lower ACTH levels at 6 months post-IM diagnosis were highly predictive of CFS (AUC p = 0.02). ACTH levels in CFS overlapped with healthy controls at 12 months, but again showed a trend towards a deficiency at 24 months. Conversely, estradiol levels depart significantly from normal at 12 months only to recover at 24 months (AUC p = 0.02). Finally, relative neutrophil count showed a significant departure from normal at 24 months in CFS (AUC p = 0.01). Expression of these markers evolved differently over time between groups. CONCLUSIONS: Preliminary results suggest that serial assessment of stress and sex hormones as well as the relative proportion of innate immune cells measured using standard clinical laboratory tests may support the diagnosis of PI-CFS in adolescents with IM.'"
 * 2014, Predictors of post-infectious [[chronic fatigue syndrome] in adolescents]"'Abstract - This study focused on identifying risk factors for adolescent post-infectious chronic fatigue syndrome (CFS), utilizing a prospective, nested case–control longitudinal design in which over 300 teenagers with infectious mononucleosis (IM) were identified through primary care sites and followed. Baseline variables that were gathered several months following IM, included autonomic symptoms, days in bed since IM, perceived stress, stressful life events, family stress, difficulty functioning and attending school, family stress, and psychiatric disorders. A number of variables were predictors of post-infectious CFS at six months; however, when autonomic symptoms were used as a control variable, only days spent in bed since mono was a significant predictor. Step-wise logistic regression findings indicated that baseline autonomic symptoms as well as days spent in bed since mono, which reflect the severity of illness, were the only significant predictors of those who met CFS criteria at six months.'"
 * 2007, Gene expression correlates of postinfective fatigue syndrome after infectious mononucleosis
 * 2006, Post-infective and chronic fatigue syndromes precipitated by viral and non-viral pathogens: Prospective cohort study"'Abstract -To delineate the risk factors, symptom patterns, and longitudinal course of prolonged illnesses after a variety of acute infections. Prospective cohort study following patients from the time of acute infection with Epstein-Barr virus (glandular fever), Coxiella burnetii (Q fever), or Ross River virus (epidemic polyarthritis). The region surrounding the township of Dubbo in rural Australia, encompassing a 200 km geographical radius and 104,400 residents. 253 patients enrolled and followed at regular intervals over 12 months by self report, structured interview, and clinical assessment. Detailed medical, psychiatric, and laboratory evaluations at six months to apply diagnostic criteria for chronic fatigue syndrome. Premorbid and intercurrent illness characteristics recorded to define risk factors for chronic fatigue syndrome. Self reported illness phenotypes compared between infective groups. Prolonged illness characterised by disabling fatigue, musculoskeletal pain, neurocognitive difficulties, and mood disturbance was evident in 29 (12%) of 253 participants at six months, of whom 28 (11%) met the diagnostic criteria for chronic fatigue syndrome. This post-infective fatigue syndrome phenotype was stereotyped and occurred at a similar incidence after each infection. The syndrome was predicted largely by the severity of the acute illness rather than by demographic, psychological, or microbiological factors. A relatively uniform post-infective fatigue syndrome persists in a significant minority of patients for six months or more after clinical infection with several different viral and non-viral micro-organisms. Post-infective fatigue syndrome is a valid illness model for investigating one pathophysiological pathway to chronic fatigue syndrome.'"
 * 2000, Acute infectious mononucleosis: Characteristics of patients who report failure to recover "'Abstract - We sought to determine how often acute mononucleosis precipitates chronic illness, and to describe the demographic, clinical, and psychosocial features that characterize patients who report failure to recover. We enrolled 150 patients with infectious mononucleosis during the acute illness and asked them to assess their recovery at 2 and 6 months. At baseline, we performed physical and laboratory examinations; obtained measures of psychological and somatic functioning, social support, and life events; and administered a structured psychiatric interview. Self-assessed failure to recover was reported by 38% of patients (55 of 144) at 2 months and by 12% (17 of 142) at 6 months. Those who had not recovered reported a persistent illness characterized by fatigue and poor functional status. No objective measures of disease, including physical examination findings or serologic or laboratory markers, distinguished patients who failed to recover from those who reported recovery. Baseline predictors for failure to recover at 2 months were older age (odds ratio [OR] = 1.4, 95% confidence interval [CI]: 1.1 to 1.8, per 5-year increase), higher temperature (OR = 1.5, 95% CI: 1.1 to 2.2, per 0.5 degrees C increase), and greater role limitation due to physical functioning (OR = 1.5, 95% CI: 1.2 to 1.9, per 20-point decrease in Short Form-36 score). At 6 months, baseline predictors for failure to recover included female sex (OR = 3.3, 95% CI: 1.0 to 12), a greater number of life events more than 6 months before the disease began (OR = 1.7, 95% CI: 1.1 to 2.5, per each additional life event), and greater family support (OR = 1.9, 95% CI: 1.1 to 4.2, per 7-point increase in social support score). We were not able to identify objective measures that characterized self-reported failure to recover from acute infectious mononucleosis. The baseline factors associated with self-reported failure to recover at 2 months differed from those associated with failure to recover at 6 months. Future studies should assess the generalizability of these findings and determine whether interventions can hasten recovery.'"