Anorexia nervosa and COVID-19 Understanding the relationship between eating disorders and infections can improve outcomes ecent concerns surrounding coronavirus disease 2019 (COVID-19) make it timely to reexamine the complex Rfindings related to eating disorders and the immune sys- tem, and the risks for and detection of infection in patients with anorexia nervosa (AN) and similar disorders. To date, there are no published studies evaluating patients with eating disorders and COVID-19. However, it may be helpful to review the data on the infectious process in this patient population to improve patient communication, enhance surveillance and detection, and possibly reduce morbidity and mortality. The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) issued warnings that individuals who are older, have underlying medical condi- KN/SHUTTERSTOCK tions, and/or are immunocompromised face the greatest risk of serious complications and death as a result of COVID-19, the Jeffrey R. DeSarbo, DO disease process caused by severe acute respiratory syndrome Medical Director coronavirus 2 (SARS-CoV-2). Due to malnutrition, patients ED-180 Treatment Programs Garden City, New York with eating disorders, especially AN, may be perceived to have an increased risk of medical conditions and infection. Despite Lukas DeSarbo, LMSW Staff Psychotherapist many studies on specific changes and differences in the immune ED-180 Treatment Programs system of patients with eating disorders, the consequences Garden City, New York of these changes remain controversial and inconclusive. This article reviews research on eating disorders, focus- ing on published data regarding the effects of AN on the immune system, susceptibility to infections, infectious detec- tion, and morbidity. We also discuss clinical considerations related to COVID-19 and patients with AN. continued Disclosures The authors report no financial relationships with any companies whose products are mentioned in this article, or with manufacturers of competing products. Current Psychiatry doi: 10.12788/cp.0011 Vol. 19, No. 8 23 Infection risks: Conflicting data Because studies that have included patients In a 1981 study that included 9 participants, with AN have evaluated only symptom- Golla et al1 concluded that patients with AN atic viral infections, some researchers have may have “resistance” to infections based proposed that patients with AN may show on a suggested protective factor within the lower rates of symptomatic viral infection immune system of these patients. Because but higher rates of asymptomatic infec- this study has been cited repeatedly in mul- tion, as evidenced by higher viral titers.6 Eating disorders tiple articles about AN and cell-mediated Further research is required. Despite con- and infections immunity,2-7 some clinicians have accepted troversy regarding infection rates, stud- this evidence of resistance to infection in ies have found that patients with AN have patients with AN, which may lower their increased rates of morbidity and mortality suspicion for and detection of infections in from infections.6,12-16 patients with AN. However, studies published both before and after Golla et al1 have shown statisti- Obstacles to detecting infections cally significant results that contradict those Several factors can complicate the surveil- Clinical Point researchers’ conclusion. A study that com- lance and detection of infections in patients Patients with pared the medical records of 68 patients with with eating disorders, especially those with AN with those who did not have AN found AN. These include: anorexia nervosa no significant difference, and concluded that • an accepted predisposition to infection have increased the rate of infection among patients with secondary to malnutrition rates of morbidity AN is the same as among controls.8 These • a lack of visual or reported infectious and mortality from researchers noted that infection rates may be symptoms higher among patients with later-stage, more • misrepresentation and assumptions infections severe AN. In a 1986 study of 12 patients from published research. with AN, Cason et al9 concluded that while Clinicians who report fewer observed cases cellular immunity function is abnormal in of infections among patients with AN may patients with AN, their results were not com- be overlooking comorbid disease processes patible with prior studies that suggested AN due to a bias from the literature and/or a patients were more resistant to infection.1,2,8 lack of awareness of symptom parameters in More recently, researchers compared 1,592 patients with AN. patients with eating disorders with 6,368 Features of AN include a loss of adipose matched controls; they reviewed prescrip- tissue responsible for pro-inflammatory tions of antibacterial, antifungal, and anti- cytokines, and excessive exercise, which viral medications as a measure of infection stimulates anti-inflammatory myokines. rates.10 Compared with controls, patients This can modulate the experience of illness with binge eating disorder (BED), patients that impacts the core features of disease,17 with bulimia nervosa (BN), and males with possibly reducing symptomatic presenta- AN more often received prescriptions for tion of infections. antimicrobial medications. There was no Fever. The presence and intensity of statistically significant difference between fever may be altered in patients with eating controls and females with AN, which is con- disorders, especially those with AN. In a sistent with other reports of no increased or study of 311 inpatients with AN, research- decreased risk of infection among females ers found that patients with AN had a sig- with AN. In terms of antiviral use, this nificant delay in fever response in AN.12 Of Discuss this article at study showed an increased prescription of 23 patients with an active bacterial infection, www.facebook.com/ antivirals only in the BN group. all but 5 had a fever <37°C, with some as MDedgePsychiatry Several other studies examining the rate of low as 35.5°C. A detectable fever response infection in patients with AN concluded that and unexplained fevers were found in 2 of there is neither an increased nor decreased the 6 patients with a viral infection. A series rate of infection in patients with AN, and of case studies found that patients with AN that the rate of infection in this population is with bacterial infections also had a delayed Current Psychiatry 24 August 2020 similar to that of the general population.8,10-12 fever response.18 For patients with infections that com- transmission, cross-contamination of facili- monly present with fever, such as COVID- ties, and higher incidences of medical com- 19, a delayed fever response can delay plications and mortality. or evade the detection of infection, thus MDedge.com/psychiatry increasing potential complications as well viral exposure to others. Thus, clini- The immunology of AN and cians should use caution when ruling out correlations with COVID-19 COVID-19 or other infections because of a Many studies examining the immune system lack of significant fever. of patients with eating disorders, especially Overlapping symptoms. The symptoms those with AN, have discovered changes of viral infection can mimic the symptoms and differences in both cell-mediated and of AN, which further complicates screening humoral response to infections.1,3,5,7,9,11,16,21,25-27 and diagnosis of infection in these patients. Whether these differences represent a dys- Although up to 80% of individuals infected functional immune system, an immunocom- with COVID-19 may be asymptomatic or promised state, or even a protective factor have a mild presentation, the most com- remains unclear. mon reported symptoms are fever (92.6%), While some studies have reported that Clinical Point shortness of breath (50.8%), expectoration AN represents an immunocompromised Studies of patients (41.4%), fatigue (46.4%), dry cough (33.3%), state, others describe the immune system of and myalgia (21.4%).19-21 Gastrointestinal (GI) patients with AN as dysfunctional or sim- with eating symptoms have been reported in patients ply altered.9,11,22,28 Some studies have found disorders have with COVID-19, as well as a loss of taste and that patients with AN had delayed reactions found differences in smell. to pathogen skin exposures compared with cell-mediated and Commonly reported physical symptoms healthy controls, which provides evidence humoral response to of AN include an intolerance to cold, general of an impaired cell-mediated immune fatigue, muscle aches and pains, restlessness, system.9,27,29 infections emesis, and a multitude of GI complaints. Some studies have considered the conse- Patients with AN also have been reported to quences of infection and immunologic find- experience shortness of breath due to condi- ings as markers of or contributing to the tions such as respiratory muscle weakness,22 onset of AN.2,30,31 Numerous studies have nutritional emphysema,23 and anxiety and noted abnormalities in AN with regards panic attack.24 These conditions could lead to to cell-mediated immunity, the humoral an increased susceptibility to COVID-19 and system, the lymphoreticular system, and increased complications during treatment. the innate immune system, and potential Cardiac abnormalities, which are common contributions from increased oxidative in patients with AN and BN, may increase stress, a chronically activated sympathetic the risk of adverse events. While