Diagnosis and Management of Cardiac Sarcoidosis: A Scientific Statement From the American Heart Association.

Cardiac sarcoidosis is an infiltrative cardiomyopathy that results from granulomatous inflammation of the myocardium and may present with high-grade conduction disease, ventricular arrhythmias, and right or left ventricular dysfunction. Over the past several decades, the prevalence of cardiac sarcoidosis has increased. Definitive histological confirmation is often not possible, so clinicians frequently face uncertainty about the accuracy of diagnosis. Hence, the likelihood of cardiac sarcoidosis should be thought of as a continuum (definite, highly probable, probable, possible, low probability, unlikely) rather than in a binary fashion. Treatment should be initiated in individuals with clinical manifestations and active inflammation in a tiered approach, with corticosteroids as first-line treatment. The lack of randomized clinical trials in cardiac sarcoidosis has led to treatment decisions based on cohort studies and consensus opinions, with substantial variation observed across centers. This scientific statement is intended to guide clinical practice and to facilitate management conformity by providing a framework for the diagnosis and management of cardiac sarcoidosis.

Renal sarcoidosis.

Renal sarcoidosis (RS) is a rare form of sarcoidosis that results in granulomatous inflammation of renal parenchyma. We describe the epidemiology, pathogenesis, clinical features, diagnostic approach, treatment strategies and outcomes of this condition. RS occurs most commonly at the time of initial presentation of sarcoidosis but can at any time along the course of the disease. The most common presenting clinical manifestations of RS are renal insufficiency or signs of general systemic inflammation. End-stage renal disease (ESRD) requiring dialysis is a rare initial presentation of RS. The diagnosis of RS should be considered in patients who present with renal failure and have either a known diagnosis of sarcoidosis or have extra-renal features consistent with sarcoidosis. A renal biopsy helps to establish the diagnosis of RS, with interstitial non-caseating granulomas confined primarily to the renal cortex being the hallmark pathological finding. However, these histologic findings are not specific for sarcoidosis, and alternative causes for granulomatous inflammation of the renal parenchyma should be excluded. Corticosteroids are the drug of choice for RS. Although RS usually responds well to corticosteroids, the disease may have a chronic course and require long-term immunosuppressive therapy. The risk of progression to ESRD is rare.

An Artificial Intelligence Platform for the Radiologic Diagnosis of Pulmonary Sarcoidosis: An Initial Pilot Study of Chest Computed Tomography Analysis to Distinguish Pulmonary Sarcoidosis from a Negative Lung Cancer Screening Scan.

PURPOSE: To determine the reliability of an artificial intelligence, deep learning (AI/DL)-based method of chest computer tomography (CT) scan analysis to distinguish pulmonary sarcoidosis from negative lung cancer screening chest CT scans (Lung Imaging Reporting and Data System score 1, Lung-RADS score 1). METHODS: Chest CT scans of pulmonary sarcoidosis were evaluated by a clinician experienced with sarcoidosis and a chest radiologist for clinical and radiologic evidence of sarcoidosis and exclusion of alternative or concomitant pulmonary diseases. The AI/DL based method used an ensemble network architecture combining Convolutional Neural Networks (CNNs) and Vision Transformers (ViTs). The method was applied to 126 pulmonary sarcoidosis and 96 Lung-RADS score 1 CT scans. The analytic approach of training and validation of the AI/DL method used a fivefold cross-validation technique, where 4/5th of the available data set was used to train a diagnostic model and tested on the remaining 1/5th of the data set, and repeated 4 more times with non-overlapping validation/test data. The probability values were used to generate Receiver Operating Characteristic (ROC) curves to assess the model's discriminatory power. RESULTS: The sensitivity, specificity, positive and negative predictive value of the AI/DL method for the 5 folds of the training/validation sets and the entire set of CT scans were all over 94% to distinguish pulmonary sarcoidosis from LUNG-RADS score 1 chest CT scans. The area under the curve for the corresponding ROC curves were all over 97%. CONCLUSION: This AL/DL model shows promise to distinguish sarcoidosis from alternative pulmonary conditions using minimal radiologic data.

The Relationship Between Serum Angiotensin Converting Enzyme Level and the Decision to Escalate Treatment of Sarcoidosis.

PURPOSE: We performed a retrospective analysis of a sarcoidosis cohort who had sACE obtained at their initial clinic visit, but the treating physician was blinded to the results. We examined the relationship between sACE and the treating physician's decision to escalate sarcoidosis treatment. METHODS: Treatment was considered escalated if the prednisone dose was increased or if the prednisone dose was not changed but an additional anti-sarcoidosis drug was added or the dose was increased. RESULTS: 561 sarcoidosis patients were analyzed. The most common target organ was the lung (84%). Using a cut-off of > 82 units/L for an elevated sACE, 31/82 (38%) with an elevated sACE had treatment escalation whereas 91/497 (18%) had treatment escalation with a normal sACE (p < 0.0001). For the need of treatment escalation, a sACE (cut-off of > 82) had sensitivity 0.25, specificity 0.89, positive predictive value 0.38, negative predictive value 0.81. These results were not appreciably different using other sACE cut-off values such as 70, 80, 90, or 100. A multivariable logistic regression model that included demographics, the target organ, spirometry results estimated that sACE level and lower FVC were significantly associated with the likelihood of treatment escalation. These findings held when sACE > 82 replaced sACE level in the multivariable logistic regression model. CONCLUSIONS: Although there was a strong correlation between sACE at the initial sarcoidosis clinic visit and subsequent treatment escalation of sarcoidosis, the predictive power was such that sACE is not adequately reliable to be used in isolation to make this determination.

Management of Advanced Pulmonary Sarcoidosis.

The term "advanced sarcoidosis" is used for forms of sarcoidosis with a significant risk of loss of organ function or death. Advanced sarcoidosis often involves the lung and is described as "advanced pulmonary sarcoidosis" (APS), which includes advanced pulmonary fibrosis, associated complications such as bronchiectasis and infections, and pulmonary hypertension. Although APS affects a small proportion of patients with sarcoidosis, it is the leading cause of poor outcomes, including death. Here we review the major patterns of APS with a focus on the current management as well as potential approaches for improved outcomes for this most serious sarcoidosis phenotype.

The treatment of sarcoidosis: translating the European respiratory guidelines into clinical practice.

PURPOSE OF REVIEW: Recently, the European Respiratory Society (ERS) developed new international guidelines for the treatment of sarcoidosis. This manuscript attempts to distill the ERS Sarcoidosis Treatment Guidelines to a manageable format that can be easily used by practitioners. RECENT FINDINGS: The ERS Sarcoidosis Treatment Guidelines addressed the treatment of pulmonary, skin, cardiac, neurologic, and sarcoidosis-associated fatigue. Therapeutic drug dosing and treatment algorithms for these conditions were also addressed. Glucocorticoids were the initial recommended treatment for these conditions except for sarcoidosis-associated fatigue where a pulmonary exercise program or a neurostimulant was initially suggested. Because of the risk of glucocorticoid side-effects, the Guidelines recommended early consideration of glucocorticoid-sparing therapy including certain antimetabolites and two specific tumor necrosis alpha antagonists: infliximab and adalimumab. SUMMARY: The ERS Sarcoidosis Treatment Guidelines used a rigorous GRADE (Grading of Recommendations, Assessment, Development and Evaluations) methodology to update treatment recommendations for this condition. This manuscript summarizes the Guideline findings in practical terms for clinicians. Suggested algorithms and treatment dosing recommendations are provided.

ERS clinical practice guidelines on treatment of sarcoidosis.

BACKGROUND: The major reasons to treat sarcoidosis are to lower the morbidity and mortality risk or to improve quality of life (QoL). The indication for treatment varies depending on which manifestation is the cause of symptoms: lungs, heart, brain, skin or other manifestations. While glucocorticoids remain the first choice for initial treatment of symptomatic disease, prolonged use is associated with significant toxicity. Glucocorticoid-sparing alternatives are available. The presented treatment guidelines aim to provide guidance to physicians treating the very heterogenous sarcoidosis manifestations. METHODS: A European Respiratory Society Task Force committee composed of clinicians, methodologists and patients with experience in sarcoidosis developed recommendations based on the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) methodology. The committee developed eight PICO (Patients, Intervention, Comparison, Outcomes) questions and these were used to make specific evidence-based recommendations. RESULTS: The Task Force committee delivered 12 recommendations for seven PICOs. These included treatment of pulmonary, cutaneous, cardiac and neurologic disease as well as fatigue. One PICO question regarding small-fibre neuropathy had insufficient evidence to support a recommendation. In addition to the recommendations, the committee provided information on how they use alternative treatments, when there was insufficient evidence to support a recommendation. CONCLUSIONS: There are many treatments available to treat sarcoidosis. Given the diverse nature of the disease, treatment decisions require an assessment of organ involvement, risk for significant morbidity, and impact on QoL of the disease and treatment.

Unique inflammatory profile is associated with higher SARS-CoV-2 acute respiratory distress syndrome (ARDS) mortality.

The COVID19 pandemic has caused more than a million of deaths worldwide, primarily due to complications from COVID19-associated acute respiratory distress syndrome (ARDS). Controversy surrounds the circulating cytokine/chemokine profile of COVID19-associated ARDS, with some groups suggesting that it is similar to patients without COVID19 ARDS and others observing substantial differences. Moreover, although a hyperinflammatory phenotype associates with higher mortality in non-COVID19 ARDS, there is little information on the inflammatory landscape's association with mortality in patients with COVID19 ARDS. Even though the circulating leukocytes' transcriptomic signature has been associated with distinct phenotypes and outcomes in critical illness including ARDS, it is unclear whether the mortality-associated inflammatory mediators from patients with COVID19 are transcriptionally regulated in the leukocyte compartment. Here, we conducted a prospective cohort study of 41 mechanically ventilated patients with COVID19 infection using highly calibrated methods to define the levels of plasma cytokines/chemokines and their gene expressions in circulating leukocytes. Plasma IL1RA and IL8 were found positively associated with mortality, whereas RANTES and EGF negatively associated with that outcome. However, the leukocyte gene expression of these proteins had no statistically significant correlation with mortality. These data suggest a unique inflammatory signature associated with severe COVID19.

Management of immunosuppressants in the era of coronavirus disease-2019.

PURPOSE OF REVIEW: Patients on chronic immunosuppressive treatments at baseline are at increased risk of opportunistic infections. These patients are at especially increased risk of morbidity and mortality during the coronavirus-19 (COVID-19) pandemic. This review will focus on patients with diseases in which immunosuppression is a vital part of the treatment regimen, including those with solid organ transplants, rheumatologic disorders, sarcoidosis, and inflammatory bowel disease (IBD). We will summarize the current knowledge of immunosuppression in these diseases and the risk of contracting COVID-19. Furthermore, we will discuss if immunosuppression increases severity of COVID-19 presentation. RECENT FINDINGS: Since the start of the COVID-19 pandemic, a large number patients receiving chronic immunosuppression have been infected with SARS-CoV-2. Moreover, our understanding of the immunology of SARS-CoV-2 is advancing at a rapid pace. Currently, a number of clinical trials are underway to investigate the role of immunosuppressive treatments in the management of this disease. SUMMARY: Currently, there is no conclusive evidence to suggest that solid organ transplant recipients on chronic immunosuppression are at increased risk of contracting COVID-19. Solid organ transplant recipients may be at increased risk for worse COVID-19 outcomes but the data are not consistent. There is evidence to suggest that patients with rheumatologic disorders or IBDs are not at increased risk of contracting COVID-19 and do not necessarily experience worse clinical outcomes. Patients with sarcoidosis are not necessarily at increased risk of COVID-19, although there is limited data available to determine if immunosuppression worsens outcomes in this population.

Income and Other Contributors to Poor Outcomes in U.S. Patients with Sarcoidosis.

Rationale: Socioeconomic factors are associated with worse disease severity at presentation in sarcoidosis, but the relative importance of socioeconomic variables on morbidity and disease burden has not been fully elucidated.Objectives: To determine the association between income and sarcoidosis outcomes after controlling for socioeconomic and disease-related factors.Methods: Using the Sarcoidosis Advanced Registry for Cures database, we analyzed data from 2,318 patients with sarcoidosis in the United States to determine the effect of income and other variables on outcomes. We divided comorbidities arising after diagnosis into those likely related to steroid use and those likely related to sarcoidosis. We assessed the development of health-related, functional, and socioeconomic outcomes following the diagnosis of sarcoidosis.Measurements and Main Results: In multivariate analysis, low-income patients had significantly higher rates of new sarcoidosis-related comorbidities (<$35,000, odds ratio [OR], 2.4 [1.7-3.3]; $35,000-84,999, OR, 1.4 [1.1-1.9]; and ≥$85,000 [reference (Ref)]) and new steroid-related comorbidities (<$35,000, OR, 1.3 [0.9-2.0]; $35,000-84,999, OR, 1.5 [1.1-2.1]; and ≥$85,000 [Ref]), had lower health-related quality of life as assessed by the Sarcoidosis Health Questionnaire (P < 0.001), and experienced more impact on family finances (<$35,000, OR, 7.9 [4.9-12.7]; $35,000-84,999, OR, 2.7 [1.9-3.9]; and ≥$85,000 [Ref]). The use of supplemental oxygen, need for assistive devices, and job loss were more common in lower income patients. Development of comorbidities after diagnosis of sarcoidosis occurred in 63% of patients and were strong independent predictors of poor outcomes. In random forest modeling, income was consistently a leading predictor of outcome.Conclusions: These results suggest the burden from sarcoidosis preferentially impacts the economically disadvantaged.

Diagnosis and Detection of Sarcoidosis. An Official American Thoracic Society Clinical Practice Guideline.

Background: The diagnosis of sarcoidosis is not standardized but is based on three major criteria: a compatible clinical presentation, finding nonnecrotizing granulomatous inflammation in one or more tissue samples, and the exclusion of alternative causes of granulomatous disease. There are no universally accepted measures to determine if each diagnostic criterion has been satisfied; therefore, the diagnosis of sarcoidosis is never fully secure.Methods: Systematic reviews and, when appropriate, meta-analyses were performed to summarize the best available evidence. The evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation approach and then discussed by a multidisciplinary panel. Recommendations for or against various diagnostic tests were formulated and graded after the expert panel weighed desirable and undesirable consequences, certainty of estimates, feasibility, and acceptability.Results: The clinical presentation, histopathology, and exclusion of alternative diagnoses were summarized. On the basis of the available evidence, the expert committee made 1 strong recommendation for baseline serum calcium testing, 13 conditional recommendations, and 1 best practice statement. All evidence was very low quality.Conclusions: The panel used systematic reviews of the evidence to inform clinical recommendations in favor of or against various diagnostic tests in patients with suspected or known sarcoidosis. The evidence and recommendations should be revisited as new evidence becomes available.

Inflammatory Pathways in Sarcoidosis.

Concepts regarding etiology and pathophysiology of sarcoidosis have changed remarkably within the past 5 years. Sarcoidosis is now viewed as a complex multi-causation disease related to a diverse collection of external environmental or infectious signals. It is generally accepted that the cause of sarcoidosis is unknown. Moreover, concepts of the inflammatory pathway have been modified by the realization that intrinsic genetic factors and innate immunity may modify adaptive immune responses to external triggers. With those potential regulatory pathways in mind, we will attempt to discuss the current understanding of the inflammatory response in sarcoidosis with emphasis on development of pulmonary granulomatous pathology. In that context, we will emphasize that both macrophages and T lymphocytes play key roles, with sometimes overlapping cytokine production (i.e., TNFα and IFN-γ) but also with unique mediators that influence the pathologic picture. Numerous studies have shown that in a sizable number of sarcoidosis patients, granulomas spontaneously resolve, usually within 3 years. Other sarcoidosis patients, however, may develop a chronic granulomatous disease which may subsequently lead to fibrosis. This chapter will outline our current understanding of inflammatory pathways in sarcoidosis which initiate and mediate granulomatous changes or onset of pulmonary fibrosis.

ICU admission body composition: skeletal muscle, bone, and fat effects on mortality and disability at hospital discharge-a prospective, cohort study.

BACKGROUND: Reduced body weight at the time of intensive care unit (ICU) admission is associated with worse survival, and a paradoxical benefit of obesity has been suggested in critical illness. However, no research has addressed the survival effects of disaggregated body constituents of dry weight such as skeletal muscle, fat, and bone density. METHODS: Single-center, prospective observational cohort study of medical ICU (MICU) patients from an academic institution in the USA. Five hundred and seven patients requiring CT scanning of chest or abdomen within the first 24 h of ICU admission were evaluated with erector spinae muscle (ESM) and subcutaneous adipose tissue (SAT) areas and with bone density determinations at the time of ICU admission, which were correlated with clinical outcomes accounting for potential confounders. RESULTS: Larger admission ESM area was associated with decreased odds of 6-month mortality (OR per cm2, 0.96; 95% CI, 0.94-0.97; p < 0.001) and disability at discharge (OR per cm2, 0.98; 95% CI, 0.96-0.99; p = 0.012). Higher bone density was similarly associated with lower odds of mortality (OR per 100 HU, 0.69; 95% CI, 0.49-0.96; p = 0.027) and disability at discharge (OR per 100 HU, 0.52; 95% CI, 0.37-0.74; p < 0.001). SAT area was not significantly associated with these outcomes' measures. Multivariable modeling indicated that ESM area remained significantly associated with 6-month mortality and survival after adjusting for other covariates including preadmission comorbidities, albumin, functional independence before admission, severity scores, age, and exercise capacity. CONCLUSION: In our cohort, ICU admission skeletal muscle mass measured with ESM area and bone density were associated with survival and disability at discharge, although muscle area was the only component that remained significantly associated with survival after multivariable adjustments. SAT had no association with the analyzed outcome measures.

Screening Sarcoidosis Patients for Occult Disease.

As sarcoidosis may involve any organ, sarcoidosis patients should be evaluated for occult disease. Screening for some organ involvement may not be warranted if it is unlikely to cause symptoms, organ dysfunction, or affect clinical outcome. Even organ involvement that affects clinical outcome does not necessarily require screening if early detection fails to change the patient's quality of life or prognosis. On the other hand, early detection of some forms of sarcoidosis may improve outcomes and survival. This manuscript describes the approach to screening sarcoidosis patients for previously undetected disease. Screening for sarcoidosis should commence with a meticulous medical history and physical examination. Many sarcoidosis patients present with physical signs or symptoms of sarcoidosis that have not been recognized as manifestations of the disease. Detection of sarcoidosis in these instances depends on the clinician's familiarity with the varied clinical presentations of sarcoidosis. In addition, sarcoidosis patients may present with symptoms or signs that are not related to specific organ involvement that have been described as parasarcoidosis syndromes. It is conjectured that parasarcoidosis syndromes result from systemic release of inflammatory mediators from the sarcoidosis granuloma. Certain forms of sarcoidosis may cause permanent and serious problems that can be prevented if they are detected early in the course of their disease. These include (1) ocular involvement that may lead to permanent vision impairment; (2) vitamin D dysregulation that may lead to hypercalcemia, nephrolithiasis, and permanent kidney injury; and (3) cardiac sarcoidosis that may lead to a cardiomyopathy, ventricular arrhythmias, heart block, and sudden death. Screening for these forms of organ involvement requires detailed screening approaches.

The diagnosis of sarcoidosis.

PURPOSE OF REVIEW: To review the diagnostic approach to sarcoidosis. There is no gold standard diagnostic test, procedure or algorithm for sarcoidosis. The diagnosis is based on a compatible clinical presentation, histologic findings of granulomatous inflammation, exclusion of alternative diseases, and evidence of systemic involvement. Occasionally, there may be exceptions to several of these requirements. RECENT FINDINGS: The diagnostic specificity of several specific clinical features are discussed. Typical histologic findings of sarcoidosis are described. Several diseases that may mimic sarcoidosis are reviewed. SUMMARY: The diagnosis of sarcoidosis usually involves weighing the clinical evidence for and against the diagnosis, coupled in most cases with histologic evidence of granulomatous inflammation. This approach requires knowledge of the varied presentations of the disease and other alternative conditions as well as histologic examination of an affected tissue in most instances.

Patient perspectives in sarcoidosis.

PURPOSE OF REVIEW: The review presents an overview of the scientific publications about patient perspectives in sarcoidosis. RECENT FINDINGS: The literature on patient perspectives in sarcoidosis is limited. Patient perspectives in sarcoidosis encompass a myriad of topics that have been addressed to some degree in the literature: patient needs and perceptions, patient-reported burden of sarcoidosis, and patient treatment priorities. Similar findings across studies were high levels of reported fatigue, a need to incorporate psychological support into the treatment plan and easy access to sarcoidosis expert centers. Furthermore, largely similar results were found across countries. SUMMARY: There is a growing focus in patient perspectives in terms of sarcoidosis treatment. A multidisciplinary approach including psychological support and attention to fatigue, may better reflect the needs of sarcoidosis patients. Further research on sarcoidosis patient perspectives in sarcoidosis is needed to optimize care.

Detecting Infections Rapidly and Easily for Candidemia Trial, Part 2 (DIRECT2): A Prospective, Multicenter Study of the T2Candida Panel.

Background: Blood cultures are approximately 50% sensitive for diagnosing invasive candidiasis. The T2Candida nanodiagnostic panel uses T2 magnetic resonance and a dedicated instrument to detect Candida directly within whole blood samples. Methods: Patients with Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis, or Candida krusei candidemia were identified at 14 centers using diagnostic blood cultures (dBCs). Follow-up blood samples were collected concurrently for testing by T2Candida and companion cultures (cBCs). T2Candida results are reported qualitatively for C. albicans/C. tropicalis, C. glabrata/C. krusei, and C. parapsilosis. T2Candida and cBCs were positive if they detected a species present in the dBC. Results: Median time between collection of dBC and T2Candida/cBC samples in 152 patients was 55.5 hours (range, 16.4-148.4). T2Candida and cBCs were positive in 45% (69/152) and 24% (36/152) of patients, respectively (P < .0001). T2Candida clinical sensitivity was 89%, as positive results were obtained in 32/36 patients with positive cBCs. Combined test results were both positive (T2+/cBC+), 21% (32/152); T2+/cBC-, 24% (37/152); T2-/cBC+, 3% (4/152); and T2-/cBC-, 52% (79/152). Prior antifungal therapy, neutropenia, and C. albicans candidemia were independently associated with T2Candida positivity and T2+/cBC- results (P values < .05). Conclusions: T2Candida was sensitive for diagnosing candidemia at the time of positive blood cultures. In patients receiving antifungal therapy, T2Candida identified bloodstream infections that were missed by cBCs. T2Candida may improve care by shortening times to Candida detection and species identification compared to blood cultures, retaining sensitivity during antifungal therapy and rendering active candidemia unlikely if results are negative. Clinical Trials Registration: NCT01525095.

Assessment of Mediastinal Lymph Node Size in Pneumococcal Pneumonia with Bacteremia.

INTRODUCTION: The significance of mediastinal lymphadenopathy in bacterial pneumonia is unclear. METHODS: We performed a retrospective analysis of mediastinal lymph node size determined by chest CT in patients with bacteremic pneumococcal pneumonia. All patients who had positive blood cultures for streptococcus pneumonia over an 11-year period and had a chest CT scan (index CT) within 2 weeks of the positive blood culture were included in the study. Two thoracic radiologists and one pulmonologist independently examined the index CT plus any chest CT scans performed prior (pre-CT) or after (post-CT) the bacteremic episode. RESULTS: The study cohort of 49 patients was 57% male, 65% White, with mean age of 53 (SD = 20) years. Mediastinal lymphadenopathy was detected in 25/49 (51%) of the cases. The mean size of the largest mediastinal lymph node in short axis was 0.99 (SD = 0.71), ranging from 0.0 to 2.05 cm. There was no correlation noted between the number of lobes involved with pneumonia, and the size of the largest mediastinal lymph node (p = 0.33) or the number of pathologically enlarged mediastinal lymph nodes (p = 0.08). There was a statistically significant increase in the mean size of the largest lymph node between the pre-CT and index-CT group (p = 0.02), and decrease between the index-CT group and the post-CT (p = 0.03). CONCLUSION: Pneumococcal pneumonia with bacteremia is associated with mild mediastinal lymph node enlargement. The presence of marked mediastinal lymphadenopathy (short axis LN size > 2 cm) should not be assumed from pneumococcal pneumonia.

Methemoglobinemia Caused by Portable Dialysis in the Critically Ill.

OBJECTIVE: To evaluate the root cause of a series of methemoglobinemia cases in a medical ICU. RESULTS: We report a sentinel case of methemoglobinemia that was associated with dialysis sessions using a portable dialysis unit in our hospital. This led to the identification of four additional patients who developed methemoglobinemia while undergoing portable dialysis. We determined that these episodes were caused by inadequate clearance of chloramine from the tap water used for portable dialysis. Introduction of larger capacity carbon filters into the portable dialysis systems resulted in no further cases of methemoglobinemia at our institution. CONCLUSIONS: Clinicians should be aware of municipal tap water as a potential cause of methemoglobinemia and monitor for excessive levels of oxidants in dialysis water sources. The capacity of the hemodialysis equipment to clear chloramine can vary as a function of external factors. Using a reliable test method to identify chloramines in the water prior to entering the hemodialysis equipment is essential.