Often seen, rarely recognized: mast cell activation disease--a guide to diagnosis and therapeutic options

Dermatologic manifestations of hematologic disorders

Distinguishing key morphologic features and understanding the pathophysiology of common cutaneous manifestations of hematologic disorders is essential to ensure prompt and appropriate treatment. In fact, classic cutaneous signs may provide the first clue to the diagnosis of an underlying hematologic disease. Disorders of coagulation, vascular abnormalities, or cutaneous infiltration and deposition are responsible for the underlying pathophysiology of cutaneous manifestations in the majority of cases. Hematologists often feel ill-equipped in identifying morphologic changes in the skin. Thus, the purpose of this review is to provide a comprehensive overview of classic cutaneous manifestations and diagnostic considerations of the associated hematologic conditions. Though there is a specific focus on non-malignant disorders, those straddling the spectrum of malignancy are also discussed. In many disease states, the skin may serve as an important marker of an emerging hematologic disorder, so close collaboration and multidisciplinary input remain essential to provide optimal and timely care for these patients.

A survey of the currently known mast cell mediators with potential relevance for therapy of mast cell-induced symptoms

Mast cells (MCs) occupy a central role in immunological as well as non-immunological processes as reflected in the variety of the mediators by which MCs influence other cells. Published lists of MC mediators have all shown only subsets-usually quite small-of the full repertoire. The full repertoire of MC mediators released by exocytosis is comprehensively compiled here for the first time. The compilation of the data is essentially based on the largely cytokine-focused database COPE®, supplemented with data on the expression of substances in human MCs published in several articles, plus extensive research in the PubMed database. Three hundred and ninety substances could be identified as mediators of human MCs which can be secreted into the extracellular space by activation of the MC. This number might still be an underestimate of the actual number of MC mediators since, in principle, all substances produced by MCs can become mediators because of the possibility of their release by diffusion into the extracellular space, mast cell extracellular traps, and intercellular exchange via nanotubules. When human MCs release mediators in inappropriate manners, this may lead to symptoms in any or all organs/tissues. Thus, such MC activation disorders may clinically present with a myriad of potential combinations of symptoms ranging from trivial to disabling or even life-threatening. The present compilation can be consulted by physicians when trying to gain clarity about MC mediators which may be involved in patients with MC disease symptoms refractory to most therapies.

Neuropsychiatric Manifestations of Mast Cell Activation Syndrome and Response to Mast-Cell-Directed Treatment: A Case Series

Mast cell activation syndrome (MCAS) is an immune disease with an estimated prevalence of 17%. Mast cell chemical mediators lead to heterogeneous multisystemic inflammatory and allergic manifestations. This syndrome is associated with various neurologic and psychiatric disorders, including headache, dysautonomia, depression, generalized anxiety disorder, and many others. Although MCAS is common, it is rarely recognized, and thus, patients can suffer for decades. The syndrome is caused by aberrant mast cell reactivity due to the mutation of the controller gene. A case series is presented herein including eight patients with significant neuropsychiatric disorders that were often refractory to standard medical therapeutics. Five patients had depression, five had generalized anxiety disorder, and four had panic disorder. Other psychiatric disorders included attention-deficit hyperactivity disorder, obsessive compulsive disorder, phobias, and bipolar disorder. All eight patients were subsequently diagnosed with mast cell activation syndrome; six had comorbid autonomic disorders, the most common being postural orthostatic tachycardia syndrome; and four had hypermobile Ehlers-Danlos syndrome. All patients experienced significant improvements regarding neuropsychiatric and multisystemic symptoms after mast-cell-directed therapy. In neuropsychiatric patients who have systemic symptoms and syndromes, it is important to consider the presence of an underlying or comorbid MCAS.

Mast cell ontogeny: From fetal development to life-long health and disease

Mast cells (MCs) are evolutionarily ancient innate immune cells with important roles in protective immunity against bacteria, parasites, and venomous animals. They can be found in most organs of the body, where they also contribute to normal tissue functioning, for example by engaging in crosstalk with nerves. Despite this, they are most widely known for their detrimental roles in allergy, anaphylaxis, and atopic disease. Just like macrophages, mast cells were conventionally thought to originate from the bone marrow. However, they are already present in fetal tissues before the onset of bone marrow hematopoiesis, questioning this dogma. In recent years, our view of myeloid cell ontogeny has been revised. We now know that the first mast cells originate from progenitors made in the extra-embryonic yolk sac, and later get supplemented with mast cells produced from subsequent waves of hematopoiesis. In most connective tissues, sizeable populations of fetal-derived mast cells persist into adulthood, where they self-maintain largely independently from the bone marrow. These developmental origins are highly reminiscent of macrophages, which are known to have critical functions in development. Mast cells too may thus support healthy development. Their fetal origins and longevity also make mast cells susceptible to genetic and environmental perturbations, which may render them pathological. Here, we review our current understanding of mast cell biology from a developmental perspective. We first summarize how mast cell populations are established from distinct hematopoietic progenitor waves, and how they are subsequently maintained throughout life. We then discuss what functions mast cells may normally have at early life stages, and how they may be co-opted to cause, worsen, or increase susceptibility to disease.

Evaluation of a tryptase depletion index for better pathologic identification of mast cell activation syndrome

BACKGROUND

Laboratory evidence supporting diagnosis of the prevalent condition of mast cell activation syndrome (MCAS) currently includes elevated levels in blood or urine of mediators relatively specific to mast cells (MCs) and/or increased numbers of MCs in luminal gastrointestinal (GI) tract tissues. However, identification of elevated mediators is technically challenging and expensive, and controversy persists regarding the normal ranges of numbers/counts of MCs in various GI tract segments, let alone challenges in determining how many of the visualized MCs are activated. To aid diagnosis of MCAS, we developed a potential new approach for the pathologist to identify the extent of GI tract MC activation easily and inexpensively.

PARTICIPANTS AND METHODS

Visualization of MCs in gastrointestinal biopsies from 251 patients vs. 95 controls using antibodies against CD117 and tryptase; MC counting per mm²; calculation of the difference between the CD117-positive MCs (identifying all MCs) vs. tryptase-positive MCs (identifying non-activated tryptase-containing MCs), which we define as the tryptase depletion index (TDI).

RESULTS

Mean total MC counts did not differ significantly between patients and controls, but mean TDIs differed significantly. Non-overlapping confidence intervals at the 99.9% level identified cut-offs of TDIs between patients vs. controls of 26, 45 and 32 MCs/mm² in gastric antrum, duodenum, and colon, respectively.

CONCLUSIONS

The TDI may discriminate between MCAS patients vs. controls. If this preliminary work can be independently confirmed, the TDI may become a useful additional minor diagnostic criterion for MCAS.

Inducible Laryngeal Obstruction Differential Diagnosis in Adolescents and Adults: A Tutorial

Inducible laryngeal obstruction (ILO), formerly referred to as paradoxical vocal fold motion and vocal cord dysfunction, is a complex disorder of the upper airway that requires skillful differential diagnosis. There are several medical conditions that may mimic ILO (or which ILO may mimic) that should be considered in the differential diagnosis before evidence-supported behavioral intervention is initiated to mitigate or eliminate this upper airway condition. A key in treatment planning is determination of an isolated presentation of ILO or ILO concurrent with other conditions that affect the upper airway. Accurate, timely differential diagnosis in the clinical assessment of this condition mitigates delay of targeted symptom relief and/or insufficient intervention. Accurate assessment and nuanced clinical counseling are necessary to untangle concurrent, competing conditions in a single patient. This tutorial describes the common and rare mimics that may be encountered by medical professionals who evaluate and treat ILO, with particular attention to the role of the speech-language pathologist. Speech-language pathologists receive referrals for ILO from several different medical specialists (allergy, pulmonology, and sports medicine), sometimes without a comprehensive team assessment. It is paramount that speech-language pathologists who assess and treat this disorder have a solid understanding of the conditions that may mimic ILO. Summary tables that delineate differential diagnosis considerations for airway noise, origin of noise, symptoms, triggers, role of the speech-language pathologist, and β-agonist response are included for clinician reference. A clinical checklist is also provided to aid clinicians in the critical assessment process.

The potential role of ischaemia-reperfusion injury in chronic, relapsing diseases such as rheumatoid arthritis, Long COVID, and ME/CFS: evidence, mechanisms, and therapeutic implications

Ischaemia–reperfusion (I–R) injury, initiated via bursts of reactive oxygen species produced during the reoxygenation phase following hypoxia, is well known in a variety of acute circumstances. We argue here that I–R injury also underpins elements of the pathology of a variety of chronic, inflammatory diseases, including rheumatoid arthritis, ME/CFS and, our chief focus and most proximally, Long COVID. Ischaemia may be initiated via fibrin amyloid microclot blockage of capillaries, for instance as exercise is started; reperfusion is a necessary corollary when it finishes. We rehearse the mechanistic evidence for these occurrences here, in terms of their manifestation as oxidative stress, hyperinflammation, mast cell activation, the production of marker metabolites and related activities. Such microclot-based phenomena can explain both the breathlessness/fatigue and the post-exertional malaise that may be observed in these conditions, as well as many other observables. The recognition of these processes implies, mechanistically, that therapeutic benefit is potentially to be had from antioxidants, from anti-inflammatories, from iron chelators, and via suitable, safe fibrinolytics, and/or anti-clotting agents. We review the considerable existing evidence that is consistent with this, and with the biochemical mechanisms involved.

Efficacy and toxicity of hydroxyurea in mast cell activation syndrome patients refractory to standard medical therapy: retrospective case series

Determine efficacy and adverse events (AEs) of hydroxyurea (HU) in mast cell activation syndrome (MCAS) patients who were refractory to standard medical therapy. An electronic chart review was performed to find MCAS patients who received HU in a MCAS medical practice. Diagnosis of MCAS was established on the basis of mast cell (MC) activation symptoms in ≥ 5 systems plus ≥ 1 abnormal MC mediators and/or ≥ 20 MC/high power field on duodenal biopsies. Medicines not providing significant clinical improvement prior to HU were tabulated. The following symptoms were evaluated by patients on a 0–10 scale prior to and at the study conclusion: bone pain, abdominal pain, diarrhea, bloating, and nausea. Safety labs were obtained on a regular basis. Twenty out of three hundred ten (8.4%) MCAS patients received HU. Patients included 22 females, average age 42.4 years. Dysautonomia was present in 60%. An average of 10.6 (SD 1.7, range 8–13) medications were used prior to adding HU to various concomitant medications. Average dose of HU was 634 mg. In 20 patients who continued therapy for ≥ 2 months, there was statistically significant reduction of bone pain, abdominal pain, diarrhea, bloating, and nausea. Fourteen patients noted prolonged success with therapy. Six patients stopped HU within 6 weeks owing to AEs. Four patients treated ≥ 2 months had AEs and 2 led to HU cessation. All AEs were reversible. Refractory MCAS patients showed clear significant improvement in bone pain and gastrointestinal symptoms on HU. Systematic monitoring was effective in preventing the occurrence of severe HU-induced adverse events.

Connecting the Dots in Emerging Mast Cell Research: Do Factors Affecting Mast Cell Activation Provide a Missing Link between Adverse COVID-19 Outcomes and the Social Determinants of Health?

Evidence continues to emerge that the social determinants of health play a role in adverse outcomes related to COVID-19, including increased morbidity and mortality, increased risk of long COVID, and vaccine adverse effects. Therefore, a more nuanced understanding of the biochemical and cellular pathways of illnesses commonly associated with adverse social determinants of health is urgently needed. We contend that a commitment to understanding adverse outcomes in historically marginalized communities will increase community-level confidence in public health measures. Here, we synthesize emerging literature on mast cell disease, and the role of mast cells in chronic illness, alongside emerging research on mechanisms of COVID illness and vaccines. We propose that a focus on aberrant and/or hyperactive mast cell behavior associated with chronic underlying health conditions can elucidate adverse COVID-related outcomes and contribute to the pandemic recovery. Standards of care for mast cell activation syndrome (MCAS), as well as clinical reviews, experimental research, and case reports, suggest that effective and cost-efficient remedies are available, including antihistamines, vitamin C, and quercetin, among others. Primary care physicians, specialists, and public health workers should consider new and emerging evidence from the biomedical literature in tackling COVID-19. Specialists and researchers note that MCAS is likely grossly under-diagnosed; therefore, public health agencies and policy makers should urgently attend to community-based experiences of adverse COVID outcomes. It is essential that we extract and examine experiential evidence of marginalized communities from the broader political–ideological discourse.

[Cystic diseases in urology : Recommendations for patients with systemic mast cell disease]

The systemic mast cell disease (MCAD; prevalence 17%) may occur frequently in urological patients. MCAD-induced changes include cysts in all organs, also in the urogenital system. In the presence of MCAD, the surgical removal of such cysts must consider specific features of the MCAD in order to reduce surgical and complication risks. Vice versa, if in urological examinations multiple cysts are found, this could be an indication of a possibly existing, in some circumstances, unrecognized MCAD.

Evaluation and Classification of Mast Cell Disorders: A Difficult to Manage Pathology in Clinical Practice

Mast cells are granulocytic immunomodulatory cells with an important role in physiologic and pathogenic processes due to their location at the junction between the internal and external environment and to their capacity to release a broad range of active mediators. Mast cells mediators have both pro-inflammatory and anti-inflammatory activities and are implicated in various and complex pathology. Mast cells disorders (MCDs) represent a heterogeneous pathology, with frequently difficult and challenging evaluation and diagnostic workup. MCDs can be primary, secondary to other diseases, or idiopathic. Increased research interest in this field was noted during the last decade and various classification criteria, as well as diagnostic and treatment recommendations, were proposed. The aim of this paper is to review the most recent published data on the classification and evaluation of mast cells disorders and to point out the main difficulties in diagnosing and managing these complex diseases in medical practice.

Post-HPV-Vaccination Mast Cell Activation Syndrome: Possible Vaccine-Triggered Escalation of Undiagnosed Pre-Existing Mast Cell Disease?

For nearly a decade, case reports and series have emerged regarding dysautonomias-particularly postural orthostatic tachycardia syndrome (POTS)-presenting soon after vaccination against human papilloma virus (HPV). We too have observed a number of such cases (all following vaccination with the Gardasil product), and have found several to have detectable mast cell activation syndrome (MCAS) as well as histories suggesting that MCAS was likely present long before vaccination. We detail 11 such cases here, posing a hypothesis that HPV vaccination (at least with the Gardasil product) may have triggered or exacerbated MCAS in teenagers previously not recognized to have it. Only recently recognized, MCAS is being increasingly appreciated as a prevalent and chronic multisystem disorder, often emerging early in life and presenting with inflammatory ± allergic phenomena following from known mast cell (MC) mediator effects. There is rising recognition, too, of associations of MCAS with central and peripheral neuropathic disorders, including autonomic disorders such as POTS. Given the recognized potential for many antigens to trigger a major and permanent escalation of baseline MC misbehavior in a given MCAS patient, we hypothesize that in our patients described herein, vaccination with Gardasil may have caused pre-existing (but not yet clinically recognized) MCAS to worsen to a clinically significantly degree, with the emergence of POTS and other issues. The recognition and management of MCAS prior to vaccinations in general may be a strategy worth investigating for reducing adverse events following HPV vaccinations and perhaps even other types of vaccinations.

Mast cell activation symptoms are prevalent in Long-COVID

Objectives

Hyper-inflammation caused by COVID-19 may be mediated by mast cell activation (MCA) which has also been hypothesized to cause Long-COVID (LC) symptoms. We determined prevalence/severity of MCA symptoms in LC.

Methods

Adults in LC-focused Facebook support groups were recruited for online assessment of symptoms before and after COVID-19. Questions included presence and severity of known MCA and LC symptoms and validated assessments of fatigue and quality of life. General population controls and mast cell activation syndrome (MCAS) patients were recruited for comparison if they were ≥18 years of age and never had overt COVID-19 symptoms.

Results

There were 136 LC subjects (89.7% females, age 46.9 ±12.9 years), 136 controls (65.4% females, age 49.2 ±15.5), and 80 MCAS patients (85.0% females, age 47.7 ±16.4). Pre-COVID-19 LC subjects and controls had virtually identical MCA symptom and severity analysis. Post-COVID-19 LC subjects and MCAS patients prior to treatment had virtually identical MCA symptom and severity analysis.

Conclusions

MCA symptoms were increased in LC and mimicked the symptoms and severity reported by patients who have MCAS. Increased activation of aberrant mast cells induced by SARS-CoV-2 infection by various mechanisms may underlie part of the pathophysiology of LC, possibly suggesting routes to effective therapy.

Effects of Primary Mast Cell Disease on Hemostasis and Erythropoiesis

Mast cell disease is an epigenetically and genetically determined disease entity with very diverse clinical manifestations in potentially every system and tissue due to inap pro priate release of variable subsets of mast cell mediators together with accumulation of either morphologically normal or altered mast cells. Easy bruising, excessive bleeding, and aberrancies of erythropoiesis can frequently be observed in patients with mast cell disease. A thorough history, including a family history, will guide the appropriate work-up, and laboratory evaluations may provide clues to diagnosis. In recent years, our understanding of the involvement of coagulation and anticoagulant pathways, the fibrinolytic system, and erythropoiesis in the pathophysiology of mast cell disease has increased considerably. This review summarizes current knowledge of the impact of the disturbed hemostatic and erythropoietic balance in patients with mast cell disease and describes options of treatment.

Selecting the Right Criteria and Proper Classification to Diagnose Mast Cell Activation Syndromes: A Critical Review

In recent years, knowledge about mechanisms underlying mast cell activation (MCA) and accumulation in various pathologic conditions increased substantially. In addition, criteria and a classification of MCA syndromes (MCASs) have been set forth. MCAS is defined by typical clinical symptoms, a substantial increase in serum tryptase level during an attack over the patient's baseline tryptase, and a response of the symptoms to drugs targeting mast cells, mediator production, and/or mediator effects. Alternative diagnostic criteria of MCAS have also been suggested, but these alternative criteria often lack specificity and validation. In this report, we critically review the contemporary literature relating to MCAS and compare the specificity, sensitivity, and strength of MCAS-related parameters within proposals to diagnose and classify MCAS and its variants. Furthermore, we highlight the need to apply specific consensus criteria in the evaluation and classification of MCAS in individual patients. This is an urgent and important medical necessity because as an increasing number of patients are being given a misdiagnosis of MCAS based on nonspecific criteria, which contributes to confusion and frustration by patients and caregivers and sometimes may delay recognition and treatment of correct medical conditions that often turn out to be unrelated to MCA.

Diagnosis of mast cell activation syndrome: a global "consensus-2"

The concept that disease rooted principally in chronic aberrant constitutive and reactive activation of mast cells (MCs), without the gross MC neoplasia in mastocytosis, first emerged in the 1980s, but only in the last decade has recognition of "mast cell activation syndrome" (MCAS) grown significantly. Two principal proposals for diagnostic criteria have emerged. One, originally published in 2012, is labeled by its authors as a "consensus" (re-termed here as "consensus-1"). Another sizable contingent of investigators and practitioners favor a different approach (originally published in 2011, newly termed here as "consensus-2"), resembling "consensus-1" in some respects but differing in others, leading to substantial differences between these proposals in the numbers of patients qualifying for diagnosis (and thus treatment). Overdiagnosis by "consensus-2" criteria has potential to be problematic, but underdiagnosis by "consensus-1" criteria seems the far larger problem given (1) increasing appreciation that MCAS is prevalent (up to 17% of the general population), and (2) most MCAS patients, regardless of illness duration prior to diagnosis, can eventually identify treatment yielding sustained improvement. We analyze these proposals (and others) and suggest that, until careful research provides more definitive answers, diagnosis by either proposal is valid, reasonable, and helpful.

Mast Cell Activation Syndrome: A Primer for the Gastroenterologist

Mast cell activation syndrome is thought to be a common, yet under-recognized, chronic multi-system disorder caused by inappropriate mast cell activation. Gastrointestinal symptoms are frequently reported by these patients and are often mistaken by physicians as functional gastrointestinal disorders. This syndrome can be diagnosed by the medical history and measurable biomarkers. Gastroenterologists manage diseases associated with active inflammatory cells including neutrophils, lymphocytes, macrophages, and eosinophils. The mast cell has only recently been recognized as a major player in our specialty. Gastrointestinal disorders from mast cell mediators often present with apparent irritable bowel syndrome, dyspepsia, chronic or cyclical nausea, and heartburn. Individuals with mast cell activation syndrome experience significant delays in diagnosis. The gastrointestinal symptoms are often refractory to symptom-targeted prescription medications. Beyond avoiding triggers, the best therapy is directed at modulating mast cell activation and the effects of the mediators. Many of these therapies are simple over-the-counter medications. In this article, we review mast cell function and dysfunction and the gastrointestinal symptoms, comorbid conditions, diagnosis, and management of mast cell activation syndrome. Gastroenterologists who become aware of this syndrome can dramatically improve the quality of life for their patients who previously have been labeled with a functional gastrointestinal disorder.

Covid-19 hyperinflammation and post-Covid-19 illness may be rooted in mast cell activation syndrome

OBJECTIVES

One-fifth of Covid-19 patients suffer a severe course of Covid-19 infection; however, the specific causes remain unclear. Mast cells (MCs) are activated by SARS-CoV-2. Although only recently recognized, MC activation syndrome (MCAS), usually due to acquired MC clonality, is a chronic multisystem disorder with inflammatory and allergic themes, and an estimated prevalence of 17%. This paper describes a novel conjecture explaining how MCAS might cause a propensity for severe acute Covid-19 infection and chronic post-Covid-19 illnesses.

METHODS

Observations of Covid-19 illness in patients with/without MCAS were compared with extensive clinical experience with MCAS.

RESULTS

The prevalence of MCAS is similar to that of severe cases within the Covid-19-infected population. Much of Covid-19's hyperinflammation is concordant with manners of inflammation which MC activation can drive. Drugs with activity against MCs or their mediators have preliminarily been observed to be helpful in Covid-19 patients. None of the authors' treated MCAS patients with Covid-19 suffered severe infection, let alone mortality.

CONCLUSIONS

Hyperinflammatory cytokine storms in many severely symptomatic Covid-19 patients may be rooted in an atypical response to SARS-CoV-2 by the dysfunctional MCs of MCAS rather than a normal response by normal MCs. If proven, this theory has significant therapeutic and prognostic implications.

Adrenal insufficiency is a contraindication for omalizumab therapy in mast cell activation disease: risk for serum sickness

Omalizumab is an effective therapeutic humanized murine IgE antibody in many cases of primary systemic mast cell activation disease (MCAD). The present study should enable the clinician to recognize when treatment of MCAD with omalizumab is contraindicated because of the potential risk of severe serum sickness and to report our successful therapeutic strategy for such adverse event (AE). Our clinical observations, a review of the literature including the event reports in the FDA AE Reporting System, the European Medicines Agency Eudra-Vigilance databases (preferred search terms: omalizumab, Xolair®, and serum sickness) and information from the manufacturer’s Novartis database were used. Omalizumab therapy may be more likely to cause serum sickness than previously thought. In patients with regular adrenal function, serum sickness can occur after 3 to 10 days which resolves after the antigen and circulating immune complexes are cleared. If the symptoms do not resolve within a week, injection of 20 to 40 mg of prednisolone on two consecutive days could be given. However, in MCAD patients whose adrenal cortical function is completely suppressed by exogenous glucocorticoid therapy, there is a high risk that serum sickness will be masked by the MCAD and evolve in a severe form with pronounced damage of organs and tissues, potentially leading to death. Therefore, before the application of the first omalizumab dose, it is important to ensure that the function of the adrenal cortex is not significantly limited so that any occurring type III allergy can be self-limiting.

Mast cell activation syndrome in pregnancy, delivery, postpartum and lactation: a narrative review

Mast cell activation syndrome (MCAS) is a chronic multisystem disease of aberrant constitutive and reactive mast cell mediator release causing generally inflammatory, allergic, and dystrophic issues. The pathobiology of MCAS drives extraordinary clinical complexity and heterogeneity, which led to only recent recognition despite increasingly apparent substantial prevalence, perhaps as high as 17%. It also has a strong female predilection. Thus, MCAS inescapably impacts pregnancy and the post-partum period in many women. No specific research in the pregnant or post-partum MCAS population has been performed yet. However, its prevalence and potential for driving substantial morbidity merit obstetric providers' acquaintance with this illness and its potential impacts on their patients during pregnancy, delivery, the post-partum period, and lactation. Extensive literature review across all medical specialities, plus direct experience in the authors' practices, provides guidance in recognising MCAS in pregnancy and diagnosing and effectively managing it. Described herein are manners in which MCAS, a protean multisystem disease, adversely affects all stages of pregnancy and post-partum. In order to reduce risks of MCAS causing complications before, during and after pregnancy, identifying and controlling the syndrome prior to pregnancy is best, but, even if the disease is not recognised until late, there may still be opportunities to mitigate its effects. There is precedent for improved outcomes if comorbid MCAS is recognised and controlled. This review provides the first comprehensive guide for obstetric providers regarding this emerging major comorbidity.

Restless legs syndrome is associated with mast cell activation syndrome

STUDY OBJECTIVES

Mast cell activation syndrome (MCAS) is an inflammatory and allergic disorder. We determined the prevalence of restless legs syndrome (RLS) in MCAS because each common syndrome may be inflammatory in nature and associated with dysautonomia.

METHODS

Individuals with MCAS were evaluated for RLS by two standard questionnaires. Prevalence comparisons included spouse control patients and two prevalence publications. MCAS diagnosis required mast cell (MC) symptoms in ≥ 2 organs plus ≥ 1 elevated MC mediators, improvement with MC therapy, and/or increased intestinal MC density. Clinical variables were studied.

RESULTS

There were 174 patients with MCAS (146 female, 28 male, mean age 44.8 years) and 85 spouse control patients (12 female, 73 male, mean age 50.9 years). Patients with MCAS as a whole had a higher prevalence of RLS (40.8%) than spouse control (12.9%) (P < .0001) Male patients with MCAS had a higher prevalence of RLS (32.1%) than male controls (12.3%, odds ratio [OR] 3.4, confidence interval [CI] 1.2-9.7, P = .025), American men (8.4%, OR 5.2, CI 2.2-12.0, P < .001), and French men (5.8%, OR 7.7, CI 3.4-17.1, P < .001). Female patients with MCAS also had a higher prevalence of RLS (42.5%) than female controls (16.7%) but this did not reach statistical significance perhaps because of the sample size of the female controls. However, female patients with MCAS had a statistically higher prevalence of RLS than American women (10.0%, OR 6.7, CI 4.5-9.7, P < .0001) and French women (10.8%, OR 6.1, CI 4.4-8.6, P < .0001).

CONCLUSIONS

RLS appears to be associated with MCAS. Effects of mast cell mediators, inflammation, immune mechanisms, dysautonomia, or hypoxia may theoretically activate RLS in MCAS.

Activity and Exercise Intolerance After Concussion: Identification and Management of Postural Orthostatic Tachycardia Syndrome

Supplemental Digital Content is Available in the Text.

Background and Purpose:

Postural orthostatic tachycardia syndrome (POTS) is increasingly recognized as a complication affecting recovery from concussion. Individuals with POTS demonstrate refractory dizziness, lightheadedness, cognitive dysfunction, fatigue, headache, chronic pain, nausea and gastrointestinal dysmotility, activity and exercise intolerance, syncope, and tachycardia. Subtypes of POTS may include hypovolemia, hyperadrenergic states, autonomic neuropathy, and underlying autoimmunity, which may variably impact response to rehabilitation in varying ways. The subtle presentation of POTS postconcussion is often mistaken for underlying anxiety, conversion disorder, or lack of motivation for recovery. This article will present clinical features of POTS that may arise after concussion, and propose a role for physical therapists in the diagnosis and management of POTS during concussion recovery.

Summary of Key Points:

Data recorded and entered into a database during clinic visits from a large pediatric institution indicate that 11.4% of individuals diagnosed with POTS report onset of symptoms within 3 months of sustaining a concussion. Activation of the sympathetic nervous system can result in lightheadedness, shortness of breath, chest pain, tachycardia, palpitations on standing or with exertion, and activity and exercise intolerance. Identified comorbidities in people with POTS such as joint hypermobility and autoimmune disorders can further influence recovery.

Recommendations for Clinical Practice:

Physical therapists may identify signs and symptoms of POTS in a subset of individuals who remain refractory to typical interventions and who exhibit symptom exacerbation with orthostatic activity. Incorporation of an individualized POTS exercise program into current established concussion interventions may be useful, with emphasis on initial recumbent exercises and ongoing physical therapy assessment of exercise tolerance for dosing of activity intensity and duration.

Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A211).

[Surgical interventions in patients with systemic mast cell activation disease : Recommendations for perioperative management]

BACKGROUND

Systemic mast cell activation disease (MCAD, prevalence 5-10%) is a multifactorial, polygenic disease with multisystemic symptoms that is characterized by an unregulated increased release of mast cell mediators and an accumulation of activated mast cells potentially in all organs and tissues. Due to the high prevalence of the disease, physicians involved in surgical, anesthesiological and interventional procedures are often unknowingly faced with MCAD patients experiencing unexpected preoperative, intraoperative and postoperative complications, if no mast cell-specific treatment regimens have been applied.

OBJECTIVE

The findings from a literature search, consensus recommendations of the various international expert groups and extensive own experience in the treatment of MCAD patients enable an empirical and evidence-based care of MCAD patients in association with invasive procedures.

RESULTS AND CONCLUSION

Due to the high prevalence of MCAD in the population, it can be assumed that patients with MCAD are correspondingly frequently represented in the surgical patient collective. When MCAD-specific peculiarities are preventively considered in the anesthesiological and surgical procedures in patients with proven or suspected mast cell disease, MCAD patients should not be classified as being at risk.

Mast cell deposition and activation may be a new explanation for epiploic appendagitis

Epiploic appendagitis is as an acute painful condition of the fat on the outside of the intestine. Thus far, there have been no publications to our knowledge that appendagitis can be caused by mast cells or can be associated with chronic pain. A patient with multisystemic disorders suffered with both chronic and acute attacks of abdominal pain for a year. The worst attack led to surgical resection of an enlarged sigmoid colon epiploic appendage. Careful review of her complex medical history and mast cell stains of gastrointestinal biopsies led to the diagnosis of mast cell activation syndrome. Re-examination of the resected appendage using an immunohistochemical stain demonstrated a high mast cell density which is a new histopathological finding. Treatment of mast cell activation syndrome and other related syndromes led to marked improvement in her health, including all types of chronic abdominal pain.

Can H2 -receptor upregulation and raised histamine explain an anaphylactoid reaction on cessation of ranitidine in a 19-year-old female? A case report

The anaphylactoid reaction described follows cessation of ranitidine in a 19-year-old female with the disease cluster: mast cell activation syndrome, hypermobile Ehlers-Danlos syndrome and postural tachycardia syndrome. Anaphylaxis can give wide-ranging symptoms from rhinorrhoea and urticaria to tachycardia and system-wide, life-threatening, anaphylactic shock. Individuals with a disorder of mast cell activation can experience many such symptoms. H2 receptor antagonists, such as ranitidine, are commonly prescribed in this population. A mechanism for the reaction is proposed in the context of ranitidine, as an inverse agonist, causing upregulation of H2 histamine receptors and raised histamine levels due to enzyme induction. This effect, following extended and/or high antihistamine dosing, may have implications for other individuals with a disorder of mast cell activation, such as mastocytosis or mast cell activation syndrome. There are potential policy and patient guidance implications for primary and secondary care with respect to cessation of H2 antagonists.

Management of a Parturient with Mast Cell Activation Syndrome: An Anesthesiologist's Experience

Mast cell activation syndrome (MCAS) is a disorder in which patients experience symptoms and signs attributable to inappropriate mast cell activation and mediator release. Multiorgan involvement in patients can result in significant morbidity and possible mortality. Limited literature exists regarding anesthetic management of patients with MCAS. We report a case of vaginal delivery with neuraxial labor analgesia in a parturient with this condition and highlight the importance of multidisciplinary planning for uneventful outcomes. Stress can trigger life-threatening symptoms, and counseling is important to allay patients' fears. Optimum medical control, adequate premedication, avoidance of triggers, and preparedness to treat serious mediator effects are key. We review MCAS and discuss anesthetic considerations for patients with this mast cell disorder.

Postural orthostatic tachycardia syndrome and the potential role of mast cell activation

Though a sizeable amount of data connects mast cell activity to the neurologic system, less is known about the true clinical implications of this relationship. Even less is understood about treatment strategies in those with both allergic and neurologic complaints. This is particularly true in postural orthostatic tachycardia syndrome (POTS), a common type of dysautonomia, where patients are burdened by symptoms of orthostatic cerebral hypoperfusion and several other comorbidities that are likely influenced by autonomic tone. Some patients describe characteristic allergic symptoms, in the absence of typical IgE mediated triggers, and also improvement with traditional mast cell directed medications. Further work is necessary to determine whether these anecdotal observations are valid. The answer to this question will likely be addressed as the mechanisms of POTS are better characterized, which may include a phenotype with distinct mast cell involvement.

Pediatric Disorders of Orthostatic Intolerance

Orthostatic intolerance (OI), having difficulty tolerating an upright posture because of symptoms or signs that abate when returned to supine, is common in pediatrics. For example, ∼40% of people faint during their lives, half of whom faint during adolescence, and the peak age for first faint is 15 years. Because of this, we describe the most common forms of OI in pediatrics and distinguish between chronic and acute OI. These common forms of OI include initial orthostatic hypotension (which is a frequently seen benign condition in youngsters), true orthostatic hypotension (both neurogenic and nonneurogenic), vasovagal syncope, and postural tachycardia syndrome. We also describe the influences of chronic bed rest and rapid weight loss as aggravating factors and causes of OI. Presenting signs and symptoms are discussed as well as patient evaluation and testing modalities. Putative causes of OI, such as gravitational and exercise deconditioning, immune-mediated disease, mast cell activation, and central hypovolemia, are described as well as frequent comorbidities, such as joint hypermobility, anxiety, and gastrointestinal issues. The medical management of OI is considered, which includes both nonpharmacologic and pharmacologic approaches. Finally, we discuss the prognosis and long-term implications of OI and indicate future directions for research and patient management.

Case Report: Treatment of systemic mastocytosis with sunitinib

Mast cell activation disease typically presents as chronic multisystem polymorbidity of generally inflammatory ± allergic theme.  Presently, treatment of the rare, cytoproliferative variant systemic mastocytosis employs empirically selected therapies to impede mast cell mediator production and action and, when necessary, inhibition of proliferation. Some tyrosine kinase inhibitors (TKIs) have been used successfully in uncommon cases of systemic mastocytosis not bearing that disease’s usual imatinib-resistant KIT ^D816V mutation. Recently, sunitinib, a multi-targeted TKI, had been successful in a case of systemic mast cell activation syndrome. In addition, most allergy is principally a mast cell activation phenomenon, and sunitinib has been shown helpful in controlling a murine model of oral allergy syndrome. Here, we present the first use of sunitinib in systemic mastocytosis.

Risk of solid cancer in patients with mast cell activation syndrome: Results from Germany and USA

Background:  It has been shown repeatedly that mast cells can promote or prevent cancer development and growth. If development and/or progression of a solid cancer is substantially influenced by mast cell activity, the frequencies of occurrence of solid cancers in patients with primary mast cells disorders would be expected to differ from the corresponding prevalence data in the general population. In fact, a recent study demonstrated that patients with systemic mastocytosis (i.e., a rare neoplastic variant of the primary mast cell activation disease) have increased risk for solid cancers, in particular melanoma and non-melanoma skin cancers. The aim of the present study is to examine whether the risk of solid cancer is increased in systemic mast cell activation syndrome (MCAS), the common systemic variant of mast cell activation disease. Methods: In the present descriptive study, we have analysed a large (n=828) patient group with MCAS, consisting of cohorts from Germany and the USA, for occurrence of solid forms of cancer and compared the frequencies of the different cancers with corresponding prevalence data for German and U.S. general populations. Results: Sixty-eight of the 828 MCAS patients (46 female, 22 male) had developed a solid tumor before the diagnosis of MCAS was made. Comparison of the frequencies of the malignancies in the MCAS patients with their prevalence in the general population revealed a significantly increased prevalence for melanoma and cancers of the breast, cervix uteri, ovary, lung, and thyroid in MCAS patients. Conclusions: Our data support the view that mast cells may promote development of certain malignant tumors. These findings indicate a need for increased surveillance of certain types of cancer in MCAS patients irrespective of its individual clinical presentation.

Siglec-8 as mast cell selective target: developing paradigms amidst inconvenient truths

Due to the limited efficacy of current drugs in treating systemic mast cell activation disease, there is an urgent need for more effective drugs selectively acting at mast cells. In the past, a large number of compounds have been claimed to be effective and mast cell selective on the basis of cell culture experiments and studies on blood leukocytes which could not be verified in organ and animal studies. Nevertheless, over time in review papers about potential mast cell targets mast cell selectivity of these targets has been no longer challenged. A recent example for such developing paradigms amidst inconvenient truths is the hype on the purported selective expression of the putative adhesion molecule sialic acid binding Ig-like lectin 8 (Siglec-8) in mast cells and eosinophils, although current data from different publically available databases/sources clearly demonstrate a widespread expression of Siglec-8 in the cells of most tissues. Two suggestions are presented: (1) In the specific case of Siglec-8, the limited mast cell selectivity should be kept in mind in the development and surveillance of Siglec-8-based mast cell- and eosinophil-targeted therapeutic strategies because of potential severe adverse effects in the Siglec-8-positive tissues. (2) In general, readers should always challenge reports about the selective expression of potential targets for drugs in a few cell types of the organism, even if they are published in highly renown journals.

Hypermobile Ehlers-Danlos syndrome (a.k.a. Ehlers-Danlos syndrome Type III and Ehlers-Danlos syndrome hypermobility type): Clinical description and natural history

The hypermobile type of Ehlers-Danlos syndrome (hEDS) is likely the most common hereditary disorder of connective tissue. It has been described largely in those with musculoskeletal complaints including joint hypermobility, joint subluxations/dislocations, as well as skin and soft tissue manifestations. Many patients report activity-related pain and some go on to have daily pain. Two undifferentiated syndromes have been used to describe these manifestations-joint hypermobility syndrome and hEDS. Both are clinical diagnoses in the absence of other causation. Current medical literature further complicates differentiation and describes multiple associated symptoms and disorders. The current EDS nosology combines these two entities into the hypermobile type of EDS. Herein, we review and summarize the literature as a better clinical description of this type of connective tissue disorder. © 2017 Wiley Periodicals, Inc.