Sarcoidosis
Lourdes R. Laraya-Cuasay, Walter T. Hughes in Interstitial Lung Diseases in Children, 2019
Although the etiology of sarcoidosis is unknown, it appears to be an immunologic response to an unknown antigenic stimulus, which gains access to the body by the lungs. The initial response to the antigen is an alveolitis, characterized by infiltration of the alveolar septae by increased numbers of mononuclear cells, T-lymphocytes and macrophages.12 Most of the T-lymphocytes are of the helper variety with proportionally fewer suppressor T-cells. A significant percentage of these helper T-cells are releasing mediators to attract mononuclear phagocytes to the lung with monocyte chemotactic factor, to immobilize them there with migration inhibitory factor and to provide polyclonal activation of B-cells.13 The peripheral blood, meanwhile, shows a lower proportion of T-helper cells compared to the numbers present in normal controls.14 The polyclonal activation of the B-cells accounts for the frequently observed hyperglobulinemia and increased levels of immunoglobulins noted in patients with sarcoidosis. The decrease in the numbers of T-helper cells in peripheral blood is a partial explanation of the parodoxical finding of a depressed response to delayed hypersensitivity skin tests to tuberculin and other antigens, another characteristic of sarcoidosis.
Sarcoidosis extra-pulmonary manifestations
Muhunthan Thillai, David R Moller, Keith C Meyer in Clinical Handbook of Interstitial Lung Disease, 2017
Sarcoidosis is present in more organs than is clinically apparent (13). However, often, sarcoidosis organ involvement has no clinical impact, no long-term consequences and does not require therapy (14). Therefore, patient care is not optimized by identifying every possible organ involved with sarcoidosis (13). It is imperative to detect sarcoidosis organ involvement that results in significant symptoms or impairment of function or quality of life. This requires all patients diagnosed with sarcoidosis to undergo a complete medical history and physical examination. As sarcoidosis may affect any organ in the body, any symptom may represent a manifestation of sarcoidosis. Obviously, knowledge of typical and atypical presentations of sarcoidosis is useful to determine the likelihood that a specific sign or symptom warrants further evaluation for sarcoidosis. Descriptions of such presentations are available in the literature (15,16).
Acute Bacterial Meningitis and Its Mimics in the Critical Care Unit
Cheston B. Cunha, Burke A. Cunha in Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Neurosarcoidosis is a common manifestation of sarcoidosis. Signs of CNS sarcoid include headaches, mental confusion, and cranial nerve palsies. Any of the cranial nerves may be affected. Patients with sarcoidosis may often present with polyclonal gammopathy on serum protein electrophoresis, an elevated ESR, leukopenia, mild anemia, and increased levels of serum angiotensin-converting enzyme (ACE). Chest X-ray shows one of the four stages of sarcoidosis, ranging from bilateral hilar adenopathy to parenchymal reticular nodular fibrotic changes. In neurosarcoidosis, the CSF is usually abnormal. A lymphocytic pleocytosis (≤300 cells/mm) is usual. Protein levels in the CSF are usually elevated. About 20% have a decreased CSF glucose level. The RBCs are not a feature of neurosarcoidosis. Aseptic meningitis with sarcoidosis may mimic viral aseptic meningitis. Patients usually have a history of sarcoidosis, which is a clue to the diagnosis. Diagnosis of neurosarcoidosis is a diagnosis of association and exclusion. Neurosarcoidosis occurs in the setting of systemic sarcoidosis and is characterized by elevated ACE levels and negative CSF Gram stain/culture. Multiple cranial nerve palsies are usual. Treatment is with corticosteroids/immunosuppressives [1,20,23,24] (Table 11.3).
Infliximab for relapsing neurosarcoidosis recurring after kidney transplantation: a case report
Published in Acta Clinica Belgica, 2021
Nicolas Hanset, Mawufemo Yawovi Tsevi, Thierry Duprez, Adrian Ivanoiu, Arnaud Devresse, Nathalie Demoulin, Nada Kanaan
Sarcoidosis is a multisystem inflammatory disease of unknown aetiology, which usually affects young adults. Both genetic and environmental factors may be involved in the pathophysiology of the disease. It is noteworthy that our patient carried both HLA-DRB1 and HLA-DQB1 alleles, which have been consistently associated with sarcoidosis.1 Nervous system involvement is rare. Neurosarcoidosis most frequently affects cranial nerves, but also meninges and parenchyma. It may occur several years after the initial diagnosis.2 Clinical features are variable, including cranial nerve palsies (most frequently II, VII, VIII), neurological or endocrine dysfunctions, hydrocephalus, seizure, myalgias, cognitive or psychiatric symptoms.3 Best-suited diagnostic investigations are gadolinium-enhanced MRI and CSF analysis.2 As in our patient, contrast-enhanced T1-weighted images reveal leptomeningeal thickening with focal or diffuse enhancement (Figure 1(c)). Parenchymal lesions appear as contrast-enhanced foci of variable size (Figure 1(a,b)).4 Analysis of CSF reveals non-specific lymphocytic inflammation, often with elevated protein levels and sometimes with decreased glucose ones. ACE levels in both CSF and serum are less helpful in the diagnosis given their low sensitivity and specificity.3,4
Is sarcoidosis related to metabolic syndrome and insulin resistance?
Published in The Aging Male, 2020
Pinar Yıldız Gülhan, Ege Güleç Balbay, Merve Erçelik, Şeyma Yıldız, Mehmet Alper Yılmaz
Immunological mechanisms involved in the pathogenesis of sarcoidosis and MetS considered these two diseases may be the cause or result by each other [6, 13]. In our study, we found that the etiology of sarcoidosis is unknown. It is thought that there is an immunological over-response against unknown antigens in people with genetic background [14]. Antigens which are phagocytosed by macrophages and dendritic cells known as antigen-presenting cells (ASHs) creates epitopes on the surface of the ASH that can match with the MHC (major histocompatibility complex) class II found on the surface of T lymphocytes. As a result of this pairing, natural T lymphocytes are transformed into the Th1 phenotype and many cytokines and chemokines are secreted, leading to the development of sarcoid granuloma formation [15].
Uveitis as a window to diagnosis of sarcoidosis – case report and review of the literature
Published in Acta Clinica Belgica, 2020
Sebastiaan Dhont, Mathias Leys, Edward De Sutter, Herwig Alaerts, Wouter Van Moerkercke
Despite extensive research, the exact etiology of sarcoidosis remains unknown. Studies suggest that genetic, host immunologic and environmental factors interact together to cause sarcoidosis. Identification of interactions between specific loci and various ubiquitous environmental modifiers will probably be important in delineating the cause [2,6]. Various exposures to airborne antigens have been linked to the development of sarcoidosis, such as irritants found in rural setting and occupational exposure such as fire rescue workers and metal-industry workers [6]. A growing body of evidence links microbial infection to sarcoidosis etiology, with Mycobacterial and Propionibacterium organisms being the target of most studies. In a Case-Control Etiologic Sarcoidosis Study (ACCES), the authors have revealed a familial risk of sarcoidosis to have an estimated odd ratio of 5.8 for siblings and 3.8 for parents [7]. Otherwise, it should be stressed that despite this significant increased risk for relatives of sarcoidosis, both the absolute risk for a sibling or a parent of a sarcoidosis case were approximately 1%, given that increased surveillance is probably not warranted [7]. Recent studies report association between sarcoidosis and MHC II classes: the MHC genes play a critical role in governing antigen presentation and regulating adaptive immunity [6]. HLA-DQ and HLA-DR had the strongest association with risk of developing sarcoidosis [6,8].
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