sarcoidosis

Sarcoidosis is a non-caseating granulomatous multisystem disease with a wide range of clinical and radiographic manifestations.

Individual systemic manifestations are discussed in respective articles:

• pulmonary and mediastinal manifestations
• cardiac manifestations 
• musculoskeletal manifestations
• head and neck manifestations
• central nervous system manifestations
• abdominal manifestations
• cutaneous manifestations

The remainder of this article pertains to a general discussion of sarcoidosis.

Epidemiology

Sarcoidosis occurs all over the world in all ages and races. Attempts to describe accurate epidemiology are complicated by the use of inconsistent diagnostic criteria and variable (often asymptomatic) disease manifestations.

Still, certain epidemiological patterns are reported in the literature:

• age of onset
  • most commonly presents between 2 through 4 decades of life, although diagnosis in children and elderly also recognized
• gender
  • inconsistent data
  • there may be a small female predominance among African-Americans
• race
  • highest incidence in African-Americans (36 to 50 per 100,000) and northern European Caucasians
  • incidence among Caucasians has been estimated at 11 to 20 per 100,000
  • reported incidence is lower in Asian populations
• heritability
  • familial clustering of sarcoidosis has been reported, suggesting either a genetic or environmental component of the disease
  • the two largest studies suggest a familial relative risk increase ~4x given a single affected first-degree relative

Clinical presentation

Clinical presentation is variable and diagnosis is usually made on the combination of clinical and radiological features.

• half of the patients are asymptomatic
• the rest develop respiratory (e.g. cough and dyspnea) or skin (e.g. erythema nodosum, lupus pernio, scars, plaques) disease
• ocular, lacrimal gland and salivary gland involvement are relatively common
• approximately 5% of patients develop neurosarcoidosis 

Additionally, patients may have specific syndromic presentations:

• Löfgren syndrome: an uncommon but specific acute presentation of sarcoidosis with a better prognosis
• Heerfordt syndrome: an uncommon variant of sarcoidosis comprising of fever, parotid enlargement, facial palsy, and anterior uveitis

Pathology

Sarcoidosis is a multisystem disorder of unknown etiology characterized by the formation of inflammatory non-caseating granulomas within affected tissues. Histologically, the lesions characteristically demonstrate an absence of a necrotic component, except in rare cases (so-called "necrotizing sarcoid granulomatosis"). The granulomas may resolve spontaneously or progress to fibrosis.

It is thought to represent a disorder of immune regulation, particularly of cell-mediated immunity . Mycobacterium and propionibacterium RNA and DNA have been detected in sarcoidosis lesions, raising the possibility of an infectious trigger . Reported familial clustering and co-occurrence in monozygotic twins suggest that genetic susceptibility may also play an important role.

Microscopic appearance

Characteristic (but not pathognomonic) histological features include:

• non-caseating granulomas
  • epithelioid cells, macrophages, multinucleated giant cells, and CD4+ T cells
  • fibroblasts, B lymphocytes, and CD8+ T cells may be present more peripherally
• Schaumann bodies: laminated calcium-containing concretions
• asteroid bodies
• necrosis is atypical and may suggest another etiology

Markers

Biochemical markers include:

• elevated angiotensin-converting enzyme (ACE)
  • 40% false negative
  • 10% false positive
• hypercalcemia and hypercalciuria

Additionally, a positive Kveim-Siltzbach skin test helps to confirm the diagnosis .

Radiographic features

90% of patients have pulmonary involvement (although many are asymptomatic) . Since chest x-rays are readily available and have low radiation burden, the pattern of nodal and parenchymal involvement is typically used to 'stage' sarcoidosis (chest x-ray staging of sarcoidosis) .

Treatment and prognosis

Treatment is primarily with judicious use of corticosteroids, to avoid adverse medication effects.

Pulmonary involvement is responsible for the majority of morbidity and mortality in patients with sarcoidosis. The overall mortality rate is approximately 5%, with patients who present insidiously faring worse than those who present with an acute onset . Likelihood of resolution depends on the stage of disease at presentation :

• stage I: 60% resolution within 1-2 years
• stage II: 46%
• stage III: 12%

Complications

Complications depend on the systemic pattern of disease involvement. As pulmonary sarcoidosis is by far the most common manifestation, so are thoracic complications. They include :

• pulmonary fibrosis (stage IV)
• pulmonary arterial hypertension and cor pulmonale
• aspergillomas, which may be complicated by hemoptysis

History and etymology

Historically, sarcoidosis was also known as Besnier-Boeck-Schaumann disease/syndrome, or various combinations thereof, e.g. Besnier-Boeck disease, Boeck disease, or Schaumann syndrome .

Sarcoidosis is derived from the Ancient Greek terms, σαρξ (sarc) meaning flesh, ειδος (eidos) meaning form, and σις (-sis), a suffix meaning a process .

Siehe auch:

• Sarkoidose der Milz
• Sarkoidose der Leber
• Aspergillom
• Neurosarkoidose
• pulmonale und mediastinale Sarcoidose
• Lungenfibrose
• Sarkoidose Stadien
• pulmonale Hypertonie
• löfgren syndrome
• bihiläre Lymphadenopathie
• heerfordt syndrome
• lambda sign
• sarcoid galaxy sign
• panda sign
• Garland Trias
• Berylliose
• kardiale Beteiligung bei Sarkoidose
• abdominelle Manifestationen der Sarkoidose
• musculoskeletal manifestations sarcoidosis

und weiter:

• verkalkte mediastinale Lymphknoten
• verkalkte Lungenherde
• Silikose
• Kerley-Linien
• Meningitis
• Kryptogene organisierende Pneumonie (COP)
• Chylothorax
• animal and animal produce inspired signs
• right middle lobe consolidation
• Ollier-Syndrom
• Nervus facialis
• Splenomegalie
• Lymphangiosis carcinomatosa
• Funikuläre Myelose
• Granulomatose mit Polyangiitis
• miliare Lungenherde
• Langerhanszell-Histiozytose der Lunge
• mediastinal lymphoma
• Bronchiolitis obliterans
• inflammatorischer Pseudotumor der Orbita
• multiple zystische Lungenherde
• apical zone
• pulmonary opacification
• akute Pyelonephritis
• chronic periaortitis
• Erythema nodosum
• Warthin-Tumor
• Parenchymband
• hyperdenser Lymphknoten
• Interstitielle Lungenerkrankung
• diffuse Trachealwandverdickung
• bilaterale hiläre Lymphadenopathie
• Sarkoidose ossäre Manifestationen
• Metastasen in der Orbita
• conditions involving skin and bone
• bilaterale axilläre Lymphadenopathie
• sausage digit
• chronic bilateral airspace opacification
• testicular sarcoidosis
• pulmonale venookklusive Erkrankung
• differential of chronic alveolar opacities
• stroke in children and young adults
• musculoskeletal manifestations of sarcoidosis
• metastases to the pituitary gland
• obliterative bronchiolitis (mnemonic)
• adenoid cystic carcinoma of lacrimal glands
• hiläre Lymphadenopathie
• Eierschalenverkalkungen
• bronchovascular spread (mnemonic)
• Meningeom Nervus opticus
• Silzbach sarcoidosis chest radiographic staging system
• Läsionen der Fingerspitze
• hyperechoic liver
• calcifying epithelioma of Malherbe
• echogenic renal pyramids
• Nasenseptumdefekt
• lambda sign of sarcoidosis
• generalised increased liver echogenicity
• pulmonale Calciphylaxie
• pulmonary arterial hypertension classification - third world symposium on PAH
• sarcoidosis: musculoskeletal manifestations of the skull
• Verkalkungen bei Sarkoidose
• vertebral sarcoidosis
• diffuse Trachealverengung
• crazy paving-Muster
• hypervaskularisierte Lymphknoten
• fibrosierende Mediastinitis
• Mikulicz-Syndrom
• Bronchusobstruktion durch granulomatöse Erkrankungen (Sarkoidose)
• Dural-Tail-Zeichen
• verdickter Nervus Opticus
• pleurale Sarkoidose
• Sarkoidose der Mamma
• tuberkulöse Daktylitis
• Sarkoidose der Hypophyse
• Kveim Stilzbach skin test
• idiopathische granulomatöse Mastitis