sarcoidosis

Question 1

definition?

Answer 1

systemic disorder characterized by widespread immune-mediated formation of noncaseating granulomas

Question 2

pathophysiology?

Answer 2

inhalation of antigen -> activation of alveolar macrophages -> t cell recruitment and local immune hyperactivity -> formation of noncaseating granulomas in the lungs and lymphatic system (composed of epithelioid cells, macrophages, t-cells)

epithelioid cells cause fibrosis and organ damage

CALCIUM DYSREGULATION: alveolar macrophages increase activity of 1-alpha hydroxylase -> high 1,25 dihidroxyvitamin D -> vitamin d toxicity -> hyperphosphatemia -> hypercalcemia

Question 3

clinical features?

Answer 3

general: fever, malaise, lymphadenopathy
dyspnea, dry cough, chest pain

CUTANEOUS:
1. erythema nodosum (tender erythematous plaques in anterior lower legs)
2. lupus pernio (PATHOGNOMONIC red plaques on cheeks, nose, chin, or ears)
3. scar sarcoidosis (papular lesions on preexisting scars like needle sites/ elevation of scars and tattoos)

LYMPH NODES: bilateral hilar lymphadenopathy

OCULAR: uveitis (pain, photophobia, redness)

MSK: arthritis and myopathy (proximal muscles weakness)

neurosarcoidosis: unilateral or bilateral facial palsy

can involve heart, spleen, liver..

Question 4

diagnosis?

Answer 4

its diagnosis of exclusion supported by clinical findings+imaging and noncaseating granuloma on biopsy

1. CBC shows leopocytopenia
2. hypercalcemia
3. ecg
4. chest xray PREFERRED INITIAL TEST
5. HRCT for better assessment
6. bronchoalveolar lavage shows high CD4:CD8 (>3.5)
7. spirometry show restrictive pattern and low DLCO
8. GOLD STANDARD is biopsy from the most easily accessible lesions with findings:
   -noncaseating granuloma with giant cells
   -asteroid bodies
   -schaumann bodies

Question 5

xray findings with stages?

Answer 5

stage 1: bilateral hilar lymphadenopathy without infiltrates

stage 2: BHL with infiltrates

stage 3: ONLY infiltrates

stage 4: fibrosis

Question 6

treatment?

Answer 6

most patients with pulmonary sarcoidosis do not need immunosuppressive therapy

only indicated if:
-progressive symptomatic dx
-progressive worsening lung function
-persistent lung infiltration

drugs of choice:
-first line is glucocortticoids
if no response add DMARDS (methotrexate, azathioprine, chloroquine, biologics)

organ transplant is available also

Question 7

complications?

Answer 7

lung fibrosis -> cor pulmonale
respiratory failure
renal failure