Sarcoidosis USMLE Notes

Spread the love

Sarcoidosis USMLE Notes & Mnemonics contains all the high-yield points you need to know.

Sarcoidosis: A multisystem granulomatous disorder of unknown etiology, characterized by the accumulation of T-lymphocytes and mononuclear phagocytes, noncaseating granulomas in organs.

Epidemiology

Age: Often presents at <50 years
Sex: More common in females
Race: Higher prevalence in African Americans and Scandinavians

Etiology

Unknown cause, but immune response to an antigen may be a factor (Ref)
Possible environmental triggers in genetically predisposed individuals

Pathophysiology

Formation of noncaseating granulomas in multiple organs
CD4+ T-helper cells play a central role
ACE level elevation: Due to production by epithelioid cells of granulomas

Clinical Features

Lungs: Dyspnea, cough
Skin: Lupus pernio, erythema nodosum
Eyes: Uveitis, conjunctivitis
Lymphatic: Bilateral hilar lymphadenopathy
MSK: Arthritis, arthralgia
Heart: Conduction abnormalities, cardiomyopathy
CNS: Cranial nerve palsies, especially facial nerve
Hypercalcemia: Due to 1-alpha-hydroxylase mediated vitamin D conversion in macrophages

Mnemonic for Symptoms: “GRUELING“

G = Granulomas (noncaseating)
R = Rheumatological (arthralgias, arthritis)
U = Uveitis
E = Erythema nodosum
L = Lymphadenopathy (bilateral hilar)
I = Interstitial lung disease
N = Neurological (cranial nerve palsies)
G = Gammaglobulinemia (hypergammaglobulinemia)

Diagnosis

Chest X-Ray: Bilateral hilar lymphadenopathy, reticular opacities
CT Scan: Assess for pulmonary fibrosis, nodules, ground-glass opacities
Pulmonary function tests: Restrictive pattern, reduced diffusing capacity
Serum ACE levels: Elevated, nonspecific
Serum calcium: Hypercalcemia due to vitamin D activation by macrophages
Biopsy: Noncaseating granulomas without central necrosis
Bronchoalveolar lavage: Increased CD4/CD8 ratio

Treatment

Asymptomatic: Observation
Symptomatic: Glucocorticoids (first-line)
Severe or refractory disease: Methotrexate, azathioprine, infliximab

Complications

Pulmonary: Fibrosis, pulmonary hypertension
Cardiac: Arrhythmias, heart failure
Neurological: Seizures, neuropathy
Ophthalmologic: Blindness

Prognosis

Varies widely: many have spontaneous remission, others have chronic disease
Prognostic factors: Acute presentation like Lofgren syndrome (erythema nodosum, fever, bilateral hilar lymphadenopathy, and polyarthralgia) has a good prognosis

Mnemonic for Prognosis: “PHACE“

P = Pulmonary involvement severity
H = Heart complications
A = Ace levels (correlate poorly with disease activity)
C = Calcium levels (hypercalcemia can worsen prognosis)
E = Eye involvement

Note: This notes format is designed for quick review before USMLE exams; understanding pathophysiology and integrating clinical scenarios is essential for success. Always cross-reference with the latest guidelines and evidence.

Check other important USMLE Notes