### Date : 2024-11-07 16:30 ### Topic : Sarcoidosis #medicine #internalmedicine ---- **Sarcoidosis** is a chronic, inflammatory disease characterized by the formation of **granulomas**—small clusters of immune cells—in various organs, most commonly the **lungs** and **lymph nodes**. The exact cause of sarcoidosis is unknown, but it is thought to involve an **abnormal immune response** triggered by environmental factors in genetically susceptible individuals. Sarcoidosis can be mild and self-limited or, in some cases, can lead to serious organ damage if granulomas interfere with normal organ function. ### Pathophysiology of Sarcoidosis Sarcoidosis is a **granulomatous disease** where immune cells aggregate into clusters called granulomas, particularly in affected organs: 1. **Immune Activation**: - The immune system reacts abnormally to an unknown trigger, leading to the activation of **macrophages** and **T-cells**. - These immune cells release cytokines, promoting inflammation and attracting additional immune cells. 2. **Granuloma Formation**: - The accumulated immune cells form granulomas, which are small clusters of macrophages surrounded by lymphocytes and fibrous tissue. - Granulomas attempt to "wall off" the trigger but can disrupt organ structure and function when they persist or increase in number. 3. **Fibrosis**: - Over time, some granulomas may heal, but others may become **fibrotic** (scarred), especially in the lungs. This can lead to pulmonary fibrosis, reducing lung elasticity and impairing gas exchange. ### Common Sites of Sarcoidosis Sarcoidosis can affect almost any organ, but it primarily involves: - **Lungs**: Pulmonary sarcoidosis is the most common form, with granulomas often found in the lung interstitium and lymph nodes. - **Lymph Nodes**: Enlarged lymph nodes, especially in the chest (hilar and mediastinal lymphadenopathy), are a hallmark of sarcoidosis. - **Skin**: Skin involvement may include erythema nodosum (painful red nodules on the legs) and lupus pernio (purplish lesions on the face). - **Eyes**: Eye involvement (uveitis) can lead to pain, redness, and potential vision problems. - **Liver and Spleen**: These organs may also develop granulomas, sometimes causing mild enlargement. - **Heart**: Cardiac sarcoidosis can lead to arrhythmias, heart block, and heart failure, which can be life-threatening. - **Nervous System**: Neurosarcoidosis can affect the central or peripheral nervous system, causing facial nerve palsy, headaches, or other neurological symptoms. ### Symptoms of Sarcoidosis Symptoms of sarcoidosis vary widely depending on the organs involved and may range from mild to severe: 1. **General Symptoms**: - Fatigue - Fever - Unintentional weight loss - Night sweats 2. **Pulmonary Symptoms** (if lungs are involved): - Shortness of breath (dyspnea) - Persistent dry cough - Chest pain 3. **Skin Symptoms**: - **Erythema Nodosum**: Tender, red nodules on the shins, often associated with an acute, self-limiting form of sarcoidosis. - **Lupus Pernio**: Purple or reddish lesions on the nose, cheeks, and ears; associated with chronic sarcoidosis. 4. **Eye Symptoms**: - Redness, pain, and sensitivity to light (uveitis) - Blurred vision or visual disturbances 5. **Cardiac Symptoms** (if heart is involved): - Palpitations, chest pain, and in severe cases, arrhythmias or heart block - Symptoms of heart failure, such as swelling and shortness of breath 6. **Neurological Symptoms**: - Headaches, seizures, or nerve problems like facial paralysis ### Diagnosis of Sarcoidosis Diagnosing sarcoidosis requires identifying granulomas and ruling out other potential causes of granulomatous disease, like infections or autoimmune disorders: 1. **Chest X-Ray and High-Resolution CT (HRCT)**: - Chest X-ray can show **bilateral hilar lymphadenopathy** (enlarged lymph nodes in the chest) and **lung involvement** with a characteristic pattern. - HRCT provides more detail on lung involvement, revealing granulomas and fibrosis. 2. **Pulmonary Function Tests (PFTs)**: - Pulmonary function tests assess lung function. Sarcoidosis may present with a restrictive pattern (reduced lung volumes) or obstructive changes depending on the extent of fibrosis. 3. **Blood Tests**: - **Angiotensin-Converting Enzyme (ACE)** levels are often elevated in sarcoidosis, although not specific. Elevated ACE can support the diagnosis but is not definitive. - **Calcium Levels**: Sarcoidosis can cause hypercalcemia (elevated blood calcium), likely due to granulomas producing vitamin D. 4. **Biopsy**: - A tissue biopsy from affected areas (lung, lymph node, skin) shows **non-caseating granulomas**, which are clusters of immune cells without the central necrosis seen in other granulomatous diseases (e.g., tuberculosis). - Bronchoscopy with lung biopsy is often used for pulmonary sarcoidosis, while skin biopsy can be useful if there are skin lesions. 5. **Electrocardiogram (ECG) and Echocardiography**: - These tests evaluate heart function, especially if cardiac sarcoidosis is suspected due to symptoms like arrhythmias. 6. **Eye Examination**: - A thorough eye examination is essential for patients with eye symptoms, as uveitis can lead to serious complications. ### Staging of Pulmonary Sarcoidosis Pulmonary sarcoidosis is often staged based on chest X-ray findings: - **Stage I**: Bilateral hilar lymphadenopathy without lung involvement. - **Stage II**: Bilateral hilar lymphadenopathy with lung infiltrates. - **Stage III**: Lung infiltrates without hilar lymphadenopathy. - **Stage IV**: Pulmonary fibrosis with scarring and honeycombing, indicating chronic, advanced disease. ### Treatment of Sarcoidosis Many cases of sarcoidosis resolve on their own, but treatment may be necessary for patients with persistent or severe symptoms, particularly if organs like the heart, eyes, or nervous system are involved: 1. **Observation**: - Mild cases, especially those limited to lymph nodes or with minimal symptoms, may not require treatment and are monitored periodically. 2. **Corticosteroids**: - **Prednisone** is the mainstay of treatment for sarcoidosis, especially for symptomatic lung disease, skin lesions, or organ involvement. - Corticosteroids reduce inflammation and granuloma formation but can have significant side effects with long-term use. 3. **Immunosuppressive Agents**: - **Methotrexate**, **azathioprine**, and **mycophenolate** are sometimes used as steroid-sparing agents to reduce the need for long-term corticosteroids. - **Tumor Necrosis Factor (TNF) Inhibitors**: Medications like infliximab may be effective for severe or refractory cases, particularly with lung or skin involvement. 4. **Antimalarial Drugs**: - **Hydroxychloroquine** can be effective for skin sarcoidosis and hypercalcemia associated with sarcoidosis. 5. **Organ-Specific Treatment**: - **Eye Involvement**: Topical or systemic corticosteroids are often used, along with close monitoring by an ophthalmologist. - **Cardiac Sarcoidosis**: May require antiarrhythmic medications or pacemaker/defibrillator placement for arrhythmias or heart block. - **Pulmonary Rehabilitation**: Exercise and breathing training for lung function improvement and quality of life. ### Complications of Sarcoidosis Sarcoidosis can lead to complications, particularly if it progresses to organ dysfunction or fibrosis: - **Pulmonary Fibrosis**: Chronic lung inflammation can lead to scarring and fibrosis, reducing lung capacity. - **Pulmonary Hypertension**: Fibrosis in the lungs can cause increased pressure in the pulmonary arteries, leading to right heart failure. - **Blindness**: Uveitis and other ocular involvement can cause visual impairment or blindness if untreated. - **Heart Failure**: Cardiac sarcoidosis can lead to heart failure, arrhythmias, or sudden cardiac death. - **Hypercalcemia and Kidney Stones**: Elevated calcium levels can result in kidney stones and renal complications. ### Prognosis The prognosis for sarcoidosis varies widely. Many people experience spontaneous remission within 1-2 years, especially in cases with only lymph node or skin involvement. However, some patients may develop chronic disease, particularly those with lung fibrosis or cardiac involvement. Early diagnosis and appropriate management are key to controlling symptoms and preventing complications. ### Summary - **Sarcoidosis**: A chronic granulomatous disease affecting multiple organs, often the lungs and lymph nodes. - **Symptoms**: Include fatigue, dry cough, shortness of breath, and organ-specific symptoms like skin lesions or visual disturbances. - **Diagnosis**: Chest imaging, biopsy showing non-caseating granulomas, elevated ACE levels, and calcium levels. - **Treatment**: Observation for mild cases; corticosteroids, immunosuppressive drugs, and antimalarials for more severe cases or organ involvement. Sarcoidosis is a complex disease with varied presentations and outcomes. Tailored management can help patients manage symptoms and improve their quality of life, especially in cases with significant organ involvement. ### Reference: - ### Connected Documents: -