Sarcoidosis: A Complex Disease Simplified

What is Sarcoidosis?

Sarcoidosis is a disease that can affect any organ in the body. It is characterized by abnormal inflammatory cells that form clumps, most commonly in the lungs, lymph nodes, and skin, but can affect the eyes, musculoskeletal system, nervous system, heart, liver, and kidneys; in that order of occurrence. These granulomas form in organs and can change the organ's structure and function. Sarcoidosis usually presents in one of two ways: acute, with symptoms lasting only a short time (usually 12-36 months), and chronic, in which patients require prolonged treatment and can be lifelong.

Who is at the Highest Risk?

While studies show that sarcoidosis can affect all ethnicities and any age, there are higher risk groups. Presentation in females is more common than in males and is more than twice as common in African Americans than Caucasians. The typical onset of symptoms is often between 25-40 years old, but there is another peak in women after age 50. The highest risks are those with a family history or exposure to environmental factors, such as infectious agents, dust, and inhaled chemicals.

Clinical Symptoms

General

Fatigue is one of the most common symptoms occurring in 70% of patients. Because the lungs and lymph nodes are commonly involved, a dry, persistent cough, shortness of breath, or enlarged painless lymph glands are often the first symptoms. Other symptoms are sudden weight loss, night sweats, and low-grade fever. Concentration disturbances are a frequent complaint but could be the result of sleep apnea or obstructive pulmonary disease, which are both comorbidities of sarcoidosis.

Lungs and Lymph Nodes

Respiratory symptoms such as cough, difficulty breathing, and chest pain are seen in 30-53% of patients. Chest x-rays will often show pulmonary nodules or white streaks throughout the lung tissue, signifying fibrotic changes. This usually results in decreased volume and bronchiectasis.  In lymph nodes, they can become calcified, look chalky, or like a "cluster of black pearls." Enlarged lymph nodes are most commonly seen in perihilar and mediastinal areas, and perilymphatic pulmonary nodules are predominantly in the upper lobes.   They usually present bilaterally and are painless.

Skin

Recognizing cutaneous sarcoidosis is important because this is often the first sign of sarcoidosis, and it is easy to biopsy and test. Skin symptoms are present in 30% of patients. There are a wide variety of skin conditions, such as tender bumps on or underneath the skin, red patches, plaques, rashes, and even deep scars. The severity often correlates with the advancement of the disease and other organ involvement.

Heart

All patients should be screened for cardiac sarcoidosis, as it is life-threatening and often not recognized. Only 5% of patients are clinically diagnosed with cardiac involvement during life, but 25% are seen during autopsy. This can involve left ventricular dysfunction, cardiac arrhythmias, and sudden cardiac death. Patients may complain of peripheral edema, orthopnea, palpitations, feelings of skipped heartbeats, and syncope.  EKGs or Holter monitoring is suggested for additional screening if the heart is believed to be involved.

Eyes

Ocular involvement occurs in 10-50% of patients with sarcoidosis, with the highest prevalence seen in African Americans and women. There are several structures of the eye that can be affected, and most patients report only mild or no vision changes. If the optic nerve is involved, permanently impaired vision is seen in about one-third of patients.

Diagnostic Tools

• Chest x-rays or Computed Tomography (CT):  Provides a picture that is used to diagnose thoracic involvement such as lungs, heart, and surrounding lymph nodes. (These are present in 90% of patients).
• Pulmonary Function Test (PFT): A breathing test to measure lung capacity. This assists in differentiating between mild and severe phases of the disease.  
• Bronchoscopy: A small tube is inserted down the trachea into the bronchial tubes. It looks for granulomas and infections and can take biopsies. These tissue samples can confirm or rule out sarcoidosis.
• Positron Emission Tomography (PET): A small amount of radioactive fluid is injected into the vein. The fluid collects in granulomas and other inflamed areas and shows up on the scan. This helps to determine where and how much of the body is affected.
• Mediastinoscopy: A surgical procedure is done under general anesthesia. An incision is made in the base of the neck, where an instrument is passed to take a biopsy of lymph nodes in the chest.

Medication

There is no cure for sarcoidosis but frequently resolves on its own. Many people have such mild symptoms that no treatment is needed. Good health practices are important, such as eating a well-balanced diet, getting adequate sleep, exercising, and avoiding exposure to dust and other chemicals that can irritate the lungs. Medication therapy can be used in conjunction with good health practices.

• Corticosteroids are the most common, as they help reduce the inflammation of the tissues. These are reserved for patients with moderate to severe symptoms because they have many unwanted side effects.
• Immunosuppressants are commonly used when steroids are ineffective or in conjunction with corticosteroids. These drugs help to keep the immune system from attacking healthy cells.
• Non-steroidal anti-inflammatory drugs (NSAIDs) help relieve pain as well as reduce acute inflammation and fever.

Conclusion

Sarcoidosis can involve many different systems within the body and may range from mild to very severe.  Comprehensive care is important, and a patient's healthcare team may consist of a variety of specialists. If symptoms are mild, medication or treatment may not be required. This usually depends on how long they have had sarcoidosis, which organs are affected, and how much scarring is present. Follow-ups should be scheduled periodically to monitor the growth of granulomas. Sarcoidosis can be a complex disease, so be sure your patients feel comfortable to ask questions and request more information whenever they have concerns.

References/Resources

Clinical Manifestations, Diagnosis, and Treatment of Sarcoidosis: PubMed (nih.gov)

Erythema Nodosum: StatPearls - NCBI Bookshelf (nih.gov)

Sarcoidosis: A Clinical Overview from Symptoms to Diagnosis: PubMed (nih.gov)

Sarcoidosis: Causes, Symptoms & Treatment: Cleveland Clinic

Sarcoidosis - an overview: ScienceDirect