Sarcoidosis

Sarcoidosis is a granulomatous disease of unknown cause that affects multiple organs, including the lung in 90% of cases.

Clinically it manifests itself in a very diverse way with an unpredictable natural history. Up to two thirds of patients present regression or improvement of symptoms over the years, and a minority have the disease chronically.

How is it produced?

Lung involvement consists of the appearance of bilateral hilar adenopathies with or without pulmonary infiltrates.

By an unknown mechanism, the appearance of an inflammatory infiltrate in the walls of the alveoli occurs until the formation of epithelioid granulomas develops and finally pulmonary fibrosis in cases that follow a chronic course.

Granulomas can also appear in other diseases such as tuberculosis.

Symptoms

It usually appears between the ages of 20 and 40, without distinction between the sexes. Even though the lung is the main affected organ, in up to 25% of cases the disease is discovered by chance in asymptomatic patients.

The initial forms usually present with general symptoms such as tiredness, loss of appetite or weight. As the disease progresses, the symptoms appear, which in the case of sarcoidosis is very diverse.

Pulmonary involvement can be undetectable in the initial forms, until respiratory distress appears with exertion and cough.

At the level of the involvement of other organs, the following stand out:

• Lupus pernio and erythema nodosum on the skin.
• Ocular involvement with anterior uveitis, uveoparotitis (Heerfordt syndrome), keratoconjunctivitis sicca.
• Bilateral lymphadenopathy palpable at the cervical level.
• cardiac arrhythmias, heart failure.
• Facial paralysis.
• diabetes insipidus
• involvement of large joints.
• hepatomegaly (20-30% alteration of liver enzymes).
• renal involvement with hypercalciuria and nephrocalcinosis.
• hematological involvement with mild anemia and neutropenia.

The combination of erythema nodosum, lung adenopathies, and joint pain is known as Lofgren's syndrome and is associated with a good prognosis.

Diagnosis

It is based on symptoms, radiology and immunology together with the demonstration of granulomas in one or more affected areas.

Chest radiology allows sarcoidosis to be classified into four stages that correlate with the probability of remission of the disease:

• Stage 0: normal chest radiograph. 10% of cases
• Stage I: bilateral hilar lymphadenopathy, symmetrical and well defined with respect to the cardiac silhouette. In chronic cases, these become chronic, giving rise to a characteristic "eggshell" image. It is the most common form of presentation.
• Stage II: in addition to bilateral hilar adenopathies, there are pulmonary infiltrates. Together with stage I, they represent 75% of sarcoidosis cases.
• Stage III: bilateral pulmonary infiltrates without hilar involvement. It is subclassified into III A: without evidence of pulmonary fibrosis, and III B: with pulmonary fibrosis in addition to other pulmonary affectations such as the appearance of bullae in the upper fields. It is the chronic and irreversible form of disease.

Computed tomography is another useful imaging test to classify these lesions.

blood tests show a slight decrease in white and red blood cells, as well as platelets. Up to 30% there is involvement of liver enzymes and the erythrocyte sedimentation rate is usually high. However, the characteristic clinical data is the elevation of Angiotensin Converting Enzyme (ACE) values.

Taking biopsies (generally of the lung) allows the identification of granulomas and thus establish the confirmatory diagnosis of sarcoidosis. In specific cases, biopsy of other areas may be indicated when the clinical context so indicates.

Treatment

In all cases, decisions are made individually based on clinical, radiological and functional terms.

Asymptomatic cases without signs of clinical or radiological progression require careful monitoring without treatment.

Symptomatic patients with clinical deterioration are treated with corticosteroids.

The prognosis for sarcoidosis is good. Of the obvious clinical cases, 60% present a complete remission or with minimal sequelae, 25% follow a slow-evolving progressive or recurrent clinical course, and only 5-10% die of progressive respiratory failure.