Scrofula disease: Description
Scrofula disease (tuberculous lymphadenitis) is an inflammation of the cervical lymph nodes caused by Mycobacteria tuberculosis.
Scrofula disease, also referred to as scrophula, struma or the King’s evil, is an inflammation of the cervical lymph nodes, which is one of the most common extrapulmonary manifestations of tuberculosis, although it may also occur due to atypical nontuberculous mycobacteria. Typically scrofula as other extrapulmonary manifestations of tuberculosis develops in individuals with impaired immunity. The word “scrofula” comes from the Latin and means “brood sow”.
In 95% of cases scrofula disease is caused by Mycobacteria tuberculosis, whereas nontuberculous (atypical) mycobacteria are the causative agents in the rest. Nevertheless, in children the situation is opposite with nearly 92% of cases caused by atypical mycobacteria (commonly Mycobacterium avium-intracellulare). In general scrofula is more often observed in children from two to ten years old than in adults.
Mycobacterium tuberculosis are transmitted through the air via airborne particles expelled with the sputum, rarely a person may catch Mycobacteria bovis via unpasteurized milk.
Nontuberculous mycobacteria include more than 50 species, about half of them may cause illnesses in humans. Unlike Mycobacterium tuberculosis atypical mycobacteria typically couldn’t be transmitted from person-to person. The prevalence of nontuberculous mycobacteria varies in accordance with the climate region – the highest prevalence is observed in hot climate regions.
- Mycobacterium tuberculosis
Scrofula disease is characterized by the painless enlarged firm cervical node/nodes with unchanged skin over them, in immunocompetent individuals on one side, while in one third of cases may appear bilaterally, especially in case of HIV-infection. Early in the course of the disease these nodes appear discrete and non-tender, although later they may become inflamed and form fistulae through which caseous material is discharged. Typically anterior and posterior cervical lymph nodes (which are located along the borders of the sternocleidomastoid muscle) and supraclavicular nodes (above the upper border of the clavicle) are affected. Less commonly the submandibular, submental, axillary, and inguinal lymph nodes are involved. Other symptoms including weight loss, fever with chills, fatigue, night sweats and general malaise are usually seen in persons with comorbid HIV-infection.
- Nontuberculous mycobacterium
Atypical mycobacteria cause the formation of chronic non-tender, somewhat fluctuant enlargement in the region of the and neck know as a cold abscess. The skin over the lymph nodes appear bluish-purple (violaceous) in color. The progression of the lesion and its growth is often characterized by the adherence of the skin to the affected lymph nodes. Later the mass may rupture.
Chest X-ray may reveal the presence of pulmonary tuberculosis, although in nontuberculous lymphadenitis chest X-ray is usually normal.
Fine-needle aspiration has high specificity and sensitivity revealing stainable acid-fast bacilli. To make a diagnosis, biopsy with culture may be required. Polymerase chain reaction nowadays may be used to verify the causative agent.
Scrofula disease is only one of the manifestations of the systemic disease, therefore, systemic chemotherapy is required. Empiric treatment includes isoniazid, rifampin, pyrazinamide and ethambutol for 2 months and then continues with 2 drugs for 4 months. However, chemotherapy is not effective in case of nontuberculous lymphadenitis.
Surgical treatment is not recommended for tuberculous lymphadenitis due to high rates of recurrence and fistulae formation, whereas surgical interventions are the mainstay for nontuberculous lymphadenitis. It is recommended to remove the lesion completely in order to prevent complications.