Mycobacterial Infections, Atypical Tuberculosis in Children

Definition

Atypical mycobacterial infections are infections caused by several types of mycobacteria.  It is quite common in Northland children. These atypical mycobacterial infections may also occur as a complication in patients with HIV

Very close to Facial nerve !

Causes 

Although there are more than a dozen species of atypical mycobacteria, the two most common are Mycobacterium kansasii and M. avium-intracellulare (MAC). These microbes are found in many places in the environment: tap water, fresh and ocean water, milk, bird droppings, soil, and house dust. The manner in which these bacteria are transmitted is not completely understood. There is no evidence that they are transmitted from person to person.

 MAC, M. kansasii, and M. scrofulaceum may cause inflammation of the lymph nodes in otherwise healthy young children.  Atypical mycobacteria infections can also occur without causing any symptoms. 

Diagnosis

The diagnosis is made from the patient's symptoms and organisms grown in culture from the site of infection.The clinical picture of this infection is commonly very specific. This consists of unilateral submandibular lymphadenopathy in the submaxillary gland area usually associated with erythema of the overlying skin and abscess formation. The age group affected is characteristic 2 to 5 years. The children have minimal systemic symptoms and normal x-rays. Skin tests for atypical organisms are strongly positive; skin tests for Mycobacterium tuberculosis are usually weakly positive.

Treatment

These nontypical mycobacteria are not easy to treat in any patient . Antibiotics are not particularly effective, although rifabutin (a cousin of the anti-tuberculosis drug rifampin) and clofazimine (an anti-leprosy drug) have helped some patients. It is also possible to contain the infection to some degree by combining different drugs, including ethionamide, cycloserine, ethambutol, and streptomycin. Clearly these drugs have significant side effects and may have to be used for 6 months or more

Ideally  Surgical management is the best option. and consists of total excision of involved lymph nodes and skin, closure without drainage, and postoperative drug therapy with clarythromycin.
In the case from the top picture I used a technique of curettage because of the closeness of the marginal mandibular branch of the facial nerve. 

the nodes can be very large

Prognosis

Usually 90% cure rate with simple surgery. those that don't get better require additional medical management.