A five year old girl, born in Romania and affected by neonatal hypoxic-ischemic encephalopathy, was admitted to our division because of fever and lymphadenopathy. The lymph-node was a latero-cervical, unilateral, painful, swelling lymph node fixed but soft in the middle, with the overlying skin appearing thin, shiny and erythematous. Lymph node characteristics did not change despite amoxicillin -clavulanate and anti-inflammatory therapy.
The neck ultrasonography (US) highlighted hypoecoic, bunched, necrotic lymph nodes measuring 4.5 cm as a whole.
TST showed a positive reaction (>15 mm induration) and the IGRA was positive.
Ziehl Nielsen staining of the smears, cultures and nucleic acid amplification, collected by three early morning gastric washings and performed for up to three consecutive days, gave negative results for Mtb. Urine tests (Ziehl Neelsen staining, cultures and nucleic acid amplification) were negative too. Chest x-ray and abdominal US evaluation were negative.
Surgical evaluation was performed and lymph nodes drainage was carried out by fine needle aspiration. The analyses carried out on the drained material showed a positivity of nucleic acid amplification (PCR) for Mtb.
An anti-TB therapy with INH, RMP and PZD was begun. After the beginning of the therapy, girl's clinical conditions improved, fever disappeared and lymph nodes size progressively diminished.
TB lymphadenitis in superficial nodes is the most common form of extrapulmonary TB in children. The laterocervical nodes become involved secondary to the extension of a primary pulmonary lesion. Lymph nodes localization develops 6-9 months after an initial TB infection.
In developed countries more than two-thirds of pediatric lymphadenopathy have infectious causes other than TB, therefore cases of lymphadenitis are commonly treated with a high-spectrum antibiotic; nevertheless, it would be mandatory to give the instruction to return for reevaluation in case of no clinical improvement in order to perform other investigations to reach a final diagnosis.
In our case, patient's medical history, familiar origins from a TB endemic country, and the particular lymph node characteristics (unilateral, involving multiple nodes, fixed to underlying tissues, initially non-tender, solid, covered by erythematous skin and successively tending to colliquation and fluctuation), should give the suspect of TB etiology and allow the beginning of the diagnostic procedures described in our clinical case. Systemic signs and symptoms other than low grade fever are usually absent.
Primary medical treatment, aimed to reduction of the high-grade inflammation, could be also followed by surgical removal in order to prevent fistulae development.
Since cross-reactivity between PPD-Mantoux test and non tubercular micobacteria (NTM) antigens, and less likely between IGRA tests and NTM antigens exists, microbiological tests performed on the infected lymph nodes should be the basis of differentiating between NTM and tuberculous lymphadenopathy.