Approximately 600 lymph nodes are located in the human body among which the submandibular, the axillary, or inguinal regions are palpable in healthy conditions . Cervical lymphadenopathy as a pathological condition is a symptom that appears often in adults as well as in children, with a rate of up to 45% of children showing palpable lymphadenopathy . Reasons for this swelling can vary from malignant to non-malignant causes. Whereas most lymph node swellings in children are caused by infections the rate of lymphadenopathies due to malignant reasons increases with age . Mean odds are stated between 1.03 and 1.05 for each 10-year increase [9, 10]. The main bacterial pathogens of suppurative cervical adenitis are described to be infections with S. aureus and group A streptococcus [11, 12]. Other pathogens, such as typical or atypical mycobacteria, Bartonella henselae, or F. tularensis are more seldom but should never be ignored as differential diagnosis.
On clinical examination, lymph nodes in the neck area greater than 1 cm are described as enlarged, except for the jugulodigastric nodes; here, 1.5 cm is accepted as normal size [13, 14]. Signs of inflammation, pain when pressing on the nodes, and insufficient movability on the underground, are further pathological markers that are not seen under healthy conditions. In particular, insufficient movability is a predictive marker for rupture of the capsule of the node in malignant processes. Additional so-called malignant B-symptoms such as fever, weight loss, or night sweats are often present at the same time .
A first algorithm for structural evaluation of patients with lymphadenopathy was proposed in 1978 by Greenfield and Jordan . Although these suggestions have been criticized a lot, basic elements are still used in examination workflows today. In a diagnostic procedure, detailed anamnesis should always be the first step. Practitioners often get first hints for the cause of swelling. Anamnesis should be followed by clinical examination. Special attention should be paid to visible extraoral or intraoral changes, such as scars (typical for Bartonella infections), decayed teeth, or malignant formations. More than half of the diagnoses can be made with these modalities . Blood analysis (at least blood count, C-reactive protein, ± procalcitonin/interleukin-6) completes these initial steps.
Medical ultrasound of the neck still remains the method of choice for instrument-based examination, especially of superficial cervical lymph nodes. Ultrasound is widely available and has no ionizing radiation. It might be superior to other imaging methods in differentiating metastatic from non-metastatic nodes using Doppler sonography . The disadvantages are a low penetration depth and big quality differences caused by experience of the investigators. For the detection of deep cervical nodes, such as those of the retropharyngeal space, a CT scan should always be done. It is first choice for a survey and follow-up of metastatic nodes in the neck . It is also the method of choice for defining accurate localization of enlarged nodes and their relationship to surrounding structures. Magnetic resonance imaging (MRI) as a radiation-free method provides high soft-tissue contrast resolution for morphologic evaluation of lymph nodes and their relationships. Diffusion-weighted imaging enables benign lymph nodes to be distinguished from malignant lymph nodes . Due to its limited availability and high price it should not be used as a standard diagnosis algorithm except for examination of children.
Histopathological evaluation of progress should follow as a diagnostic in persisting lymph node pathologies. Open excision biopsy of lymph nodes is considered to be the gold standard especially in the diagnosis of malignant lymphoma . Methods such as fine-needle aspiration or cutting needle biopsy are less invasive, less time consuming, and can be done under local anesthesia. Due to advances in immunohistochemical and cytopathological methods their accuracy has increased in the last few years but never reached the accuracy of excision especially in enlarged lymph nodes showing a heterogeneous pattern of disease . In metastasis diagnosis of lymph nodes or in examination of deep-seated lymph nodes with close proximity to vital structures, such as mature blood vessels and nerves, excision biopsy should remain the method of choice .
For the disease of tularemia all the diagnostic methods mentioned above are useful. Detailed anamnesis often reveals contact with animals in the past or patients to be farmers or hunters with close contact with wild animals. Scars in the face, mouth, or the hair might be visible as portals of entry in the ulceroglandular form in addition to a massive lymph node swelling in the neck region. Indirect diagnostic methods such as serum screenings are not precise especially in the first 2 weeks after primary infection. Early diagnosis, therefore, needs to be done by direct identification of the pathogen using molecular biological methods such as Enzyme-linked immunosorbent assay (ELISA) or different PCR methods like reverse transcriptase (RT)-PCR or even 16S rDNA PCR which shows a lower sensitivity compared to conventional RT-PCR . Sample material for investigation might be achieved from swabs of the ulcerative lesion. Enlarged lymph nodes or “meltings” in lymph nodes should be illustrated by ultrasound examination. Additional CT imaging can be used for a more detailed localization of the suppurative lymph nodes or empyemas especially in advance of possible drainage. This intervention should always be combined with a direct reconfirming identification of the pathogen.