Cervical Tuberculous Lymphadenitis Notes

Cervical Tuberculous Lymphadenitis

Cervical Tuberculous Lymphadenitis is the most common form of extrapulmonary tuberculosis.

• Tuberculous infections of the cervical lymph nodes—often termed scrofula and king’s evil—are typically caused by tuberculous mycobacteria, but may also be caused by non-tuberculous mycobacteria.
• It is seen in endemic areas and in immunocompromised individuals.
• Lymph node tuberculosis constitutes 20–40% of extrapulmonary tuberculosis. It is more common in children and women and in Asians and Pacific Islanders.
• The disease may be caused by Mycobacterium tuberculosis, atypical mycobacteria, or Mycobacterium bovis.

Read And Learn More: General Surgery Notes

Cervical Tuberculous Lymphadenitis Aetiopathogenesis

In 80% of the cases, mycobacteria pass through tonsillar crypts and affect the tonsillar node or jugulodigastric group of nodes in the anterior triangle of the neck.

• In 20% of the cases, lymph nodes in the posterior triangle are affected due to adenoid involvement.
• Rarely, infection can spread from tuberculosis at the apex of the lung. Organisms directly penetrate Sibson’s fascia (suprapleural membrane) and may cause enlargement of the supraclavicular node.
• Other lymph nodes in the neck, such as the preauricular and submandibular nodes, may also be affected.
• Tuberculous bacilli survive within macrophages and release a toxin called tuberculosis necrotising toxin (TNT), which causes host cell death.
• In general, the incidences of lymphadenopathy at various sites are shown.

Cervical Tuberculous Lymphadenitis Pathological Types

1. Caseating type: The most common type seen in young adults.
2. Hyperplastic type: Lymph nodes show a marked degree of lymphoid hyperplasia. Least caseation is seen in patients with good body resistance.
3. Atrophic type: Seen in elderly patients. Lymphoid tissue undergoes degeneration. Glands are small with early caseation. A few lymph nodes may show scattered calcifications.

Cervical Tuberculous Lymphadenitis Clinical Features

Common in the age group of 11–30 years.

• HIV-immunocompromised disease is a strong risk factor for developing tuberculous infections.
• Tuberculous lymphadenitis presents as a gradually increasing painless swelling of one or more lymph nodes and lasts from a few weeks to a few months. Multiple sites may be involved.
• Systemic symptoms such as chills, fever, weight loss, fatigue, and night sweats are common, especially in those with extensive disease. Seen in about 40% of patients.
• In tuberculosis, interleukin-1(IL-1) and interleukin-6 (IL-6) are released, resulting in high-grade fever. However, this effect is somewhat counteracted by cortisol levels (which are also increased), resulting in low-grade fever.

Stages of Tuberculous (TB) Lymphadenitis

1. Stage of Lymphadenitis

• Common in young adults between 20 and 30 years of age.
• Upper anterior deep cervical nodes are enlarged.
• Nontender, discrete, mobile, firm lymph nodes are palpable.

2. Stage of Periadenitis or Stage of Matting

• Results due to capsular involvement
• Nodes move together—matting
• Firm, non-tender
• Matting is pathognomonic of tuberculosis
• Other rare causes of matting are chronic lymphadenitis and anaplastic variety of lymphoma.

3. Stage of Cold Abscess

• It occurs due to caseating necrosis of the lymph nodes, which results in a fluctuant swelling in the neck. Clinical features of a cold abscess in the neck are:
• No local rise in temperature, tenderness, or redness
• Soft, cystic, fluctuant, transillumination—negative swelling.
• It becomes less prominent on the sternocleidomastoid contraction test, indicating that it is deep to the fascia.

Tuberculous (TB) Lymphadenitis Differential Diagnosis

Branchial cysts may be confused for cold abscess in the anterior triangle. Cold abscess is of a shorter duration and may present with other lymph nodes in the neck. Branchial cyst, being a congenital swelling, is of a longer duration.

Tuberculous (TB) Lymphadenitis Treatment of Cold Abscess

• Nondependent aspiration using a wide bore needle to avoid a persistent sinus.
• A wide bore needle is preferred because the caseous material is thick.
• Incision and drainage should not be done as they cause persistent tuberculous sinus.
• Antituberculous treatment is administered.

4. Stage of Collar Stud Abscess

It results when a cold abscess deep to the deep fascia ruptures through the deep fascia and forms another swelling, which is fluctuant, in the subcutaneous plane.
Cross fluctuation test may be positive. It is treated like a cold abscess.

5. Stage of Sinus

• A sinus is a blind tract leading from the surface down into the tissues.
• Sinus occurs when a collar stud abscess ruptures through the skin.
• In India, the tubercular sinus is the most common sinus in the neck.
• Sinus is common in young females. There may be multiple sinuses.
• Tubercular sinuses have a wide opening.
• The sinus resembles an ulcer with an undermined edge.
• There is no induration.
• Surrounding skin is hyperpigmented and sometimes bluish in colour.
• A group of lymph nodes is usually palpable underneath the sinus.

Tuberculous (TB) Lymphadenitis Tuberculosis Of Intrathoracic Nodes

• Occurs in about 25% of all TB lymphadenitis cases.
• Pressure on the bronchus gives rise to atelectasis and lung infection.
• Pressure on the oesophagus causes dysphagia and oesophagotracheal fistula.
• Retroperitoneal nodes may give rise to chylous ascites and chyluria.
• HIV infection and lymph node TB.

HIV Infection and Lymph Node Tuberculosis

• It is more common than lymphoma and sarcoma
• Patients are male and older
• Multiple sites are more commonly affected
• Disseminated disease (virulent) may be seen
• Nodes can be tender
• Weight loss is more common

TB-IRIS: Tuberculosis-associated Immune Reconstitution Inflammatory Syndrome. This is seen in patients with tubercular lymphadenitis on retroviral therapy.

• TB-IRIS manifests as deterioration of a treated infection or as a new presentation of a previously subclinical infection. Thus, lymph nodes may persist or may become bigger.
• TB-IRIS occurs due to an antigenic response caused by the bactericidal action of antitubercular drugs.
• TB-IRIS needs only reassurance and anti-inflammatory drugs.
• A short course of steroids may be needed if pressure symptoms are present.
• However, if lymph nodes do not respond and are increasing, a biopsy should be done to rule out lymphoma.

Tuberculous (TB) Lymphadenitis Investigations

TB lymphadenitis is most commonly diagnosed by histopathology. Other investigations used for diagnosis are acid-fast bacilli (AFB) smear or Ziehl-Neelsen (ZN) staining and culture of lymph node material. Collection of samples or material for examination may be done by either:

1. Fine needle aspiration, or
2. Excisional lymph node biopsy.

1. Fine needle aspiration (FNA): It is considered as the first line of evaluation of suspected tuberculous lymphadenopathy. FNA had good sensitivity and specificity (77% and 93%, respectively). Materials

Obtained should be tested for:

• AFB smear microscopy (ZN staining or fluorescence microscopy)
• Mycobacterial culture with drug susceptibility testing
• Cytology
• Nucleic acid amplification testing (Xpert MTB/RIF) and line probe assays.

2. Excisional biopsy: This allows for a larger sample to be collected and has a higher diagnostic yield than FNA. Because a sinus tract may form if an incisional biopsy is performed, an excisional biopsy is preferred. Materials obtained should be tested for:

• AFB smear microscopy (ZN staining or fluorescence microscopy)
• Mycobacterial culture with drug susceptibility testing
• Histology: TB may be confirmed if epithelioid cell granulomas and caseation are seen. The chance of diagnosing TB is increased if multinucleated cells are present.
• In patients living with HIV, these typical granulomas are usually not found, as T cells (which are essential for their formation) are affected.
• Nucleic acid amplification testing (Xpert MTB/RIF) and line probe assays.
  • Histopathology findings of caseating granulomas, Langhans giant cells and foreign body giant cells are suggestive of TB.
  • Nucleic acid amplification testing (NAAT)—CBNAAT (cartridge-based NAAT) or Xpert MTB or RIF helps in both the diagnosis of TB and in the detection of rifampicin resistance.
  • NAAT identifies the complex nucleic acid of Mycobacterium tuberculosis but cannot assess the viability of the bacteria.
  • It cannot be used for monitoring the response to the treatment as it identifies the complex nucleic acid of dead Mycobacterium tuberculosis bacilli as well.
  • Line probe assays are molecular tests which make use of PCR to evaluate drug susceptibility to isoniazid, rifampicin, aminoglycosides, and fluoroquinolones.
  • Mycobacterial culture is the gold standard for diagnosis. It also helps in performing drug susceptibility testing (DST) on MTB complex growth, which may be used for decision-making by the treating physician or surgeon.
  • Tuberculin skin test (Mantoux test) is a delayed-type hypersensitivity reaction to antigens of Mycobacterium tuberculosis. The reagent used is protein purified derivative (PPD) which is injected intradermally.
  • The induration is measured between 48 and 72 hours. An induration >10 mm is considered to be reactive and is suggestive of M. tuberculosis infection. However, it does not indicate active disease.
  • A 5–9 mm induration is an intermediate response and may be attributed to BCG vaccination, M. tuberculosis, or atypical mycobacterial infections. An induration <4 mm is considered negative.
  • Interferon-gamma release assays (IGRAs) may be used in place of the Mantoux test for diagnosing TB infection.
• Imaging:
  • Chest X-ray should be done in all patients suspected of lymph node tuberculosis, as the lungs are the portal of entry for bacilli.
  • It may show features suggestive of active pulmonary tuberculosis or apical fibrosis suggesting previous exposure to tuberculosis. Positive chest radiograph abnormalities are more commonly seen in patients living with HIV.
  • HRCT scan of the thorax or abdomen may be done if mediastinal or abdominal lymphadenopathy is suspected.
  • Ultrasound scanning of the suspected anatomical site may be done to confirm the lymph node swelling, and abscess and also helps in guided FNA.
  • EBUS (endobronchial ultrasound) helps in localising the mediastinal lymph node and in guiding transbronchial needle aspiration (FNA) of mediastinal lymph nodes (mediastinoscopy or CT-guided FNA/biopsy are preferred if mediastinal lymph nodes are not accessible through EBUS).

Definitions of Diagnosis (INDEX TB Guidelines)

• Bacteriologically Confirmed LNTB Cases (Lymph Node TB)
• A patient with symptoms and signs of LNTB who has at least one of the following:
• Positive microscopy for AFB on examination of lymph node fluid or tissue
• Positive culture of Mycobacterium tuberculosis from lymph node fluid or tissue
• Positive validated PCR-based test (such as Xpert MTB/RIF)