Common causes of lymphadenopathy are

I. Inflammatory Causes
A. Acute Lymphadenitis
B. Chronic Lymphadenitis:

• Septic
• Tuberculosis
• Filariasis
• Syphilis
• Lymphogranuloma inguinale

II. Neoplastic
A. Primary: Lymphosarcoma
B. Secondary: Carcinoma, sarcoma, malignant melanoma.

III. Hematological
A. Hodgkin’s disease
B. Non-Hodgkin’s lymphoma
C. Chronic lymphatic leukemia
D. AIDS

IV. Immunological

• Serum sickness
• Drug reaction
• SLE
• Rheumatoid arthritis

Differential Diagnosis

Acute Lympadenitis:

• Enlarged, tender and fixed lymph nodes.
• Overlying skin may become red, hot and brawny.
• Primary infective focus may be found.

Chronic Septic Lymphadenitis:

• Enlarged, slightly tender lymph nodes which may or may not be matted.
• If abscess has occurred, fluctuation in the centre and pitting on pressure at the periphery will be evident. It is often difficult to differentiate from tuberculous lymphadenitis.

Tuberculous Lymphadenitis:

• Commonly affects the deep cervical, mesenteric and axillary agents.
• The lymph nodes may be discrete (when it resembles chronic septic lymphadenitis) or may be matted.
  If caseation has occurred, cold abscess results which may burst forming tuberculous ulcer or sinus which takes a long time to heal.
• Fever with chills weight loss, anorexia and respiratory complaints may be present.

Syphilitic Lymphadenitis:

• Painless, firm, discrete and shotty glands which do not suppurate.
• In secondary syphilis, generalized lymphadenopathy occurs involving especially epitrochlear and occipital glands.
• Other evidence of syphilis with positive tests for syphilis like WR, VDRL, TPI, and FTA ABS.

Filarial Lymphadenitis:

• Pain, tenderness and swelling of the inguinal lymph nodes, spermatic cord and scrotum.
• Lymphangiectasia (dilation of the lymph vessels) of the inguinal region and spermatic cord.
• Eosinophilia and microfilaria can be demonstrated in the blood.
• Lymph nodes biopsy may reveal adult worm.

Lymphogranuloma Inguinale:

• Suppurative lymphadenitis with ulceration, sinus formation and extensive scarring of the inguinal lymph nodes.
• Frei’s test is confirmatory.

Lymphosarcoma:

1. Commonly affects the cervical glands which are enlarged, firm and fixed.
2. The overlying skin is stretched and shiny with dilated blue veins under it.
3. Highly malignant tumor grows rapidly and invades the surrounding tissues.

Secondary Carcinoma:

• The nodes are enlarged, irregular and fixed to all structures including the skin.
• Hard consistency.
• Primary growth may be detected.
• Patient may be cachectic and wasted.

Hodgkin’s Disease:

• Affects young adolescent males.
• Cervical glands are affected early but later all lymph nodes are involved.
• Lymph nodes are elastic and rubbery, discrete and movable with little tendency towards matting, softening or suppuration.
• Edema, venous engorgement and cyanosis of head and neck may occur due to pressure on the superior vena cava and the bronchus by the mediastinal glands. Root pains and paraplegia may develop due to pressure on the spinal cord.
• Hepatosplenomegaly and anemia occurs.
• Weight loss more than 10% of body weight and night sweats.
• Peripheral smear will show lymphocytosis and eosinophilia.
• Lymph node biopsy will show Reed Sternberg’s cell.

Non-Hodgkin’s Lymphoma:

Similar to Hodgkin’s lymphoma in clinical presentation except

• Enlargement of nodes in Waldeyer’s ring and supratrochlear glands
• Symptoms are less common
• Can be a manifestation of HIV infection
• Diagnosis confirmed by histological examination of the bone marrow.

Infectious Mononucleosis:

• Acute onset of fever, sore throat, headache, malaise and tiredness
• The lymph nodes are enlarged, discrete and slightly tender affecting especially the cervical and submandibular nodes.
• Non-tender splenomegaly may occur.
• Petechial rash may occur at the junction of soft and hard palate on the fourth day and may persist for 3-4 days.
• Peripheral smear shows leucocytosis (absolute lymphocyte count more than 1500/cmm) with atypical lymphocytosis.
• Paul-Bunnel test may be positive in 1:32 dilution or more usually in the first 10 days.