Introduction

• Lymph nodes measuring less than 2cm are usually benign. Hence detailed evaluation is needed for nodes measuring more than 2cm.
• Nodal areas include:
  • Right cervical- Preauricular, upper cervical, lower cervical, supraclavicular
  • Left cervical
  • Mediastinal- Paratracheal, mediastinal, hilar
  • Right axillary
  • Left axillary
  • Right epitrochlear
  • Left epitrochlear
  • Para-aortic- common iliac- external iliac
  • Mesenteric-Splenic hilar, portal-celiac
  • Right inguinal
  • Left inguinal
  • Right popliteal
  • Left popliteal

Causes of lymphadenopathy

• Viral infections –Infectious mononucleosis, infectious hepatitis, herpes simplex, HHV-6, varicella zoster, rubella, measles, HIV, CMV
• Bacterial- streptococcus,staphylococcus, cat scratch disease, brucellosis,tularemia, plaque, Chandroid, meliodosis, tuberculosis , atypical mycobacteria, syphilis, diphtheria, leprosy.
• Fungal – Histoplasmosis,Coccidioidomycosis, paracoccidioidomycosis, blastomycosis  
• Chlamydial- lymphogranulomavenerum, trachoma.
• Parasitic-Toxoplasmosis, Leishmaniasis, trypanosomiasis, filariasis.
• Rickettsial- Scrub typhus, rickettsial pox.
• Immunological- RA, JRA, mixed connective tissue disease, SLE, dermatomyositis, Sjogren’s syndrome,  serum sickness, GVHD, ALPS, CVID, HLH, sarcoidosis
• Drugs-Diphenhydantoin, hydralazine, allopurinol, primadone, Gold, carbamazepine etc.
• Malignancies- HL, NHL, ALL, CLL, HCL, histiocytosis, metastatic disease (neuroblastoma, rhabdomyosarcoma, carcinoma, fibrosarcoma, germ cell tumors )
• Lipid storage disease- Goucher’s, Neimann Pick disease, Fabry’s disease, Tangier's disease
• Endocrine- Hyperthyroidism
• Others – Castleman’s disease,  dermatopathic lymphadenopathy, Kikuchi disease, Rosai-Dorfman disease, Kawasaki disease, IgG4 related disease, immune reconstitution inflammatory syndrome.

Investigations

• CBC
• Peripheral  smear: Can detect
  • CLL, ALL and other leukemias
  • Virocytes in viral infections
  • Lymphoma spillover
  • Lymphopenia and eosinophilia are seen in Hodgkin’s lymphoma 
  • Neutrophilia is seen in case of bacterial infection
• LDH
• Uric acid
• EBV serology/ Monospot test
• CMV serology
• HIV
• Bartonella titters
• Toxoplasma titters
• CXR
• USG
• ANA
• RA factor
• VDRL
• Lymph node biopsy- If there are
  • Systemic symptoms
  • Associated hepatosplenomegaly
  • Supraclavicular nodes
  • >2cm size
  • Immobile/hard nodes
• Avoid doing FNAC of lymph nodes
• BM Aspiration and biopsy in suspected carcinoma, lymphoma or granulomatous disease.
• CT chest-abdomen-pelvis

Diagnostic algorithm: