B Symptoms in Lymphoma
B symptoms are defined as three specific systemic manifestations: unexplained fever >38°C, drenching night sweats (requiring changing of clothes or bedding), and unexplained weight loss >10% of body weight within 6 months of diagnosis. 1, 2
Clinical Definition and Components
The presence of B symptoms is designated by adding "B" to the stage classification (e.g., Stage IIB), while their absence is designated "A" (e.g., Stage IIA). 1, 2
The Three Cardinal B Symptoms:
- Fever: Unexplained temperature >38°C (100.4°F) 1
- Night sweats: Drenching episodes requiring changing of clothes or bedding—not just feeling warm 2
- Weight loss: >10% of body weight lost within 6 months prior to diagnosis 1
Clinical Significance and Prognostic Impact
B symptoms indicate systemic disease involvement and consistently predict worse outcomes across lymphoma subtypes. 1, 2
Prognostic Implications:
- B symptoms are independent unfavorable prognostic factors in early-stage (I-II) Hodgkin lymphoma, along with bulky disease, elevated ESR >50, and >3 nodal sites 1
- In follicular lymphoma, B symptoms are part of high tumor burden criteria and mandate treatment initiation even in otherwise asymptomatic patients 1, 2
- Patients with B symptoms more commonly present with advanced stage disease, extranodal involvement, and bone marrow involvement 1
- B symptoms are associated with increased myelosuppression from chemotherapy, independent of other risk factors 3
Disease-Specific Considerations:
In HIV-associated Hodgkin lymphoma, B symptoms are more common and should always prompt investigation for opportunistic infections before attributing them solely to lymphoma. 1
Diagnostic Workup When B Symptoms Present
When evaluating patients with suspected lymphoma and B symptoms, the workup must include:
- Complete blood count with differential and platelets 1, 4
- Erythrocyte sedimentation rate (ESR), which is particularly elevated with B symptoms 1
- Comprehensive metabolic panel, LDH, and liver function tests 1, 4
- PET/CT scan from skull base to mid-thigh for staging 1, 4
- Excisional lymph node biopsy (core needle acceptable if diagnostic; fine needle aspiration insufficient) 1, 4
A critical pitfall: In immunocompromised patients or those with HIV, infectious etiologies (tuberculosis, toxoplasmosis, other opportunistic infections) must be excluded before attributing B symptoms to lymphoma alone. 1
Treatment Implications
The presence of B symptoms directly impacts treatment decisions and urgency:
- In follicular lymphoma, B symptoms are an absolute indication to initiate systemic therapy, even in advanced stage disease that might otherwise be observed 1, 2
- Resolution of B symptoms serves as an important treatment response indicator and should be assessed at each follow-up 4, 5
- B symptoms predict increased chemotherapy-related myelosuppression, warranting consideration of growth factor support and closer monitoring 1, 3
Response Assessment:
B symptom resolution often precedes radiographic response and can occur even with partial remissions. 5 Persistent B symptoms during treatment should prompt re-evaluation for progressive disease or alternative diagnoses. 4