HNY Policy and Pathway Repository - North Yorkshire

A mild lymphocytosis has two main causes, either reactive (especially in children) or related to a lymphoproliferative disorder, e.g. CLL (especially in the elderly).

None provided

Differential Diagnosis:

• Normal - mild lymphocytosis is normal post-splenectomy or in children <5 years.
• Viral infection
• Bacterial infection - especially pertussis or chronic tuberculosis.
• Low-grade lymphoproliferative disorder blood film report comment such as `smear cells` may point towards this diagnosis.

Examination:

• Look for evidence of recent infection.
• Check for lymphadenopathy, hepatomegaly or splenomegaly.

Baseline investigations:

• Consider likelihood of viral aetiology and relevance of viral serology.
• If isolated lymphocytosis with no other disturbance in blood counts then repeat in 6-8 weeks to see if resolved.

Note that the diagnosis of an asymptomatic early-stage lymphoproliferative disorder (e.g. CLL) generally requires no treatment and often does not influence the life expectancy of an elderly patient. Consider the possibility of monitoring the blood count 6-12 monthly in General Practice rather than causing undue concern to the patient by confirmatory testing.

Referral:

Consider Haematology referral if:

• Lymphocyte count >10 x 10⁹/L
• Associated anaemia or thrombocytopenia.
• Lymphadenopathy, hepatomegaly or splenomegaly.
• B-symptoms unexplained weight loss, fevers, drenching night sweats, recurrent infections, extreme lethargy. It would be unusual to have significant symptoms with a lymphocyte count <20-30 x10⁹/L and no palpable lymphadenopathy.

Patients who are referred to ourselves with early, asymptomatic, low risk disease may be offered ongoing community follow-up, if agreed with their General Practice. See following letter for recommendations on monitoring and re-referral.

• Chronic lymphocytic leukaemia (CLL) Letter

Haematology Handbook - South Tees Hospitals NHS Foundation Trust

• South Tees Hospitals