Castleman Disease
Overview: Castleman disease is a rare lymphoproliferative disorder that can present in two forms:
- Unicentric Castleman Disease (UCD): Involves a single lymph node or region and is usually asymptomatic or causes localized symptoms.
- Multicentric Castleman Disease (MCD): Involves multiple lymph nodes and can cause systemic symptoms. It is often associated with human herpesvirus 8 (HHV-8) and can be seen in patients with HIV.
Clinical Manifestations:
- Unicentric Form: Presents with localized lymph node enlargement, often asymptomatic or causing compressive symptoms depending on location.
- Multicentric Form: Presents with generalized lymphadenopathy, systemic symptoms like fever, night sweats, weight loss, and organomegaly.
Diagnosis:
- Biopsy: Histopathological examination reveals characteristic lymph node changes, including abnormal germinal centers and increased vascularity.
- Laboratory Tests: Elevated interleukin-6 (IL-6) levels, anemia, and elevated inflammatory markers (e.g., CRP, ESR) are common.
- Imaging: Used to identify the extent of lymphadenopathy and involvement of other organs.
Treatment:
- Unicentric Disease: Surgical excision of the affected lymph node is often curative.
- Multicentric Disease: Managed with a combination of corticosteroids, chemotherapy, and targeted therapies like tocilizumab (an IL-6 receptor antagonist).
Filariasis (Elephantiasis)
Pathophysiology: Filariasis is caused by the parasitic worms Wuchereria bancrofti, Brugia malayi, and Brugia timori, transmitted by mosquitoes. The parasites invade the lymphatic system, leading to chronic lymphatic obstruction and subsequent lymphedema.
Clinical Manifestations:
- Lymphedema: Progressive swelling, most commonly affecting the lower limbs, but can also involve the genitalia and breasts.
- Elephantiasis: Severe, chronic lymphedema with thickened skin, leading to disfigurement.
- Recurrent Infections: Due to the compromised lymphatic drainage, patients are prone to recurrent bacterial infections, exacerbating the lymphedema.
Diagnosis:
- Blood Smear: Detection of microfilariae in blood samples, typically drawn at night when parasites are most active.
- Serology: Antibody tests to detect past or current infection.
- Ultrasound: Can visualize adult worms in the lymphatic vessels.
Treatment:
- Antiparasitic Drugs: Diethylcarbamazine (DEC) is the drug of choice, often combined with ivermectin and albendazole.
- Management of Lymphedema: Includes hygiene measures, compression therapy, and elevation of affected limbs.
- Hygiene Measures: To prevent secondary bacterial infections and worsening of lymphedema.
Lymphocytic Leukemia
Types:
- Chronic Lymphocytic Leukemia (CLL): Characterized by the slow accumulation of functionally incompetent lymphocytes in the blood, bone marrow, and lymphoid tissues.
- Acute Lymphoblastic Leukemia (ALL): A rapid proliferation of immature lymphocytes, primarily affecting children.
Pathophysiology: Lymphocytic leukemia involves the malignant proliferation of lymphocytes, disrupting normal hematopoiesis in the bone marrow and leading to immunosuppression, anemia, and thrombocytopenia.
Clinical Manifestations:
- Lymphadenopathy: Widespread, painless lymph node enlargement.
- Splenomegaly: Enlargement of the spleen, leading to abdominal discomfort.
- Fatigue: Resulting from anemia and the overall burden of the disease.
- Frequent Infections: Due to immunosuppression caused by the proliferation of abnormal lymphocytes.
Diagnosis:
- Blood Tests: Elevated lymphocyte count with characteristic “smudge cells” in CLL.
- Bone Marrow Biopsy: Confirms the diagnosis by showing an infiltration of leukemic cells.
- Flow Cytometry: Used to determine the immunophenotype of the leukemic cells, which helps in diagnosis and prognosis.
Treatment:
- Chemotherapy: The mainstay of treatment, particularly in ALL.
- Immunotherapy: Monoclonal antibodies (e.g., rituximab) targeting specific antigens on leukemic cells.
- Targeted Therapy: Drugs like ibrutinib and venetoclax for CLL.
- Bone Marrow Transplantation: Considered in refractory or relapsed cases, particularly in ALL.