HIV
with persistent generalised lymphadenopathy
Definition: palpable lymphadenopathy larger than 1 cm, involving two or more non-contiguous lymph node groups, and lasting longer than 3 months without an alternative explanation .
Lymphoid hyperplasia:
Due to HIV (commonest) occurs in 3 phases: 1. explosive follicular hyperplasia with large germinal centres; 2. germinal centre involution and lymphocyte depletion; 3. proliferation of blood vessels inside the lymph nodes. It is inversely related to CD4 count and common in the head, neck, parotid and axilla.
Tuberculosis:
in TB endemic areas. Caseating granuloma showing as low attenuation in imaging. CD4 count is usually 200–500 cells/mcl.
MAC:
Non-TB-endemic areas. Uniform low-attenuation large mesenteric or retroperitoneal lymph nodes, hepatomegaly, splenomegaly & diffuse jejunal thickening - is more suggestive of MAC then TB. CD$ is usually <50.
Immune Reconstitution Inflammatory Syndrome:
Occurs in 25% of patients after initiation of HAART. A CD4<50, drug-naïve patients, and a high viral load could be associated with IRIS. The clinical feature of IRIS is an interval increase in CD4 and decrease in viral load. MAC infection is the most common infectious complication of IRIS.
Lymphoma
Risk of non-Hodgkin lymphoma in patients with HIV infection is 60–200 times that of the general population. Disproportionately larger generalised lymphadenopathy (most common site – neck). Extra-nodal disease (most common in CNS, gastrointestinal tract, and bone marrow).
Castleman Disease
Typically multicentric in AIDS and exclusively associated with human herpesvirus 8 (HHV-8) infection. Imaging Hallmark - avid enhancement of enlarged lymph nodes. Concomitant systemic features - diffuse pulmonary infiltrates, pleural or pericardial effusions, hepatomegaly, splenomegaly, and ascites. It is difficult to differentiate from lymphoma.
It may have concomitant Kaposi sarcoma.
Kaposi Sarcoma
Caused by HHV8, KS commonly affects mucocutaneous sites (purple polypoid lesions in face and mucocutaneous are). LN is affected 72% of the time followed by GI and lung (peribronchovascular consolidation with a characteristic flame shape).
Diffuse Infiltrative Lymphocytosis Syndrome
It is a host response to HIV infection, characterized by infiltration of the solid organs by CD8+ lymphocytes, more common in black population. Patients presents with sicca symptoms (dry mouth and eyes) and generalised lymphadenopathy and salivary gland enlargement. Lymphocytic pneumonia (ground glass appearance), hepatitis, peripheral neuropathy, myositis.
Other infection/condition
Toxoplasma
Disseminated fungal infection
histoplasmosis