Crescentic glomerulonephritis associated with polycythaemia
Glomerular diseases are one of the most challenging entities in terms of diagnosis and management, especially when associated with systemic illnesses such as malignant disorders. Herein, a case of crescentic glomerulonephritis (CrGN) associated with polycythaemia vera (PV) in a 50-year-old female is described. She presented with bilateral pedal oedema, splenomegaly, renal dysfunction and severe proteinuria. On evaluation, we found PV and CrGN. The possible pathogenesis of PV associated-renal disease may be as follows:
-An increase in blood volume and viscosity causes passive expansion of the capillaries and intimal injury, ultimately leading to tissue ischaemia and renal injury
-PV is often associated with hypertension and hyperuricemia, which affect renal microcirculation
-The medications used for PV treatment can cause renal impairment e.g., interferon, hydroxyurea
-Abnormal activation of megakaryocytes leading to glomerulosclerosis
-Various cytokines and growth factors PDGF, TGF- has also been implicated in the pathogenesis.

Renal involvement in PV is rare and generally considered as a manifestation of hypervolemia or high-viscosity-induced renal hyper-perfusion and hyper-filtration. This is a unique case of immunologically-mediated renal disease in PV.