<prompt> In which of the following are linear IgA deposits in mesangium noted?Henoch Schoenlein PurpuraMalariaGood Pastures SyndromeWegeners Granulomatosis  <response>: Ans. A. Henoch Schoenlein Purpura. Ref. Harrisons 17thpg. 1813, 1789Ref. Harrisons 17thpg. 1789...Henoch-Schonlein purpura is distinguished clinically from IgA nephropathy by prominent systemic symptoms, a younger age 20 years old, preceding infection, and abdominal complaints. Deposits of IgA are also found in the glomerular mesangium in a variety of systemic diseases, including chronic liver disease, Crohns disease, gastrointestinal adenocarcinoma, chronic obstructive bronchiectasis, idiopathic interstitial pneumonia, dermatitis herpetiformis, mycosis fungoides, leprosy, ankylosing spondylitis, relapsing polychondritis, and Sjogrens syndrome. IgA deposition in these entities is not usually associated with clinically significant glomerular inflammation or renal dysfunction and thus is not called IgA nephropathyDiscussion:IgA nephropathy: Berger first described it. It is classically characterized by episodic hematuria with the deposition of IgA in the mesangium. IgA nephropathy is one of the most common forms of glomerulonephritis worldwide. There is a male preponderance, a peak incidence in the second and third decades, and rare familial clustering. The two most common presentations of IgA nephropathy are recurrent episodes of macroscopic hematuria during or immediately following an upper respiratory infection in children Henoch-Schonlein purpura or asymptomatic microscopic hematuria most often seen in adults. Rx: - ACE inhibitors in patients with proteinuria or declining renal function.- Tonsillectomy, steroid therapy, and fish oil have all been suggested to benefit some patients.- When presenting as RPGN, patients need steroids, cytotoxic agents, and plasmapheresis.RENAL INVOLVEMENT in Hemolytic Uremic Syndrome HUS and Thrombotic Thrombocytopenic Purpura TTP Microscopic hematuria 78 and subnephrotic proteinuria 75 are the most consistent findings. The characteristic lesion in HUSTTP is thrombotic microangiopathy. Microthrombi are demonstrated in renal arterioles and capillaries. In TTP, microthrombi are composed mainly of platelet aggregates and thin layer of fibrin and stain strongly for vWF, implicated in its pathogenesis. In contrast, microthrombi in HUS contain predominantly fibrin. Subendothelial hyaline deposits and endothelial cell swelling also contribute to vascular occlusion. Glomerular lesions are ischemic. The glomerular capillary walls are wrinkled, the glomerular tuft may be atrophied, and the Bowman capsule is thickened. Acute cortical or tubular necrosis may occur. Immunofluorescence studies invariably demonstrate fibrinogen along the glomerular capillary walls and in arterial thrombi. Granular deposits of C3 and IgM may be observed in vessel walls and glomeruli. Electron-microscopic studies demonstrate swelling of the glomerular endothelial cells and detachment from the glomerular basement membrane. 