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Discussion Starter · #1 ·
Dr. Goljan and wiki say that henosch schonlein purpura is essentially a systemic IgA nephropathy but they seem to me have different presentations. Can someone help me distinguish the two if you don't have the purpura? If I have a question with IgA nephropathy symptoms is the a common complication HSP? I'm a little confused as to what leads to what and the exact relationship...
 

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Difficult to distinguish

Henoch-Schönlein purpura nephritis (HSPN) and IgA nephropathy (IgAN) are considered to be related diseases since both can be encountered consecutively in the same patient, they have been described in twins, and bear identical pathological and biological abnormalities. The kidney biopsy does not show any differences between the two conditions.

Here's a number of useful distinctive features:

  • The peak age ranges between 15 and 30 years for a diagnosis of IgA Nephropathy, whereas HSP is mainly seen in childhood.
  • The extra renal manifestations of HSP (skin, GI, CNS, Joints) is not seen in IgA nephropathy.
  • HSP has been described in association with hypersensitivity.
  • Endocapillary and extracapillary inflammations as well as fibrin deposits in the glomerulus are more frequent in HSP.
  • No major biological differences have been found between the two illnesses, except for a larger size of circulating IgA-containing complexes (IgA-CC) and a greater incidence of increased plasma IgE levels in HSP.
  • As tissue infiltration by leukocytes is a major feature of HSP vasculitis, a possible role of a more potent activation of the latter cells by IgA-CC and/or circulating chemokines in HSP can be considered.
Remember that in USMLE they won't ask you to differentiate the two without giving you an obvious hint such as the age and the extra renal manifestations in HSP.

References:
http://cat.inist.fr/?aModele=afficheN&cpsidt=916232
http://www.aafp.org/afp/980800ap/kraft.html
http://www.ncbi.nlm.nih.gov/pubmed/18332712

You may also find the following threads useful:

 

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I learned in class that HSP and IgA nephropathy may be a continuum of the same disease, particulary because of the different age groups that present with them and the similar pathological features on kidney biopsy.
 

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Discussion Starter · #4 ·
That helps a lot - thanks guys... I'll look at the age and the extrarenal manifestations on the patient and on the USMLE.
 
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