Post-streptococcal glomerulonephritis

Thanks to Whitney for presenting a great case! This is a case of a young person with a recent upper respiratory tract illness who was found to have acute kidney injury, nephritic syndrome with positive streptozyme antibodies consistent with post-streptococcal glomerulonephritis.

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Main points:

1) Glomerulonephritis can be divided into 3 categories: immune complex, pauci-immune and anti-GBM. Each of these can present as acute or chronic GN or RPGN. See this previous blog post regarding the differential.

2) Pauci-immune small vessel GN in older patients can present as an RPGN, leading to kidney failure in weeks.

3) A good way to try and figure out which form of GN a patient may have is order complements (for immune complex), ANCA (for pauci-immune) and anti-GBM antibodies as a first pass. Thanks Kyle Kent!


Want to learn more?

Glomerulonephritis associated with infections

Here is an excellent comparison chart (thanks Whitney!) of the common causes of glomerulonephritis after an infection.

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Urinalysis: Dip/ Micro /Spin

We talked a little bit about the confusing terminology between the different tests to order for urine studies. A urine dipstick is a litmus-paper like strip used in clinic that detects gross changes by having multiple different chemical pads that look for things like presence of protein, nitrite, pH. Urine microscopic is done after urine is spun down and the sediment is examined under a microscope by a lab tech (who is also looking at many of these slides a day throughout the hospital). When you consult nephrology, the same technique is used but examined by the consulting team who has more time to look at the slide and consider the findings in the clinical context of the presenting patient. It is important to spin fresh urine as sample degradation does happen over time.

See this excellent American Family Physicians review and video series by Palo Alto VA Hospitalist Eric Strong on how to interpret each aspect of a urinalysis.