Thread by @drM_sudha

1/ 📢Hello #MedTwitter
Let’s talk about pediatric #MPGN / ‘Immune complex GN’ #ICGN today
A few pearls from the 1st @ASPNeph pathology webinar of 2021
#tweetorial #NephTwitter

Let's begin with a poll:
❓Which of the following is true about IC-MPGN?

2/ All the above

⚡️There is limited data on epidemiology

⚡️The estimated prevalence is 1 to 2/ million children, 5 to 15 years of age

3/💥MPGN denotes “pattern of injury” not etiology

⚡️Characteristic mesangial & endocapillary cellularity

⚡️Thickening of glomerular capillary walls due to subendothelial deposition of IC/complement factors

4/ 💥Type III hypersensitivity reaction💥 is the hallmark of the disease

⚡️”Anything” can form IC→IC deposition→activation of immune cells→ ‘complement activation’→ Glomerular injury

⚡️complement dysregulation is the key🗝️factor

5/ 💥Currently, “triggers/ risk factors” for host injury are unknown

⚡️Damage is inversely proportional to Antigen (Ag) clearing
⚡️In other words, chronic antigenemia = chronic inflammation

6/ 💥Latest classification is based on IF-

⚡️C3 dominant deposits→ C3 Glomerulopathy (C3GN & DDD)- rare
⚡️C3 + Ig deposits→ Ig- MPGN (Immunoglobulin asso. MPGN)
⚡️No deposits MPGN→ Chr. TMA, transplant glomerulopathy, etc.

7/ 💥Etiopathogenesis:

⚡️IC- MPGN is via CLASSICAL complement pathway activation,

⚡️C3G is due to primary alternative complement pathway dysregulation

8/💥 MPGN is associated with a variety of disorders. Common one being
⚡️Complement system abnormalities
⚡️SLE
⚡️Hepatitis B &C
⚡️>50y -monoclonal gammopathies

9/ 💥What is the most common presentation of IC-MPGN?

10/ Ans: Hematuria
💥Clinical presentation is heterogeneous
⚡️ranges from asymptomatic hematuria to AKI
⚡️In a pediatric study: hematuria> HTN > NS kireports.org/article/S2468-…

11/💥 A 14 yr old adolescent male patient presented with HTN, hematuria, nephrotic syndrome, and AKI. Kidney biopsy revealed IC-MPGN. What will be your initial workup?

12/ 💥Ans: All the above

⚡️GOAL: identifying Treatable Target⚡️

📌Rule out PIGN prior to assigning IC-GN/ C3GN diagnosis
📌Hx driven work-up: Viral titers, Autoimmune/ Rheum. evaluation, Immune Cell Abnormality, etc
📌If no etiology is found--> assess complement dysregulation

13/💥 Kidney Biopsy in IC-MPGN shows:

⚡️LM: Mesangial proliferation and GBM thickening.
“smashed blueberry pancake” appearance - by @Trumidor

⚡️IF: C3 deposits + Ig deposits

⚡️EM: Mesangial proliferation, GBM thickening, mesangial deposits

14/ 💥Rx: treating the etiology, ↓ underlying immune dysregulation & burden of HTN & proteinuria
⚡️No curative option
⚡Mostly expert-opinion based Rx data
⚡️RAASi, HTN & Lipid-lowering agents - all
⚡️Steroids, MMF & rarely CNI
⚡️PLEX, Rituximab, Eculizumab- inconsistent data

15/ 💥Prognosis:

⚡️pediatric pts with IC-MPGN/ C3G have better outcomes than adults
⚡️Progression to advanced CKD- rare in children
⚡️HTN & proteinuria remain suboptimally controlled
⚡️Poor prognosis: NS, low eGFR at the onset, persistent HTN & chronic changes on biopsy

16/💥Thank you for scrolling till the end!

For case-based discussion on this topic logon to @ASPNeph January pathology webinar
Until next time…
#MOC2credits

#FellowFOAMgroup #pediatricnephrology
@pedsnephrology @Trumidor @kidnyhealth @priti899 @RoshanPGeorgeMD