Glomerulopathies - A Deep Dive for Internists with Dr. Ali Mehdi

Segment 1: Glomerulopathies – Definition and Presentation

Wardrop:

Dr. Mehdi let's start at the beginning. What exactly are glomerulopathies and how do they present in patients?

Dr. Mehdi:

Segment 2: Nephrotic Syndrome

Tarek:

Let’s assume we are suspecting nephrotic syndrome in a patient that presents with lower extremity edema, hypoalbuminemia and proteinuria. What should be our next steps?

Dr. Mehdi:

Tarek:

Talking about diagnostic tests, what are the major causes of NS that we need to keep in mind?

Dr. Mehdi:

We need to distinguish between the histological diagnosis and definite etiologic diagnosis.

For example, diabetic nephropathy, membranous nephropathy, focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), light chain deposition, amyloidosis can be seen on the biopsy. MCD can be either primary or secondary, therefore we do not always get a definite diagnosis with the biopsy and sometime we need to go search for a wide range of secondary causes of nephrotic syndrome.

Tarek:

While awaiting the results of our etiologic workup, how do you recommend managing the patients’ symptoms?

Dr. Mehdi:

The general management of Nephrotic Syndrome involves a multifaceted approach:

Dr. Wardrop:

You mentioned the risk of VTE in patients with NS. This leads us to ask about the complications directly related to NS that we should be aware of. Dr. Mehdi:

Segment 3: Nephritic Syndrome

Modern understanding groups glomerulonephritis (GN) into five categories based on immunopathogenesis:

This categorization informs appropriate treatment approaches, like infection control for infection related GN and suppression of adaptive immunity for autoimmune GN.

Tarek:

So, what does this spectrum of GN look like clinically?

Dr. Mehdi:

It's a broad canvas. On one end, you have mild cases with microscopic blood in the urine. On the other, severe cases can cause acute kidney injury, hypertension, and noticeable blood and protein in the urine.

Acute GN often presents with hypertension, proteinuria, and hematuria. In cases with podocyte injury, nephrotic syndrome with massive proteinuria and leg edema may occur. Proteinuria primarily consisting of albumin indicates podocyte injury, whereas hematuria implies ruptures of the glomerular basement membrane (GBM). Kidney biopsy is essential for a precise diagnosis and to define GN subcategories.

Tarek:

Is it important to differentiate acute vs. chronic GN? What are the major differences and implications?

Dr. Mehdi:

Acute and chronic glomerulonephritis are distinguished by their duration, progression, and underlying mechanisms:

The distinction is crucial in diagnosis and treatment, as acute GN might be reversible with timely intervention, while chronic GN usually requires long-term management to slow disease progression and preserve kidney function.

The Initial Evaluation when suspecting GN

Wardrop:

When a presents with these symptoms, what's your first move?

Dr. Mehdi:

The detective work starts with a urinalysis. We're looking for clues - hematuria, proteinuria, pyuria. Next, we assess kidney function and consider specific tests like C3/C4, ANCA, cryoglobulins, and anti-GBM.

Types of GN

Tarek:

Could you walk us through the different types of GN?

Dr. Mehdi:

Absolutely. Imagine GN as a tree with three main branches.

Treatment Landscape

Wardrop:

How do we approach treating these conditions?

Dr. Mehdi:

Each type needs a tailored approach. A few examples:

Segment 4: Case Study - Bringing Theory to Practice

Tarek:

Let's put theory into practice with a case study.

Tarek:

Dr. Mehdi, what is your differential diagnosis in front of such a case, and what additional tests would you order?

Dr. Mehdi:

Tarek:

Dr. Mehdi, can you tell us a bit more about IgA nephropathy and what will be the treatment plan?

Dr. Mehdi:

Segment 5: Two final questions

Wardrop:

As we saw in the case, kidney biopsy was able to provide us with a definite diagnosis of the glomerular disease at play and helped us guide therapy. Can you share your take on kidney biopsy in a more general sense, when to get it, and how useful it is in other cases?

Dr. Mehdi:

In essence, a kidney biopsy is not used in every case but can be invaluable when the diagnosis is unclear, the disease is progressing, or specific treatment decisions hinge on knowing the exact type and extent of kidney damage.

Tarek : One last question. Can you share in a few words your thoughts on the role of kidney imaging in evaluation of glomerular disease (if any)?

Dr. Mehdi:

Kidney imaging still holds significant value.

Segment 6: Conclusion and Takeaways

Wardrop:

This has been an incredibly enlightening discussion on Glomerulopathies. Dr. Mehdi, Tarek, thank you for shedding light on this complex topic and guiding us through the intricacies of diagnosis and treatment. Dr. Mehdi, can you please provide us with 5 key takeaways for the listeners?

Dr. Mehdi:

Dr. Mehdi’s reflects on some Key Takeaways