62 _ Nephrotic Syndrome

KYJ 62 - Nephrotic Syndrome

So a middle aged fit healthy man arrived with bilateral pitting oedema to the knees. He has noted the progressing swelling from ankle oedema a week ago to this today, and mentions that he was short of breath just getting dressed.
No medical history. Fit as an ox, hard working farming labourer.

Ankle oedema is a really common symptom with lots of causes, but these can be condensed into two principles.

To understand both it is important to recap how capillaries leak.  Capillaries are pipes full of microscopic pin holes. The holes are big enough to allow water and salts and other small molecules to leak from the blood stream but large molecules like protein (eg Albumen) stay inside.  Albumen is like a water magnet.  It attracts water, holding on to blood volume and preventing excessive volume loss (hypovolaemia).

If the blood pressure is too high (hydrostatic pressure) then plasma is pushed out of capillaries causing oedema.

Likewise if there is not enough albumen in the blood stream (oncotic pressure), then there are not enough water magnets in the capillary to hold in plasma.  Water then leaks out, causing oedema.

So, low albumen levels in blood could be :
1: loss of albumen or
2: reduced production of Albumen

In Nephrotic syndrome, inflammation of the glomerular apparatus (all 1.2 million of them in your kidneys), causes these sieve like filters to allow big albumen and other proteins to slip through the kidneys and be lost into urine.

Over time albumen levels in blood drop to a critical level, allowing capillaries in the legs, abdomen and lungs to leak plasma.  This causes oedema.

On pathology the Biochem shows elevated Urea and creatinine. And s markedly reduced Glomerular filtration rate (GFR).
LFTs results typically show normal LFTs but markedly reduced serum Albumen.

Urine will predictably show large protein, and, depending on inflammation, occasionally blood.

The clincher is often hypertension. As kidneys fail, they leak protein, but overall filtration of blood is reduced leaving the patient hypervolaemic.  This excess vascular fluid increases blood pressure, which causes even more oedema.

Viscous cycle.

Treatment is to reduce BP,  administer anti inflammatories, and if needed, give Albumen.

Interesting case. With some cool pathophysiology.

Have seen an interesting case of something recently?