Short and Long-term Outcomes of HUS
Related Information: Outcomes of hus, effect of HUS
The treatment for D+ HUS has seen a great improvement after the introduction
of kidney dialysis along with intensive care facilities. In 1950, the
mortality rate due to HUS was 40% and now it has been decreased to 3-5%
in the developed world. In spite of this, patients die owing to inability
to avoid and treat renal injury. Though damage to brain seems to be the
commonest cause for death, multi-organ damage is also common.
Though people survive after treatment, in nearly 3-5% of people, extra-renal
damage lasts long and another 3-5% with kidney damage. All this requires
chronic dialysis or kidney transplants from the beginning or after a few
years. And still others develop future sequelae that can be linked to
the presence of anuria and oliguria. Sequelae includes low glomerular
filtration rate [GFR], proteinuria, and hypertension. This can vary from
mild to severe in people based on the condition of anuria and oliguria.
High BP occurs later in nearly 10% of those without oligoanuria, and 33%
in those with oligoanuria (exceeding 15 days) and 66% in those with anuria
(lasting for 15 days or more). Low GFR and proteinuria, both indicates
impaired renal functions along with ongoing hyperfiltration injury. Such
a combination exists in utmost 10% of people until there is anuria or
oliguria for 5-10 days. Hence it will go up to 15% in people with oliguria
greater than 10 days and 40% in case it lasts for greater than 15 days.
Such a combination is exhibited in 20% for those with anuria lasting greater
than 5 days, 33% in people with anuria lasting greater than 10 days and
66% for greater than 15 days.
In the long term, this leads to ESRD (end-stage renal disease) owing to
ongoing hyperfiltration injury, occurring when greater than 50% of nephrons
are destroyed (can happen in the acute phase). The remaining good nephrons
enlarge to balance the lowered renal population. These nephrons are able
to manage the work for several years, but they become overworked at the
end. This deficiency will come out as microalbuminuria. This can serve
to be a good marker to determine “hyperfiltration injury”. As the value
increases, the injury is greater. Microalbuminuria can sometimes lead
the beginning of proteinuria by a few years.
In addition, from the age of 30 onwards, there will be a decrease in the
volume of nephrons. This places an additional damage to the kidneys. Angiotensin
receptor blockers and angiotensin enzyme inhibitors lowers hyperfiltration
injury and this can slow the natural process of nephron loss. But finally,
if greater than 90% of nephrons are destroyed, ESRD results.
It is strongly recommended to assess the patients many times in the initial
stages for determination of BP, serum creatinine, urinalysis and microalbuminuria.
This helps in tracking the risk of ESRD well before. Even after the first
year, evaluations must be continued. Even after recovery, a medical check
every two years is recommended. And monitoring during pregnancies is a
must owing to the increased risk of pre-eclampsia and eclampsia.