Dr.S.Venkatesan MD

Infective endocarditis (IE) continues to be a dreaded  medical problem. The clinical outcome has not improved much , in spite of  availability of powerful antibiotics. Early surgery in eligible patients  could provide the best possible results.

One of the major determinants of morbidity and mortality  in IE  is the renal involvement.

Kidney gets affected in almost all the patients  with IE.  As IE is a  a systemic illness and  immunological activation is  the  norm ,  some degree of renal involvement is universal. Microscopic hematuria confirms this. This is due to clogging and  globulin mediated  damage to glomerular membranes. There is a linear co relation between  the size of the vegetation and degree of renal involvement.

The following  mechanisms are attributed   for  rapid deterioration of renal function in patients with IE .

1. Renal arterial emboli-occlusion-renal infarct
2. Immune complex mediated  focal nephritis .
3. Diffuse ,  rapidly progressive glomerulonephritis
4. Drug induced renal dysfunction, especially with  aminoglycosides, vancomycin etc
5. Finally &  most importantly , the underlying cardiac condition, which result in refractory cardiac failure  may either be primarily responsible for the renal compromise or aggravate the situation.
6. Combination of each of the above can occur

How to manage renal failure and IE ?

This forms a deadly combination.  Aggressive  planning  & implementation  is  required. Cardiologists, cardiothoracic surgeons, nephrologists  should  discuss the strategies  together.  A microbiologist  is also welcome !

• If it is purely a pre -renal failure due to CHF, there is no major worry.The  patient should  do well with cardiac failure management.
• The role of CT surgeon is always vital, since 75% of times , IE patients require  valve replacement or vegetation/abscess  removal  in  an  emergency or semi emergency basis.
• Pre operative and peri-operative dialysis will  improve the results.
• Renal replacement therapy , combined with valve  replacement may be the ultimate therapy .It  could be the most heroic way to save a patient but carries near death mortality.

If ,  there is strong  evidence  to suggest  immune activation ,there could be a role for steroid administration. Literature  does not address this issue . Long term follow up of renal function is required in these patients .

Final message

Renal failure in IE is common and the underlying mechanisms are often complex.Early intervention is the key as there is  almost  “no  option” for   conservative management in this situation.