Kidney infections (Table 64.6)
Aetiology
Renal infections arise in the following ways.
• Haematogenous infection from a primary site in the tonsils or carious teeth, or from cutaneous infections, particularly boils or a carbuncle. Renal tuberculosis occurs by blood-borne spread from lymph nodes in the neck, chest or abdomen.
• Ascending infection in the urinary tract is the most common route, and it
is most likely to occur when there is vesicouretenic reflux. Urinary stasis and
the presence of calculi are common contributory factors.
Bacteriology. Escherichia coli and other Gram-negative organisms are commonly
responsible. When Streptococcus faecalis is
present it is usually accompanied by other organisms. In E. coli and streptococcal infections the urine is acid. Proteus
sp. and staphylococci split urea, forming ammonia which makes the urine
alkaline and promotes the formation of calculi.