**8.5 Emphysematous pyelonephritis and renal papillary necrosis**

Emphysematous pyelonephritis is a severe, multifocal, necrotizing, and gasforming form of acute ascending bacterial infection of the renal parenchyma. Extracapsular extension is common. The disease is most often seen in patients with poorly controlled diabetes mellitus. The common causative pathogens are *Enterobacteriaceae*, particularly *Escherichia coli* and *Klebsiella pneumoniae* [58–60].

*E. coli*-induced emphysematous pyelonephritis in a male patient aged 60's is demonstrated. The patient suffering from alcoholic cirrhosis manifested lumbar pain and high fever. Septic shock killed the patient. The total clinical course was

#### **Figure 25.**

*Enterococcal intrahepatic cholangitis superimposed on cholangiocellular carcinoma in the surgically resected liver (gross and H&E). Colonization of culture-proven* Enterococcus faecalis *is demonstrated in the necrotic cancer tissue (arrowheads), provoking acute intrahepatic cholangitis. Asterisk indicates poorly differentiated adenocarcinoma. High-powered H&E picture of the cocci is shown in the right panel.*

Renal papillary necrosis is another form of lethal renal infection of *E. coli* seen in

poorly controlled diabetic patients (**Figure 28**). The disease is characterized by coagulation necrosis of the renal medullary pyramid: the renal papillae are anatomically vulnerable to ischemic changes [61]. *E. coli* septicemia often follows, and the

Endophthalmitis represents bacterial or fungal infection of the eyeball, as an acute illness (medical emergency) having up to a few days duration [62–64]. Patients complain of blurred vision, red eye, pain, and lid swelling. Due to progressive vitritis, hypopyon can be seen at the time of presentation. Exogenous organisms invade the eyeball via trauma, surgery, or corneal infection. When infection

spreads to the adjacent orbital soft tissue, it is called as panophthalmitis. Endophthalmitis is localized to the eye, and it does not result in bacteremia or fungemia. Patients with Hansen's disease (leprosy) are highly susceptible to traumatic eyeball infection. Streptococcal infection may be proven in the surgical specimen. Prolonged inflammation results in ophthalmophthisis (**Figure 29**). Grampositive cocci, including *Staphylococcus epidermidis* and *Streptococcus viridans*, are commonly isolated after surgery for cataract or intravitreal injection. Gramnegative bacteria such as *Pseudomonas aeruginosa*, *Hemophilus influenzae*, and *Moraxella catarrhalis* infrequently cause endophthalmitis. *Bacillus cereus* and fungi, particularly *Fusarium* spp., are the major cause of post-traumatic endophthalmitis [65]. **Figure 30** illustrates a surgical specimen of a *Fusarium*-infected eyeball. Traumatic corneal infection extended to the surrounding tissues such as the lens, palpebra, and orbit to provoke panophthalmitis. The fungal colonies on the surface microscopically reveal several-celled (chained or beaded), fusiform to sickle-shaped

Endocarditis-associated endogenous endophthalmitis is usually caused by *Staphylococcus aureus* and streptococci. *Klebsiella pneumoniae* is another important

*Renal papillary necrosis in a male patient aged 60's with uncontrolled diabetes mellitus (gross and H&E). The patient manifested symptoms of acute pyelonephritis and died of acute renal failure. At autopsy, the renal papillae are necrotic and demarcated with yellowish zones. Ascending infection of* E. coli *was associated.*

prognosis is poor.

*Pathology of Gangrene*

*DOI: http://dx.doi.org/10.5772/intechopen.93505*

**8.6 Endophthalmitis**

macroconidia (hyphae).

**Figure 28.**

**113**

#### **Figure 26.**

*Pulmonary gangrene (gross, H&E, Gram). Necrotizing (cavity-forming) pneumonia is noted in bilateral upper lobes of the lung. Foul smell was characteristic. Gangrenous inflammation is evident histologically. Microbial culture from the lung lesion identified* Bacteroides*,* Pseudomonas aeruginosa *and* Peptostreptococcus*. Pseudomonal infection is indicated by arrowheads, and Gram-positive cocci (probably representing* Peptostreptococcus*) are phagocytized by neutrophils.*

9 days. At autopsy, both kidneys were enlarged and accompanied multifocal gangrenous changes in association with small foamy bubbles. Foul smell was not associated. Microscopically, gas formation was evident in the necrotic renal parenchyma, in association with diffuse neutrophilic infiltration (**Figure 27**). Numerous Gram-negative rods immunohistochemically expressing *E. coli* antigens are clustered within the necrotic renal tubules and around gas-filled bubbles. Microbial culture confirmed infection of *E. coli*. The condition can be categorized in non-clostridial gas gangrene.

#### **Figure 27.**

E. coli*-infected emphysematous pyelonephritis in a diabetic male patient aged 70's (gross, H&E and immunostain for* E. coli *antigens). The enlarged kidney shows multifocal gangrenous changes with formation of small bubbles. Gas-forming infection of* E. coli *is evident both histologically and immunohistochemically in severe acute purulent pyelonephritis.*

### *Pathology of Gangrene DOI: http://dx.doi.org/10.5772/intechopen.93505*

Renal papillary necrosis is another form of lethal renal infection of *E. coli* seen in poorly controlled diabetic patients (**Figure 28**). The disease is characterized by coagulation necrosis of the renal medullary pyramid: the renal papillae are anatomically vulnerable to ischemic changes [61]. *E. coli* septicemia often follows, and the prognosis is poor.
