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CPC #2:
Fever, cough, dyspnea,
and change in mental status
Barbara J. Crain, M.D., Ph.D.
October 7, 2008
Heart
 Borderline cardiomegaly
Hypertensive changes
Heart weight 460 gm
for height: 229=399 gm
for weight 241-481 gm
Occasional “boxcar nuclei”
 Mild to moderate coronary
atherosclerosis
Kidney
 Nephrosclerosis
 Arteriolosclerosis
 Hypertensive changes
Brain (striatum)
Dilated perivascular spaces
Arteriolosclerosis
Perivascular hemosiderin
Hypertensive changes in blood vessels
Brain (deep cortical white matter)
Normal white matter (H&E) Normal astrocytes (GFAP)
Reactive astrocytes (GFAP)
Focal pallor and reactive astrocytosis,
most likely hypertensive in origin
Liver
 Mild acute congestion
 Mild macrosteatosis
 Mild nonspecific
inflammation of triads
 No evidence of fibrosis,
cirrhosis, or alcoholic
hepatitis
Lungs – gross examination
 Small pleural effusions
 Markedly increased weight: 2,900 gm
(reference 685 – 1,050 gm)
 Firm, red parenchyma, most marked in right lung
 2-cm cavitary lesion in right upper lobe
 Gross impression: severe bronchopneumonia with
abscess
Lung abscesses
Lung with congestion and hemorrhage
Lung with hemorrhage, necrosis
Lung with hemorrhage, necrosis
Lung with hemorrhage, necrosis and
bacteria: pneumonia in leukopenic patient
Gram-positive cocci
Gram-positive cocci
??
http://swampie.files.wordpress.com/2008/02/staphylococcus-aureus.jpg
http://images.encarta.msn.com/xrefmedia/sharemed/targets/images/pho/t028/T028362A.jpg
Blood culture from night of admission
ORG 1: METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS IN
ANAEROBIC BOTTLE
-------------------------------------------------------------RESULT
ANTIBIOTIC
MIC (mcg/ml) INTERPRETATION
Oxacillin ------------- >2 -------------- Resistant
Vancomycin ------------- 2 ------------ Susceptible
Staphylococcal isolates that are resistant to oxacillin (MRS) should
not be treated with penicillins, beta-lactam/beta-lactamase inhibitor
combinations, cephalosporins and carbapenems.
Sputum culture
1. BACT MICRO EXAM
TYPE 2 - ADEQUATE SPECIMEN. MANY POLYMORPHONUCLEAR
CELLS AND MANY SQUAMOUS EPITHELIAL CELLS. MANY
NORMAL UPPER RESPIRATORY FLORA
2. BACTERIOLOGY CULTURE
MODERATE MIXED RESPIRATORY FLORA AT 1 DAY
POSITIVE AT 1 DAY
ORG 1: HEAVY METHICILLIN RESISTANT STAPHYLOCOCCUS
AUREUS
Major autopsy findings
 Severe hemorrhagic and necrotizing bronchopneumonia
with abscess formation, right > left
 Culture-positive for MRSA
 Chronic changes associated with hypertension
Borderline cardiomegaly
Arteriolonephrosclerosis of kidneys
Hypertensive cerebral vascular disease
Focal chronic white matter damage
 Mild to moderate coronary atherosclerosis
Cause of death
Part I
a) Sepsis (due to or as a consequence of)
b) Acute MRSA bronchopneumonia with abscess formation
Part II
a)
b)
c)
d)
Atherosclerotic vascular disease
Hypertension
Cardiomegaly
History of smoking
Hospital-acquired MRSA infections
 First described in 1960, increasing problem in 1980’s
 MSSA vs. MRSA: includes a large genetic element ;



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staphylococcal cassette chromosome mec (SCCmec)
SCCmec carries the mec gene complex and various resistance
genes against non ß-lactam antibiotics
Over half the Staph isolates in some hospitals are now MRSA
Infections often in very ill patients, particularly in ICUs
Bacteremia, pneumonia, endocarditis
High morbidity and mortality
Clin Infect Dis 2008; 46:S344-49
Brit J Anaesth 2004;92:121-130
Community-acquired MRSA infections
 More often children and young adults without underlying


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illnesses
Generally skin / soft tissue infections
(cellulitis, abscess)
Emerging problems: necrotizing fasciitis,
Waterhouse-Friedrichsen syndrome, empyema,
necrotizing pneumonia
Person-to-person transmission
Strains causing CA-MRSA going back into hospitals
http://www.jems.com/Images/mrsa_tcm16-33808.jpg
Community-acquired MRSA pneumonia
 Rapidly progressive necrotizing pneumonia
 Effusions, bacteremia common
 Primarily children, young adults
 High mortality rate
(>50% in some series)
 Median survival time 4-7 days
 Often preceded by viral-like illness
(particularly influenza A)
Emerg Infect Dis 2006;12:498-500
MMWR 2007;5614):325-329
Ann Clin Microb Antimicrob 2008;7:1
Pathogenesis of CA-MRSA
 Well characterized strains: USA300 most common
in US
 Basis for apparent increased virulence
Increased fitness of bug?
Improved evasion of host immune system?
Unique toxin production?
 Panton-Valentine leukocidin (PVL) gene: toxin with
leukocytolytic and dermonecrotic activity
Clin Infect Dis 2008; 46:S350-5
http://a.abcnews.com/images/Health/ld_mrsa_080425_mn.jpg9
Prevention of MRSA
http://www.health.alberta.ca/influenza/SC_handwashing.jpg
http://www.health.alberta.ca/influenza/SC_handwashing.jpg