CPC #2:Fever, cough, dyspnea,

and change in mental status

Barbara J. Crain, M.D., Ph.D.

October 7, 2008

Heart

Borderline cardiomegalyHypertensive 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 Ia)Sepsis (due to or as a consequence of)

b)Acute MRSA bronchopneumonia with abscess formation

Part IIa)Atherosclerotic vascular diseaseb)Hypertensionc)Cardiomegalyd)History of smoking

Hospital-acquired MRSA infections

First described in 1960, increasing problem in 1980’s MSSA vs. MRSA: includes a large genetic element ;

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:S344-49Brit J Anaesth 2004;92:121-130

Community-acquired MRSA infections

More often children and young adults without underlying 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;12:498-500MMWR 2007;5614):325-329Ann Clin Microb Antimicrob 2008;7:1

Pathogenesis of CA-MRSA

Well characterized strains: USA300 most common in US

Basis for apparent increased virulenceIncreased 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:S350-5http://a.abcnews.com/images/Health/ld_mrsa_080425_mn.jpg9

http://www.health.alberta.ca/influenza/SC_handwashing.jpg

Prevention of MRSA

http://www.health.alberta.ca/influenza/SC_handwashing.jpg