Background

In spite of the tremendous advance that modern medicine has made, we are continually humbled by the smallest of organisms. Infections have influenced the development of civilization and will continue to do so. Modern antibiotic and antimicrobial drugs can barely keep up with the proliferation of newer and more resistant organisms. Infections can broadly be classified into bacterial, viral, fungal, and parasites. In addition, there are some organisms which do not fit neatly into a single category.

Atypical Mycobacteria
Bacteria
Chlamydia
Fungus
Mycoplasma
Parasites
Prions
Protothecosis
Tuberculosis
Viruses

OUTLINE

Reference Methods
Clinical Utility
Interfering Diseases or Substances that Alter Levels
Commonly Used Terms
Internet Links

 

CLINICAL UTILITY

CHARACTERIZATION

Infectious Diseases Detected at Autopsy at an Urban Public Hospital, 1996-2001 Lian A. Bonds, MD, Loretta Gaido, MD, PhD, Jan E. Woods, MD, David L. Cohn, MD, and Michael L. Wilson, MD

Am J Clin Pathol 2003;119:866-872 Abstract quote Previous studies have demonstrated significant discrepancy rates between clinical and autopsy diagnoses. However, infectious diseases have not received emphasis in these studies. We conducted a study to determine whether the clinical and autopsy diagnoses of infectious diseases are concordant or discrepant and to determine discrepancy rates. Retrospective reviews of the records of 276 patients (adults, 182; fetuses and neonates, 94) who underwent autopsy during the years 1996 through 2001 were performed. Comparison of clinical and autopsy diagnoses was performed using the Goldman classification scheme. Of 182 adult patients, 137 (75.3%) had an infectious disease at autopsy. In 59 (43.1%) of 137 patients, the infectious disease diagnoses were unknown clinically. Of 94 fetuses and neonates, 45 (48%) had an infectious disease at autopsy. In 26 (58%) of 45 patients, the infectious disease diagnoses were unknown before death. There are substantial discrepancies between clinical and autopsy diagnoses of infectious diseases. In adults, acute bronchopneumonia is the infectious disease most often missed clinically; in fetuses and neonates, it is acute chorioamnionitis.

 

INTERFERING SUBSTANCES	CHARACTERIZATION
STOOL CULTURES
Limited Value of Routine Stool Cultures in Patients Receiving Antibiotic Therapy Yoginder K. Chitkara, MD	Am J Clin Pathol 2005;123:92-95 Abstract quote In the laboratory investigation of suspected community acquired diarrhea, stool cultures may be ordered on patients receiving antibiotic therapy. Because many antibiotics cause profound changes in intestinal microbial flora, the value of these cultures is not known. To determine the effect of concurrent antibiotic therapy on results of routine stool cultures in the isolation of enteropathogens, a retrospective analysis of fecal cultures submitted during a 14-month period was performed. Of 930 specimens from 856 patients, there were 236 samples (25.4%) from 223 patients (26.1%) receiving antibiotics. Of these, 198 cultures (83.9%) from 186 patients (83.4%) receiving antibiotic therapy showed no growth on all media or growth of only gram-positive organisms. None of these specimens revealed enteropathogens. The results of this study demonstrate that there is little value in culturing of stools of patients receiving antibiotics. Significant cost savings can be realized by elimination of these cultures.

Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Rosai J. Ackerman's Surgical Pathology. Ninth Edition. Mosby 2004.
Sternberg S. Diagnostic Surgical Pathology. Fourth Edition. Lipincott Williams and Wilkins 2004.
Robbins Pathologic Basis of Disease. Seventh Edition. WB Saunders 2005.
DeMay RM. The Art and Science of Cytopathology. Volume 1 and 2. ASCP Press. 1996.
Weedon D. Weedon's Skin Pathology Second Edition. Churchill Livingstone. 2002
Fitzpatrick's Dermatology in General Medicine. 6th Edition. McGraw-Hill. 2003.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.

Abscess-This is a collection of neutrophils, or acute inflammatory cells, that obliterate the underlying tissue and form a pocket of pus.

Cytopathic changes-When a micro-organism, most commonly a virus, infects a cell, it may lead to changes in that infected cells that are identified under the microscope. Viral particles may proliferate within the nucleus or cytoplasm of the cell leading to characteristic pathology.

Granuloma-These characteristic structures are composed of histiocytes that from rounded structures sometimes associated with necrosis or caseation. They are commonly associated with giant cells, formed by the fusion of these histiocytes.

Basic Principles of Disease
Learn the basic disease classifications of cancers, infections, and inflammation

Commonly Used Terms
This is a glossary of terms often found in a pathology report.

Diagnostic Process
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Surgical Pathology Report
Examine an actual biopsy report to understand what each section means

Special Stains
Understand the tools the pathologist utilizes to aid in the diagnosis

How Accurate is My Report?
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Last Updated July 6, 2009

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