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Background
This parasitic disease is caused by a protozoan which is prevalent in as much as 50% of some populations. It can be both an acquired and congenital infection. Congenital cases occur via transplacental transmission from mother to fetus and often leads to stillbirth. Acquired cases may result from ingestion of raw meat or water which has been contaminated by the organism.
The most common clinical presentations are asymptomatic or subclinical, with fever, cervical lymphadenopathy, and general malaise. In immunocompromised patients, the presentations may be devastating with disseminated disease resulting in encephalitis, myocarditis, and pneumonia. It is one of the major complications associated with heart transplantations. Cutaneous signs inclued a macular, papular, maculopapular, and hemorrhagic eruption which is followed with desquamation.
In tissue sections, the parasite is crescent shaped and may be found in many infected organs including skin.
Arch Pathol Lab Med 1997;121:869-873.
OUTLINE
Disease Associations Pathogenesis Laboratory/Radiologic/Other Diagnostic Testing Gross Appearance and Clinical Variants Prognosis Treatment Commonly Used Terms Internet Links
DISEASE ASSOCIATIONS CHARACTERIZATION CERVICAL LYMPHADENOPATHY
Diagnostic aspects of cervical lymphadenopathy in children in the developing world: a study of 1,877 surgical specimens.Moore SW, Schneider JW, Schaaf HS.
Department of Paediatric Surgery, University of Stellenbosch, Cape Town, South Africa,
Pediatr Surg Int 2003 Apr 17 Abstract quote Chronic cervical lymphadenopathy is a common clinical problem frequently requiring surgical biopsy.
To evaluate the characteristics of surgically excised cervical lymph nodes (LN) in children in a developing country, we studied 1,332 children less than 15 years old (1,877 surgically removed cervical LNs) over a 23-year period (1976-1999).
Indications for biopsy included failure to respond to antibiotic therapy, rapid increase in size, hard, matted LNs in the preauricular, supraclavicular, and posterior triangle of the neck, and difficulty in diagnosis. Clinical and pathological characteristics investigated included age, malignancy, and granulomatous disease such as tuberculosis (tbc).
The mean age was 7 years (tbc 5.8/neoplastic disease 8.5 years). Twenty LNs (1.5%) were histologically normal. There were 637 (47.8%) with nonspecific reactive lymphoid hyperplasia and 484 with chronic granulomatous changes (36.3%).
Tuberculous lymphadenitis was confirmed in 332 of these (25%). In 181 (54.5%) Mycobacterium tuberculosis was cultured and a further 149 had acid-fast bacilli. Other granulomatous diseases identified included sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfmann disease) (3), syphilis (4), yaws (2), and toxoplasmosis (1). No mycobacteria other than M. tuberculosis were encountered. More than two-thirds (108) of 154 patients with neoplastic LN involvement had a lymphoma; in a further 10 lymphadenopathy was associated with leukemia.
Pyogenic organisms were identified in 32, and 5 were positive for human immunodeficiency virus, 1 of whom had Kaposi's sarcoma.
A second pathology was identified in 18 of the 637 cases of reactive lymphoid hyperplasia (3 with tuberculosis); in 15 (1.3%) a diagnosis of lymphoma was made from other sites (pleural fluid, etc.) within 6 months of initial biopsy. This represents a diagnostically difficult subgroup requiring further investigation.Chronic lymphadenopathy in children in developing countries has a high incidence of infective causes, including a significant incidence of M. tuberculosis. The incidence of serious pathology in more than one-half of the cervical LNs examined justifies aggressive surgical investigation.
PATHOGENESIS CHARACTERIZATION GENERAL
Toxoplasma gondii: transmission, diagnosis and prevention.Hill D, Dubey JP.
Animal and Natural Resources Institute, Agricultural Research Service, US Department of Agriculture, Beltsville, Maryland 20705-2350, USA.
Clin Microbiol Infect 2002 Oct;8(10):634-40 Abstract quote Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common parasitic infections of man and other warm-blooded animals. It has been found world-wide from Alaska to Australia. Nearly one-third of humanity has been exposed to this parasite.
In most adults it does not cause serious illness, but it can cause blindness and mental retardation in congenitally infected children and devastating disease in immunocompromised individuals.
LABORATORY/
RADIOLOGIC/
OTHER TESTSCHARACTERIZATION RADIOLOGIC LABORATORY MARKERS PCR
PCR for the diagnosis of toxoplasmosis after hematopoietic stem cell transplantation.Lewis JS Jr, Khoury H, Storch GA, DiPersio J.
Washington University, Department of Pathology and Immunology, 660 S. Euclid Ave., Box 8118, St. Louis, MO 63110, USA.
Expert Rev Mol Diagn 2002 Nov;2(6):616-24 Abstract quote Toxoplasma gondii is a ubiquitous pathogen that causes significant morbidity and mortality in immunocompromised patients.
Although relatively uncommon, toxoplasmosis is increasingly recognized as a severe complication of hematopoietic stem cell transplantation. Timely and accurate diagnosis of this treatable infection is critical. PCR-based testing has become the preferred method for diagnosis, occasionally replacing tissue biopsy.
This article reviews the clinical, diagnostic and therapeutic aspects of toxoplasmosis in the setting of hematopoietic stem cell transplantation and the current and future role of PCR-based testing for early detection and diagnosis.
GROSS APPEARANCE/
CLINICAL VARIANTSCHARACTERIZATION GENERAL VARIANTS STOMACH
Gastric toxoplasmosis in a patient with acquired immunodeficiency syndrome. A case report and review of the literature.Ganji M, Tan A, Maitar MI, Weldon-Linne CM, Weisenberg E, Rhone DP.
Department of Pathology, Advocate Illinois Masonic Medical Center, Chicago, Ill 60657, USA.
Arch Pathol Lab Med 2003 Jun;127(6):732-4 Abstract quote Toxoplasmosis is a common opportunistic pathogen in patients with acquired immunodeficiency syndrome (AIDS). It usually presents with ocular, central nervous system, or pulmonary disease.
Gastric toxoplasmosis is uncommon in AIDS patients, especially in the absence of central nervous system manifestations. In the few reported cases, patients have presented with abdominal pain and other digestive complaints that usually are attributed to the more common gastrointestinal manifestations of human immunodeficiency virus infection.
We describe a 49-year-old man with AIDS who presented with abdominal pain, diarrhea, dry cough, and systemic symptoms and was diagnosed with toxoplasmosis by a gastric biopsy.
TREATMENT CHARACTERIZATION GENERAL ANTIBIOTIC PROPHYLAXIS
Successful toxoplasmosis prophylaxis after orthotopic cardiac transplantation with trimethoprim-sulfamethoxazole.Baden LR, Katz JT, Franck L, Tsang S, Hall M, Rubin RH, Jarcho J.
Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA 02215, USA.
Transplantation 2003 Feb 15;75(3):339-43 Abstract quote BACKGROUND: The efficacy of trimethoprim-sulfamethoxazole (TMP/SMX) in the prevention of toxoplasmosis after orthotopic cardiac transplantation has been the subject of some controversy, with many transplant groups preferring to use the combination of pyrimethamine and sulfadiazine. Although effective, this latter regimen does not offer equal protection against other pathogens, such as or. To assess the value of TMP/SMX, we reviewed the experience in our heart transplant patients, all of whom received TMP/SMX (160/800 mg) three times weekly for approximately 8 months after transplantation.
METHODS: We report on 417 orthotopic cardiac transplants during a 17-year period. We have 100% one-year patient follow-up after transplantation. Data was collected on pretransplantation donor and recipient anti- serology, immunosuppression, allograft rejection, survival, yearly posttransplantation anti- serology, development of acute toxoplasmosis, and the occurrence of other infections.
RESULTS: In this cohort, acute toxoplasmosis developed after transplantation in one case (0.2%). Among the highest risk patients (D+R-) who were treated for at least one episode of rejection, the risk of acute toxoplasmosis was 5% (1 of 22 patients). No change in survival was found between the different anti- IgG serogroups (D-R-, D-R+, D+R-, or D+R+). Anti- IgG seroconversion occurred in eight -seronegative recipients after transplantation; all patients, except the case already noted, were asymptomatic and required no specific anti- therapy. No cases of, or infections were identified. Five proven and two suspected cases of pneumonia were found (only 2 of these 7 patients were receiving TMP/SMX at the time of pneumonia diagnosis).
CONCLUSIONS: These data demonstrate that TMP/SMX prophylaxis (160/800 mg) three times per week is effective prophylaxis after orthotopic cardiac transplantation and has prophylactic benefits against other posttransplantation opportunistic pathogens.
VACCINE
Prospects for a human Toxoplasma vaccine.Bout DT, Mevelec MN, Velge-Roussel F, Dimier-Poisson I, Lebrun M.
UFR de UMR Universite-INRA d'Immunologie Parasitaire, Pharmacie Tours, 31 Av. Monge, F-37200 Tours, France.
Curr Drug Targets Immune Endocr Metabol Disord 2002 Oct;2(3):227-34 Abstract quote Human toxoplasmosis is usually benign, but may occasionally lead to severe or lethal damages when combined with immunosuppressive states or when transmitted to the fetus during pregnancy. Only a vaccine could prevent these harmful effects. The oral route is the natural portal of entry of T. gondii. A protective immune response at the mucosal level is required to kill the parasite as soon as it penetrates the intestinal barrier thus preventing toxoplasma from invading the host and settling into tissues.
The probable major roles played by both CD8 T cells and antibodies, specially IgA, suggest that the best strategy would be to stimulate both the cellular and humoral arms of the mucosal immune system. Mucosal dendritic cells have been shown to induce good protection against oral toxoplasma challenge.
Our hypothesis is that an acceptable and effective human vaccine would have to carry the optimized synthetic vaccine (subunit, DNA or replicon) plus an appropriate adjuvant and to target the mucosal dendritic cells by means of an inert delivery system such as polymer microparticles, which can be endocytosed by M cells of the gut or nasal-associated lymphoid tissues.
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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. 5th Edition. McGraw-Hill. 1999.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.
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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