eMedicine Specialties > Emergency Medicine > Infectious Diseases

Toxoplasmosis: Differential Diagnoses & Workup

Author: Deepika Singh, MD, Staff Physician, Department of Emergency Medicine, Brown University
Coauthor(s): Richard Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center
Contributor Information and Disclosures

Updated: Dec 20, 2007

Differential Diagnoses

Brain Abscess
Progressive multifocal leukoencephalopathy
CNS lymphoma
Sarcoidosis
Cytomegalovirus encephalitis
Syphilis
Cytomegalovirus ventriculitis
Tularemia

Other Problems to Be Considered

Other lesions caused by Cryptococcus neoformans, Aspergillus species , Mycobacterium tuberculosis, Nocardia species

Workup

Laboratory Studies

  • Indirect detection
    • Indirect detection is performed in pregnant women and immunocompromised patients.
    • Detection of immunoglobulin G (IgG) is possible within 2 weeks using enzyme-linked immunoassay (ELISA), IgG avidity test, and agglutination and differential agglutination test.
    • Immunoglobulin M (IgM) rises within the first week of infection. Negative detection essentially rules out the disease. However, the false-positive rate is 60%. 
  • Direct detection
    • Polymerase chain reaction (PCR) amplification of T gondii gene is possible.
    • Tachyzoites may be demonstrated in tissues or smears. They also can be seen in CSF. CSF also shows mononuclear pleocytosis and elevated protein level.
    • Detection of tissue cysts confirms the diagnosis, but it does not differentiate between acute disease and chronic disease.
    • Brain biopsy is the definitive diagnosis.

Imaging Studies

  • MRI is more sensitive than CT (and CT with contrast is more sensitive than without) for detecting brain lesions due to toxoplasmosis. One study showed that MRI detected abnormalities that influenced diagnosis and treatment of 40% of patients; those abnormalities were not detected on CT.
  • A broad differential diagnosis remains in patients with abnormalities identified on CT or MRI.
  • Single-photon computed tomography (SPECT) is useful in distinguishing between CNS lymphoma and infection (ie, toxoplasmosis or any other infection).

More on Toxoplasmosis

Overview: Toxoplasmosis
Differential Diagnoses & Workup: Toxoplasmosis
Treatment & Medication: Toxoplasmosis
Follow-up: Toxoplasmosis
Multimedia: Toxoplasmosis
References
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References

  1. Garcia LS, Bruckner DA. Diagnostic Medical Parasitology. 111-121. 3rd ed. American Society of Microbiology: Washington DC; 1997:423-424; 577-589.

  2. Hardman JG, Limbird LE. Protozoal infections. In: Goodman LS, et al, eds. Goodman & Gilman's The Pharmacological Basis of Therapeutics. 9th ed. New York: McGraw-Hill; 1992:989.

  3. Hoeprich PD, Jordan MC, Ronald AR. Infectious Diseases. In: A Treatise of Infectious Processes. Lippincott-Raven Publishers; 1994:1201-1213.

  4. Reese RE, Betts RF. A Practical Approach to Infectious Diseases. 648-649. Philadelphia, Pa: Little, Brown & Co; 1996:755-759; 1274-1275.

  5. Robert-Gangneux F, Gavinet MF, Ancelle T, Raymond J, Tourte-Schaefer C, Dupouy-Camet J, et al. Value of prenatal diagnosis and early postnatal diagnosis of congenital toxoplasmosis: retrospective study of 110 cases. J Clin Microbiol. Sep 1999;37(9):2893-8. [Medline].

  6. Sanford JP, Gilbert DN, Moellering RC. The Sanford Guide to Antimicrobial Therapy. Hyde Park, Vt: Antimicrobial Therapy, Inc; 1997:86-87.

  7. Wong SY, Remington JS. Biology of Toxoplasma gondii. AIDS. Mar 1993;7(3):299-316. [Medline].

  8. Buzoni-Gatel D, Werts C. Toxoplasma gondii and subversion of the immune system. Trends Parasitol. Oct 2006;22(10):448-52. [Medline].

  9. Davaro RE, Thirumalai A. Life-threatening complications of HIV infection. J Intensive Care Med. Mar-Apr 2007;22(2):73-81. [Medline].

  10. Dodds EM. Toxoplasmosis. Curr Opin Ophthalmol. Dec 2006;17(6):557-61. [Medline].

  11. Montoya JG, Liesenfeld O. Toxoplasmosis. Lancet. Jun 12 2004;363(9425):1965-76. [Medline].

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Further Reading

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Keywords

Toxoplasma gondii, T gondii, T gondii infection, toxoplasmosis, ocular toxoplasmosis cat feces, undercooked meat , congenital toxoplasmosis, acquired toxoplasmosis, toxoplasmosis in immunocompromised host, exposure to cats, retinochoroiditis, food-borne disease

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Contributor Information and Disclosures

Author

Deepika Singh, MD, Staff Physician, Department of Emergency Medicine, Brown University
Deepika Singh, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, American Nurses Association, Emergency Medicine Residents Association, and Sigma Theta Tau International
Disclosure: Nothing to disclose.

Coauthor(s)

Richard Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center
Richard Sinert, DO is a member of the following medical societies: American College of Physicians and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Theodore Gaeta, DO, MPH, FACEP, Clinical Associate Professor, Department of Emergency Medicine, Joan and Sanford Weill Medical College at Cornell University; Vice Chairman and Program Director of Emergency Medicine Residency Program, Department of Emergency Medicine, New York Methodist Hospital
Theodore Gaeta, DO, MPH, FACEP is a member of the following medical societies: American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, New York Academy of Medicine, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Mark L Plaster, MD, JD, Editor-in-Chief of Emergency Physicians' Monthly, Department of Emergency Medicine, Memorial Hermann Hospital System
Mark L Plaster, MD, JD is a member of the following medical societies: American Academy of Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School
John Halamka, MD is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Jonathan Adler, MD, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital; Division of Emergency Medicine, Harvard Medical School
Jonathan Adler, MD is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
Disclosure: eMedicine.com, Inc. Consulting fee Consulting

 
 
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