{
 "topic": "Toxoplasmosis",
 "slug": "toxoplasmosis",
 "category_id": 15336,
 "summary": "Congenital and acquired toxoplasmosis: trimester-dependent transmission and severity, the classic triad, hydrocephalus management, and serologic diagnosis of ocular disease.",
 "written_by": "claude-sonnet",
 "references": [
  {
   "title": "Netters Pediatrics (Florin Т., Ludwig St.)",
   "author": null,
   "pages": [
    688
   ]
  },
  {
   "title": "CURRENT Diagnosis and Treatment Pediatrics, Twenty-Fourth Edition",
   "author": "Hay, William W., Levin, Myron J., Deterding, Robin R., Abzug, Mark J.",
   "pages": [
    90,
    1350,
    1351,
    1352
   ]
  },
  {
   "title": "Gomella's Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs, Eighth Edition",
   "author": "Tricia Lacy Gomella, Fabien G. Eyal and Fayez Bany-Mohammed",
   "pages": [
    1230,
    1231
   ]
  },
  {
   "title": "Red_Book_2021_2024_Report_of_the_Comm_z_library_sk,_1lib_sk,",
   "author": null,
   "pages": [
    817
   ]
  },
  {
   "title": "Textbook of Pediatric Gastroenterology, Hepatology and Nutrition (Stefano Guandalini, Anil Dhawan)",
   "author": null,
   "pages": [
    833
   ]
  },
  {
   "title": "Zitelli and Davis' Atlas of Pediatric Physical Diagnosis: Expert Consult - Online",
   "author": null,
   "pages": [
    786
   ]
  },
  {
   "title": "Kliegman R. Nelson Textbook of Pediatrics 2-Volume Set 22ed 2024",
   "author": null,
   "pages": [
    2199,
    2200
   ]
  },
  {
   "title": "Red Book Atlas of Pediatric Infectious Diseases",
   "author": "American Academy of Pediatrics (AAP);Tan, Tina Q.;",
   "pages": [
    740
   ]
  }
 ],
 "short": [
  {
   "title": "In short",
   "content": "- Toxoplasmosis is caused by Toxoplasma gondii, an obligate intracellular protozoan parasite, and is one of the TORCH congenital infections; sources of infection include exposure to cat feces and ingestion of raw or undercooked meat.\n- Congenital toxoplasmosis occurs in roughly 1 in 3,000-10,000 live births in the US (some estimates as low as 0.23-0.91 per 10,000); maternal infection occurs in about 0.1-0.5% of pregnancies and is usually asymptomatic in the mother.\n- As gestation advances, the likelihood of fetal transmission rises (up to about 90% near term) while disease severity falls; the most severe fetal damage occurs with maternal infection in the second to sixth month of gestation, and first/early-second-trimester infection can cause fetal death.\n- Most congenitally infected infants (70-90%, some sources say 85%) appear normal or are initially asymptomatic at birth, but many go on to develop visual impairment, learning disabilities, or intellectual/developmental problems within months to years, often presenting in the second or third decade of life.\n- The classic triad - chorioretinitis, intracranial calcifications, and (obstructive) hydrocephalus - occurs in fewer than 10% of congenitally infected infants.\n- Chorioretinitis develops in about 70% of congenitally infected infants of untreated mothers, versus up to 25% when the mother was treated during pregnancy; up to 80% of severely affected neonates have retinochoroiditis.\n- Hydrocephalus may be the sole neurologic manifestation and almost always requires shunt placement.\n- Diagnosis in an older child with eye findings relies on T. gondii IgG/IgM serology plus a typical eye lesion; PCR for T. gondii DNA in aqueous humor can confirm but is rarely performed.\n- Treatment of confirmed congenital infection uses pyrimethamine, sulfadiazine, and folinic acid (leucovorin).\n"
  }
 ],
 "long": [
  {
   "title": "Definition",
   "content": "Toxoplasmosis is an infection caused by Toxoplasma gondii, an obligate intracellular protozoan parasite. It is grouped among the TORCH infections (toxoplasmosis, other, rubella, cytomegalovirus, herpes simplex virus) because of its capacity to cause intrauterine infection. Clinical toxoplasmosis can be divided into four categories: congenital infection, infection acquired in an immunocompetent host, infection acquired or reactivated in an immunocompromised host, and ocular disease.\n"
  },
  {
   "title": "Epidemiology",
   "content": "Congenital toxoplasmosis occurs in an estimated 1 in 3,000 to 10,000 live births in the United States, though newborn-screening-based estimates run as low as 0.23-0.91 per 10,000 live births; the true incidence may be higher because the newborn screening IgM assay has only about 50-75% sensitivity, and severe cases lost to fetal death are not captured. Maternal infection during pregnancy occurs in about 0.1-0.5% of pregnancies and is usually asymptomatic. Seroprevalence of T. gondii among women of childbearing age (15-44 years) in the US has declined over time. Sources of infection include exposure to cat feces and ingestion of raw or undercooked meat.\n"
  },
  {
   "title": "Etiology and Transmission",
   "content": "The risk and severity of fetal disease depend heavily on the trimester of maternal infection: the likelihood of fetal infection increases as pregnancy progresses (transmission risk approaches 90% near term), while the severity of resulting disease decreases. Maternal infection in the first or early second trimester can cause fetal death, while infection acquired in the second through sixth month of gestation carries the greatest risk of severe fetal damage; third-trimester infection may still produce chorioretinitis and encephalomyelitis but the pregnancy is more likely to remain viable.\n"
  },
  {
   "title": "Clinical Features",
   "content": "The majority of congenitally infected infants - commonly cited as 70-90% (or 85% in some sources) - appear normal or are asymptomatic at birth. When disease is evident in the newborn period, it may be disseminated or limited to isolated CNS or ocular disease, with late sequelae related primarily to these two systems. The classic triad of chorioretinitis, diffuse intracranial calcifications, and obstructive hydrocephalus occurs in fewer than 10% of cases. Other findings in symptomatic infants include abnormal CSF (elevated protein), anemia, seizures, direct hyperbilirubinemia, fever, hepatosplenomegaly, lymphadenopathy, eosinophilia, bleeding diathesis, hypothermia, rash, and pneumonitis; some of these may only develop over the first few months of life. Even infants who are subclinical at birth can later show intellectual impairment. Chorioretinitis develops in roughly 70% of infants of mothers who were not treated during pregnancy, versus up to 25% among infants of treated mothers, and up to 80% of severely affected neonates have retinochoroiditis. Hydrocephalus can be the only neurologic manifestation and may present prenatally, progress perinatally, or (less often) appear later in life; it almost always requires shunting. Visual/hearing impairment, learning disabilities, or severe developmental delay become apparent later in life in a large proportion of congenitally infected infants, and toxoplasmosis classically presents with visual and learning difficulties in the second or third decade of life. In the immunocompetent host, acquired T. gondii infection usually presents as self-limited lymphadenopathy, though hepatosplenomegaly and hepatitis can occur.\n"
  },
  {
   "title": "Diagnostics",
   "content": "Findings of toxoplasmosis are present on routine newborn physical examination in only a minority of infected infants; more specific evaluation - CSF analysis, dilated eye examination, or CNS imaging - can reveal evidence of infection even when the exam is normal. In an older child with visual complaints, diagnosis is usually established by finding T. gondii IgG or IgM antibodies in serum together with a typical eye lesion; PCR detection of T. gondii DNA in the aqueous humor can confirm the diagnosis but is rarely performed. CT imaging in congenital infection classically shows diffuse intracranial calcifications with hydrocephalus, and periventricular calcification on imaging should prompt consideration of toxoplasmosis alongside rubella, cytomegalovirus, and herpes simplex.\n"
  },
  {
   "title": "Differential Diagnosis",
   "content": "Congenital toxoplasmosis must be differentiated from the other major causes of congenital infection: rubella virus, cytomegalovirus, herpes simplex virus, Treponema pallidum, and Listeria monocytogenes. Ocular toxoplasmosis presents as a focal necrotizing retinochoroiditis whose appearance is nonspecific and can mimic other granulomatous ocular diseases.\n"
  },
  {
   "title": "Treatment",
   "content": "Confirmed congenital toxoplasmosis is treated with pyrimethamine, sulfadiazine, and folinic acid (leucovorin). Ocular toxoplasmosis in children most often reflects reactivation of congenital infection - typically presenting as focal necrotizing retinochoroiditis adjacent to a preexisting chorioretinal scar, due to rupture of tissue cysts releasing bradyzoites and tachyzoites into the retina - but can also follow acquired infection.\n"
  }
 ],
 "clinical": [
  {
   "title": "Evaluating a Neonate with Suspected Congenital Toxoplasmosis",
   "content": "Consider congenital toxoplasmosis in any infant with hepatosplenomegaly, microcephaly or macrocephaly, abnormal tone, seizures, or intrauterine growth restriction, and specifically in any infant under 1 year with undiagnosed neurologic disease, especially when retinal lesions are present. Remember that a normal newborn exam does not exclude infection - most infected infants look normal at birth - so pursue CSF analysis, a dilated eye exam, and CNS imaging when suspicion is raised by maternal history or other findings. On imaging, look for diffuse intracranial calcifications and hydrocephalus; periventricular calcification on head CT should prompt toxoplasmosis serology alongside consideration of rubella, CMV, and herpes simplex. Hydrocephalus may be the only sign of congenital toxoplasmosis and typically requires shunt placement regardless of other findings. Treat confirmed congenital infection with pyrimethamine, sulfadiazine, and folinic acid.\n"
  },
  {
   "title": "Ocular and Later-Presenting Disease",
   "content": "In an older child or adolescent presenting with visual symptoms, evaluate for ocular toxoplasmosis with T. gondii IgG/IgM serology plus dilated eye examination looking for focal necrotizing retinochoroiditis adjacent to a chorioretinal scar; PCR of aqueous humor can confirm the diagnosis but is rarely needed. Counsel families that congenitally infected children who appear normal in infancy remain at risk for visual impairment, learning disability, or hearing loss emerging later, often in the second or third decade of life, so long-term ophthalmologic and developmental follow-up is warranted even after an initially reassuring newborn evaluation.\n"
  }
 ]
}