TORCH complex

Micrograph of cytomegalovirus (CMV) infection of the placenta (CMV placentitis), a TORCH infection. The characteristic large nucleus of a CMV infected cell is seen off-centre at the bottom-right of the image. H&E stain.

TORCH complex (also known as TORCHES or the TORCH infections) is a medical acronym for a set of perinatal infections (i.e. infections that are passed from a pregnant woman to her fetus). The TORCH infections can lead to severe fetal anomalies or even fetal loss. They are a group of viral, and some bacterial, infections that gain access to the fetal bloodstream transplacentally via the chorionic villi. Hematogenous transmission may occur at any time during gestation or occasionally at the time of delivery via maternal-to-fetal transfusion.^[1]

Conditions

The TORCH complex was originally considered to consist of four conditions,^[2] with the "TO" referring to "Toxoplasma". The four-term form is still used in many modern references,^[3] and the capitalization "ToRCH" is sometimes used in these contexts.^[4]

Alternatively, the "O" is redefined as "other",^[5] and the acronym is spelled out as follows:

1. T – Toxoplasmosis / Toxoplasma gondii
2. O – Other infections (see below)
3. R – Rubella
4. C – Cytomegalovirus
5. H – Herpes simplex virus

The "other agents" included under O are Hepatitis B, Syphilis, Varicella-Zoster Virus, HIV, and Parvovirus B19.

The acronym has also been listed as TORCHES, for TOxoplasmosis, Rubella, Cytomegalovirus, HErpes simplex, Syphilis.

Features

The diseases present similarly, involving the heart, skin, eye, and CNS. They all cause chorioretinitis, microcephaly, and focal cerebral calcification. Listeria, E. coli and group B streptococci can also be acquired after membrane rupture, and are the three most common causes of meningitis of the newborn.

Symptoms of a TORCH infection may include fever and poor feeding. The newborn is often small for gestational age. A petechial rash on the skin may be present, with small reddish or purplish spots due to bleeding from capillaries under the skin. An enlarged liver and spleen (hepatosplenomegaly) is common, as is the yellowish discoloration of the skin and eyes called jaundice. However, this is less common in Hep B as jaundice occurs due to an immune response against the liver and the immune system in a newborn is not effective enough to damage the liver enough to cause jaundice. Hearing impairment, eye problems, mental retardation, autism, and death can be caused by TORCH infections. The mother often has a mild infection with few or no symptoms.

It is possible for genetic conditions (Aicardi-Goutieres syndrome) to present in a similar manner.^[6][7]

Diagnosis

When physical examination of the newborn shows signs of the TORCH syndrome, the examiner may test blood, urine, and spinal fluid for evidence of the infections listed above. Diagnosis can be confirmed by culture of one of the specific pathogens or by increased levels of IgM against the pathogen.

Treatment and prevention

Some of the TORCH infections, such as toxoplasmosis and syphilis, can be effectively treated with antibiotics if the mother is diagnosed early in her pregnancy. Many of the viral TORCH infections have no effective treatment, but some, notably rubella and varicella-zoster, can be prevented by vaccinating the mother prior to pregnancy. If the mother has active herpes simplex, delivery by Caesarean section can prevent the newborn from contact, and consequent infection, with this virus.

Prognosis

Each type of TORCH infection has a different prognosis. The stage of the pregnancy at the time of infection also can change the effect on the newborn.

Additional images

CMV placentitis.

CMV placentitis.

References