Basics
Description
Chlamydiae are obligate intracellular bacteria responsible for pulmonary infections, ocular trachoma, sexually transmitted diseases, and infections of the genital tract in the pediatric and adult population.
- The genus Chlamydophila has 3 species known to affect humans:
- Chlamydia trachomatis
- Chlamydophila psittaci
- Chlamydophila pneumoniae
- All 3 species can produce the clinical picture of the so-called atypical or interstitial pneumonia.
- C. trachomatis can cause afebrile pneumonia in 10-20% of infants born to infected mothers. Infected infants usually present prior to 2 months of age. Up to 50% of patients have a history of inclusion conjunctivitis.
- C. psittaci is mainly pathogenic for birds and occasionally affects humans, typically causing interstitial pneumonitis with associated fever, headache, malaise, and nausea.
- C. pneumoniae causes pneumonia, pharyngitis, sinusitis, and bronchitis in humans.
Alert
- C. trachomatis
- Infection can occur in infants delivered by cesarean section, even without rupture of amniotic membranes.
- Ocular prophylaxis at birth does not reliably prevent conjunctivitis or extraocular infection, even if erythromycin ointment is used. Topical treatment alone is not recommended because it does not eradicate the nasopharyngeal colonization.
General Prevention
- Adequate surveillance and treatment of C. trachomatis colonizing the genital tract of pregnant women is the best way of preventing disease in the infant.
- Annual chlamydia screening for all sexually active women younger than age 25 years and for all pregnant women in the 1st trimester of pregnancy is recommended.
Epidemiology
- C. trachomatis
- There are at least 18 serologically distinct variants with different associations:
- A-K: oculogenital
- A-C: trachoma
- B, D-K: genital and perinatal infection
- L1-L3: lymphogranuloma venereum (LGV)
- C. trachomatis is the most frequent cause of epididymitis in sexually active young men.
- Incubation period: 5-14 days after delivery for conjunctivitis
- The possibility of sexual abuse should be considered in older infants and children with vaginal, urethral, or rectal C. trachomatis.
Incidence
- This is the most common reportable sexually transmitted infection in the United States. The number of new infections exceeds 4 million annually.
- C. trachomatis is responsible for neonatal conjunctivitis, trachoma, pneumonia in young infants, genital tract infection, and LGV.
- Rates of infection in adolescent girls are 15-20%.
- 23-55% of all cases of nongonococcal urethritis in men are caused by C. trachomatis. Up to 50% of men with gonorrhea may be coinfected with C. trachomatis.
- C. trachomatis pneumonia usually develops in infected infants <2 months of age (2 weeks to 5 months). The contagiousness of pulmonary disease is unknown, but is considered low.
- Half of the neonates born to infected mothers via vaginal delivery will acquire C. trachomatis. Conjunctivitis may develop in 30-50%.
- Pneumonia may develop in up to 30% of infants with nasopharyngeal infection.
- Ocular trachoma caused by serovars A, B, Ba, and C is the most common cause of preventable blindness in the world, but is rare in the United States.
Diagnosis
History
- Presents between 4 and 12 weeks of age
- Insidious onset
- Afebrile illness
- Rhinorrhea
- Repetitive cough
- Staccato type in >50% of infants
- Sometimes, pertussis-like coughing spells
- Conjunctivitis in up to 50% of infants
- Mild to moderate respiratory distress
Physical Exam
- Afebrile
- 50% of patients will have conjunctivitis with discharge (can be seen up to several weeks after birth).
- Rhinitis with mucoid discharge or nasal stuffiness, sometimes causing significant airway obstruction
- Hypoxia is frequently present.
- Apneic episodes may be seen in preterm infants.
- Moderate tachypnea (50-60 breaths/min)
- Staccato cough
- Scattered rales on chest auscultation
- Wheezing is an uncommon finding.
Diagnostic Tests & Interpretation
Lab
- Cell culture
- Definitive diagnosis is by isolation of the organism in tissue culture.
- Confirmation is by microscopy of the characteristic inclusions by fluorescent antibody staining.
- Specimens are obtained from the nasopharynx, conjunctiva, vagina, or rectum.
- Dacron polyester-tipped swabs should be used for collection.
- Nucleic acid amplification methods:
- FDA-approved nucleic acid amplification methods such as polymerase chain reaction (PCR), strand displacement amplification (SDA), and transcription-mediated amplification (TMA) are more sensitive (98%) than cell culture and more specific and sensitive than DNA probe, direct fluorescent antibody (DFA), or enzyme immunoassay (EIA).
- In addition, these have been approved for urine studies in both men and women, making them useful noninvasive tests for adolescents.
- Direct antigen tests:
- DNA probe, DFA, and EIA are the most common nonculture direct antigen-detection tests approved by the FDA.
- These are most sensitive (90%) and specific (95%) in conjunctival specimens.
- These methods can have false-positive results when used for vaginal or rectal specimens.
- Serum antibody detection
- Difficult to perform
- Tests are not widely available.
- Eosinophilia of 300-400/mm3, hyperinflation, bilateral diffuse infiltrates on chest radiograph, and elevation of IgM (>110 mg/dL) and IgG (>500 mg/dL) are indirect evidence that indicate C. trachomatis pneumonia.
- Only culture should be used for sexual abuse or other forensic purposes.
Imaging
Chest radiography
- Hyperinflation with bilateral diffuse infiltrates
Differential Diagnosis
- Viral respiratory pathogens:
- Respiratory syncytial virus (RSV),
- Adenovirus
- Influenza A
- Influenza B
- Parainfluenza
- Other agents that can cause pneumonitis:
- Cytomegalovirus
- Pneumocystis carinii
- Ureaplasma urealyticum
- Bordetella pertussis
Treatment
Medication
- Erythromycin, 50 mg/kg/day divided q.i.d. for 14 days (therapy is effective in 80-90% of cases). Additional topical therapy is unnecessary. An association between oral erythromycin and infantile hypertrophic pyloric stenosis (IHPS) has been reported in infants <6 weeks of age. Parents should be informed of the possible risk of IHPS and its signs.
- If the patient does not tolerate erythromycin, oral sulfonamides may be used after the immediate neonatal period. Children >8 years can be treated with tetracycline, 25-50 mg/kg/24 h divided q.i.d. for 7 days.
- A single 1-g oral dose of azithromycin may be used in children ≥45 kg or ≥8 years of age.
- In adults and adolescents, a single 1-g dose of azithromycin or doxycycline 100 mg b.i.d. orally for 7 days is 1st-line treatment.
Ongoing Care
Prognosis
- In general, good
- Infection with C. trachomatis has been associated with long-term respiratory sequelae, such as an increased incidence of reactive airway disease and abnormal pulmonary function tests.
- Slow recovery
- Cough and malaise may persist for several weeks.
Complications
- 40% of women whose chlamydial infection is untreated develop pelvic inflammatory disease. 20% of these women may become infertile.
- Role of chlamydia in pathogenesis of asthma and atherosclerosis is under investigation.
Additional Reading
- Chandran L, Boykan R. Chlamydial infections in children and adolescents. Pediatr Rev. 2009;30(7):243-250. [View Abstract]
- Geisler WM. Management of uncomplicated Chlamydia trachomatis infections in adolescents and adults: evidence reviewed for the 2006 Centers for Disease Control and Prevention sexually transmitted diseases treatment guidelines. Clin Infect Dis. 2007;44(Suppl 3):S77-S83. [View Abstract]
- Harris JA, Kolokathis A, Campbell M, et al. Safety and efficacy of azithromycin in the treatment of community-acquired pneumonia in children. Pediatr Infect Dis J. 1998;17(10):865-871. [View Abstract]
- Sexually transmitted disease guidelines 2002. Centers for Disease Control and Prevention. MMWR. 2002;51(RR-6):1-78. [View Abstract]
- U.S. Preventative Services Task Force. Screening for chlamydial infection: U.S. Preventative Services Task Force recommendation statement. Ann Intern Med. 2007;147(2):128-133. [View Abstract]
Codes
ICD09
- 079.98 Unspecified chlamydial infection
- 770.0 Congenital pneumonia
- 076.1 Trachoma, active stage
- 099.53 Other venereal diseases due to chlamydia trachomatis, lower genitourinary sites
- 099.54 Other venereal diseases due to chlamydia trachomatis, other genitourinary sites
ICD10
- A74.9 Chlamydial infection, unspecified
- P23.1 Congenital pneumonia due to Chlamydia
- A71.1 Active stage of trachoma
- A56.19 Other chlamydial genitourinary infection
SNOMED
- 240589008 Chlamydia trachomatis infection (disorder)
- 233610007 Neonatal chlamydial pneumonia (disorder)
- 240591000 Neonatal chlamydial conjunctivitis
- 428015005 Chlamydia trachomatis infection of genital structure
- 446471004 Infection of epididymis due to Chlamydia trachomatis (disorder)
FAQ
- Q: If the mother has an untreated genital infection, should we treat the asymptomatic newborn?
- A: Yes. The child should receive oral erythromycin for 14 days.
- Q: Do we need to pursue the diagnosis of other sexually transmitted diseases?
- A: Yes. Gonorrhea, syphilis, hepatitis B, and human immunodeficiency virus infection need to be ruled out. If conjunctivitis is present, an ocular swab to exclude Neisseria gonorrhoeae infection must be included.
- Q: When do we need to suspect C. trachomatis pneumonia?
- A: In any infant <4 months of age who presents with cough, tachypnea, and rales on examination, when the chest radiograph shows bilateral infiltrates with hyperinflation