Chlamydial Infections

Chlamydial Infections: Excerpt from The 5-Minute Pediatric Consult

Sumit Bhargava, MD

Chlamydial Infections - BASICS

Chlamydial Infections - description

Chlamydiae are obligate intracellular bacteria responsible for pulmonary infections, ocular trachoma, STDs, and infections of the genital tract in the pediatric and adult population.

• The genus Chlamydophila has 3 species known to affect humans:
  • C. trachomatis
  • C. psittaci
  • C. 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. Along with Mycoplasma pneumoniae, C. pneumoniae probably accounts for most of the community-acquired pneumonias (CAPs) in school-age children and adolescents.

• 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.
• C. pneumoniae:
  • Lack of a commercially reliable test for diagnosis. Microimmunofluorescence (MIF) is proven diagnostic in >50% of infected children. An increase in antibody titer may be delayed for several weeks after onset of symptoms. Early antimicrobial therapy may interfere with the development of detectable antibodies.
  • Sometimes it is difficult to differentiate between infection and carrier state, and between recent and past infection.
  • Recurrent infections are common. Prolonged nasopharyngeal shedding can occur for months after acute disease.
• Isolation: Standard precautions for both C. pneumoniae and C. trachomatis
• Control measures: In infants infected with C. trachomatis, the mother and her sexual partner should be treated. None for C. pneumoniae

Chlamydial Infections - 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.

Chlamydial Infections - epidemiology

• C. trachomatis:
  • There are at least 15 serologically distinct variants (serovars).
  • 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.
• C. psittaci (psittacosis/ornithosis):
  • Both healthy and sick birds can transmit the bacteria via the airborne route by their excrement or secretions.
  • Important sources of human disease are parakeets, parrots, macaws, pigeons, and turkeys.
  • Workers in poultry slaughter plants, poultry farms, pet shops, laboratory workers, and pet owners are at high risk.
  • Although usually rare in children, it should be considered in any child with environmental exposure who develops an atypical pneumonia. The incubation period is 7–14 days.
• C. pneumoniae: Antigenically, morphologically, and genetically distinct from other chlamydiae
  • It is assumed to be transmitted from person to person through aerosolized respiratory secretions.
  • C. pneumoniae has recently been associated with atherosclerotic cardiovascular disease. Limited evidence associates C. pneumoniae with asthma and bronchospasm, Alzheimer disease, multiple sclerosis, Kawasaki disease, HIV and other immune disorders, malignancy, otitis media, and episodes of acute chest syndrome in patients with sickle cell disease.
  • Coinfection with other respiratory pathogens, especially M. pneumoniae and Streptococcus pneumoniae, is frequent.
  • Incubation period: ~21 days

Chlamydial Infections - incidence

C. trachomatis:

• This is the most common reportable sexually transmitted infection in the US. The number of new infections exceeds 4 million annually.
• 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 US.

Chlamydial Infections - prevalence

C. pneumoniae:

• Increased prevalence rates of C. pneumoniae specific antibody have been documented in school-age children, reaching 30–45% in adolescents.
• Studies of CAPs in children have found C. pneumoniae in 6–19% of cases. Evidence of lower respiratory tract infection has been found in 0–18% of the pediatric population.
• Most infections are mild or asymptomatic. Acute infection does not appear to vary by season. A carriage state has been detected in 2–5% of patients. Recurrent infection is common, especially in adults.

Chlamydial Infections - DIAGNOSIS

Chlamydial Infections - signs & symptoms

Chlamydial Infections - history

• C. trachomatis:
  • Presents between 4 and 12 weeks of age
  • Insidious onset
  • Afebrile illness
  • Rhinorrhea
  • Repetitive cough: Staccato type in >50% of infants; sometimes pertussislike coughing spells
  • Conjunctivitis in up to 50% of infants
  • Mild-to-moderate respiratory distress
• C. pneumoniae:
  • Often insidious onset
  • May manifest as pharyngitis, sinusitis, bronchitis, or pneumonia
  • Fever
  • Hoarseness
  • Prolonged cough; can be productive
  • Biphasic course

Chlamydial Infections - physical exam

• C. trachomatis:
  • 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 frequently present
  • Moderate tachypnea (50–60 breaths/min)
  • Frequent cough during examination
  • Scattered rales on chest auscultation
  • Wheezing is an uncommon finding.
• C. pneumoniae:
  • Patients may be asymptomatic or mildly to moderately ill.
  • Cervical lymphadenopathy
  • Postnasal discharge
  • Nonexudative pharyngitis
  • Wheezing, frequently without rales, on chest auscultation

Chlamydial Infections - tests

Chlamydial Infections - lab

• C. trachomatis:
  • 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.
  • FDA-approved nucleic acid amplification methods such as polymerase chain reaction (PCR), strand displacement amplification (SDA), and transcription-mediated amplification (TMA) are more sensitive than cell culture and more specific and sensitive than DNA probe, direct fluorescent antibody (DFA), or enzyme immunoassay (EIA). These have also been approved for urine in both men and women, making them useful noninvasive tests for adolescents.
  • 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 is difficult to perform, and 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 suggest C. trachomatis pneumonia.
  • Only culture should be used for sexual abuse or other forensic purposes.
• C. pneumoniae:
  • No reliable test is available commercially. Serologic testing is the primary laboratory means of diagnosis.
  • The nasopharynx is the optimal site for recovery of C. pneumoniae. Also isolated from sputum and pleural fluid
  • Serologic diagnosis by MIF is the most sensitive and specific test. Evidence of acute infection: 4-fold elevation of IgG titers, specific IgM titer of ≥1:16, specific IgG titer of ≥1:512, WBC count is usually normal.

Chlamydial Infections - imaging

Chest radiography:

• C. trachomatis: Hyperinflation with bilateral diffuse infiltrates
• C. pneumoniae: Focal to bilateral infiltrates; pleural effusions

Chlamydial Infections - differencial diagnosis

• C. trachomatis:
  • Viral respiratory pathogens: Respiratory syncytial virus (RSV), adenovirus, influenza A and B, parainfluenza
  • Other agents that can cause pneumonitis: cytomegalovirus, Pneumocystis carinii, Ureaplasma urealyticum, Bordetella pertussis
• C. pneumoniae:
  • M. pneumoniae
  • Influenza A and B
  • Parainfluenza
  • Adenovirus
  • Respiratory syncytial virus
  • Can resemble typical bacterial pneumonia
  • Less frequently: C. psittaci, Coxiella burnetii, or Legionella pneumophila

Chlamydial Infections - medication

• C. trachomatis:
  • Erythromycin, 50 mg/kg/d 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/d 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 first-line treatment.
• C. pneumoniae:
  • Erythromycin suspension: 50 mg/kg/d divided q.i.d. for 14 days. For adolescent patients, erythromycin 500 mg q.i.d. for 14 days or 250 mg q.i.d. for 21 days. An alternative for children >9 years is doxycycline 100 mg b.i.d. for 14 days.
  • Clarithromycin: 15 mg/kg/d divided b.i.d. for 10 days is as effective as erythromycin.
  • Azithromycin: 10 mg/kg on day 1 (maximum, 500 mg) followed by 5 mg/kg days 2–5 (maximum, 250 mg) is as effective as erythromycin in pediatric studies.
  • Adolescents can be treated with doxycycline 100 mg b.i.d. for 14–21 days, tetracycline 250 mg q.i.d. for 14–21 days, azithromycin 1.5 g for 5 days, levofloxacin 500 mg/d PO or IV for 7–14 days, or moxifloxacin 400 mg/d PO for 10 days.
  • Antibiotic treatment failure rate is ~20%. A 2nd course of therapy is sometimes needed. Follow-up should be recommended.

Chlamydial Infections - FOLLOW UP

Chlamydial Infections - 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.

Chlamydial Infections - complications

• In very young infants, chlamydial pneumonia can lead to apnea or respiratory failure. Untreated infection can persist for weeks to months.
• Complications of psittacosis include myocarditis, hepatitis, pancreatitis, and secondary bacterial pneumonia.

Chlamydial Infections - bibliography

American Academy of Pediatrics. 2006 Red Book: Report of the Committee on Infectious Diseases. Elk Grove Village, IL: American Academy of Pediatrics; 2006:249–251.
1. Centers for Disease Control and Prevention. Sexually transmitted disease guidelines 2002. MMWR. 2002;519(No:RR-6):1–75.
2. Hammerschlag MR. Chlamydia trachomatis and Chlamydia pneumoniae infections in children and adolescents. Pediatr Rev. 2004;25(Feb):43–51.
3. 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. 1997;16:293–297.

Chlamydial Infections - CODES

Chlamydial Infections - icd9

483.1 Chlamydia

Chlamydial Infections - 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 STDs?
• 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.

Book Source Details

• Book Title: The 5-Minute Pediatric Consult
• Author(s): M. William Schwartz MD; et al.
• Year of Publication: 2008
• Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.

More About Psittacosis

• Back to disease: Psittacosis: Introduction
• Next Book Extract About Psittacosis: Psittacosis (The 5-Minute Pediatric Consult)
• More Book Extracts: All Online Books for Psittacosis

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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.

More About This Book: Title: The 5-Minute Pediatric Consult Authors: M. William Schwartz MD; et al. Publisher: Lippincott Williams & Wilkins Copyright: 2008 ISBN: 0-7817-7577-9

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