Chlamydia

Exam Cram

• Chlamydia Trachomatis causes sexually transmitted disease (STI)

• Chlamydia Tachomatis can cause LGV (lymphogranuloma venerum)- painless ulcer with lymphadenopathy

• Treatment: doxycyline, azithromycin (if pregnant/ doxy allergy)

• Chlamydia pneumonia causes an 'atypical' lung infection in pigeon keeper

• Treatment: macrolide (azithromycin), fluoroquinolone (levofloxacin) or doxycyline

Chlamydia TrachomAtis

Background 

Diagnosis

Diagnostic criteria: 

History:

Examination:

Ix

Differentials

Management

1. Doxycycline

2. Azithromycin (if pregnant or doxy allergy)

Consent

• Patient's should inform previous partners and be encouraged to do so ++

• As of 2024, my understanding is that healthcare providers should not break confidentiality to inform partners if patient's refuse to (varies between countries)

• Having unprotected sex, whilst aware of chlamydia infection and without informing partner can be classified as assault (varies upon country)

• The same rules apply for syphilis, gonorrhoea and chlamydia however confidentiality can be broken for HIV (see HIV)

Comments

• For MCQs it is definitely worth earning pen allergy & pregnant alternatives. 

Deeper Dive

Common antibiotic regimes: 

• Doxycycline: 100mg BD 7d

• Azithromycin: 1g stat IV

Therefore the azithromycin can be an attractive option in an individual with concerns around ability to complete course. 

JH syndrome

spirochetes

Chlamydia pneumonia (Psitticosis)

Background

• 'Atypical' lung infection associated with pigeons and caged birds

• Commonly called: Psittacosis

Assessment

History

• 1-14d

• SoB, pleurisy, headache, malaise, myaglia

• Keeps pigeons/ caged birds

Examination

• Unilateral crackles

• Pyrexic +- hypoxia

Investigations

• CXR: consolidation

Diagnosis

Management

1. Tetracycline (doxycyline)

References

1. Gautam J, Krawiec C. Chlamydia Pneumonia. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560874/

Resources

• BASH

• WHO

Written in 2025