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Donovanosis

Chapter 178 | Part 5: Infectious Diseases · Part 5 – Infectious Diseases: Bacterial · Chapter 178

Key Clinical Points

  1. Donovanosis (granuloma inguinale) is a chronic, progressive bacterial infection primarily affecting the genital region.
  2. Caused by Klebsiella granulomatis (formerly Calymmatobacterium granulomatis).
  3. Pathognomonic finding: Donovan bodies (1.5 × 0.7 μm) found in macrophages and stratum malpighii.
  4. Classic lesion is a beefy red ulcer that bleeds easily on touch; affects genitals in 90% of cases.
  5. Diagnosis confirmed by microscopy showing 'safety-pin' morphology of Donovan bodies in tissue smears.
  6. Extragenital involvement occurs in 6% of cases (e.g., lip, pharynx).
  7. Risk factor for HIV transmission; associated with poor hygiene and lower socioeconomic status.
  8. Pregnancy leads to faster lesion progression and slower response to treatment.
  9. Clinical diagnosis has high positive predictive value.
  10. Serologic tests are not used due to poor specificity.

1. DEFINITION & OVERVIEW

• Definition: Donovanosis is a chronic, progressive bacterial infection that usually involves the genital region. • Alternative Name: Granuloma inguinale. • Causative Organism: Klebsiella granulomatis (formerly Calymmatobacterium granulomatis). • Taxonomy Note: Reclassified as Klebsiella granulomatis comb nov based on phylogenetic analysis; however, this is debated due to discrepancies in 16S rRNA gene sequence analyses. • History of Culture: Not reproducibly cultured until the mid-1990s (isolated in peripheral-blood monocytes and human epithelial cell lines). • Microscopic Hallmark: Donovan bodies (1.5 × 0.7 μm) found in macrophages and stratum malpighii.

2. EPIDEMIOLOGY

• Geographic Distribution: ◦ Papua New Guinea, Southern Africa, India, Caribbean, French Guyana, Brazil, and Aboriginal communities in Australia. ◦ Note: In Australia and South Africa, the disease is nearly eliminated through public health initiatives. • Historical Context: ◦ U.S. (1947): 5,000–10,000 cases reported. ◦ Dutch South Guinea (Marind-anim population, 1922–1952): 10,000 of 15,000 individuals affected. • Risk Factors: ◦ Poor hygiene ◦ Lower socioeconomic status ◦ Male gender predominance • HIV Link: Donovanosis is a risk factor for HIV transmission.

2.1 Geographic Distribution

• Regions: Papua New Guinea, Southern Africa, India, Caribbean, French Guyana, Brazil, Australia.

2.2 Risk Factors

• Factors: Poor hygiene, lower socioeconomic status, male gender, HIV risk factor.

3. ETIOLOGY & PATHOPHYSIOLOGY

• Organism: Klebsiella granulomatis (formerly Calymmatobacterium granulomatis). • Pathogenesis: ◦ Donovan bodies are intracytoplasmic cysts within macrophages (1.5 × 0.7 μm). ◦ These structures rupture to release infectious organisms. • Molecular Differentiation: Unique base changes in the phoE gene eliminate HaeIII restriction sites, allowing differentiation from related Klebsiella species.

4. CLINICAL FEATURES

• Lesion Progression: Typically begin as papules or subcutaneous nodules → ulcerate after trauma. • Morphology of Lesions: ◦ 1. Classic ulcerogranulomatous: Beefy red ulcers with easy bleeding. ◦ 2. Hypertrophic/verrucous: Raised, irregular edges. ◦ 3. Necrotic: Offensive-smelling tissue destruction. ◦ 4. Sclerotic/cicatricial: Fibrous scar tissue (fibrosis). • Anatomic Distribution: ◦ Genitals: 90% of cases (prepuce, coronal sulcus, glans in men; labia minora/fourchette in women). ◦ Inguinal region: 10% ◦ Extragenital: 6% (lip, gums, pharynx, chest). • Systemic Spread: Hematogenous spread to liver or bone reported. • Special Populations: ◦ Pregnancy: Faster lesion progression → slower treatment response. ◦ Newborns: May present with ear infection. ◦ Children: Transmission via contact with infected adults (e.g., sitting on infected adults).

4.1 Lesion Types

• Types: ◦ Classic ulcerogranulomatous (beefy red, easy bleeding) ◦ Hypertrophic/verrucous (raised edges) ◦ Necrotic (offensive odor) ◦ Sclerotic/cicatricial (fibrous scar)

4.2 Anatomic Distribution

• Distribution: ◦ Genitals: 90% ◦ Inguinal: 10% ◦ Extragenital: 6% ◦ Hematogenous: Liver/bone

4.3 Special Populations

• Pregnancy: Faster progression, slower response. • Newborns: Ear infections. • Children: Transmission via contact with adults.

5. DIFFERENTIAL DIAGNOSIS

• Common STIs: Syphilitic chancres, secondary syphilis (condylomata lata), chancroid, lymphogranuloma venereum, genital herpes. • Other Conditions: Amebiasis, neoplasm. • Histologic Differentiation Required From: Rhinoscleroma, leishmaniasis, and histoplasmosis. • Note: Mixed infections are common.

6. INVESTIGATIONS & DIAGNOSIS

  1. Clinical Assessment: High positive predictive value for experienced practitioners.
  2. Microscopy (Primary Confirmatory): ◦ Preparation: Smear preparation must precede swab collection for other pathogens. ◦ Technique: Rapid Giemsa/Wright's stain on granulation tissue or Pund cells. ◦ Finding: Identification of Donovan bodies (safety-pin morphology) in mononuclear cells.
  3. Molecular Methods: ◦ PCR targeting phoE gene changes (differentiation from other Klebsiella). ◦ Colorimetric detection systems for routine use. ◦ Genital ulcer multiplex PCR.
  4. Serology: Not used due to poor specificity.

6.1 Microscopy

• Techniques: Giemsa/Wright's stain. • Target: Pund cells with intracytoplasmic Donovan bodies (safety-pin morphology). • Mechanism: Gram-negative cysts rupturing to release organisms.

6.2 Molecular & Serology

• PCR: PhoE gene analysis; Colorimetric detection systems. • Serology: Not used due to poor specificity.

7. MANAGEMENT & TREATMENT

  1. Psychosocial Support: ◦ Provide reassurance and counseling regarding embarrassment and low self-esteem.
  2. Medical Treatment: ◦ Antibiotic therapy (specific agents not detailed in source).
  3. Public Health Coordination: ◦ Coordinate with sexual health services for partner notification.

7.1 Clinical Approach

• Actions: Address embarrassment, emphasize treatability, coordinate partner notification.

8. PROGNOSIS & COMPLICATIONS

• Local Complications: Pseudoelephantiasis, urethral/vaginal stenosis, and neoplastic changes. • Systemic/Rare Complications: Polyarthritis, osteomyelitis. • Metastatic Spread: Hematogenous spread to liver or bone.

9. SPECIAL CONSIDERATIONS

• Pregnancy: ◦ Faster lesion development. ◦ Slower treatment response. • Pediatrics: ◦ Transmission via contact with infected adults. ◦ Newborns: Presentation as ear infections.

9.1 Pregnancy

• Clinical Course: Faster progression, slower treatment response.

9.2 Pediatrics

• Transmission: Contact with adults. • Newborns: Ear infections.

10. KEY PEARLS & CLINICAL TRAPS

• Key Pearls: ◦ Characteristic 'beefy red' ulceration that bleeds easily. ◦ High prevalence of genital involvement (90%). ◦ Risk factor for HIV transmission. ◦ Extragenital lesions occur in 6% of cases. • Clinical Traps: ◦ Confusion with syphilis or chancroid. ◦ Delayed presentation leading to complications like stenosis or neoplasm. ◦ Relying on serology (not specific enough).