Rhinoscleroma

Written by

in

 

Clinical Pathology: Rhinoscleroma

High-Yield Revision Notes for NEET PG / NEXT

Rhinoscleroma is a chronic, progressive, granulomatous bacterial infection of the upper respiratory tract. It characteristically targets the nasal cavity but can extend to the nasopharynx, larynx, trachea, and bronchi. For board examinations, focus heavily on its distinct histological markers and its classic stage-by-stage progression.

1. Etiology & Transmission

  • Causative Organism: Driven by Klebsiella pneumoniae subsp. Rhinoscleromatis (also known as the Frisch Bacillus).
  • Microbiologic Profile: A Gram-negative, capsulated, non-motile, facultative anaerobic diplobacillus.
  • Epidemiology: Endemic in specific pockets worldwide, particularly in North Africa, Central America, and South Asia (including parts of Northern India). It is heavily associated with low socioeconomic status and poor hygiene.

2. The Three Clinical Stages

The disease progresses chronologically through three distinct phases, mimicking different clinical conditions as it evolves:

Stage Clinical Presentation & Signs Differential Diagnosis Mockery
1. Atrophic / Catarrhal
(Initial Phase)		 Presents with foul-smelling, purulent nasal discharge, crusting, and progressive nasal obstruction. The mucosa looks dry and atrophic. Closely mimics **Atrophic Rhinitis**. A distinction is made when it fails to respond to standard conservative douching.
2. Granulomatous / Nodular
(Proliferative Phase)		 The crusting is replaced by painless, hard, non-ulcerating bluish-red nodules inside the nasal cavity. These nodules expand to infiltrate the septum, alae, and upper lip, causing broadening of the nasal bridge. Heberden’s “Hebra Nose”: The extensive external infiltration yields a characteristic hard, woody expansion of the external nose resembling a “tapir snout.”
3. Cicatricial / Fibrotic
(Terminal Phase)		 Extensive, dense deposition of collagenous fibrous tissue. This causes severe scarring and mechanical stenosis of the nares, choanae, or upper airway tracts. Can cause absolute nasal stenosis or respiratory compromise if scarring involves the subglottic space.

3. High-Yield Histopathology (The Ultimate Board Targets)

A definitive diagnosis is established via tissue biopsy of the granulomatous lesions. Microscopic examination reveals a dense chronic inflammatory infiltrate rich in two pathognomonic cells:

1. Mikulicz Cells (Foamy Histiocytes): Large, vacuolated, foamy macrophages containing clusters of the intracellular *Frisch bacilli*. The cell’s cytoplasm looks empty or bubbly because the macrophage is unable to digest the thick mucoid polysaccharide capsule of the bacterium.
2. Russell Bodies (Cellular Inclusions): Degenerated plasma cells featuring altered, eosinophilic, homogeneous immunoglobulin inclusion complexes. They stain intensely red on H&E. *(Note: While highly characteristic of rhinoscleroma, Russell bodies are seen in other chronic plasma-cell-rich inflammatory states as well.*

4. Management & Treatment Protocol

The therapeutic strategy relies on long-term systemic antibiotics combined with surgical reconstruction if airway narrowing has occurred:

  • Antibiotic Therapy: Regimens must be continued for a prolonged duration (often **4 to 6 weeks or months** until two consecutive tissue cultures from the mucosa return completely negative).

    • First-Line Drugs: **Streptomycin** combined with **Tetracycline** (or Doxycycline).

    • Alternatives: Rifampicin or Ciprofloxacin.

  • Surgical Intervention: Indicated exclusively during the cicatricial stage or for massive nodular obstructions. Procedures include excision of granulomatous masses to restore airway patency, surgical dilatation of stenotic areas, or plastic surgical revision of the *Hebra nose* deformity.