Rhinoscleroma is a chronic
granulomatous disease of the nasal mucosa (less commonly, nasopharynx,
larynx, and trachea) caused by Klebsiella rhinoscleromatis, an
encapsuted, nonsporulating, nonmotile gram-negative bacillus.
Rhinoscleroma is prevalent in the USSR,
Poland, and central Europe and is endemic in Mexico, Central America,
and upper South America.
Age and sex:
Rhinoscleroma is a disease
of young and middle-aged adults, slightly more common in women and
without racial predisposition.
Clinical presentation:
The onset is slow and insidious, usually over many years, and the
patient’s general health is unaffected.
At first, the symptoms are those of a
common cold.
An initial granularity of the nasal
mucosa is replaced by reddish, waxy, granulomatous infiltrates and
firm, nodular, intranasal masses.
In fully developed rhinoscleroma
hyperplastic changes of the alae and tip of the nose (the “Hebra
nose”) are severely disfiguring.
Airway obstruction, anaemia, and speech
difficulties develop as the disease advances.
Anesthesia of the soft palate and
enlargement of the uvula suggest rhinoscleroma, but any part of the
upper airways, the paranasal sinuses and orbit may be involved.
Compressive destruction of bone and
soft tissue mimics invasive tumours.
Scar tissue persists after the disease
runs its course.
Pathological features:
There are 3
pathologic stages of development.
(i) the catarrhal
stage, ii) granulomatous stage, iii) and fibrotic stage.
In the catarrhal
stage, the mucosa consists of inflamed granulation tissue containing
neutrophils and cellular debris.
In the
granulomatous stage, the characteristic lesion of rhinoscleroma is
seen.
In the fibrotic
stage, the characteristic Mikulicz cells are absent, fibrosis is
extensive, and the inflammatory infiltrate contains lymphocytes and
plasma cells.
Characteristic
microscopic feature of Rhinoscleroma:
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Microscopically, the most conspicuous
feature is the presence of histiocytic granulomas, with fibrosis and
an abundant infiltrate of lymphocytes and plasma cells.
The mucosal surfaces display variable
changes, ranging from squamous metaplasia to extreme
pseudoepitheliomatous hyperplasia.
Large
vacuolated, “foamy” histiocytes, known as
Mikulicz cells, are characteristic of rhinoscleroma and are most
numerous in the nodular stage.
Klebsiella organisms are seen within
cells and in extracellular locations.
The bacteria
stain very well with periodic acid–Schiff, Giemsa, Gram, and silver
stains.
Differential
diagnosis:
Granulomatous
bacterial, fungal, or protozoan infections ; vasculitis ; and
tumours involving the nose and upper airways, including the lips and
soft palate. Rhinoscleroma should be distinguished from
tuberculosis
,
leprosy ,
syphilitic gumma ,
histoplasmosis ,
blastomycosis
,
paracoccidioidomycosis
,
rhinosporidiosis
,
leishmaniasis
, Wegener
granulomatosis , T-cell/natural killer cell lymphomas , and
carcinomas.
Diagnosis of Rhinoscleroma:
The diagnosis of
rhinoscleroma is confirmed by isolating Klebsiella rhinoscleromatis in
culture or by demonstrating the organism in tissue sections.
The
bacteria stain very well with periodic acid–Schiff, Giemsa, Gram, and
silver stains.
Pathogenesis:
The pathogenesis of rhinoscleroma is not clear.
Cellular immunity
is impaired in these patients.
Humoral immunity
is preserved. The CD4–CD8 ratio within the lesion is altered, showing
decreased CD4 lymphocytes and increased CD8 lymphocytes, possibly
inducing a diminished T-cell response.
The macrophages
are not fully activated (hence groups of histiocytes instead of
bactericidal epithelioid macrophages are seen in the granulomatous
stage).
Rhinoscleroma in
patients with human immunodeficiency virus infection has also been
reported.
The
mucopolysaccharides of the bacterial capsule probably contribute to
inhibition of phagocytosis.
Treatment:
Antibiotic of choice are
streptomycin, tetracycline, and chloramphenicol. In some patients
surgical intervention is necessary to relieve airway obstruction or to
repair the facial features.
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