Rhinoscleroma: causes, symptoms, diagnosis, and treatment

Rhinoscleroma, also known as scleroma, is a low-infectious chronic inflammatory granulomatous disease caused by klebsiella rhinoscleromatis, also known as Frisch bacillus. Lesions occur initially in the nose and then spread to the upper respiratory tract, forming an indurated granulomatous inflammatory mass, which can cause deformity or obstruction.


Causes

Klebsiella rhinoscleromatis is a Gram-negative bacillus with a length of about 2.0 - 3.0μm, only found in the pharynx of patients. After invading the nasal vestibular mucosa, the bacteria reproduce locally, and neutrophils migrate into the interstitial space and die soon after bacterial phagocytosis. Histiocytes enlarge significantly and progress into Mikulicz cells after entrance of bacteria and neutrophil fragments. The capsular mucopolysaccharides of klebsiella rhinoscleromatis can protect the bacteria from being digested by lysozyme in histiocytes, allowing the bacteria to survive in histiocytes and to be chronic antigen stimulations, constantly stimulating macrophage activation, resulting in proliferation of histiocytes, thereby forming granulomatous lesions. Proliferating granuloma and reaction of plasma cells and lymphocytes are the main causes of local tissue lesions.


Signs and Symptoms

The disease usually occurs initially in the nose, progressing slowly, without systemic symptoms.

The duration of the disease can be divided into three stages.

Catarrhal stage
 
The initial symptoms are headache, disturbance in respiration, viscous nasal discharges with stenches, pus-filled scabs in the nasal cavity, laryngoxerosis, hemorrhinia, and mucosal hypertrophy, especially hypertrophy in the mucous membrane of nasal septum, resembling atrophic rhinitis.

Granulomatous stage

When the symptoms of rhinitis subside, infiltration and obstruction occur in the lower nasal septum, and then throat is also involved. There are many pea sized, dark purplish red nodules beneath the mucosa, which can fuse to form a mass and adhere to the underlying tissue. Patients may have tone changes, numbness of soft palate, dyspnoea, anosmia, and ageusia.

Scarring stage

The condition continues to progress, the granulation tissue is fibrotic, indurated scars are formed, and complete loss of sensation is present. With the development of the condition, nostrils are completely obstructed, forming a permanent stenosis. Cicatricial contracture leads to facial destruction. Severe obstruction of the respiratory tract can cause dyspnea, and lesions involving the bronchi can cause death from suffocation. In some cases, osteolysis occurs around the lesion.


Histopathology

Specific granuloma, a large number of plasma cells, highly specific Mikulicz cells, Russell bodies, and Frisch bacillus, as well as few spindle cells, and collagenation can be seen.

Mikuliez cells are large, vacuolated histiocytes with a diameter of 100 - 200μm. The cytoplasm is lightly stained, reticulated, with blurred boundaries, and the nucleus is on one side. Klebsiella rhinoscleromatis can be found in the cytoplasm.

Russell bodies are round or elliptical, bright red, evenly stained, refractive, anucleate bodies with a diameter of 20 - 40μm, which are doubled in size compared with normal plasma cells. The bodies are formed in plasma cells and may be intracellular degenerative changes.


Diagnosis

The diagnosis is based on characteristic clinical symptoms, specific histopathological changes, pathogens found in the lesions, and positive result in complement fixation test.


Treatment

This disease has a good response to cephalosporins, streptomycin, and sulfonamides. Medications should be selected under the guidance of drug sensitivity test. The course of treatment should be more than one year as this disease can relapse after clinical and bacteriological cure.

Patients with stenosis caused by scar contracture require surgical treatment to improve the symptoms of airway obstruction. Plastic surgery is used to restore the shape and function of the face and nose.