Keywords
rhinosporidiosis - epidemiology - host factors
Introduction
Rhinosporidiosis is a granulomatous disease of humans and animals that is caused by
Rhinosporidium Seeberi. This disease is endemic in certain states of India, such as Chhattisgarh, Tamil
Nadu, Kerala, Orissa, and eastern Madhya Pradesh. The taxonomy of this organism has
always been controversial. Now, it is regarded as an aquatic member of the Protista.[1]
The disease is transmitted to humans through direct contact with spores of the organism,
infected fingers or clothes, and pond bathing. The organism mainly targets the mucous
membrane of the nasal cavity and nasopharynx. Other uncommon sites are conjunctiva,
oral mucosa, epiglottis, trachea, larynx, external genitalia, urethra, rectum, bone,
and skin.[2]
[3]
[4]
[5]
Four clinical forms of rhinosporidiosis have been described: nasal, ocular, cutaneous,
and disseminated form. Classical lesion of rhinosporidiosis is pedunculated or sessile
polypoid mass. In humans, R. Seeberi triggers the immune mechanism; however, it evades host's immunity through immune
suppression, immune distraction, immune deviation, and binding of host immunoglobulins,
which might explain certain aspects of the disease, such as chronicity, recurrence
and dissemination.[6]
[7]
Rhinosporidium Seeberi cannot be grown in the culture media. Histopathology of the lesion is the gold standard
for diagnosis.[8] In biopsy, sporangia of various sizes containing endospores in various stages of
maturation are seen. The sporangia and endospores can be stained with Gomorimethenamine
silver (GMS), mucicarmine, periodic acid Schiff (PAS), Grocott's and hematoxylin &
eosin stain.[9]
Wide local excision of the lesion followed by cauterization of the base is the treatment
of choice for rhinosporidiosis. The newer treatment modalities include lasers, harmonic
scalpel and coblation. Though chemotherapy is found to be unsuccessful, dapsone has
been found to be effective in this disease.[10]
Though many studies have been conducted on this disease, very few have shed light
on host risk factors and the role of public health education in the prevention of
this disease. As the disease takes a chronic course with recurrence, and Chhattisgarh
having a high burden of this disease, the current study was conducted to study the
epidemiology of the disease, especially host risk factors. Also, we aimed to identify
the regions and tribal belts of Central India with large disease burden so that further
preventive measures can be suggested.
Methods
We conducted a retrospective, record-based study in the department of ENT & Head and
Neck Surgery of a tertiary case institute of Chhattisgarh, India. A total of 55 histologically
proven rhinosporidiosis patients who were surgically treated in the department over
a period of 2 years from November 2014 to November 2016 were included after getting
approval from the ethics committee of the institute. Records of all patients were
retrieved from hospital case records and detailed history was recorded in a predesigned
proforma. The updated BG Prasad scale was used for analyzing the patients' socioeconomic
status.[11] The records revealed that all patients underwent a detailed clinical history and
examination and were thoroughly investigated (routine blood investigations, plain
X-ray nose & para nasal sinuses, computed tomography of paranasal sinuses, nasal endoscopy
and biopsy). Surgical excision and electrodessication of the base of the lesion was
performed in all patients under general anesthesia. All nasal and nasopharyngeal lesions
were operated using nasal endoscopes and powered instruments, like microdebrider and
coblator. All excised specimens were sent for histopathological examination. The obtained
data were collected, complied, and analyzed. Analysis of the data was done with the
help of the statistical software IBM SPSS Statistics for Windows, Version 19.0. (IBM
Corp., Armonk, NY, USA).
Result
The present study involved 55 histologically proven rhinosporidiosis cases, who were
surgically treated. Forty-eight (87.27%) patients were male and 7 (12.73%) patients
were female. The mean age was 25.17 years ranging from 6 to 70 years. The most common
age group was 11 to 30 years, with 37 patients [[Table 1]]. Of 55 cases, 24 (43.64%) were students, followed by laborers (18, 32.73%), housewife
(7; 12.73%) and others (6, 10.91%). The majority of the cases (45 cases, 81.82%) were
residing in rural areas followed by semi-urban (6 cases, 10.91%) & urban areas (4
cases, 7.27%). Most of the cases belonged to lower socioeconomic status (92.73%),
followed by middle socioeconomic status (7.27%). All the cases had history of pond
bathing.
Table 1
Age distribution of patients with rhinosporidiosis
|
Age group (years)
|
Number of cases
|
Percentage (%)
|
|
< 10
|
6
|
10.92
|
|
11–20
|
20
|
36.36
|
|
21–30
|
17
|
30.91
|
|
31–40
|
3
|
5.45
|
|
41–50
|
4
|
7.27
|
|
51–60
|
1
|
1.82
|
|
61–70
|
4
|
7.27
|
|
Total
|
55
|
100
|
The most common symptom of the disease was nasal obstruction (43.67%) followed by
epistaxis (23.67%). The symptoms of the disease are mentioned in [Table 2]. Of the 55 cases, 45 (81.81%) were of primary rhinosporidiosis and 10 (18.18%) were
of recurrent rhinosporidiosis. Both right (22; 40%) and left (23; 41.82%) sides of
the nasal cavity were affected almost equally. Bilateral nasal involvement was seen
in 3 cases (5.45%), pharynx in 6 (10.90%), and larynx in 1 (1.82%). The most affected
site was the nasal cavity (87.27%), followed by the nasopharynx (10.91%) ([Fig. 1], [Fig. 2]). The site of attachment of the mass in the nasal cavity was the inferior turbinate
and floor in 19 cases (34.55%), followed by the nasal septum, in 16 cases (29.09%),
multiple sites in 6 cases (10.90%), pharynx in 6 cases (10.90%), lateral wall in 5
cases (9.09%), inferior meatus & nasolacrimal duct in 2 cases (3.64%), and larynx
in 1 case (1.82%). Of 55 cases, 27 (49.09%) had O+ blood group, followed by A+ in
10 (18.18%), B+ in 9 (16.36), and AB+ in 9 (16.36%). Of the 10 cases of recurrence,
most of them had O+ blood group (7, 70%). However, this difference was not statistically
significant (p-value = 0.49). The patients were from different districts of Chhattisgarh, the maximum
burden of disease was found in the Raipur district, where the facility is located,
followed by Durg ([Table 3]). The district of Raipur was with maximum case load (47.27%).
Table 2
Symptoms of patients with rhinosporidiosis
|
Symptom
|
Number of cases
|
Percentage (%)
|
|
Nasal obstruction
|
24
|
43.67
|
|
Epistaxis
|
13
|
23.67
|
|
Nasal mass
|
5
|
9.09
|
|
Nasal discharge
|
5
|
9.09
|
|
Breathing difficulty
|
4
|
7.27
|
|
Voice change
|
2
|
3.64
|
|
Foreign body sensation
|
2
|
3.64
|
|
Total
|
55
|
100
|
Fig. 1 Naso-oropharyngeal rhinosporidiosis.
Fig. 2 Nasal rhinosporidiosis.
Table 3
District-wise distribution of rhinosporidiosis in Chhattisgarh
|
District
|
Number of cases
|
Percentage (%)
|
|
Raipur
|
26
|
47.27
|
|
Durg
|
11
|
20
|
|
Baloda Bazar
|
7
|
12.72
|
|
Mahasamund
|
3
|
5.45
|
|
Bemetra
|
2
|
3.64
|
|
Raigarh
|
2
|
3.64
|
|
Jangir
|
1
|
1.82
|
|
Balod
|
1
|
1.82
|
|
Dhamtari
|
1
|
1.82
|
|
Rajnandgaon
|
1
|
1.82
|
|
Total
|
55
|
100
|
Discussion
In the present study, rhinosporidiosis was seen more frequently in males as compared
with females (M:F 6.86:1). In the literature, the ratio of male to female incidence
of this disease varies from 1.3:1 to 9:1.[9]
[12]
[13]
[14]
[15] A few studies have shown female predominance also.[16] The reason for the lower number of females affected might be less frequent pond
baths. Some authors are of the opinion that estrogen may have a protective role.[17] In the present study the most affected age group was 11 to 30 years (67.27%). Sinha
et al[9] and Manonmany et al[14] have found that 20 to 40 years was the most affected age group. In a study by Karthikeyan
et al[12], 21 to 50 years was the most commonly affected age group, with 31 to 40 years age
group being even more predominantly affected; however, it was not statistically significant.[12] Other studies also found that the most affected age group was 21 to 30 years.[13]
[14]
[15] Hence, we can conclude that mostly young and middle aged persons are affected by
rhinosporidiosis.
Most studies have found that farmers, students, and manual laborers were mainly affected
by rhinosporidiosis[4]
[12]
[16]
[17] The disease was found to affect people residing in rural areas,[12]
[15]
[17]
[18]
[19]
[20] and some studies show higher incidence in tribal populations.[16]
[21] People belonging to lower socioeconomic status were found to be more affected.[12]
[15]
[17] In the current study, the majority of the cases was from rural areas (81.82%), and
most of the affected individuals were students, followed by laborers. The major portion
of cases belonged to the lower socioeconomic status. Thus, rhinosporidiosis shows
a strong association with rural residential and low socioeconomic status.
Previous studies have found that patients affected with the disease had history of
taking baths in ponds, rivers, tanks, lakes, reservoirs, and wells.[4]
[12]
[15]
[16]
[17]
[18]
[19]
[20]
[21] All cases in the present study also had history of pond bathing. This shows the
constant exposure of the patients to infected water sources. In endemic areas, many
people take baths in common water bodies; however, few people develop rhinosporidiosis.
This indicates that there are some factors in the hosts that predispose them for rhinosporidiosis.
To date, blood group is the only predisposing factor of host on which some data are
available. Kameswaran et al reported maximum incidence rate of rhinosporidiosis in
blood group O (70%), followed by blood group AB.[22] However, Jain et al denied the role of blood group as a predisposing factor for
rhinosporidiosis.[23] A study conducted by Sinha et al revealed that the major portion of cases belonged
to the O blood group (44%), followed by the AB group (22%).[9] Vadakkan et al reported maximum incidence rate of rhinosporidiosis in the blood
group O (75%), followed by the blood group A (20%).[24] Manonmonyet al concluded that the majority of the cases belonged to the B + , followed
by the O+ blood group.[18] In our study, the highest incidence was seen in the O+ blood group, followed almost
equally by A + , B + , and AB + . Another host factor that needs to be investigated
is human leukocyte antigen (HLA) typing.
In the present study, the most common symptom of rhinosporidiosis was nasal obstruction,
followed by epistaxis, nasal discharge, and nasal mass. Similar findings were found
in other studies.[12]
[25] In one study, the most common symptom was epistaxis.[15] In the current study no predilection to any specific side of nasal cavity was seen,
both right and left sides were affected almost equally, whereas Manonmony et al, in
their study, found a higher incidence on the right side of the nasal cavity (47%),
followed by left side (33%).[18] In the present study, the nasal cavity was the most common site involved, followed
by multiple sites, pharynx, and larynx. Among the multiple site involvement, one patient
had nasopharyngeal and cutaneous rhinosporidiosis [[Fig. 3]]. Most other studies have reported that the site most frequently affected was the
nasal cavity, followed by the nasopharynx.[8]
[12]
[15]
[17]
[19]
[20]
[21]
[24]
[25] Manonmony et al[18] concluded that the most frequently affected site was the nose, followed by the oropharynx.
Other sites affected include the larynx, trachea, eyes, skin, bone, penis, nasolacrimal
duct, parotid gland, soft palate, and muscles.[8]
[12]
[15]
[19]
[20]
[21]
[24]
[25]
[26]
Fig. 3 Cutaneous rhinosporidiosis.
In a study of nasal rhinosporidiosis cases by Guru and Pradhan, the lateral wall of
the nose, followed by the septum and floor, was the most common site of attachment
of the mass.[15] Karthikeyan et al found the septum, followed by the inferior turbinate and inferior
meatus, as the most common site of attachment.[12] While in our study of nasal rhinosporidiosis cases, the inferior turbinate and floor
were the most common sites, followed by the nasal septum and lateral wall.
High chance of recurrence is seen in rhinosporidiosis even after medical and surgical
therapy, according to the literature recurrence rate ranges from 5 to 63%.[12] Of the 55 cases in the present study, 10 (18.18%) cases were of recurrence. Vadakkan
et al, in their study, mentioned a case having 42 episodes of recurrent nasal and
nasopharyngeal rhinosporidiosis.[24] Similarly, in our study, 1 patient had 21 episodes of recurrent nasal and nasopharyngeal
rhinosporidiosis.
In the present study, analysis of the distribution of the disease in the Chhattisgarh
state of India found that the highest incidence of rhinosporidiosis was in the district
of Raipur, followed by Durg. It was also found that the disease was more prevalent
in central part of the state when compared with the northern and southern parts. This
might be either due to the drainage area of the institute being in the central part
of Chhattisgarh or disease may be endemic to central Chhattisgarh.
Conclusion
Rhinosporidiosis is associated with the male gender, young and middle age group, low
socioeconomic status, rural background, pond bathing and blood group O + . Additionally,
more studies are required to know the role of other host factors, such as HLA typing
and immune system. The disease is chronic with a high recurrence rate. The nasal mucosa
is commonly involved, and nasal obstruction is the most common presentation. The first
choice of treatment is surgical excision, preferably using endoscope and powered instruments
with cauterization of the base. Rhinosporidiosis is more prevalent in the central
part of Chhattisgarh. A strong public health education system is required in these
endemic areas to prevent this disease.
