Evaluation of clinical, scintigraphic, and histopathological features in patients with patients with a presumptive diagnosis of Sjögren’s syndrome

Abstract

Introduction

Sicca syndrome is characterized by the presence of dry eye (xerophthalmia - keratoconjunctivitis sicca), dry mouth (xerostomia), and dry skin (xeroderma), this triad may be related to Sjögren’s syndrome.

Objective

To associate the clinical, scintigraphic, and histopathological characteristics of patients with xerostomia and diagnosis of SS and presumptive diagnosis of Sjögren's syndrome in Medellín-Colombia, 2018–2020.

Materials and methods

The study was a quantitative approach, with cross-sectional analysis. The participants were grouped into two groups: diagnosis of Sicca syndrome and presumptive diagnosis of Sjögren's syndrome, and a survey of sociodemographic data was applied. For each group, salivary flow measurements, Schirmer’s test, salivary gland scintigraphic study, and histological evaluation were performed. Statistical analysis was performed using measures of central tendency (median) and dispersion (interquartile range), Fisher’s exact test, and the Wilcoxon test (U Man-Whitney).

Results

The total sample studied consisted of 24 women, whose most frequent systemic clinical symptom was joint pain in Sicca syndrome (90%), and in the group of presumptive diagnosis of Sjögren’s syndrome (92.9%), while the most frequent sign was tongue depapillation in Sicca syndrome (100%) and in the group of presumptive diagnosis of Sjögren’s syndrome (92.9%). Functional tests, unstimulated salivary flow rate, and salivary gland scintigraphy showed greater involvement in the group of presumptive diagnosis of Sjögren’s syndrome. Histopathological analysis showed atrophic changes, fibrosis, and fatty changes in both categories.

Conclusion

The findings suggest that patients with a presumptive diagnosis of Sicca syndrome may be in an early phase of Sjögren's syndrome progression, so this study aims to establish an association of signs, symptoms, and diagnostic aids to define an accurate diagnosis and therapy.

Resumen

Introducción

El síndrome seco o síndrome Sicca se caracteriza por la presencia de ojo seco (xeroftalmia - queratoconjuntivitis sicca), boca seca (xerostomía) y piel seca (xerodermia). Esta triada puede estar relacionada con el síndrome de Sjögren.

Objetivo

Asociar las características clínicas, gammagráficas e histopatológicas de pacientes con xerostomía y diagnóstico de síndrome Sicca con el diagnóstico presuntivo de síndrome de Sjögren, en Medellín (Colombia), en el periodo 2018–2020.

Materiales y métodos

Estudio de enfoque cuantitativo, de tipo analítico transversal. Las participantes se agruparon en dos grupos diagnósticos: síndrome Sicca y diagnóstico presuntivo de síndrome de Sjögren. Se aplicó una encuesta de datos sociodemográficos. Para cada grupo se hicieron mediciones de flujo salival, test de Schirmer, estudio gammagráfico de glándulas salivales y evaluación histológica. Se realizó análisis estadístico mediante medidas de tendencia central (mediana) y de dispersión (rango intercuartílico), prueba exacta de Fisher y prueba Wilcoxon (U Man-Whitney).

Resultados

La totalidad de la muestra estudiada estuvo constituida por 24 mujeres, cuyo síntoma clínico sistémico más frecuente fue el dolor articular en el síndrome Sicca (90%), y en el grupo de diagnóstico presuntivo de síndrome de Sjögren (92,9%), en tanto que el signo frecuente fue la depapilación lingual en el síndrome Sicca (100%) y en el grupo de diagnóstico presuntivo de síndrome de Sjögren (92,9%). Las pruebas funcionales tasa de flujo salival no estimulada y gammagrafía de glándulas salivales presentaron un mayor compromiso en el grupo diagnóstico presuntivo de síndrome de Sjögren. En el análisis histopatológico se observaron cambios atróficos, fibrosis y cambios grasos en ambas categorías.

Conclusión

Los hallazgos sugieren que los pacientes con diagnostico presuntivo de síndrome Sicca pueden encontrarse en una fase temprana de progresión de síndrome de Sjögren, por lo cual este estudio orienta a establecer una asociación de signos, síntomas y ayudas diagnósticas para hacer un diagnóstico y definir una terapéutica acertada.

Introduction

Henrik Sjögren used the term Sicca syndrome (SS),¹ characterized by a phenotypic pattern of dryness in the ocular and oral mucosa that most frequently affects postmenopausal women. These symptoms of SS are present in Sjögren’s syndrome (SJS), which can generate confusion in diagnosis and treatment.

SJS is a systemic autoimmune disease that generates epithelitis and acinar atrophy, due to infiltrates of mononuclear cells in exocrine glands and some extraglandular tissues.^2,3 These morphological changes are generated by the progressive migration of leukocytes and the persistence of specific immune reactions against endogenous glandular tissues that trigger functional alterations, which are expressed through the reduction or absence of secretions (xerostomia and keratoconjunctivitis), which in turn can be accompanied by joint pain, which corresponds to the clinical triad of pathognomonic symptoms associated with the disease.^4,5 SJS can occur primarily (pSJS) or it can be part of other chronic inflammatory diseases, a case in which it is called secondary Sjögren’s syndrome.

It has been considered that the etiopathogenesis of SJS is multifactorial, involving environmental, genetic and molecular agents, which constitute great challenges for diagnosis and therapies to improve symptoms and prevent complications in people who suffer from it, given that quality of life can be affected to varying degrees.⁶ This has allowed that since 1965 different classification or diagnostic criteria have been proposed. Today are accepted those elaborated by the American College of Rheumatology/European League Against Rheumatism Classification Criteria for Primary Sjogren’s Syndrome (ACR/EULAR-2016) consensus, which includes subjective criteria, such as ocular and oral symptoms; objective evidence of ocular and salivary involvement; lymphocytic infiltration in minor salivary gland biopsy (gold standard), with a focus score ≥ 1, defined as a number of lymphocytic foci (containing ≥ 50 lymphocytes) per 4 mm² of glandular tissue; and presence of SS-related antigen A antibody markers (anti-Ro or SSA) and anti-Sjogren type B (anti-La or SSB).⁷

Nardi et al.⁸ argue that difficulties may arise in the diagnosis of pSJS, due to the variable presence of autoantibodies against nuclear and non-nuclear antigens, with anti-smooth muscle antibodies being more frequent (62%) than SSA and SSB. Therefore, some authors recommend that for cases in which SSA and SSB antibody patterns are inconclusive for pSJS, whenever a clinical suspicion persists, a minor salivary gland biopsy is suggested.^9,10

On the other hand, SS, characterized by dryness in the eyes, mouth and vaginal mucosa, increases with age; it involves about 30% of the population over 65 years of age, with a higher prevalence in women.^11,12 The distinction between SS and SSJ becomes relevant to guide diagnosis, therapy, and exocrine gland involvement. Therefore, some imaging studies have been gaining importance for the diagnosis of SJS, including ultrasound and Doppler. that can provide information for the identification of patients at risk of developing complications of the disease, as well as to document structural and vascularization alterations of the glands.¹³ Another useful, but seldom used, diagnostic aid is major salivary gland scintigraphy, which is considered minimally invasive, generates little radiation, has an affordable cost and allows morphofunctional evaluation of the major salivary glands (parotid and submandibular); characteristics not estimated in other tests. In addition, it provides information to establish risk factors, such as most severe hypouptakes of the radiotracer, that usually suggest higher possibility of systemic and autoimmune involvement, higher incidence of B-cell lymphoma and less survival.¹⁴

Although the pathophysiology of SS is also multifactorial, its diagnosis is challenging, since the diagnostic aids may differ, depending on the severity of the patient’s signs and symptoms. Pijoan et al.⁹ propose an algorithm for the diagnosis of SS and suspicion of SJS with the analysis of the different immunological, functional and histopathological aids, which can help in early, perhaps undiagnosable phases of SJS. Therefore, the objective of this study was to associate the clinical, scintigraphic, and histopathological characteristics of patients with xerostomia and presumptive diagnosis of SS and SJS in Medellín (Colombia), in the period 2018–2020.

Materials and methods

The study design is quantitative, cross-sectional analytical, conducted on patients who consulted the stomatology services of the Faculty of Dentistry of the Universidad de Antioquia and to the private consultation of the co-investigators in Medellín (Colombia), between April 2018 and January 2020. It was approved by the Bioethics Committee of the Faculty of Dentistry of the Universidad de Antioquia, with Concept No.14-2018, Record No. 04 of 2018, Medellín, 21 April 2018.

Inclusion and exclusion criteria

For the sample size, the convenience sampling criterion was used; all patients were over 18 years of age. As inclusion criteria, patients who presented symptoms of dry mouth and suspicion of SJS, with a histopathological study of minor salivary glands indicated by their treating doctor and a negative immunological test were taken into account. As exclusion criteria, patients with a history of radiotherapy for the head and neck. chemotherapy or direct trauma to the salivary glands, as well as the intake of medications that cause xerostomia (antihypertensives, antiresorptives and antidepressants), hyper and hypothyroidism, consumption of tobacco or psychoactive substances, history of active hepatitis C, human immunodeficiency virus (HIV), sarcoidosis, amyloidosis, graft-versus-host disease, or immunoglobulin G4-related syndrome (IgG4) were not taken into account.

Collection of information

Once it was identified that each participant met the inclusion criteria and was eligible for the study, they were informed about the project to determine their willingness to participate. An appointment to attend the clinical evaluation was scheduled for the women who agreed to participate. All participants signed the informed consent form and, subsequently, through a face-to-face interview, a survey was applied in which sociodemographic data were collected, and the physical examination was performed by two residents of the Specialization in Oral and Maxillofacial Surgery of the Universidad de Antioquia. These data were recorded in a database created in Excel for subsequent analysis.

Clinical characteristics

For salivary flow measurements, tests for unstimulated and stimulated saliva were included, and for dry eyes, the Schirmer test, guaranteeing a calm clinical environment for the performance of these tests.

• 1

  Saliva collection without stimulation: each patient deposited the saliva, which passively flowed into the mouth and was accumulated for 5 min into a bottle (Falcon 50 mL sterile) for subsequent quantification.⁷

• 2

  Saliva collection with stimulation: each patient was previously instructed to chew alternately on both sides, a piece of paraffin of 5 g for 60 s, to the rhythm of the metronome at 60 mastications per minute (MPM). The saliva produced during this time was discarded and then the patient was asked to accumulate saliva in the mouth for 5 min, to collect it in a bottle (Falcon 50 mL sterile) and subsequently quantify it.⁷

• 3

  Schirmer’s test: to perform the test, Whatman No. 41 filter paper was used, with a 5 mm fold made to suspend it in the lower eyelid of each eye, and it was left for 5 min for subsequent measurement.⁷

Scintigraphy of major salivary glands

A scintigraphic study of the salivary glands was performed following fasting for four hours, after explaining the procedure to the patient and the signature of an informed consent. 10 mCi (37 Mbq) of 99 mTc-pertechnetate were administered intravenously, performing a dynamic acquisition for 30 min (30 images of 60 s) and static acquisitions in anterior and lateral projections (700 kilocounts/image) at the end of the exploration. At 20 min, lemon juice was administered orally as a citric stimulus to assess excretory function. The salivary glands and the thyroid were included in the detection field.

All studies were performed on the dual-detector Infinia™ Hawkeye 4 gamma camera (General Electric, Medical Systems, Milwaukee, United States) using the low-energy, high-resolution multipurpose collimator. A 64 × 64 matrix was used for the dynamic study and a 256 × 256 matrix was used for the static images, in both cases with a magnification of 1.33. The processing was carried out on the Xeleris 3 platform (General Electric, Medical Systems, Milwaukee, United States). A region of interest (ROI) was drawn in the parotid and submaxillary glands, the values of the maximum (mC) and total (tC) counts were obtained and an activity/time curve was generated for each of the ROIs.

The studies were analyzed and interpreted by two nuclear medicine physicians, in a semi-quantitative way, taking into account the images and assessing the profile of the curves, determining whether or not adequate incorporation by the parotid and submaxillary glands was found and assessing excretion to rule out functional alterations both in the dynamic study and in the activity/time curves (Fig. 1).

Figure 1.

A) Parotid and submaxillary glands with normal scintigraphic characteristics. B) Scintigraphic signs of functional involvement in submandibular glands characterized by decreased radiopharmaceutical uptake. C) Scintigraphic signs of severe unilateral functional compromise of the parotid without radiopharmaceutical uptake and bilateral submandibular glands, evidenced by radiopharmaceutical hypouptake.

The report of each patient was delivered in writing and on a CD, plus graphs on acetates, with a description of the function of each of the major salivary glands, uptake percentages and a conclusion. Subsequently, these data were also recorded in the database.

Histopathological analysis

With the prior written authorization of the patients to access the pathology blocks and slides, a new reading was made by an oral pathologist, who did not know the clinical information of the patients. Histological findings were expressed according to the Chisholm and Mason scale (CH-M) to categorize patients into SS (CH-M 0-2) and presumptive diagnosis of SJS (presumptive SJS) (CH-M 3-4), As detailed in Table 1.

Table 1.

Chisholm and Mason scale.¹⁵

Degree	Lymphocytes per 4 mm^2 of tissue	Interpretation
0	Without lymphocytic infiltrate	Negative criteria for SS
1	Slight diffuse lymphocytic infiltrate
2	Moderate lymphocytic infiltrate (<1 focus)
3	Presence of 1focus
4	Presence of more than 1 focus	Positive criteria for SS

SS: Sicca syndrome.

Focus: aggregate of 50 cells/4 mm² (lymphocytes).

Statistical analysis

The characteristics of the patients were described using measures of central tendency (median) and dispersion (interquartile range [IQR]). For comparisons between the SS and presumptive diagnosis of SJS groups, Fisher's exact test was used for categorical variables and Mann Whitney’s U test for quantitative variables. A Pearson correlation analysis was performed to measure the degree of association between the amount of stimulated and unstimulated salivary flow produced by each gland and the SS and presumptive diagnosis of SJS groups. The statistical tests were two-tailed and a value of p < 0.05 was considered as statistical significance. The analyses were performed using STATA V.12 (Stata Corporation, College Station, Texas, USA).

Ethical considerations

This study was reviewed and approved by the Bioethics Committee of the Faculty of Dentistry of the Universidad de Antioquia, with Concept Number 14-2018, Record Number 04 of 2018, in the city of Medellín, on April 21, 2018. The implementation of this research project complies with the provisions of the Universal Declaration on Bioethics and Human Rights of the United Nations Educational, Scientific and Cultural Organization (UNESCO) of the year 2005 and the Scientific-Technical and Administrative Standards for Health Research, Resolution N.° 008430 of 1993 of the Ministry of Health of Colombia, in its title II, chapter VI, on the handling of tissues, articles 47–48; and in its title IV, chapter I, alluding to the biosafety of research and the recommendations for biomedical research of the Declaration of Helsinki of 1964 (updated in 2008). Written informed consent was obtained, which authorized participation in the project, as well as the use of the data and results for academic dissemination.

Results

Participants

Of 40 eligible patients, 24 were included after excluding 10 patients who did not agree to participate in the study and six from whom it was not possible to obtain pathology blocks or slides in the laboratories (Fig. 2).

Figure 2.

Flowchart of the patients included in the study.

The entire sample studied consisted of 24 women. The SS group (CH-M 0-2), made up of 10 patients, had a median age of 52.5 (IQR 41-57) years and for the group with presumptive diagnosis of SJS of 63.5 (IQR 51-69) years, and there were no significant differences between the groups.

In the evaluation of clinical signs and symptoms, there were no differences between the groups. However, between the groups, a higher frequency of symptoms of joint pain was observed in SS (90%) and in presumptive diagnosis of SJS (92.9%), dry skin in SS (80%) and in presumptive diagnosis of SJS (85.7%), polydipsia in SS (80%) and in presumptive diagnosis of SJS (71.4%), muscle fatigue in SS (80%) and in presumptive diagnosis of SJS (78.6), and ocular dryness in SS (70%) and in presumptive diagnosis of SJS (71.4%).

The most frequent clinical signs in both groups were tongue depapillation in SS (100%) and in presumptive diagnosis of SJS (92.9%). followed by lip desquamation in SS (80%) and in presumptive diagnosis of SJS (78.6%), and mucosal erythema in SS (60%) and in presumptive diagnosis of SJS (71.4%).

Among other symptoms, in the SS group there was burning in the mucous membranes (80%), muscle fatigue (80%), change in taste, dysphagia and vaginal dryness (60%) and the sign of conjunctival erythema (60%).

In relation to the comparison of salivary flow rate between the SS and presumptive SJS groups, there was a significant difference with p value = 0.005 and p = 0.009 for unstimulated and stimulated salivary flow, respectively (Table 2).

Table 2.

Summary of clinical findings obtained from participants according to diagnostic categories.

Clinical parameter	Diagnostic category		p value
	SS (CH-M 0-2)^a	Presumptive SJS (CH-M 3-4)^a
	(n = 10)	(n = 14)
Age (years)^b	52.5 (41–57)	63.5 (51–69)	0.252^d
Dry skin^c
Yes	8 (80.0)	12 (85.7)	1.000^e
No	2 (20.0)	2 (14.3)
Dry eye^c
Yes	7 (70.0)	10 (71.4)	1.000^e
No	3 (30.0)	4 (28.5)
Vaginal dryness^c
Yes	6 (60.0)	7 (50.0)	0.697^e
No	4 (40.0)	7 (50.0)
Dysphagia^c
Yes	6 (60.0)	9 (64.3)	1.000^e
No	4 (40.0)	5 (35.7)
Polydipsia^c
Yes	8 (80.0)	10 (71.4)	1.000^e
No	2 (20.0)	4 (28.6)
Burning sensation in mucosa^c
Yes	8 (80.0)	6 (42.9)	0.104^e
No	2 (20.0)	8 (57.1)
Pruritus^c
Yes	2 (20.0)	5 (35.7)	0.653^e
No	8 (80.0)	9 (64.3)
Voice changes^c
Yes	4 (40.0)	4 (28.6)	0.673^e
No	6 (60.0)	10 (71.4)
Taste changes^c
Yes	6 (60,0)	6 (42.9)	0.680^e
No	4 (40.0)	8 (57.1)
Joint pain^c
Yes	9 (90.0)	13 (92.9)	1.000^e
No	1 (10.0)	1 (7.1)
Muscle fatiguer^c
Yes	8 (80.0)	11 (78.6)	1.000^e
No	2 (20.0)	3 (21.4)
Xeroderma^c
Yes	5 (50.0)	10 (71.4)	0.403^e
No	5 (50.0)	4 (28.6)
Conjunctival erythema^c
Yes	6 (60.0)	6 (42.86)	0.680^e
No	4 (40.0)	8 (57.14)
Eyelid desquamation^c
Yes	1 (10.0)	1 (7.1)	1.000^e
No	9 (90.0)	13 (92.9)
Mucosal erythema^c
Yes	6 (60.0)	10 (71.4)	0.673^e
No	4 (40.0)	4 (28.6)
Sphacelation^c
Yes	1 (10.0)	3 (21.4)	0.615^e
No	9 (90.0)	11 (78.6)
Oral ulcers^c
Yes	3 (30.0)	4 (28.6)	1.000^e
No	7 (70.0)	10 (71.4)
Tongue Depapillation^c
Yes	10 (100.0)	13 (92.9)	1.000^e
No	–	1(7.1)
Angular cheilitis^c
Yes	5 (50.0)	11 (78.6)	0.204^e
No	5 (50.0)	3 (21.4)
Lip desquamation^c
Yes	8 (80.0)	11 (78.6)	1.000^e
No	2 (20.0)	3 (21.4)
Schirmer's test (mm)^b	5.5 (4–13)	4.5 (4–8)	0.744^d
Unstimulated salivary flow (mL)^b	2.45 (1.6–2.8)	0.7 (0.5 – 0.9)	0.005^d
Stimulated salivary flow (mL)^b	2.3 (1.8–3)	1.06 (0.6–1.5)	0.009^d

SS: Sicca syndrome; SJS: Sjögren’s syndrome.

a

Chisholm-Mason Classification (CH-M).

b

Values given as median and interquartile range (IQR).

c

Values given as n (%) for each parameter according to the diagnostic category.

d

Mann-Whitney U Test.

e

Fisher’s exact test.

Scintigraphic findings and correlation with quantitative clinical parameters

When evaluating the scintigraphic findings, there was evidence of a trend towards lower uptake of 99 mTc, lower percentage of uptake and greater functional involvement in the submandibular glands in patients with a presumptive diagnosis of SJS, when comparing both groups, without statistically significant differences (Table 3). The uptake of 99 mTc had a positive correlation with the salivary flow test for the submandibular glands, when evaluating Pearson's correlation coefficients, with p values close to 0.05 (Table 4).

Table 3.

Summary of scintigraphic findings per major salivary gland with reference to diagnostic categories.

Scintigraphic parameter/gland	Diagnostic category		p value
	SS (CH-M 0−2)^d	Presumptive SJS (CH-M 3−4)^d
	(n = 10)	(n = 14)
Uptake percentage of 99 mTc^a
Right parotid	24.1 (22.1–27.9)	25.6 (21.9–29.1)	0.618^e
Left parotid	24.1 (22.3–27.6)	22.5 (21–28.4)	0.265^e
Right submandibular	26.1 (25.1–26.4)	27 (19.4–20.1)	0.725^e
Left submandibular	27.2 (24.5–29.8)	23.9 (20.6–28.1)	0.197^e
Uptake of 99 mTc^b
Right parotid	86.6 (83.1 – 120.7	87 (68.4–137.6)	0.906^e
Left parotid	90 (81.8–113.7)	82 (67.1–104.3)	0.291^e
Right submandibular	98.8 (60.9–134.5)	91.7 (67.8–105.4)	0.598^e
Left submandibular	103.1 (61.64–140.9)	93.9 (71.24–109.5)	0.348^e
Functional compromise^c
Right parotid
Positive	7 (70.0)	8 (57.1)	0.678^f
Negative	3 (30.0)	6 (42.9)
Left parotid
Positive	5 (50.0)	8 (57.1)	1.000^f
Negative	5 (50.0)	6 (42.9)
Right submandibular
Positive	1 (10.0)	6 (42.9)	0.172^f
Negative	9 (90.0)	8 (57.1)
Left submandibular
Positive	1 (10.0)	5 (35.7)	0.341^f
Negative	9 (90.0)	9 (64.3)

SS: Sicca syndrome; SJS: Sjögren’s syndrome.

a

Values given as median and interquartile range (IQR) obtained from the counts at 15 min–fund/fund.

b

Values given as median and interquartile range (IQR) obtained from the proportion of counts/mCi.

c

Values given as n (%) for each parameter according to the diagnostic category.

d

Chisholm-Mason classification (CH-M).

e

Mann-Whitney U Test.

f

Fisher's exact test.

Table 4.

Analysis of statistical correlation between the significant quantitative clinical parameters and scintigraphic results.

Clinical parameters	Scintigraphic findings
	Uptake percentage of 99 mTc								Uptake of 99 mTc
	Right parotid		Left parotid		Right submandibular		Left submandibular		Right parotid		Left parotid		Right Submandibular		Left submandibular
	r^a	p value	r^a	p value	r^a	p value	r^a	p value	r^a	p value	r^a	p value	r^a	p vlue	r^a	p value
Unstimulated salivary flow (mL)	0.122	0.572	0.311	0.139	0.104	0.630	0.233	0.274	0.083	0.700	0.223	0.294	0.152	0.480	0.199	0.351
Stimulated salivary flow (mL)	−0.069	0.748	0.100	0.643	0.060	0.781	0.025	0.908	0.185	0.388	0.317	0.131	0.337	0.108	0.328	0.118

a

r = Pearson’s correlation coefficient.

Histological findings

According to the histomorphological analysis, 14 of the 24 patients with xerostomia had findings consistent with a presumptive diagnosis of SJS (CH 3-4), and with respect to other parameters evaluated, more atrophic changes were observed in patients with a diagnosis of SS and a higher percentage of fibrosis and fatty changes in those with a presumptive diagnosis of SSJ, with a statistically significant difference for the latter parameter (p = 0.047) (Table 5).

Table 5.

Other histological findings.

Histological parameter	Diagnostic category, n (%)		p value^a
	SS (n = 10)	Presumptive SJS (n = 14)
Atrophy	8 (80)	8 (57.1)	0.387
Dilatation	8 (80)	12(85.7)	1.000
Fibrosis	7 (70)	13 (92.8)	0.272
Fatty changes	2 (20)	9 (64.3)	0.047

SS: Sicca syndrome; SJS: Sjögren’s syndrome.

a

Fisher’s exact test.

Discussion

SS can present with transient or persistent signs and symptoms that involve the oral and ocular mucosa and the dermis, with an impact on the patient's health and quality of life. The subjective symptoms of SS, especially xerostomia, may be related to hyposalivation, in which the rate of salivary flow is altered by abnormal function of the salivary glands.¹⁶ Such changes in the quantity and quality of saliva lead to the appearance of symptoms and signs in the oral mucous membranes, such as tongue depapillation, desquamation of the lips, erythema, burning, dysgeusia, voice changes and dysphagia, among others, consistent with what was found in this study (Table 4), which are contrasted with what was reported in the literature.¹⁷ However, all these signs and symptoms may be related to progressive salivary gland atrophy, which suggest to evaluate differential diagnoses such as SJS.¹⁸

SJS is the second most common chronic rheumatic disease, after rheumatoid arthritis, with a prevalence ranging from 0.4 to 3.1 million individuals.³ It is characterized by lymphocytic infiltration of exocrine glands and other organs, together with the production of various autoantibodies. It is associated with high morbidity, not only due to xerostomia and keratoconjunctivitis sicca, but also due to extraglandular manifestations, including the development of B-cell non-Hodgkin lymphomas.^4,16 The etiology of SJS is multifactorial, may be determined by epigenetic susceptibility, and secondarily by autoimmune rheumatological disease.¹⁹

The most common symptoms of SJS are fatigue, dry eye and mouth, which are related to SS, therefore, the adequate diagnosis of suspected SJS should include subjective oral and ocular symptoms, positive objective signs of the Schirmer’s test, salivary gland scintigraphy, focal sialadenitis, and immunological parameters.⁵ According to the ACR/EULAR-2016 consensus, for the diagnosis of pSJS the criteria include the minor salivary gland biopsy, the presence of anti-SSA/anti-RO antibodies, Schirmer’s test, the ocular staining score and unstimulated salivary flow.⁷ In this study, patients with a diagnosis of SS and a presumptive diagnosis of SJS were evaluated with a histological study that oriented towards the positive presence of SJS, positive results were obtained in the clinical findings in the category of presumptive diagnosis of SJS, Schirmer’s test (4.5 [IQR 4-8]), unstimulated salivary flow (0.7 [IQR 0.5-0.9]) and glandular histological alterations (atrophy, dilatation, fibrosis, and fatty changes) which suggest long-term follow-ups to establish a definitive diagnosis. Pijoan et al.⁹ propose an algorithm for the diagnosis of SS with Schirmer’s test ≤ 5 mm and a negative autoimmunity test (SSA[-] or SSB [-]). They suggest doing a minor salivary gland biopsy to confirm or rule out SJS. In contrast, if a Schirmer’s test > 5 mm is obtained, with a scintigraphic evaluation of the salivary glands and an autoimmunity analysis where only one of the two is positive, they suggest performing the histological study to confirm or rule out the diagnosis of SJS. In this study, immunological tests were not available, because the patients referred were not positive for them. The results obtained then guide us to analyze the development of SJS by stages of progression and an individual phenotypic and genotypic evaluation of each patient to define therapeutics.

In the evaluation of the functional tests of the salivary glands, the salivary gland scintigraphy studies and the salivary flow tests showed a significant difference, with p values = 0.002 and p = 0.019 for the unstimulated and stimulated salivary flow rate in patients in the presumptive SJS diagnostic category. This suggests a functional alteration of the major salivary glands, which is consistent with the study conducted by Kalk et al.,²⁰ in which patients with SJS showed lower submandibular/sublingual (SM/SL) flow rates and a modification in the composition of the saliva from the major salivary glands.

Nuclear medicine studies are usually used to evaluate salivary gland involvement in patients with xerostomia symptoms. Scintigraphy with 99 mTc is sensitive enough to detect the destruction of 25% of the glandular parenchyma and has been correlated with histopathological findings and salivary function tests, however, the reduced or absent uptake of the radiopharmaceutical agent by the salivary glands is a nonspecific phenomenon, so its abnormal finding should not be considered pathognomonic of SJS.^21,22

The most common early scintigraphic abnormality in patients with SJS is impaired excretion, followed by decreased uptake of the radiopharmaceutical agent, reflecting damage to the glandular parenchyma.²³ Wu et al.²⁴ recently described a decrease both in excretion and uptake of 99 mTc by salivary glands in 10 patients with SJS. Different studies^25–27 report multiglandular involvement, with predominance in the submandibular glands, which is related to the degree of subjective xerostomia, results comparable with those obtained in the scintigraphic activity of the major salivary glands. The results show a greater functional compromise in patients with a presumptive diagnosis of SJS in the submandibular glands compared to the group with a diagnosis of SS, which correlates with the unstimulated salivary flow rate (Table 4). However, for both categories, functional involvement of the parotid glands was observed to a lesser degree, which can be contrasted with the xerostomia, since the type of serous saliva generates the biofilm in the oral mucosa. These findings may suggest involvement in early stages of SJS, as reported by Güne et al.,²⁸ who propose a pattern of asymmetric activity in the parotid glands in early stages of the disease and that may be a predictor of progression.

It has been considered that a biopsy of minor salivary glands that includes more than five glands, as well as histopathological evaluation of focal lymphocytic sialadenitis with a score ≥ 1 focus in 4 mm² of tissue surface area, can provide information about the extent and nature of the process of the disease.²⁹ In our study, 14 of 24 patients had histological findings compatible with SJS (CH-M 3-4), with a higher percentage of fibrosis and fatty changes when comparing the study groups. This finding coincides with that of Leehan et al.,³⁰ who evidenced that quantified fibrosis is a characteristic of SJS pathology, and not only a characteristic of age. Therefore, the cases classified as a presumptive diagnosis of SJS had a higher percentage of area of fibrosis than those that did not meet the classification criteria for SJS. Likewise, the studies of Skarstein et al.³¹ found that adipose tissue is prominent in the salivary glands of patients with Sjögren’s syndrome and seems to influence the microenvironment of these organs, in addition to being detected in regions rich in interleukin 6 (IL-6), which suggests its possible participation in immune reactions. Consequently, there is a need for studies with larger and more diverse cohorts to verify this concept, given that Leehan et al.³² concluded in their study that fatty infiltration is a phenomenon associated with age and not a characteristic of SJS, because patients with dry symptoms who did not meet the criteria for SJS had similar rates of fatty infiltration of the minor salivary glands.

Among the limitations of the study stands out a small sample of patients, which could have affected the magnitude of the effect of the variables considered, and, consequently, the absence of statistically significant differences for some parameters. It is also pertinent to mention the possibility of measurement bias when performing a single reading of the scintigraphy and histopathology study; however, this scenario resembles the usual conditions of clinical diagnosis.

Conclusion

SS and SJS are pathologies that share clinical characteristics (dry eye, dry mouth), which suggests to analyze the different diagnostic aids to establish an accurate diagnosis. The physical examination, functional tests, and immunological and histological tests may be discrepant in defining the definitive diagnosis of SJS, which is why they must be evaluated objectively, in order to establish possible early stages of progression of the SJS. The results guide us to the establishment of precision medicine and dentistry for SJS, applied individually to each patient.

CRediT authorship contribution statement

This project was part of the academic research process of Drs. Vanessa Flórez and Mónica Posso during their residency. Functions within the project: the co-researchers, students of the Postgraduate Clinical Specialization in Oral and Maxillofacial Surgery, who carried out the collection and processing of samples, the histological and immunostaining analysis, tabulation of information, analysis of results, presentation of advances and preparation of required and publishable articles.

Dr. Leonor Victoria González, Professor of the Faculty of Dentistry of the Universidad de Antioquia, served as an oral pathologist at the time of confirmation of diagnoses of the slides/blocks of biopsies derived from the minor salivary gland.

Funding

The funding was the financial support from Euroetika for the performance of the major gland scans.

Acknowledgement

Thanks to Euroetika for its contribution in the financing of scintigraphies.