Atypical Mumps; are We Heading Towards an Outbreak?

Abstract

Mumps, caused by the mumps virus, is a contagious disease primarily affecting children and young adults. While typically presenting with salivary gland swelling and systemic symptoms, mumps can lead to various complications including SNHL, orchitis/ oophoritis, aseptic meningitis. Recent observations suggest atypical features in mumps cases, raising concerns of a potential outbreak in India. To discuss the etiopathogenesis and clinical presentation in cases of atypical mumps with increasing number of cases, a prospective multicentric study was conducted across five major centers - SMS Medical College Jaipur, RDBP Jaipuria Hospital, Jaipur, Shri Ashwini Saxena ENT Hospital Rewari, AIIMS Bhubaneswar and SP Medical College Bikaner, in India to evaluate patients with acute salivary gland swellings. Clinical and laboratory data were collected, including demographics, presenting symptoms, history of vaccination, imaging findings, and treatment outcomes. Patients were followed for four weeks post-treatment to monitor for delayed complications. Among 53 patients, a bimodal age distribution was observed, with peaks in early adolescents and middle-aged individuals. Vaccination status was recorded based on recall. Fever and salivary gland swelling were predominant symptoms, with a significant proportion experiencing submandibular gland involvement. Elevated serum amylase and CRP levels correlated with disease severity and prolonged symptomatic resolution. Notably, cases of sensorineural hearing loss (SNHL) and airway complications emerged as significant concerns. The study highlights a shift in mumps demographics, with higher age groups affected and increased incidence of complications like SNHL and airway compromise. International trends also suggest periodic outbreaks and evolving clinical manifestations post-COVID-19 pandemic. Factors contributing to mumps resurgence include lack of vaccination or vaccine efficacy, population immunity, and seasonal variations. India appears to be facing a potential mumps outbreak, characterized by atypical features and increased risk of complications like SNHL and airway compromise. Serum amylase and CRP serve as valuable markers for disease severity. Early recognition and management of complications are crucial, emphasizing the importance of mumps immunization to mitigate the impact of the disease. ENT specialists should remain vigilant for emerging complications, particularly SNHL, advocating for comprehensive immunization strategies.

Introduction

Mumps is a highly contagious disease of children and young adults which is caused by mumps virus, a single-stranded RNA paramyxovirus [1]. Infections spread either by direct contact or through droplets from the upper respiratory tract. The infection may remain asymptomatic for an incubation period that ranges from 14 to 25 days [2]. It typically presents with a prodrome of headache, fever, fatigue, anorexia, malaise followed by painful swelling of the salivary glands. Parotitis is seen in about 95% of patients with clinical symptoms. The disease resolves spontaneously in most of the cases within 2 weeks. Complications such as epididymo-orchitis is seen in 15–30% of adult men [3], oophoritis in 5% of adult women [4], meningitis in 1–10% [5], permanent unilateral deafness 0·005% [6] and spontaneous abortion in about 27% of first-trimester pregnancies after mumps [7].

Submandibular gland swelling is observed in approximately 10% of patients with common mumps [8, 9]. Submandibular swelling increases the risk of laryngeal oedema. Lymphatic flow obstruction due to circulatory disturbance by swollen salivary glands is a probable cause [8].

As of now, the mumps vaccine is not given in India in its National Immunization Programme. Some patients may get vaccinated along with the vaccine of Measles and Rubella in the form of MMR if the immunization is done in private health care setups. It is reported that a 78% risk reduction against mumps following one dose, rises to 88% after receiving two doses of MMR vaccine [10]. Studies in other countries show a cyclical trend with outbreaks every 4–5 years.

Incidence of mumps in ENT practice has generally been less, with bulk of the cases showing spontaneous resolution or seeking paediatrician consultation in view of being a disease primarily affecting children. However we have observed a significant increase in this number in the last few months along with a change in the age of presentation and severity of symptoms. The demographic profile and clinical course of these patients is being discussed in this study conducted in five major centres across India.

Materials and methods

A prospective interventional multicentric clinical study was conducted from October 2023 to December 2023 at SMS Medical College Jaipur, RDBP Jaipuria Hospital, Jaipur, Shri Ashwini Saxena ENT Hospital Rewari, AIIMS Bhubaneswar and SP Medical College Bikaner. Patients presenting with acute onset salivary gland swellings were evaluated. For the purpose of this study, a case of mumps is defined clinically as “any person who had acute onset of unilateral or bilateral tender, self-limited swelling of the parotid or other salivary gland, lasting two or more days and without other apparent cause [11]”.

A good clinical history was taken which included age, sex, day of presentation to outpatient department / emergency, laterality, presenting complaints of pain, fever, swelling, ear ache, swallowing difficulty, airway embarrassment, positive family history of other members suffering from similar complaints and preceding prodrome of viral illness with symptoms of generalized malaise, fever, cold and cough. Any comorbid conditions were noted. History of immunisation was taken based on recall from patients.

Patients who presented with mumps like symptoms were examined and investigated. Ultrasonography neck, Complete Blood Count, C- Reactive Protein and Serum Amylase was done for further evaluation for every patient. Pure tone audiometry was performed in those patients who complained of hearing loss.

Laboratory tests for confirmation included mumps specific immunoglobulin Ig M or RT-PCR for mumps virus.

Patients were managed symptomatically based on severity of symptoms and derangement of biochemical parameters with antipyretics and pain killers.

Those patients who had significant swelling, more than 3 documented spikes of fever > 102 F, swallowing or breathing difficulty, C Reactive Protein levels more than double and Serum Amylase levels more than double were admitted and treated with IV Fluids, antibiotics to cover secondary bacterial infection, antipyretics, painkillers and antacid for three to four days. Patients who reported difficulty in breathing, were evaluated further by fibreoptic laryngoscopy and laryngeal oedema was noted as a significant finding. Airway for these patients was secured by oxygen supplementation and steroids.

All patients were followed up for four weeks after resolution of symptoms to see for development of any late complications.

Results

Demographics

Out of a total of 53 patients- 23 were male and 30 were female with a bimodal age of presentation, early adolescents and middle aged- either in the age group of 11–15 years and second group in the age 45–50 years. Extremes of age were uncommon in our study.

History

30% patients had a positive family history with more than 1 member of the family having similar or milder complaints of a viral prodrome with cough, cold, fever with spontaneous resolution of symptoms.

The most common trend observed was presentation to outpatient department/emergency on an average of day 4–5 of illness, when the patient did not respond to conservative over the counter treatment, fever persisted beyond three days, swelling became clinically apparent with pain and difficulty in swallowing.

Another notable finding in our study was the local and regional belief of using tape and a mixture of cooling herbal paste over the swelling- which is the first home remedy tried by more than 74% of patients before seeking allopathic treatment and opinion (Figure 1a and b).

Fig. 1.

Fig. 2(a and b) Patients using tape and a mixture of cooling herbal paste over the swelling, a widely followed first home remedy

History of vaccination was sought on recall, with only 5 patients having documented vaccination records and evidence of having received vaccination against mumps. 48 patients were either vaccinated under the national immunisation schedule and thus did not receive the mumps vaccine or could not recall confidently where the vaccination was carried out, if at all.

Fig. 2.

(a) and (b) showing involvement of major salivary glands and (c) showing involvement of major salivary glands

Symptoms

Fever was the most common presenting feature in our study with 95% patients noticing it as the first symptom of their illness. which was followed by unilateral or bilateral swelling in parotid and/or submandibular region, pain in the region of the swelling, difficulty in opening mouth, chewing and swallowing difficulty. A significant criterion for admission was decreased oral intake due to painful swallowing.

Seven patients presented with difficulty in breathing secondary to neck swelling.

Four patients presented with unilateral decreased hearing.

Twenty-one patients out of fifty-three had submandibular involvement along with parotid involvement which was significantly higher as compared to the previous reports of about 10%.

Pathology tests

Serum amylase (normal level < 90 u/L) was found to be raised ranging from 153u/L-300u/L in 39 out of 53 patients. C Reactive Protein (normal level < 6 mg/dL) was raised in 41 out of 53 patients ranging from 10 to 32 mg/dL.

Blood parameters which showed significant correlation, p value < 0.05 with clinical severity and duration of symptom resolution were C Reactive Protein and Serum Amylase. Those patients who had C ReactiveP more than double and serum amylase values more than 150u/L in the first week of illness, needed addition of antibiotics and/or iv supplementation. They also took over 2 weeks for complete symptomatic resolution and subsidence of swelling. 12 patients who had normal CRP values and Serum Amylase levels- had a self-limiting disease with no sequelae and resolved within a week to ten days.

Out of 53 clinically diagnosed cases of mumps, only 5 had laboratory confirmation with RT-PCR for mumps virus using buccal swab sample. Ig M antibody for mumps was found in the sera of 7 patients. 41 patients were clinically diagnosed and only 12 had laboratory confirmation for the same. Lack of immunisation / partial immunisation, timing of collection and sensitivity of testing- served as confounding factors in the confirmatory laboratory diagnosis.

In our study, all patients who developed complications following initial infection were found to have significantly elevated biochemical markers. Significant correlation (p < 0.05) was found between serum amylase and CRP levels with severity and duration of disease.

Ultrasound

The most common findings on ultrasound of the neck was bulky homogenous enlargement of the salivary glands with significant increase in vascularity. There was no formation of abscess or cervical lymph node enlargement in the cases in our study.

Discussion

Populations in other countries have also shown increased incidence during recent years: a 2006 outbreak in the United States [12], a 2009–2010 outbreak in Canada [13], a 2012 outbreak in the United Kingdom [14], a 2009–2012 outbreak in Netherlands [15] and an outbreak in children and adolescent males in Korea in 2013–2015 [16].

Mumps had a periodic spike of two to five years and peak incidence in children (5–7 years old) in the pre-vaccine era, across the globe [17–20]. As in many other infectious diseases, the introduction of vaccines have shifted the pool of susceptible populations to people who have either not been vaccinated or have been infected earlier. Various reasons can be advocated for these occurrences. Unvaccinated population (as vaccination against Mumps is not included in National Immunization Programme), fading immunity [21, 22]; the efficacy of the vaccine and the virus strains used for production of these vaccine [23–26]; and the duration of persistence of antibody after vaccination or natural infections [18, 27]. The infection also tends to increase as temperature and humidity increases attributing to the seasonality of the infection in winters [28]. The reasons for the seasonal pattern may be due to the following factors: the fluctuating levels of immunity [31]; indoor crowding [20]; and meteorological factors including temperature, sunshine, wind, and relative humidity [29, 30, 32].

Mumps is more common in childhood. However, the age of presentation in our study was higher and atypical with no particular predilection towards any sex. We postulate this atypical presentation in age to the lack of vaccination in Indian population and possible change in viral strain.

Mumps vaccine is not included in the National Immunisation Schedule, although many states and private hospitals continue to give the MMR vaccine at 9 months of age as a single dose. Therefore there is no uniformity of vaccination status in the community.

Attached here is the National Immunisation Schedule followed in India reproduced from the Ministry of Health and Family Welfare website.

The clinical spectrum of diseases after Covid 19 pandemic has shown dramatic changes. In our study, severe dysphagia, bilateral parotid swelling and generalized neck swelling have emerged as early and presenting symptoms. (Fig. 1(a) & 1(b)) Fiberoptic laryngoscopy in these patients revealed significant laryngeal oedema, a probable cause of the impending airway embarrassment. (Fig. 1(c)).

Though mumps may lead to several complications, adults have been reported with more serious complications than children [33, 34].

Submandibular gland swelling is observed in approximately 10% of patients with mumps [8, 9]. Submandibular swelling increases the risk of laryngeal oedema. In our study, significant increase in the incidence of airway embarrassment has been observed, due to the involvement of the deep lobe of parotid, submandibular involvement and subsequent parapharyngeal space involvement.

Epididymo-orchitis is rare in children but it arises in approximately 15–30% of adult men with mumps infection [42–49]. It presents as abrupt swelling, warmth, and tenderness of the affected testicle, and inflammation of the scrotum [48]. Oophoritis and mastitis in women with mumps is rare [4, 41].None of our patients suffered from these complications.

The inner ear may also be involved in mumps. Hearing loss associated with mumps is reported in five out of 10,000 cases [40]. Deafness following mumps is usually unilateral acquired sensorineural deafness. It is usually sudden in onset, profound or complete, and may be associated with vestibular symptoms [39]. It may be due to direct viral invasion of the cochlea affecting the organ of Corti and tectorial membrane, and myelin sheath of the eight nerve. Microscopic studies on humans showed degeneration and atrophy of the stria vascularis, tectorial membrane and organ of Corti and collapse of the Reissner’s membrane [40, 42]. Our study has shown 4 out of 53 patients suffering from unilateral sensorineural hearing loss (SNHL). Patients were treated with oral and intratympanic steroids and hearing loss could not be reversed in any patient. These patients had a rapid onset of this symptom after about a week of the initial prodrome. The hearing loss was acute, profound and sensorineural in nature. None of them had vertigo. Pure tone audiometry revealed severe to profound unilateral sensorineural hearing loss. They were treated by trans-tympanic and oral steroids like any other case of sudden sensorineural hearing loss but none of the cases responded to the treatment. In our study, we found a much higher rate of SNHL as complication at 7.5% as compared to the existing data.

The neurological complications are dominated by aseptic meningitis followed by severe manifestations like meningoencephalitis, which can cause permanent sequelae, including paralysis, seizures, cranial nerve palsies, aqueductal stenosis and hydrocephalus [35–38]. No neurological complications were noted in our study.

Miscellaneous complications like pancreatitis [33]; electrocardiographic abnormalities—such as depressed ST segments, flattened or inverted T waves, and prolonged PR intervals [50, 51]; single-joint arthritis or migratory polyarthritis [52, 53]; abnormal renal function [54], hepatitis, acalculous cholecystitis [55]; kerato-uveitis [56]; haemophagocytic syndrome [57] and thrombocytopenia [58]are also rare manifestations of mumps. None of these complications were noted in our study.

In our study patients were followed for four weeks after initial visit and initiation of treatment for any delayed complications and we found complete resolution with no delayed complications, except sensorineural hearing loss which was irreversible.

Conclusion

India, right now, seems to be heading towards an outbreak of mumps with some atypical features: higher age group, more incidence of submandibular gland involvement and more chances of complications like SNHL and airway issues. Serum amylase and CRP were found to be significant biochemical markers which helped in predicting the severity of disease, treatment protocol to be followed and time taken for symptomatic resolution.

It is important that all patients with suspected mumps be evaluated carefully and physicians should be wary of any complications which might occur and treat them early. From an otolaryngologist perspective, the incidence of sudden SNHL following mumps infection has notably increased and in view of its irreversible nature, strong advocacy for immunisation against mumps virus and its inclusion in the national immunisation program is recommended.