Mumps And Its Association With Pancreatitis

Introduction

Acute pancreatitis is a common complication of infection with the mumps virus. Both mumps and acute pancreatitis are largely self-limiting diseases (resolve on their own) and treatment options are limited, but they can be very painful. Hospitalisation is often required to monitor someone suffering from these as complications can arise quickly and unexpectedly.

Mumps: An Overview

Firstly, someone with mumps is likely to experience mild respiratory symptoms. Then they often develop a symptom known as “chipmunk cheeks”. 

“Chipmunk cheeks” – so called because of the physical resemblance to the rodent – are painful swellings of both sides of the jaw and the cheeks. When they occur a few days after a fever, this is a tell-tale sign of mumps disease.

Definition and cause (mumps virus)

Mumps is a vaccine-preventable disease caused by infection by a paramyxovirus, a family of viruses also associated with measles. Before the introduction of the MMR (mumps, measles, and rubella) vaccine in 1967, mumps was considered a morbidly contagious childhood infection. Nowadays, in the post-vaccine era, mumps instead tends to be mild and self-limiting.

Transmission and epidemiology

Mumps is a highly contagious disease transmitted via saliva. Sharing cutlery or drinks with an infected person can transmit the mumps virus, as can inhaling cough droplets or touching contaminated surfaces.

Therefore mumps is prevalent in areas where people are in close proximity for a stretch of time - for example in a school or university. According to UK data, the highest incidence of mumps in 2019 was in 20 - 24 year olds.

Symptoms and clinical presentation

On average, the symptoms of mumps occur after a 17-day incubation period, that is 17 days after being infected with the virus. As well as a fever and the subsequent “chipmunk cheeks,” a person with mumps may experience the following:

• Headache
• Nausea
• Dry mouth
• Mild stomach aches
• Testicle pain
• Mild front neck pain
• Mild ache in front of ears
• Difficulty chewing
• Muscle aches
• Loss of appetite

Complications associated with mumps

Serious complications of mumps are rare, but encephalitis and permanent hearing loss have been known to occur as a direct result of mumps. It is approximated that these complications occur in 0.1% and 0.005% all mumps patients respectively.

Common complications of mumps are mild and easily treatable with painkillers. From most to least common, the common complications of mumps are:

• 1 in 3 people assigned male at birth (AMAB): Orchitis (swelling of the testicle/s)
• 1 in 4 cases: Viral meningitis
• 1 in 15 people AFAB: Oophoritis (swelling of the ovaries)
• 1 in 25 cases: Pancreatitis 

Pancreatitis: An Overview

Acute and chronic pancreatitis

Pancreatitis is inflammation of the pancreas. Like all inflammation, pancreatitis can be categorised as acute (short-term and sudden) or chronic (long-term and progressive). In 4% of mumps cases, acute pancreatitis (AP) occurs as a direct result. There is no concrete evidence to suggest that mumps has ever caused chronic pancreatitis (CP); however, there is a greater risk of developing CP if you have previously suffered from AP, particularly in people who drink or smoke copiously.^1,2

Symptoms and clinical presentation

If a person develops acute pancreatitis following infection with mumps virus, the predominant symptom will be a sudden, severe pain in the centre of the abdomen where the pancreas sits. They may also experience the following:

• Nausea and/or vomiting
• Indigestion
• Fever
• Jaundice
• Swelling of the abdomen
• Tachycardia (rapid heart rate) or rapid breathing

Pathophysiology of Mumps-Associated Pancreatitis

The exact pathophysiology (biological cause) of mumps-associated pancreatitis remains unclear; however, mumps virus is known to both directly invade the pancreatic cells causing inflammation, and spread to the pancreas after initially infecting and replicating in the upper respiratory tract.^3,4

Diagnosis

Diagnosing mumps

Self-diagnosis for mumps is common and usually stems from observing the hallmark “chipmunk cheeks”. 

However, if mumps is suspected, it is important to get a clinical diagnosis to rule out more serious illnesses such as glandular fever – which, for example, also presents with a high body temperature and swelling in the lower face.

Clinical diagnosis for mumps can be made after feeling the swelling, checking body temperature, and looking inside the patient’s mouth at their tonsils. It will then be confirmed by lab analysis of a saliva swab, ideally no more than 3 days after the onset of the swelling. This may involve determining levels of immunoglobulin M – the antibody produced during early stages of mumps, detectable approximately a week after infection – or detecting the virus RNA itself with PCR.⁵

Diagnosing pancreatitis

An acute pancreatitis diagnosis will usually follow a discussion with a physician about family history and symptoms. 

Then, a blood test will be carried out to determine the level of amylase, a protein secreted by the pancreas. Elevated levels of serum amylase is known as hyperamylasemia, and is indicative of inflammation in the pancreas. Serum amylase levels three times the upper limit of 110 units per litre are likely to be related to acute pancreatitis.

If necessary, further testing may include a CT/MRI/ultrasound scan. These are used to confirm the current diagnosis and carry out a risk assessment of developing more serious complications, such as chronic pancreatitis.⁶

Methods to establish a link between mumps and pancreatitis

When establishing a link between mumps and pancreatitis, physicians may employ various methods, from laboratory testing to imaging. To make an accurate association, it is important for these methods to be used in conjunction with one another, following an assessment of symptoms.

Serum amylase testing

As mentioned above, a pancreatitis diagnosis is confirmed by detecting elevated levels of amylase in the blood, or hyperamylasemia. Amylase is secreted from two locations in the body: the pancreas and the parotid glands. Therefore, if significant hyperamylasemia is observed in a mumps patient who is experiencing more severe stomach pain, this may be a sign of pancreatic involvement.

Ultrasound and CT scans

Another method that has been used to determine both a mumps and pancreatitis diagnosis is medical imaging. Typically, this is done as final confirmation of the suggested disease/illness, after initial laboratory testing. The same is the case for mumps and pancreatitis.

Ultrasound images will be taken of the side of the face where swelling occurs after infection with mumps virus. From this, physicians will use various medical criteria to confirm inflammation of the parotid glands (parotitis).

Then, a CT scan of the abdomen can be carried out to confirm pancreatitis. CT scans of the pancreas are often used in place of standard x-rays because of the increased level of detail offered, providing a more conclusive image (of inflammation and the quantity of fluid in surrounding tissue) to diagnose acute pancreatitis in a mumps patient.⁶

Treatment and Management

Treatment options for mumps

At present, there is no viable treatment option for mumps disease. Instead, the focus of public health measures is on ensuring that as many people as possible are vaccinated. The MMR (measles, mumps, and rubella) vaccine is a live, attenuated vaccine, meaning it contains a weakened form of the virus which is just enough to build up immunity without causing disease. 

It can be given at any age, but is recommended as two doses at the ages of 1 year old at 3 years and 4 months. An adult booster jab is not needed providing the two doses were administered correctly. According to the NHS, the MMR vaccine protects approximately 88% of all recipients against mumps. If the virus is caught, an immunised person will suffer milder symptoms than someone who is not immunised.

Treatment options for pancreatitis

Treatment for pancreatitis is given in a hospital. The treatment options for acute pancreatitis include:

• IV administration of fluids
• Oxygen tubes/ventilation equipment if necessary
• Painkillers for stomach pain
• Antibiotics if infection accompanies pancreatitis
• Treatment of underlying cause (there is currently no existing antiviral medication for mumps which is self-resolving)

Case studies of the management of mumps-associated pancreatitis

There is currently no recent literature (from the last 20 years) discussing severe mumps-associated pancreatitis. However, there have been recent cases declaring an association of pancreatitis after mumps reinfection, all of which resolved within a few weeks. In only one of these cases, the patient had received the MMR vaccine.^7,8,9 

In terms of management of mumps-associated pancreatitis, these cases all demonstrate the importance of:

• Initial confirmation of mumps virus, and negative results for other viruses and autoimmune cause of swelling (parotitis)
• Consideration of differential diagnoses before making diagnoses
• Continuous monitoring of serum amylase levels and peripancreatic fluid levels/inflammation via repeated CT scans
  • Failure to do so may resort in pancreatitis becoming more severe requiring emergency medical intervention
  • Additionally, to avoid multisystem organ failure or sepsis, the rest of the body should also be monitored

Summary

Better understanding of the pathophysiology of mumps and associated pancreatitis for better understanding of how this conjunction of diseases develops, but currently it is believed that mumps virus can be associated with pancreatitis from both direct and indirect infection. Treatment is typically limited to pain medication as the majority of both mumps and acute pancreatitis are self-limiting. The MMR vaccine is a common prevention method to stop someone contracting mumps, but it is not always effective. Management is focused not on treatment but continuous monitoring to avoid further complications, such as severe acute pancreatitis, sepsis, or multisystem organ failure.