How Mumps Is Diagnosed

mumps diagnosis
© Verywell, 2018

Mumps is diagnosed based on clinical symptoms, particularly the swelling of the neck and lower face region, which is a trademark of mumps infection.

Additionally, there are some diagnostic tests that can help confirm the diagnosis. Blood tests and samples of saliva obtained from inside your mouth are the most useful. Imaging tests can be useful in assessing some of the complications of mumps.

Self-Checks/At-Home Testing

If you or your child has not received the immunization for mumps, there is a strong risk of becoming sick with the infection. If either you or your child is at risk for developing mumps, you should familiarize yourself with the early signs of the condition so that you can recognize it and avoid spreading it to others. These can include fever, headaches, swollen neck, muscle aches, pain when eating or swallowing, or just generally feeling run down.

Labs and Tests

There are several tests that can identify the virus in your body. Blood tests can also identify the antibodies that your body forms to fight off the virus.

Buccal Swab Polymerase Chain Reaction (PCR)

The buccal area is the area deep in your mouth, behind the back teeth. A buccal swab is a collection of saliva, and possibly a scraping of tissue, from that area.

The saliva that is collected can be tested for the presence of viral RNA, which is the genetic material of the mumps virus. A genetic test called a PCR test indicates exactly which type of virus is collected in the saliva. 

Antibody Tests

The body forms antibodies in response to infection. Because mumps immunization triggers antibody formation, you may have antibodies to the mumps virus if you have been immunized or if you have had the infection and successfully fought it off.

A simple blood test can detect the antibodies in your blood and can also differentiate whether you are immune to the virus or whether you have an active infection. If you have serum IgG antibodies present in your blood, this indicates that you are immune to mumps. If you have an active infection your tests would show IgM antibodies.

Salivary Culture

A salivary culture is a test in which fluid collected from the saliva is taken to a lab to evaluate for growth of the virus itself. It is easy for your doctor to obtain saliva from your mouth by swabbing the buccal area, as with the PCR test.

A culture takes time to show growth of the virus, and it may take two to three weeks for your test to become positive.

Spinal Fluid Sample and Culture

If you or your child has possible meningitis or encephalitis due to mumps, your medical team may need to do a lumbar puncture to collect a sample of cerebrospinal fluid (CSF), the fluid that surrounds the brain.

A lumbar puncture, also called a spinal tap, is a test in which your doctor inserts a needle into an area of your back, between the vertebral bodies, to collect a sample of the fluid that surrounds your brain and spinal cord. This fluid may show increased white blood cells and protein, and sometimes a decrease in glucose, which is indicative of an infection, but does not specifically mean that you have mumps.

However, if the mumps virus grows in a CSF culture, then this is highly suggestive that you have meningitis or encephalitis due to mumps.

Pancreatic Enzyme Testing

If you have pancreatitis as a complication of mumps, your blood tests may show some specific abnormalities that indicate pancreatic involvement. The pancreatic enzymes—amylase, lipase, and elastase-1—may be elevated if you have pancreatitis due to mumps infection.

Imaging

In general, imaging studies are not part of the routine diagnosis of mumps. However, for some of the complications of mumps, imaging studies may the helpful.

Neck CT

If the cause of your neck swelling is unclear, you might need a CT scan of your neck to identify other possible causes of neck swelling, such as trauma, abscesses, or in rare cases cancer.

Brain CT or MRI

If you have encephalitis due to mumps, you could have serious symptoms, such as seizures, that require further evaluation with brain imaging. If you have neurological symptoms, your doctor may need to see a CT scan of your brain prior to doing a lumbar puncture. 

Abdominal CT or Ultrasound

If you have signs or symptoms of pancreatitis, your doctor may need to order an abdominal CT or ultrasound to better evaluate your condition and to see if you have evidence of other abdominal inflammation or disease.  

Testicular Ultrasound

If you have testicular swelling, one of the complications of mumps infection, your doctor might order an imaging test to determine whether there is another problem causing the swelling and whether you need any medical or surgical intervention.

Differential Diagnosis

Mumps causes a number of symptoms that are similar to those of other conditions. Because mumps is relatively uncommon, your doctor is likely to consider other causes for your symptoms.

Viral Infection

Many viral infections cause headaches, fevers, fatigue, and muscle aches. Swelling of the parotid glands is a characteristic of mumps, but many infections can cause swelling of the lymph nodes in the neck and the armpits.

In general, the swelling caused by most viral infections is not as prominent as that of mumps. The antibody tests, PCR test, and cultures can differentiate one virus from another.

Bacterial Infection

Most bacterial infections that affect the respiratory tract can cause the same symptoms as mumps, and they often cause lymph node enlargements as well. However, bacterial infections usually can be treated with antibiotics, so your doctor is likely to run tests to identify the bacteria if your infection is considered highly likely to be a bacterial infection.

Abscess

An abscess is an enclosed infection that can develop due to trauma, a bacterial infection, or rarely a viral infection. The swelling and pain of mumps, along with the fever, can mimic an abscess. A physical examination or an imaging test can help clarify the difference.

Neck Trauma

The swelling of the neck that occurs with mumps can look like swelling after a traumatic injury. If you cannot tell whether your child has been injured or has an infection, there are a few ways that your child’s doctors will know the difference.

The medical history can be helpful, but sometimes very active children cannot remember falling or hurting themselves. The presence of fever, headaches, fatigue, and generalized muscle aches suggests that your child has mumps. If there is excessive pain in the swollen area, bruising, or signs of injuries elsewhere on the body, this suggests that trauma may be the cause of the swelling rather than mumps.

Cancer

The swelling of mumps may be asymmetric, and swelling can be the first sign of cancer. Your doctor may order imaging tests and possibly a biopsy to clarify the cause of your swelling. Don't be alarmed if these tests are ordered though—if anything, they'll help rule out a cancer diagnosis.

Testicular Torsion

Testicular swelling and inflammation may require urgent medical treatment. Testicular torsion, which is anatomical twisting or obstruction of the spermatic cord, is among the most common and treatable causes of testicular swelling.

The signs and symptoms of testicular torsion may appear similar to that of the testicular swelling caused by mumps. If your doctor is concerned that the cause of your testicular swelling is something besides mumps, you may need an imaging test to differentiate the cause and to determine whether you need urgent treatment.

View Article Sources