Diagnosing Lupus

 

 

 . This article will discuss how a diagnosis of systemic lupus erythematosus is made.

There are several factors that make diagnosis of lupus potentially difficult. First of all, systemic lupus erythematosus is a systemic disease, meaning that it can affect many different organs and tissues in the body, including the skin, the heart and blood vessels, the lungs, the kidneys, the joints, the nervous system and so on. This means that different patients with systemic lupus erythematosus can have different parts of their body affected and have vastly different clinical presentations.

Second, lupus symptoms do not all occur at the same time. Because of this, it is not always clear early on in the diagnostic process that a person’s problem is actually a systemic disease. For example, if a person comes in to the doctor’s office for the first time with just pleurisy, which is painful inflammation in the tissue that surrounds the lungs, the doctor is not immediately going to think that the person has a systemic illness like lupus. They will probably suspect an infection, prescribe a course of antibiotics and send the patient home. If the patient comes in with a second complaint of a different health problem months later, the doctor may not make the connection and think that these two instances are unrelated. This phenomenon can delay the process of diagnosis.

Third, in some lupus patients, damage to certain organs and tissues is not always symptomatic until the damage becomes severe. This can again cause doctors to miss the fact that the patient has a systemic illness. In addition, lupus is less common than many other, less serious illnesses that can cause specific symptoms, so lupus might not even be suspected in patients with more subtle, less severe or fewer symptoms.

In spite of these obstacles to diagnosis, there are certain tools that doctors can use to make a diagnosis of systemic lupus erythematosus. A doctor may begin to suspect lupus when a patient exhibits four of eleven criteria that have been defined for the disease. These criteria are: butterfly-shaped rash on the face, scaly rash called a discoid rash on the skin, sun sensitivity of the skin, pleurisy or pericarditis, arthritis in at least two joints, mouth sores, kidney disease, low red blood cell count, white blood cell count or platelet count, neurological problems, positive blood test for anti-nuclear antibodies and other positive blood test results. The blood tests used to diagnose lupus will be described in detail later in the article. The patient can have four of these criteria at the same time or over time and still qualify for a diagnosis of systemic lupus erythematosus. Because these symptoms can occur over time, a detailed, accurate medical history can be extremely helpful in making a diagnosis of systemic lupus erythematosus.

In addition to blood tests, there are some other tools that can point a doctor in the right direction towards a diagnosis of systemic lupus erythematosus. X-rays of the chest can show pneumonia, lung inflammation or pericardial effusion, which is fluid buildup in the sac that surrounds the heart muscle. These conditions can all be directly caused by lupus. An electrocardiogram can show damage to the heart, which may be caused by lupus. Urine tests that show an elevated level of protein or blood in the urine can provide detection of kidney damage, which can also be caused by lupus. In some cases, a kidney biopsy may be done to check for kidney damage on the microscopic level.

Various blood tests can be used to detect lupus as well. A simple blood cell count can show whether someone has a low red blood cell count, a condition that is known as anemia. This test can also show whether they have low white blood cells. Both of these conditions can be a consequence of systemic lupus erythematosus. Blood tests can also be used to check up on how the liver and kidneys are functioning, to assess whether there has been any damage to these organs by lupus.

A blood test called the Anti-Nuclear Antibody (ANA) test shows when levels of antibodies produced by the immune system in people with autoimmune disorders are present. This test is not specific for lupus, as it just shows that a person has an autoimmune disease or an infection. But, paired with other symptoms that indicate lupus, this test can help to confirm a diagnosis.

Interestingly, another confirmatory blood test for a diagnosis of systemic lupus erythematosus is to run a blood test for syphilis. A person with lupus can have antibodies in their blood that can generate a positive syphilis test result when the person does not have syphilis at all. This is an example of a false positive test result that is clinically useful.

All of these tests are pieces of the puzzle that must be put together to diagnose systemic lupus erythematosus.