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Dynamic Chiropractic – March 11, 2008, Vol. 26, Issue 06

Diagnostic Testing Criteria

By John Cerf, DC

Chiropractors who associate with hospitals have the added responsibility of enhancing the reputation of the institution and working in an integrated manner with the medical staff. The added responsibility is encouragement for honing one's diagnostic skills.

Periodic reassessment of the criteria for ordering diagnostic testing is essential to maintaining a high level of diagnostic accuracy. It is equally important to avoid the complacency that follows prolonged periods of evaluating patients who present with typical and similar findings. A good diagnostician periodically renews the infatuation for uncovering disorders that most others might be expected to miss.

My older brother, Dr. Dean J. Cerf, is an accomplished and very successful veterinarian in Ridgewood, N.J. Upon graduating from chiropractic college, I asked my brother what I needed to do to be as successful in chiropractic as he is in veterinary medicine. Without hesitation, he answered that there are two primary keys to success. He said, "First, you have to care. You care enough when you lose sleep due to concern for your patients." He continued, "Equally important, you have to diagnose better than anyone."

Diagnosis requires the attitude of a detective. Good detectives maintain a high level of suspicion. While non-mechanical (i.e., visceral or organic) causes of lower back pain are infrequent in the chiropractor's office, they nonetheless require consideration with every patient. The presence of obvious mechanical back pain does not exclude the possibility of a comorbidity of visceral origin.

Patient safety is always the first concern when considering diagnostic testing. One of the most important concerns is exposure to ionizing radiation. The single most effective way to reduce excessive radiation exposure from radiographic procedures is to only radiograph when clinically indicated.

Clinically indicated plain-film radiography is helpful for detecting arthritic changes, fractures, reduced bone mass, reduced bone height, spondylolisthesis and abnormal biomechanical features. Spinal CT or MRI becomes a diagnostic consideration when the back pain radiates around the trunk or into the limbs. CT or MRI also are indicated in cases of persistent back pain when the physical examination supports the need to rule out spinal canal stenosis and/or spinal nerve-root compression.

Bone scans are sensitive but relatively nonspecific tests. Bone scans are useful for detecting physiologic reactions to occult fractures, tumors and infection. Bone scans can detect the early stages of osteomyelitis, malignancy and inflammatory disease before changes are observable with plain-film radiography. Bone scans are useful in cases of multiple traumas to help the provider focus on the areas that may require additional diagnostic imaging.

Bone densitometry can predict an increased risk of osteoporosis. As osteoporosis is a relative risk factor to spinal manipulation, knowledge of its presence is essential. Patients older than 50, those with small and thin frames, a family history of osteoporosis, Caucasian or Asian women, history of anorexia, history of heavy alcohol use or smoking, and/or a history of long-term use of glucocorticoids are all risk factors of osteoporosis and reason to consider bone densitometry.

Electromyography (EMG) studies are useful for screening limb pain in order to differentiate neurological diseases from nerve compression syndromes. EMG is helpful for determining the specific location of a nerve injury as well as for providing information concerning the severity and age of the lesion.

When the physical examination findings do not support a diagnosis limited to mechanical low back pain, the level of suspicion for a non-neurological and non-orthopedic condition elevates, and the need for medical consultation and/or other diagnostic testing increases. An abdominal ultrasound scan can help rule out aortic aneurysm or pelvic tumor. Prostatic and pancreatic tumors are also considerations that may be discovered with abdominal ultrasound imaging.

Since most back pain is mechanical in nature, normal blood test results are expected for most chiropractic patients. When there is suspicion of an underlying non-mechanical cause of pain (e.g., infection, inflammatory disease or tumor), the practitioner should consider blood tests and urinalysis. Laboratory testing becomes a consideration when there is an exacerbation of chronic back pain without obvious trauma or other obvious mechanism of exacerbation. Complete blood count (CBC), erythrocyte sedimentation rate (ESR), and blood chemistry (SMAC 25) are good initial screening tests.

It is appropriate to order a CBC for patients who are new to your practice. This is a general health screening tool and may help establish an understanding of the patient's general health status or establish a baseline when it is necessary to monitor certain conditions. A CBC also is indicated when the patient complains of fatigue or weakness, to help evaluate bruising, bleeding or inflammation, and when there is a question of possible infection or malignancy.

Some medications can decrease the number of white blood cells and increase the possibility of occult infection. Platelet counts are important for evaluating apparent problems with bleeding, bruising or clotting. A low platelet count raises the possibility of occult bleeding. Rarely, some arthritis medications will lower the platelet count. Chronic inflammation such as with rheumatoid arthritis may cause the number of red blood cells to be low.

A low red blood cell count in conjunction with signs and symptoms of arthritis should alert the provider to order an arthritis profile. Early symptoms of rheumatoid arthritis include fatigue, morning stiffness lasting more than one hour, widespread muscle aches, loss of appetite and weakness. There may be conjunctivitis, low-grade fever, paresthesia, paleness or rubor, and swollen glands.

The arthritis profile may contain tests for rheumatoid factor (RF), anti-nuclear antibody (ANA), uric acid, ASO AB (i.e., anti-streptolysin O antibody, anti-CCP antibody test, C-reactive protein and HLA-B27). The results of the arthritis profile may reveal a diagnosis of rheumatoid arthritis, ankylosing spondylitis, Reiter's syndrome or psoriatic arthritis. There also may be other rheumatologic disorders including systemic lupus erythmatosis (SLE), mixed connective-tissue disease, Sjogren's syndrome, scleroderma, polymyositis, CREST syndrome or neurologic SLE. A decrease in WBC, HCT and Hgb with an increase in ESR raises suspicion of a rheumatoid disorder and increases the importance of ordering an arthritis profile.

ESR is a sensitive, but not specific test that can reveal systemic inflammation. C-reactive protein is another sensitive screening test for systemic inflammation. A positive test reveals the need for additional testing to determine the source of the inflammation.

A patient presenting with back pain who also has some of the following symptoms: oral or nasopharyngeal ulcers, alopecia, anorexia, photosensitivity, chest pain, seizures, nervous system symptoms, lymphadenopathy, low-level fever, weight loss, erythema of the palms and weakness, should be evaluated for SLE. Blood tests for suspected SLE include ANA, ESR, RF, CBC and blood chemistry.

Blood chemistry is usually ordered as a "Chem 25" or "SMAC 25" for new patients. The Chem 25 provides information concerning kidneys, liver and electrolytes. Data will differ from lab to lab, but typically include glucose, blood urea nitrogen, sodium, potassium, chloride, carbon dioxide, creatinine, uric acid, calcium, phosphorus, total protein, albumin, total bilirubin, alkaline phosphatase, gamma-glutamyl transpeptidase, SGPT (ALT), lactate dehydrogenase, SGOT (AST), creatine phosphokinase, cholesterol, triglycerides, amylase, lactic acid and magnesium.

Additional laboratory testing may include prostate-specific antigen in older males. Blood culture is ordered when there is suspicion of osteomyelitis. A Mantoux test is ordered when there is a possibility of tuberculosis. Urine tests including urinalysis and culture are ordered to detect urinary tract infection. Serum protein electrophoresis and urine-protein electrophoresis is performed to detect multiple myeloma, the most common type of bone cancer of the spine.

While it is preferable for the medical physician who prescribes medication to patients to be responsible for the side effects and adverse reactions, there are instances when the chiropractor may want to order tests to rule out medication-related organ damage. While most chiropractors strive to help their patients avoid analgesic medications, not all patients are honest about their medication usage. Patients with signs and symptoms of anemia may be suffering from occult bleeding secondary to chronic oral analgesia. A CBC is an appropriate test for patients suspected of chronic analgesic usage. The practitioner should scrutinize the results for low hematocrit and hemoglobin counts, as these findings may be indicative of blood loss secondary to medication-related gastric ulceration

Blood chemistry is useful for assessing possible medication-related liver damage. It is important to consider liver enzyme tests for patients who are taking analgesic medication and have a history of liver damage. Nonsteroidal anti-inflammatory drugs (NSAIDs) can inflame the liver. Patients who imbibe alcohol and medicate with acetaminophen for pain should be checked for liver damage.

Patients who take medications for cancer or autoimmune diseases are also at risk for liver damage. Laboratory testing of patients who chronically medicate can help reveal blood and protein in the urine, low numbers of platelets in the blood, autoimmune problems including drug-induced lupus, pulmonary disease, bone marrow suppression and hepatitis.

Some drugs for rheumatologic disease cause a higher than normal risk of leukemia and other types of cancers. Other medications can be responsible for kidney problems and/or hypertension.

You may want to order a salicylate level to evaluate patients who have been taking large doses of aspirin or other salicylates for prolonged periods. High salicylate levels can be harmful and lead to ketosis, respiratory alkalosis and metabolic acidosis. Symptoms of salicylate poisoning include tinnitus, nausea, vomiting and/or fever. Symptoms are not always present with salicylate poisoning. Severe salicylate poisoning can lead to central nervous system (CNS) depression. CNS depression brings the possibility of coma, cardiovascular collapse and respiratory failure.

Patients suffering from rheumatoid arthritis sometimes present to a chiropractor's office in an effort to avoid the medications prescribed by their rheumatologist. Muscle enzyme tests such as CPK and aldolase can be used to measure the amount of muscle damage resulting from the inflammation of rheumatic disease. This information will prove useful in helping the patient understand the need to follow-up with the rheumatologist - even while remaining under chiropractic care.

Creatinine levels should be ordered when there is a question concerning kidney function. Creatinine is a normal waste product of the muscle metabolism. High creatinine levels in the blood indicate renal insufficiency. Renal insufficiency is generally asymptomatic, so patients who chronically medicate for analgesia should be checked periodically. A 24-hour urine test is ordered when there is high serum creatinine. This will help to provide a clearer picture of kidney function.

Chiropractors have the opportunity to bring about earlier diagnosis and to uncover occult illness as part of the integrated chiropractic/medical model. The essential components of the process are caring, continuing education and a high level of suspicion.

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