Lower Back Pain: Organic v. Psychological Illness

The back is a common site for somatic distress to be manifested because of vagueness of diagnosis and treatment. This situation is particularly true with workers compensation cases, since the compensation may allow a patient to use the condition maladaptively for both primary and secondary gain. The presence of non-organic findings does not preclude some degree of organicity in a patient with low back pain.

In one study, of 200 chronic low back pain patients, even when the category of somatoform pain disorder was excluded, 77% of patients met lifetime diagnostic criteria, and 59% demonstrated current symptoms, for at least one psychiatric diagnosis. 51% met criteria for at least one personality disorder. This percentage is significantly higher than the prevalence rate for the general population. The most common diagnoses were major depression, substance abuse, and anxiety disorders.

Significantly, 54% with depression, 94% with substance abuse, and 94% with anxiety disorders had experienced these syndromes before the onset of their back pain. Physicians need to be aware of potentially high rates of emotional distress syndromes in chronic low back pain patients, and when these syndromes are manifested early in the course of low back pain, it suggests that the patient is high risk to develop chronicity (Polatin et al l992).

INFLAMMATORY

Inflammatory diseases are systemic, and when they are the predominant cause of low back pain, one should examine for extraspinal joint involvement and extraarticular disease. For example, there may be hip disease, dactylitis, conjunctivitis or uveitis, and constitutional signs, such as weight loss or fever. Examination may reveal psoriasis or bowel disease.

Case Report: a 20 year old college student sought treatment for LBP that he attributed to lifting at his part time job at the school bookstore. He denied trauma; pain had begun insidiously, since he had started working four months previously. Pain was marked in the morning, and improved once he became active after an hour or so. He admitted that he seldom experienced pain at work, although he insisted that the lifting at work had precipitated the onset of pain. He denied health problems on history. Exam findings included a flattened back, with palpable tenderness diffusely. He had palpable pain at both SI joint areas. He had mild pain to flexion and to extension, with guarded range of motion. Neuro exam, abdominal exam, and hip tests were all normal. The patient was noted to have a markedly swollen, bluish middle toe on his left foot. He had noted it for several weeks and had assumed he must have hit his toe and injured it. He was also noted to have pitting and discoloration of his nailbeds. There were no skin lesions noted. Radiograph, cbc, and sed rate were all normal. An inflammatory disease was suspected and the patient was referred to a rheumatologist, who found a small, single psoriatic plaque on the patient’s anus. He diagnosed the swollen toe as being dactylitis, and the diagnosis of psoriatic arthritis was made.

A. ANKYLOSING SPONDYLITIS: As affects 1% of the Caucasian population, with a 3:1 male to female ratio. AS generally occurs in men between the ages of 15-40. Women tend to have milder forms. 30% of AS patients have peripheral joint disease too.
HISTORY: Intermittent LBP and stiffness slowly progressing over a period of months. Pain is worse in the morning and increases with inactivity. Exercise helps.
EXAM: Tenderness over the SI joints. Decreased ROM, and when advanced, decreased chest expansion.
TESTING: cbc may show mild anemia. 80% have elevated sed rate with active disease. 90% have a positive HLA B27, but it is not a specific test. (8% of the population has a positive HLA B27). Radiographs will be normal initially. SI joint will show reactive sclerosis, and eventual ankylosis. Vertebral bodies will have ‘squaring’ and apophyseal joint fusion.
TREATMENT: Refer, since this is a non-work-related condition. Treatment includes NSAIDS, ice, and exercise. The primary role of the occupational medicine specialist is generally to determine whether or not LBP is work-related, or due to underlying disease.
WORK: The general course of disease is benign, with an intermittent course. Most patients remain employed. If there is minimal spine motion restriction and no peripheral joint involvement, restrictions generally aren’t needed. If spinal rigidity is present, the patient should avoid lifting over 40 pounds or so. The prime predictor of more severe dysfunction is the presence of peripheral joint involvement, particularly the hips, and a majority of these patients will develop severe spinal restriction. Patients with fixed flexion contractures of the hips and ankylosis of the spine are severally limited in their functional capacity (Weisel, l985).

B. PSORIATIC ARTHRITIS: 10-20% of patients will have arthritis or LBP before the appearance of psoriatic lesions. 80% of patients with psoriatic arthritis will have evidence of nail disease. cbc, sed rate, and ANA are generally normal, though anemia may be present.

C. INFLAMMATORY BOWEL DISEASE: Clinical and radiograph findings are similar to ankylosing spondylitis. The spondylitis of inflammatory bowel disease has a course totally independent of the bowel disease. Though back pain may improve with improvement of the bowel disease, it doesn’t necessarily correlate.
TREATMENT: NSAIDS, if tolerated, or steroids for acute flare-ups. Zostrix HP topical cream, ice, and aerobic exercise can help. PT can be helpful for education, home program, and flare-ups.
WORK: Similar to ankylosing spondylitis. If spine rigidity and peripheral disease are present, the patient should generally be restricted from heavy lifting over 40 pounds.

D. REITERS: Reiter’s syndrome is the most common cause of arthritis in young men and primarily affects the lower extremity joints and the low back. It is very uncommon in women. The syndrome is associated with the triad of urethritis, arthritis, and conjunctivitis, though in many patients, arthritis is their only manifestation. Back pain is a frequent symptom of arthritis. The knees, ankles, and feet are most commonly affected in an asymmetrical manner. Plantar fasciitis is also common. LBP usually improves with activity. Occasionally the pain will radiate into the posterior thighs, but rarely below the knees; it may be unilateral. Unilateral sacroiliitis is common, which contrasts with the symmetrical involvement of ankylosing spondylitis. A complete physical exam is essential to diagnose all the organ systems that may be involved in the process. Labs are minimally helpful. Sed rate is elevated in 70-80%, and the HLA B27 antigen is positive in 80%. Radiographs may show peripheral joint destruction. Sacroiliac involvement may be unilateral or bilateral, with vertebral hyperostoses that are markedly thickened, compared to the thin syndesmophytes of ankylosing spondylitis.
WORK: Restrictions must be determined by the extent and severity of the overall systemic disease. In a five year follow-up study of 131 consecutive patients with Reiter’s, 51% had continued LBP; 34% had disease activity that interfered with their job, while 26% had to change jobs or were unemployed (Weisel, l985).

MEDICAL CONDITIONS

A. CHOLELITHIASIS: Biliary colic may present, with pain that radiates into the thoracolumbar area in over 50% of cases. There will be pain to palpation of the right upper quadrant on the abdominal exam.

B. NEPHROLITHIASIS: May cause dull flank pain or colicky back pain. Patients may present for work-related injury, giving a history of occurrence of pain following lifting, bending, etc. Pain can be referred into the anterior thigh. Pain is not usually position or activity related, i.e., the patient complains of pain in all positions, which is unaffected by activity.

C.POSTERIOR WALL PUD: Back pain may occur in absence of abdominal pain, though back pain plus abdominal pain is more characteristic. Back pain occurs 1-3 hours
after a meal, may awaken the patient at night, and is made better by eating.

D.HERPES ZOSTER: Patients may have back pain and skin sensitivity for several days prior to skin lesions, which they attribute to a work-related lifting or bending episode. The pain may antedate the skin lesions by 4-7 days.

E.INFECTION: Uncommon in the spine. Disc space infections can occur following surgery – even occurring several months later. Sed rate is elevated 75% of the time. Bone scan is positive.

F. ABDOMINAL AORTIC ANEURYSM: Extension of an abdominal aneurysm may cause low back pain, though abdominal pain is more common. Most commonly, patients
complain of abdominal pain that is steady and unrelated to activity or eating. When low back pain is present, it is generally associated with epigastric discomfort. Pain may radiate to the hips or thighs. Patients with stable aneurysms are asymptomatic, and the aneurysm may be discovered incidentally on a radiograph, or as a pulsatile non tender abdominal mass in the mid abdomen. AP and lateral radiographs of the abdomen will demonstrate a curvilinear layer of calcification in the wall of the aorta in approximately 70% of patients with aneurysms. Obstruction of the aorta can also be associated with pain in the low back muscles and gluteal area. Acute embolic obstruction may cause acute claudication to the lower extremities, and severe low back pain.

G. UTERUS: Large leiomyomas may produce back or lower extremity pain by placing pressure on the nerves in the pelvis. Myomas are palpable on physical exam of the pelvis.
PREGNANCY: The most common reason for severe back pain during pregnancy is sacroiliac dysfunction. Since the majority of pregnant women work through most of their pregnancy, the occupational medicine specialist will, at times, need to assess and even manage LBP of a pregnant worker. Safe and effective treatment options include ice application, SI belts or pregnancy lumbar support belts, as well as exercises to improve posture and abdominal strength. The standing pelvic tilt is helpful, as is the cat exercise (e.g., the woman assumes a crawling position, then arches her back to tighten her abdominal muscles). The Kegel exercise should also be performed repeatedly during the day, unless the woman also has hypertonic/nonrelaxing pelvic floor dysfunction, in which case, Kegal exercises should be avoided. (Faubion, Shuster, & Bharucha, 2012; Gourley, l990). The pregnant worker should also be advised to avoid sitting or standing in an asymmetric position, as that can exacerbate symptoms.

METABOLIC

OSTEOPOROSIS: Usually painless, but some patients have nagging dull spinal pain even when there is no associated fracture. This is theorized to be due to micro fractures. Early osteoporosis may not be apparent on radiograph until at least 30% of bone loss has already occurred The course of osteoporosis is variable and it is difficult to predict the severity and frequency of fractures. To minimize the risk of fracture, the patient with osteoporosis should be restricted from lifting and carrying heavy weights, and should avoid repeated bending and activities that jar the spine.
WORK: Heavy lifting (over 10-40 pounds, depending on severity of disease) should be avoided, as should repetitive bending.

NEOPLASTIC

A. METASTATIC CANCER: Findings associated with underlying cancer in patients who present with low back pain most often include age over 50, previous history of cancer, duration of pain greater than one month, failure to improve with conservative treatment, and an elevated erythrocyte sedimentation rate. In a study by Deyo, et al.(l988), by combining historical features with the sed rate, they were able to detect all the cases of cancer in the cohort with an imaging rate of only 22%. Low back pain not relieved by rest is another risk factor (also present with arthritis and stress reaction). A marked increase in pain with recumbency that occurs shortly after lying down is suggestive of a benign or malignant neoplasm in or near the spinal column. Night pain that begins only after being in bed for several hours is more suggestive of an inflammatory condition such as arthritis or the spondyloarthropathies. Depression and emotional distress can also contribute to night symptoms.

B. PRIMARY TUMORS: Spinal tumors are rare causes of low back pain. It must be included in the differential diagnosis, however, since of all causes of low back pain, tumors are associated with the highest morbidity and mortality. Low back pain is usually the initial symptom of a tumor, and it is not uncommon for a patient to associate onset with trauma or some activity such as lifting. Pain increases with recumbency; generally shortly after lying down. Pain may be relieved by OTC NSAIDs.
EXAM: Physical examination generally reveals localized tenderness. Neurologic dysfunction may be evident if the spinal cord is affected. Tumor may be evident on radiograph, but a bone scan may be necessary early on to identify it.

C. MULTIPLE MYELOMA: Multiple myeloma is a malignant tumor of plasma cells, and low back pain is the presenting symptom in 35% of patients. It is the most common
primary malignancy of bone in adults (45% of all malignant bone tumors). Usually in older patients between 50 and 70; rare under age 40. Multiple myeloma is more
common in African Americans.
SYMPTOMS: Pain is generally mild and intermittent initially, and is worse with standing and walking. While pain may be initially relieved by lying down, pain with recumbency is not uncommon. Initially PE may be unremarkable, although diffuse bony tenderness may be found.

TESTING: Cbc: may demonstrate anemia, thrombocytopenia, leukocytosis, and an elevated sed rate. Serum chemistry: hypercalcemia, hyperuricemia, and elevated creatinine. Characteristic serum protein abnormalities occur. Osteolysis may resemble osteoporosis on radiograph. Bone scans are not helpful because the osteolytic lesions will not be positive. CT may demonstrate vertebral body involvement before radiographs.

D. SPINAL METASTASES: Metastases is a much more common cause of low back pain than primary spine tumors, with an overall ratio of 25:1. Men and women are at equal risk for developing metastatic lesions to the spine, and the vast majority are over the age of 50. The most frequently associated primary cancers that frequently metastasize to the spine include prostate, breast, lung, kidney, thyroid, and colon.
Pain may be gradual in onset, and may be made worse with activity. It is not uncommon for a worker to attribute pain to a work-related activity. The two biggest risk factors for metastatic disease of the spine are low back pain in the person who has a previous history of malignancy, and low back pain in the adult over age 50. Pain persisting for more than one month in patients over fifty or with a prior history of malignancy warrant further workup. Pain with recumbency should also raise the index of suspicion.
EXAM: Initial findings may be non-specific though not uncommonly there may be palpable pain over the affected bone.

TESTING: The most helpful early laboratory test is the ESR. Anemia may be present on cbc. Early in the course, plain radiographs will be normal, since there must be a 30-50% bone loss before an abnormality is evident. Bone scan is the single most useful test in detecting metastatic disease, and will detect up to 85% of patients with metastases.