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Intellectual and Behavioral Outcomes After Febrile Seizures
Although most children with a history of febrile seizures do not have subsequent seizures or epilepsy as they grow older, data suggest that some of these children may have permanent cognitive deficits, including mental retardation. Verity and colleagues with the Child Health and Education Study evaluated the long-term intellectual and behavioral outcomes of children with a history of febrile seizures.
This British study initially enrolled 16,163 children born during the same week in April 1970. Intellectual and behavioral assessments were conducted when the children were five and 10 years of age. A total of 381 children (212 boys and 169 girls) with febrile convulsions were assessed. The children and their mothers, teachers, community care nurses and physicians completed questionnaires. The mothers were specifically asked about any history of "convulsions, fits or seizures." Affirmative answers to these questions were confirmed by hospital and physician records. Children were further stratified according to whether they had simple or complex febrile seizures, the latter defined as lasting more than 15 minutes or having a focal component.
The authors chose 102 different measures to assess intellectual and behavioral outcomes. Some of these measures were the full-scale IQ test, academic progress, speech and language development, attention span, motor coordination and self-esteem.
Of the 381 children evaluated, 287 had a history of simple seizures, and 94 had a history of complex seizures. No significant differences existed between the seizure group and control children with regard to parents' social class, level of education, housing, race or ethnic background.
Only four of the 102 measures in the children with febrile seizures showed a significant difference from those in the control group. On the maternal questionnaire, children with a seizure history were reported to be more impulsive or excitable. The mothers also rated these children as more anxious compared with the ratings of mothers from the control group. On the children's questionnaire, 2.6 percent of those in the seizure group reported not doing well in gym class compared with 2.0 percent of the control group.
Finally, the children with febrile seizures actually had better reading skills than did the control children. There were no notable differences among the children who had simple seizures or complex seizures in terms of academic progress or intellectual abilities. Another analysis compared the outcomes in children with only one seizure versus outcomes in children with more than one seizure. Children who had more than one episode of simple febrile seizures had better reading skills than those with only one seizure episode.
The authors conclude that childhood febrile seizures, including complex seizures, do not result in long-term adverse effects on intellectual or behavioral development. This information should be reassuring to both clinicians and parents of children with a history of febrile seizures.
JEFFREY T. KIRCHNER, D.O.
Verity CM, et al. Long-term intellectual and behavioral outcomes of children with febrile convulsions. N Engl J Med June 11, 1998;338:1723-8.
Diabetic Ketoacidosis and Venous Blood Gas Values
Diabetic ketoacidosis consists of elevated blood glucose, measurable ketone bodies and metabolic acidosis. Arterial blood gas determination is considered essential in the initial evaluation of patients with suspected diabetic ketoacidosis. Arterial blood sampling is painful, may be technically difficult and must be done in addition to venous sampling when testing for electrolytes and other values. The general correlation between arterial and venous pH measurements is well established, although this correlation has not been studied in patients with diabetic ketoacidosis. Brandenburg and Dire prospectively studied the relationship between arterial and venous blood gas values in the initial evaluation of patients with suspected diabetic ketoacidosis.
Thirty-eight patients with 44 episodes of diabetic ketoacidosis who presented to an emergency department with blood glucose levels greater than 250 mg per dL (13.9 mmol per L), urine dipstick results positive for ketones and clinical suspicion of diabetic ketoacidosis were included in the study. Arterial and venous samples were obtained as temporally close to each other as possible for blood gas analysis.
The mean difference between arterial and venous pH values was 0.03 (range: 0 to 0.11). Arterial and venous pH results, arterial and venous bicarbonate measurements and arterial bicarbonate and serum carbon dioxide results were also closely correlated.
The authors conclude that the peripheral venous pH measurement is a valid and reliable substitute for arterial pH in patients with diabetic ketoacidosis. A potential disadvantage of using venous determinations to determine the presence of diabetic ketoacidosis is that it may be more difficult to detect when mixed acid-base disturbances are present, since venous blood values may not reflect hypoxia in patients with respiratory depression. In patients with suspected mixed acidbase disorders or evidence of respiratory depression or hypoxemia on pulse oximetry, arterial blood gas analysis remains an appropriate means of testing for diabetic ketoacidosis. To ensure that venous sampling does not underestimate the degree of acidosis, a larger patient sample would be needed to examine more patients with severe acidosis. In addition, a study of final patient outcomes is necessary to determine whether the use of venous rather than arterial gas values affects outcome.
RICHARD SADOVSKY, M.D.
Brandenburg MA, Dire DJ. Comparison of arterial and venous blood gas values in the initial emergency department evaluation of patients with diabetic ketoacidosis. Ann Emerg Med April 1998;31:459-65.
Management of Children with Closed Head Trauma
It is often difficult to determine when a child with head trauma can be discharged safely from the emergency department. Roddy and colleagues reviewed the medical records of children with closed head injuries to evaluate whether the children had deterioration in neurologic status or needed a prolonged stay in the hospital.
FIGURE
Proposed algorithm for evaluation of minimal head injury in children. (CT=computed tomographic; GCS=Glasgow Coma Scale; CNS=central nervous system; PICU=pediatric intensive care unit)
FIGURE UNAVAILABLE
AT THIS TIMEChildren under 16 years of age were included in the study if they had a closed head injury, a normal neurologic examination and a normal result on computed tomographic (CT) scan of the head. Patients were also required to have a score of 15 on the Glasgow Coma Scale. Each medical record was reviewed for information about any deterioration in status, whether on neurologic examination or a subsequent CT of the head. The length of hospitalization was also recorded for each child.
Sixty-two children met the criteria for inclusion in the study. One half of these children had a documented loss of consciousness. None of the patients were admitted to an intensive care unit. Fifteen percent of the patients were hospitalized longer than 24 hours. Four of these children had symptoms that may have been referable to neurologic problems or had a delay in CT interpretation, and the others had non-neurologic reasons or no documented reason for a longer stay. The daily hospital charge incurred was $2,473, bringing the total for the 62 patients to $177,874.
The authors conclude that pediatric patients with a Glasgow Coma Scale score of 15, a normal neurologic examination and a normal noncontrast CT scan of the head are unlikely to develop subsequent significant neurologic complications. The accompanying figure shows an algorithm for the management of such patients.
GRACE BROOKE HUFFMAN, M.D.
Roddy SP, et al. Minimal head trauma in children revisited: is routine hospitalization required? Pediatrics April 1998;101:575-7.
Annual Mammographic Screening in Older Women
Women who are 65 years of age and older account for a significant proportion of newly diagnosed breast cancer cases. Many organizations recommend annual mammograms in this age group. As of January 1, 1998, Medicare started reimbursing for annual screening mammograms for women ages 40 years and older; in addition, the deductible was waived for screening mammograms. A recent recommendation was made to lengthen the screening interval in this age group because of the slower growth rates of breast tumors in this age group. Field and associates evaluated the significance of the screening interval in women age 65 and older who were diagnosed with breast cancer.
Women at least 65 years old who were enrolled in a breast screening program and had been diagnosed with breast cancer were studied retrospectively. Women who had been diagnosed with breast cancer within six to 30 months after a normal mammogram and normal findings on physical examination of the breasts were included in the study group. All mammography films were reviewed by two radiologists who specialized in breast imaging. The diameter of invasive tumors was measured. All patients were divided into four groups based on severity of disease, which included tumor size and presence or absence of metastatic disease. Screening intervals were defined as annual if performed within 18 months or less and as biennial if performed between 19 and 30 months.
A total of 119 patients qualified for the study. The size of invasive tumors was smaller in the annual screening group when compared with tumor size in the biennial screening group. Also, the severity of disease and the incidence of axillary node metastatic disease was significantly less in the patients who received annual screening mammograms. More patients presented with palpable breast masses in the biennial screening group.
The authors conclude that an annual mammography screening interval would be appropriate in patients 65 years of age and older. They state that they found significantly smaller tumors, less severe disease and less axillary lymph node involvement in women who underwent annual screening. Women who underwent screening at a longer interval had a higher incidence of more advanced breast cancer. Discovering breast cancer at an earlier stage of development increases the chance of long-term survival.
KARL MILLER, M.D.
Field LR, et al. Mammographic screening in women more than 64 years old: a comparison of 1- and 2-year intervals. Am J Roentgen April 1998;170:961-5.
Iatrogenic Hyperthyroidism in Patients Receiving Levothyroxine
Synthetic thyroid preparations are taken by about 2 percent of the U.S. population and account for approximately 1 percent of prescriptions each year. Correct use often requires dosage titration or adjustments based on the patient's thyroid-stimulating hormone (TSH) level. Studies performed over the past 12 years indicate that excess exogenous thyroid hormone contributes to osteoporosis and cardiac problems, including left ventricular hypertrophy and atrial fibrillation. Watsky and Koeniger performed a retrospective study to determine the prevalence of inappropriate TSH suppression in patients receiving levothyroxine.
The authors reviewed the medical records of all patients who received a prescription for levothyroxine from a military base pharmacy in 1994 and in whom at least one TSH determination was obtained during the same year. TSH suppression was defined as a TSH level of less than 0.1 µU per mL. The records of all patients with a suppressed TSH level were further examined to determine diagnoses and duration of levothyroxine therapy. Suppressive therapy was considered appropriate in patients with thyroid cancer, nodular thyroid disease, goiter and central hypothyroidism (although the authors cite this approach as controversial). TSH suppression was considered inappropriate in patients who had suppressed TSH values and were being treated for primary hypothyroidism or were receiving thyroid hormone for questionable indications, such as chronic fatigue or obesity.
Out of 1,652 patients who had received a prescription for levothyroxine during 1994, 905 had at least one TSH value measured at the base laboratory. Of these 905 patients, 110 (12.2 percent) had a TSH level of less than 0.1 µU per mL on at least one occasion. Of these 110 patients, 34 (30.9 percent) had a diagnosis for which suppressive therapy might be appropriate. However, therapy was considered inappropriate in 63 (57.3 percent) of the 110 patients with TSH suppression. Also of note were 116 patients (12.8 percent) with TSH values higher than 5.66 µU per mL, suggesting undertreatment with levothyroxine.
Overt hyperthyroidism, defined as a free thyroxine (T4) level above the upper limit of normal, was present in 21 (2.3 percent) of the 905 patients. Three of these patients were in the group in whom TSH suppression was considered appropriate, and 18 were in the group in whom TSH suppression was considered inappropriate.
The authors conclude that many patients appear to be inappropriately treated with levothyroxine. They also note that TSH suppression for thyroid cancer and nodular goiter is controversial and not fully supported by the literature. If the cutoff for TSH suppression were a level of 0.4 µU per mL, as suggested by some authors, the degree of overtreatment in this study group would have been much greater. Women appear to be at greater risk for inappropriate treatment with levothyroxine. The authors encourage physicians to educate patients about the potential toxicity associated with thyroid suppression and to prescribe levothyroxine only for patients who are most likely to benefit from this therapy.
JEFFREY T. KIRCHNER, D.O.
Watsky JG, Koeniger MA. Prevalence of iatrogenic hyperthyroidism in a community hospital. J Am Board Fam Pract May-June 1998;11:175-9.
Removal of Foreign Bodies from Children's Ears
Physicians are frequently called on to remove foreign bodies from the ears of pediatric patients. Ansley and Cunningham reviewed records of children who had presented with aural foreign bodies to determine how best to treat them.
Indications for Surgical Extraction of Aural Foreign Bodies
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Indications for Otolaryngologic Referral for Removal of Aural Foreign Body
The rightsholder did not grant rights to reproduce this item in electronic media. For the missing item, see the original print version of this publication. Records of pediatric patients who presented with foreign bodies in their ears were reviewed to determine what the object was, the age of the child and how the object was removed (in what setting and with what instrument). Duration of the presence of the foreign body was also recorded when possible. Trauma was assessed to determine whether it was due to the foreign body or to the removal of the foreign body.
Most of the 191 patients included in this study were younger than eight years old. The most commonly found objects in the external auditory canal were beads, plastic toys, pebbles and insects. In about one quarter of the patients, the foreign body had been present for more than 24 hours. About one half of the patients sought assistance with removal of the object within 24 hours. Methods of removal included irrigation, suction or other instrumentation, sometimes with an operating microscope. Surgical removal with general anesthesia was necessary in nearly one third of patients. The most serious complication was severe damage to the external auditory canal caused by a disc battery, but other patients suffered abrasions and lacerations of the external auditory canal. Disc batteries are particularly troublesome since leakage of alkali electrolyte solution can cause liquefaction necrosis of the external auditory canal and the tympanic membrane, as well as direct-pressure necrosis. Attempted removal may cause bleeding, which wets the battery and allows leakage. Irrigation should never be used in an attempt to remove this type of battery from the external auditory canal.
The authors conclude that removal of aural foreign bodies is generally fairly straightforward if the foreign body is in the lateral one third of the external auditory canal and if sufficient staff support is available. On the other hand, attempted removal of foreign bodies in the medial two thirds of the external auditory canal may be much more painful (because of the vascularity of the skin overlying the periosteum in this portion of the ear canal), and otolaryngologic referral may be advisable. The authors provide summaries of recommendations for otolaryngologic referral and surgical extraction (see the accompanying tables).
GRACE BROOKE HUFFMAN, M.D.
Ansley JF, Cunningham MJ. Treatment of aural foreign bodies in children. Pediatrics April 1998;101:638-41.
Pulmonary Embolism or Venous Thrombosis and Risk of Cancer
The pathogenic factors for thromboembolic disease in patients with cancer include hypercoagulability related to clotting activation by malignant cells, vessel-wall injury and venous stasis. Several studies suggest the need to look for occult cancer in patients who have deep venous thrombosis or pulmonary embolism. To examine the possible association between thromboembolic disease and occult cancer, Sørensen and colleagues performed a large, population-based study of the frequency of cancer in patients with deep venous thrombosis and pulmonary embolism.
The authors identified cases of deep venous thrombosis and pulmonary embolism reported to the Danish National Registry of Patients from 1977 to 1992. Patients were excluded if they were pregnant, had undergone a surgical procedure within six months of the diagnosis of thromboembolism or had preexisting cancer. A total of 11,305 patients with pulmonary embolism and 15,348 patients with deep venous thrombosis were identified. All of the patients were linked by a national registration number to the nationwide Cause of Death Registry and to the Cancer Registry.
The patients were divided into three groups according to age (younger than 60 years, 60 to 74 years and older than 74 years). Each group consisted of approximately similar proportions of men and women and contained approximately one third of the patients studied. Another cohort consisted of patients who had a recurrent thrombotic event.
An incidence ratio of 1.3 for all types of cancer was found in the cohort with deep venous thrombosis and in the cohort with pulmonary embolism. Among patients with deep venous thrombosis, there were 1,737 cases of cancer, but only 1,372 cases would have been expected based on the population size. In patients with pulmonary embolism, there were 730 cases of cancer, but only 556 cases would have been expected.
The cancer risk was highest in the first six months following the occurrence of thromboembolic disease. The risk was approximately three times the expected risk. However, the risk then declined to a constant level of slightly more than 1.0 at one year after the thrombotic event and for the remainder of the follow-up period.
In both groups during the first year of follow-up, the strongest association of thromboembolic disease and cancer occurred with cancers of the pancreas, ovary, liver and brain. No association was observed in either group with melanoma or with breast, bladder or rectal cancer. Interestingly, patients younger than 60 years had the highest estimated risk of all types of cancer in the first year. The standardized incidence ratio in this cohort was 3.6 during the first year, compared with 2.2 in the 60- to 74-year group and 1.8 in the group older than 74 years of age. After one year of follow-up, the slight but significant increase of cancer incidence was evenly distributed among all cancer types and sites. In a subgroup of 3,762 patients with more than one thromboembolic event, the risk of all types of cancer combined was 3.2 during the first year of follow-up but declined to 1.3 thereafter.
The authors conclude that the association between cancer and thromboembolic disease seems to be most significant during the first year after the thrombotic event. However, they do not believe that an extensive evaluation for occult cancer is justified in patients with deep venous thrombosis or pulmonary embolism, especially in light of the fact that early screening for most of the primary cancers found in this population has not been shown to improve prognosis. The authors advocate using only currently recommended standards for screening and basing further testing on the presence of signs or symptoms of cancer.
JEFFREY T. KIRCHNER, D.O.
Sørenesen HT, et al. The risk of a diagnosis of cancer after primary deep venous thrombosis or pulmonary embolism. N Engl J Med April 23, 1998;338:1169-73.
False-Positive Screening Results for Breast Cancer
The effectiveness of mammography for breast cancer screening has been documented by several randomized clinical trials. Most physicians also recommend annual breast examinations for female patients. Whether this latter practice is effective in the early diagnosis of breast cancer is unknown. The majority of recommendations call for women to undergo initial screening mammography at 40 years of age. Elmore and colleagues performed a retrospective cohort study of the cumulative risks of false-positive results on mammography and clinical breast examination in women screened over a 10-year period.
Women included in the study were members of Harvard Pilgrim Health Care, a large health maintenance organization based in New England. The subjects included women who were between the ages of 40 and 69 years on July 1, 1983. According to guidelines put forth by the health maintenance organization, these women were screened by breast examination and mammography every other year from ages 40 to 49 and annually beginning at age 50. Patients were excluded if they had a history of breast cancer, breast implants or prophylactic mastectomy. Most of the mammograms were performed at community or academic radiology centers, and all were read by board-certified radiologists.
In reviewing the data for mammography and clinical breast examinations, the diagnostic impressions were recorded as one of the following: normal; abnormal and probably benign; abnormal but indeterminate; or abnormal and suspicious for cancer. Recommendations for follow-up testing were reviewed, including second-opinion review of the films, repeat mammography within 12 months, ultrasonography, physical examination or biopsy. A test was classified as positive if it required follow-up testing. True-positive results were those in which a diagnosis of breast cancer was made on the basis of pathologic findings within one year of the screening tests. The remainder of patients who underwent additional investigations but did not have breast cancer were considered to be false positives.
A sample of 2,400 women were enrolled in the study. During this 10-year period, 9,762 screening mammograms were performed. The median number of mammograms for each patient was four, with a range of one to nine studies. The mammograms were read by a total of 93 radiologists. Also during the study period, 10,905 screening clinical breast examinations were performed by 381 health care providers.
A total of 88 breast cancers were diagnosed in the patient population, with 58 being detected by mammography. False-positive results on mammography occurred in 631 studies (6.5 percent) and in 402 breast examinations (3.7 percent). More significantly, the highest rates of false-positive mammograms (7.8 percent) and false-positive breast examinations (6.0 percent) were in women between the ages of 40 and 49 years. For these same women, the cumulative risks of a false-positive mammogram after five studies was 30.3 percent. For all patients, the cumulative risk of having at least one false-positive study after 10 screening mammograms was determined to be 49.1 percent, and for clinical breast examinations the risk of a false-positive result was 22.3 percent. The costs of further evaluations following false-positive screening were estimated to be $329,649.
The authors conclude that there is a considerably high rate of false-positive results with both screening mammography and clinical breast examinations. False-positive test results increase expenses significantly and add psychologic stress for patients. The authors propose having radiologists available on site to obtain more expedient work-ups of patients with abnormal mammograms. They also encourage educating patients about the risks of false-positive results before seeking screening examinations.
JEFFREY T. KIRCHNER, D.O.
Elmore JG, et al. Ten-year risk of false positive screening mammograms and clinical breast examinations. N Engl J Med April 16, 1998;338:1089-96.
Evaluation of Recent Advances in the Treatment of Vaginitis
Although vaginitis is a common problem, its diagnosis and treatment are sometimes problematic. Carr and colleagues review the most common causes of vaginitis (yeast infection, bacterial vaginosis and Trichomonas vaginalis infection) and suggest an evaluation of vaginal discharge and treatment options.
An abnormal vaginal discharge is one that adheres to the vaginal walls, causing irritation, pruritis or urinary symptoms, and ranging from white to yellow, gray or green in color. Besides infectious causes of vaginitis, noninfectious etiologies of vaginal discharge include chemical vaginitis and atrophic vaginitis.
Approximately 80 percent of yeast infections are due to Candida albicans. Women who are pregnant or taking oral contraceptives, broad-spectrum antibiotics or steroids, and those who are obese, immunocompromised or have diabetes have an increased susceptibility to yeast vaginitis. A stress-induced yeast vaginitis has also been described, although the pathophysiology of this condition is poorly understood. Yeast vaginitis often presents with severe irritation or pruritis of both the vagina and the vulva. Urinary tract symptoms are not uncommon. Examination reveals erythema, inflammation and an adherent discharge described as "cottage cheeselike." The diagnosis is made when hyphae are seen on a potassium hydroxide wet mount. Other characteristics of candidal vaginitis include a pH of less than 4.5 and a lack of odor to the discharge. Infrequent infection can be successfully treated with an over-the-counter preparation of miconazole or clotrimazole for seven days. Vaginal and vulvar involvement may necessitate use of both vaginal suppositories and creams. Women with recurring yeast vaginitis should be treated with a prescription anti-fungal medication. Some single-dose treatments are available, but they may cause adverse effects (e.g., nausea, vomiting and diarrhea) or may not be as efficacious as longer courses of treatment. In women with frequent vaginal yeast infections, consideration should be given to discontinuing oral contraceptives as well as testing for human immunodeficiency virus infection.
Bacterial vaginosis, formerly known as nonspecific vaginitis, has a poorly understood pathophysiology and may be asymptomatic in up to 50 percent of women with the disorder. It is associated with abnormal Papanicolaou smears (usually atypical squamous cells of undetermined significance), pelvic inflammatory disease (although this is controversial) and upper genital tract infection. The risk of premature rupture of the membranes and preterm delivery has also been reported in patients with bacterial vaginosis, although it has been shown that this risk can be reduced with oral metronidazole treatment.
Women with bacterial vaginosis do not have a standard clinical presentation. Typically, three of the following four criteria must be present to meet the diagnosis of bacterial vaginosis: a pH of at least 4.5, a positive "whiff" test, a thin homogeneous discharge and the presence of clue cells on microscopic examination of a normal saline wet mount. A vaginal smear should always be obtained, whereas a vaginal culture may not be necessary. Treatment generally consists of oral or topical metronidazole or clindamycin. Treatment of asymptomatic patients is not necessary unless the patient is pregnant or scheduled for a vaginal surgical procedure.
Trichomonas vaginalis infection is more likely to occur in women of lower socioeconomic status and women with multiple sexual partners. The "strawberry cervix," caused by intraepithelial hemorrhages, is present in only about 5 to 10 percent of patients with trichomonal infection. Trichomonas infection may be associated with abnormal Pap smears and pelvic inflammatory disease, as well as premature rupture of the membranes and neonatal respiratory tract infections. Trichomonas infection is characterized by a foul-smelling, profuse, watery green discharge. Inflammation of the vaginal mucosa is generally only mild. The pH is usually 6 to 7, and often many leukocytes are present. A normal saline wet mount is the best way to see the organism, a protozoan with four flagella. Options for treatment of trichomonal infection include metronidazole, with higher dosages in women with more resistant infections. Pregnant women with Trichomonas infection should take 2 g of metronidazole in a single dose and their sexual partners should also be treated.
GRACE BROOKE HUFFMAN, M.D.
Carr PL, et al. Evaluation and management of vaginitis. J Gen Intern Med May 1998;13:335-46.
Warfarin Therapy and Joint Aspiration and Injection
Soft tissue aspirations and injections may be used diagnostically and therapeutically in a variety of rheumatic conditions. The patients who require these procedures often are older and may be taking warfarin for the treatment of atrial fibrillation, valvular heart disease or cerebrovascular disease. The risk of traumatic hemorrhage or hemarthrosis following a soft tissue or joint injection in these patients is unknown. Thumboo and O'Duffy performed a prospective study at the Mayo Clinic to evaluate the frequency of joint or soft tissue bleeding in patients receiving warfarin therapy who required aspiration or injection of the soft tissue or joints.
The primary inclusion criteria for the trial included the use of a stable dosage of warfarin and an International Normalized Ratio (INR) of less than 4.5. Patients were excluded if the INR was more than 4.5, or if they had overlying cellulitis or were receiving concomitant heparin therapy.
The injections or aspirations were performed by a staff rheumatologist, a rheumatology fellow or an internal medicine resident under supervision. The medications used were either betamethasone or methylprednisolone, with 1 percent lidocaine typically given before aspiration procedures. The patients were instructed to avoid any strenuous activity or movement of the affected joint for 24 to 48 hours after the procedure. One of the two authors contacted all patients by telephone four weeks after the procedure to obtain information about warmth, swelling or bruising at the injection site. The patients were also asked about follow-up treatment for any complications related to the procedure. Patients who received corticosteroid injections were also asked to rate their pain as worse, slightly better, much better or fully resolved.
Thirty-two aspirations or injections (15 joint and 17 soft tissue procedures) were performed in 25 patients. Members of the study group had a median age of 74 years, and the median INR was 2.6. The INR assays were performed from zero to 129 days before the procedure, but the median time was only 1.5 days. There were no patient-reported joint or soft tissue hemorrhages. Based on a statistical rule known as the "rule of threes" (if no events of a specific type occur in a study group of X individuals, it is 95 percent certain that the event occurs no more than three times per X), the risk of significant soft tissue or joint hemorrhage in this study group can be calculated as less than 10 percent. Resolution or marked improvement in pain was reported by 74 percent of patients who received corticosteroid injections, and specific diagnostic information was obtained in 53 percent of patients who had joint aspirations.
The authors conclude from their study that joint or soft tissue aspirations and injections in patients who are undergoing anticoagulation with warfarin are associated with a low risk of hemorrhage. In addition, these procedures often provide therapeutic or diagnostic benefits.
JEFFREY T. KIRCHNER, D.O.
Thumboo J, O'Duffy JD. A prospective study of the safety of joint and soft tissue aspirations and injections in patients taking warfarin sodium. Arthritis Rheum April 1998;41:736-9.
EDITOR'S NOTE: This is a small but clinically useful study. I believe most physicians would feel comfortable performing a soft tissue or joint injection in a patient taking warfarin provided a recent and therapeutic INR was available. If there is uncertainty, one could wait several hours until a prothrombin time could be obtained before administering a corticosteroid injection. On the other hand, if more urgent diagnostic information is required, as in a case of a possible septic joint, knowing that an INR less than 4.5 appears to be safe is reassuring. There would, however, still be a theoretic concern about bleeding in patients receiving concomitant therapy with aspirin or other nonsteroidal anti-inflammatory drugs.
J.T.K.
Calcium Channel Blockers and Cardiovascular Mortality
Calcium channel blockers are a diverse and widely used class of medications for patients with hypertension, ischemic heart disease and certain arrhythmias. All calcium channel blockers dilate coronary and peripheral blood vessels. Recent case control studies have raised concern about increased cardiovascular mortality in patients with hypertension who are receiving calcium channel blockers (particularly short-acting forms) when compared with patients receiving other antihypertensive medications. Given the large number of patients taking these medications, it is important to determine if there is in fact a specific risk associated with the use of calcium channel blockers. Michels and associates performed a prospective study to determine if there is an increased risk of cardiovascular disease and mortality in patients with hypertension who took calcium channel blockers compared with patients who used other antihypertensive medications.
A total of 14,617 women from 30 to 55 years of age who had hypertension and regularly used antihypertensive medications were observed over a six-year period. A first fatal or nonfatal cardiovascular event (234 myocardial infarctions, 162 strokes and 12 sudden deaths) occurred in 385 women during this period. Women who used calcium channel blockers alone had an age-adjusted relative risk of myocardial infarction of 2.36 compared with women receiving thiazide diuretics alone.
Adjustment for coronary disease risk factors decreased the association considerably, but it still remained elevated. Women receiving calcium channel blocker therapy had a relative risk of 1.64 compared with a 1.88 relative risk in women receiving combination therapy.
The authors found a significant elevation in the relative risk of total myocardial infarction among women who used a calcium channel blocker compared with those who did not. However, it remains unclear if the elevation in risk for myocardial infarction among women who use calcium channel blockers is real or a result of confounding factors based on study methodologies.
Clinical trials comparing long-acting calcium channel blockers against other antihypertensive agents (notably thiazide diuretics and beta blockers) are currently under way. Until more data are available, the authors advise following the recommendations of the Sixth Report of the Joint National Committee on the Detection, Evaluation, and Treatment of High Blood Pressure. Specifically, diuretics and beta blockers should be considered "first-line" choices for hypertension therapy, and calcium channel blockers should be reserved for special indications (e.g., isolated systolic hypertension in older patients who do not respond to thiazide diuretics).
JIM NUOVO, M.D.
Michels KB, et al. Prospective study of calcium channel blocker use, cardiovascular disease, and total mortality among hypertensive women. The Nurses' Health Study. Circulation April 1998;97:1540-8.
Colorectal Cancer Screening with Flexible Sigmoidoscopy
Colorectal cancer is the second most common fatal malignancy in the United States and resulted in approximately 55,000 deaths in 1997. Because a reduction in cancer mortality with the use of screening sigmoidoscopy has been demonstrated in two case-control studies, screening of patients older than 50 years with flexible sigmoidoscopy has been recommended by the U.S. Preventive Services Task Force. Despite this recommendation, it is estimated that most patients are not being screened. Cooper and associates surveyed primary care physicians to identify characteristics of physicians who perform screening with flexible sigmoidoscopy and to identify barriers to initiation of screening.
The survey sample was obtained from the American Medical Association master file and included both family physicians and general internists from 10 states. A random sample of 1,000 physicians from each specialty was selected. All 2,000 physicians were mailed a questionnaire that asked if they screen for colon cancer with flexible sigmoidoscopy and if they do screen, whether they perform the tests themselves or refer patients to another physician. The physicians were asked to indicate reasons for screening or not screening.
The survey was initially mailed in the Spring of 1994 and, if there was no response within six weeks, a second survey was sent. If the second mailing got no response, a telephone call was made to verify the physician's address, and a third mailing was sent to eligible physicians who were willing to participate in the study.
From the original study sample of 2,000 physicians, 238 were eliminated because they were not practicing a primary care specialty. A total of 884 of the remaining eligible physicians responded, including 51 percent who were internists and 49 percent who were family physicians. Eighty-five percent were men, 76 percent were board certified and 89 percent were engaged in office practice.
Of all responders, 90 percent reported recommending flexible sigmoidoscopy to their patients. Forty-four percent performed the test themselves, and 46 percent referred their patients for the procedure. The overall use of screening did not correlate with gender, board certification status, year of medical school graduation or specialty. However, the physicians who performed sigmoidoscopy were more likely to be men, to have graduated after 1970, to be board certified and to specialize in family practice. The most frequently cited barrier to screening was poor patient acceptance (more than 40 percent of respondents). This was followed by lack of training, excessive time required, lack of equipment, lack of reimbursement and, finally, questionable effectiveness, which was cited by a minority of physicians.
The authors conclude that the majority of primary care physicians recommend colorectal cancer screening for their patients, although at least one half do not perform the procedure themselves. The authors suggest that targeting and training older, nonboard-certified primary care physicians may be one way to increase flexible sigmoidoscopy screening for colorectal cancer. They also advocate improved patient education and population-based interventions as ways to improve the low rate of public acceptance of flexible sigmoidoscopy.
JEFFREY T. KIRCHNER, D.O.
Cooper GS, et al. Factors associated with the use of flexible sigmoidoscopy as a screening test for the detection of colorectal carcinoma by primary care physicians. Cancer April 15, 1998;82:1476-81.
Improving Diagnosis of Deep Venous Thrombosis
Simplified Clinical Model for Identification of Deep Venous Thrombosis
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Suggested diagnostic approach in patients with suspected deep venous thrombosis. (DVT=deep venous thrombosis; PTP=pretest probability)
The rightsholder did not grant rights to reproduce this item in electronic media. For the missing item, see the original print version of this publication. The serious import of deep venous thrombosis, the effectiveness of treatment and the difficulty of clinical evaluation of this condition make accurate diagnosis essential. Since the specificity of symptoms and signs of deep venous thrombosis is low, most patients who are symptomatic do not have deep venous thrombosis. Anand and associates reviewed the literature and devised a clinical prediction guide to aid in the diagnosis of this condition.
A literature search yielded five studies that addressed the usefulness of clinical findings of deep venous thrombosis compared with venographic confirmation. Risk factors for deep venous thrombosis are recent surgery, immobility, age greater than 60 years, malignancy or cancer chemotherapy, and pregnancy or estrogen use. It was previously thought that careful inspection of the affected leg, looking for tenderness, swelling, redness and Homans' sign, could help diagnose deep venous thrombosis. Physical examination was found not to distinguish patients with deep venous thrombosis from those without it. Impedance plethysmography and compression ultrasonography are two noninvasive techniques used to reliably diagnose proximal but not calf vein thrombosis.
The authors propose estimating the pretest probability of deep venous thrombosis (that is, the probability before impedance plethysmography, compression ultrasonography or venography is performed) using a simplified clinical model (see the accompanying table). The model assigns points based on clinical parameters, such as active cancer, being bedridden for more than three days, pitting edema or an alternative diagnosis that is as likely or more likely than deep venous thrombosis. This pretest probability is then used to determine the diagnostic approach (see the accompanying figure). For example, a patient with a clinical assessment that leads a physician to determine that there is a moderate pretest probability of deep venous thrombosis with an abnormal result on ultrasound examination should begin anticoagulant therapy since deep venous thrombosis is likely.
The authors note that the risk of fatal pulmonary embolus is reduced to less than 1 percent in patients with deep venous thrombosis who are appropriately treated. Application of this prediction guide may help clinicians achieve improved diagnosis and management of deep venous thrombosis.
GRACE BROOKE HUFFMAN, M.D.
Anand SS, et al. Does this patient have deep vein thrombosis? JAMA April 8, 1998;279:1094-9.
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Copyright © 1998 by the American Academy of Family Physicians.
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