Diagnosing pulmonary embolism
Ann Intern Med 2011; 155: 448-60
Pulmonary emboli (PE) are relatively common and can be fatal if left untreated, but signs and symptoms can be non-specific. For the clinician there is a fine balance between not missing PEs and over-investigating.
This study was a meta-analysis of research looking at PE diagnosis, either by what they call 'gestalt' (pure clinical assessment) or through use of clinical rule tests (Wells rule, Geneva rule and modified Geneva rule), in combination with D-dimer testing. The principle is the same: definite PEs are sent straight for testing, whereas a D-dimer test is done if the diagnosis is in doubt.
The authors found that both approaches, when combined with a sensitive D-dimer, can safely exclude a PE.
They do, however, recommend using a clinical decision tool because this has a higher specificity than gestalt - in other words, there tend to be more false positives and unnecessary investigations with a purely clinical assessment.
Margin width in malignant melanoma excision
Lancet 2011; 378: 1635-42
The incidence of melanoma is increasing and the age of occurrence decreasing. The mainstay of treatment is surgical excision. For lesions of greater than 2mm thickness, the optimum width of excision margins is uncertain. The greater the width, the more problems there are with grafting and reconstruction, but whether this translates into greater survival is unknown.
This study aimed to address this uncertainty. In nine European centres, patients with a melanoma greater than 2mm depth were randomised into having a 2cm or a 4cm surgical resection margin.
More than 460 patients were allocated to each group and were followed up for a median of 6.7 years. It was found that five-year survival was the same for both groups (65%). There was no statistical difference for melanoma recurrence or death from the melanoma between the two groups.
The researchers also found that most 2cm margin excisions (with a diameter of 4cm) could be closed without the need for grafting, reducing operative morbidity.
Opioid use in fibromyalgia
Am J Med 2011; 124: 955-60
Fibromyalgia is difficult to diagnose because there are no confirmatory tests and difficult to treat because there are no gold standard guidelines. Recently the use of opioids in treatment has increased. This Canadian study examined the use of opioids in patients with fibromyalgia attending a tertiary care centre.
They found that 32% of patients were using opioids and of these, two-thirds were using strong opioids. Opioid use is discouraged and is not included in any guidelines.
The authors noted more negative personal factors in those using opioids: they were more likely to be on disability benefits, have poorer education levels, be unemployed, have a history of substance abuse and suicide attempts, and have a current unstable psychiatric problem.
The authors recognise that this needs further investigation and recommend responsible prescribing of opioids in this condition.
Prenatal exposure to cocaine and tobacco in adolescents
J Pediatr 2011; 159: 771-5
Previous studies looking at brain MRI changes in children who were prenatally exposed to cocaine have showed smaller volumes in cortical grey matter and increased blood flow to the anterior structures but a decreased flow overall. Results are often confounded by concurrent tobacco exposure.
This study used diffusion tensor scanning and a sensation-seeking scale in adolescents prenatally exposed to cocaine, tobacco, both or neither.
Unexpectedly those exposed to cocaine showed no greater propensity to sensation seeking and their MRIs were not particularly abnormal, while those exposed to tobacco did show greater sensation seeking and MRI changes.
Using CT to diagnose COPD
JAMA 2011; 306(16): 1775-81
This was a study set in Belgium and Holland. The authors proposed that patients at high risk of getting lung cancer who were undergoing regular lung CT screening could also be screened for COPD at the same time using an expiratory CT, rather than having spirometry. The study assessed whether the CT scans were as accurate as spirometry for diagnosing COPD.
The patients were already in a trial looking at early diagnosis of lung cancer.
The study found that with men who were either past or current heavy smokers, CT screening for COPD had a sensitivity of 63 per cent and a specificity of 88%. The authors felt this could help earlier diagnosis.
Antibiotic prescribing in France
Arch Dis Child 2011; 96: 1033-7
Public health campaigns were carried out in France in 2000 and 2002 to promote more careful antibiotic prescribing in children.
This study looked at the impact of the campaigns by assessing how often children attending daycare centres in the south east were prescribed antibiotics in 1999, 2004 and 2008. They also examined the reasons for prescribing and the antibiotic given.
The success of the campaigns was mixed. The headline figure was very good, with the number of children having had an antibiotic in the past three months dropping from 58.5% to 29.7%.
Respiratory tract infection prescribing had fallen, but otitis media prescribing had risen. Disappointingly, prescriptions for third-generation cephalosporins had risen from 26% to 49.5%.
- Dr Hunter is a GP in Bishops Waltham, Hampshire, and a member of our team who regularly review the journals
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