New content quiz November 2015

A 2013 Cochrane review found that limited evidence is available from RCTs on the relative effectiveness of surgical versus conservative treatment for acute middle third clavicle fractures and reported benefits overall are of marginal clinical and statistical significance. (link)

A 2015 prospective RCT of mostly older patients in the UK who had displaced humeral neck fractures did not demonstrate any benefit in functional outcome or quality of life from fixation of displaced fractures in unselected patients. (link)

A patient with a clean wound who received a primary tetanus immunisation course for tetanus and a booster 8 years ago requires no tetanus prophylaxis. (link)

A patient with a contaminated wound who had a primary tetanus immunisation course and a last tetanus booster 8 years ago requires tetanus toxoid (as last booster > 5 years ago) but no tetanus immunoglobulin. (link)

Myocardial ischaemia and non-obstructive coronary arteries (MINOCA) is the cause of myocardial ischaemia in approximately 5% percent of cases. (link)

Patients with myocardial ischaemia and non-obstructive coronary arteries (MINOCA) tend to be younger and female, have ECG changes of typical regional ischaemia in 25% of cases and have 12 month all cause mortality (4.7%) about 2/3 of those with obstructive coronary artery disease. Unfortunately the overlap of historical and ECG findings are such that MINOCA cannot be reliably excluded on these grounds alone. (link)

The liver is normally slightly more echogenic than the renal cortex and less echogenic than the spleen. The common bile duct lies immediately anterior to the portal vein and the portal vein walls are echogenic, whilst the hepatic veins are not. (link)

Echogenicity is increase in steatosis, but surprisingly not increased in fibrosis. Hepatitis can cause some reduced echogenicity, particularly in the peri-portal regions however echogenicity is usually normal. Traumatic lesions of the liver are usually found in the posterior part of the right lobe of the liver. (link)

Vancomycin resistant enterococcus (VRE) is usually cleared spontaneously with time: 85% within a year; close to 100% by 4 years. (link)

In patients with acute stroke and no advanced cerebral imaging (CT perfusion/ DWI MRI) treated with tPA between 3 – 4.5 hours of symptom onset there is no clinically significant functional benefit (NNT > 50) and a high probability of 1.5% absolute increase in 7 day and 6 month mortality. (link)

In trigeminal neuralgia, baclofen is the first line treatment in patients with MS. Surgery is indicated if there is failure of single agent medical therapy. Microvascular decompression provides rapid relief of pain in 70-80% of patients and has a long duration of effect (10-20 years), but appears to be much less effective in patients with MS and requires general anaesthesia. Stereotactic radiosurgery
does not require general anaesthesia but the pain relieving effects are not immediate. (link)

An arterial tourniquet is usually only used when other methods fail or if severely mangled extremity. Limb loss commonly occurs after use, however this may have occurred anyway and the patient’s life may be saved instead. The cuff pressure display does not always mean the correct pressure has been applied as the cuff can get caught on itself and not actually compress the limb. The absence of distal flow should be checked with US whenever possible as this is more effective than by pulse palpation. (link)

The sensitivity of a FAST scan for > 800mL of intraperitoneal blood when performed by an experienced operator (>200 scans) is approximately 96%. The sensitivity for > 250mL is only 90%. (link)

Each cm of fluid width between the mid point of the kidney and the liver on the the RUQ FAST scan view corresponds to approximately 1000mL intraperitoneal fluid. (link)

When applying a pelvic sling slight flexion and internal rotation of hips is important to closing the pelvis – this requires the use of blankets/pillows to achieve and binding of the leg just above the knees to maintain the position. A correctly applied sling usually has the buckle of the sling at the level of the greater trochanter and close to the midline. (link)

All the tests listed are tests that compare categorical variables. The Chi-squared test compares the frequency of non paired categorical observations of binomial data in a population and the Yate’s correction is applied when the sample size is < 40. The Fisher’s exact test is used instead of the Chi-squared test when there are < 5 expected counts in any cell and the sample size is > 130. The McNemar Chi squared test is used with paired data in a 2 x 2 table. The Cochran Q Test is used for comparison of proportions between more than 2 dependent samples and can be used to test for heterogenicity (differences in degree of effect reported) in meta-analyses of trials. The Phi coefficient is a measure of correlation between 2 dichotomous variables. (link)