New content quiz October 2013

The forehead is the most accurate, and most rapidly responsive site to monitor SpO2 in patients with poor perfusion. The finger is more affected by sympathetic tone and the ear more dependent on arterial blood pressure. The toe is usually the least reliable site in this situation. (Link)

A 2013 Australian study demonstrated that 10%-12% of patients attending tertiary EDs may be suitable for general practice whilst the Australian Institute of Health and Welfare method of calculating ‘GP’ attendances to EDs overestimates the actual figure and impact on ED occupancy by 10 -15% (Link)

The methodology used in most studies to determine if an ED attendance is “inappropriate” use the discharge diagnosis to determine this however a JAMA 2013 study showed that 90% of “inappropriate” ED attendances have presenting symptoms indistinguishable from “appropriate” ED attendances. The concept of appropriateness is subjective and usually reflects the administrators views and values, rather than those of the patient. A 2013 Australian study demonstrated
that ‘GP’ patients comprised 3 – 5% of total ED length of stay in an adult tertiary ED and proportionally more ‘GP’ patients presenting during weekday daytime (08:00-17:00) and proportionally fewer overnight (00:00-08:00)

. (Link)

Cat bites are equivalent to cat claw injuries. They are usually puncture wounds and have a higher infection rate than dog bites. Pasteurella multocida is one of the organisms responsible for infection in about 75% of cases.(Link)

Wounds over the MCP joint should be assessed  with the fingers fully flexed as this is usually the position the injury occurred. In the extended position, a damaged tendon may retract out of view. A partially divided extensor tendon may still produce full finger extension. Gas in an MCP joint implies joint penetration, however radiography is insensitive in this situation so should not be used to exclude the need for exploration. Although rare, consider Hepatitis B and HIV prophylaxis in patients with injuries from high risk individuals.(Link)

The NEXUS Chest criteria apply only to patients > 14 years of age. The criteria to perform radiography are the presence of any one of: age > 60 years; rapid deceleration mechanism; chest pain; intoxication; abnormal alertness/mental status; distracting painful injury; tenderness on chest wall palpation. The rule is about 99% sensitive and 13% specific for significant thoracic injury. (Link)

Superficial phlebitis not affecting the great or small saphenous vein, and with no other risk factors for DVT does not usually require investigation due to the low risk of DVT. Repeat examination within 7 – 10 days in patients with confirmed thrombophlebitis at risk of developing DVT is advised.
Indications include; superficial phlebitis of the proximal third of the medial thigh; clinical evidence of extension of phlebitis; lower extremity swelling greater than expected from superficial thrombophlebitis alone; or if the diagnosis of superficial phlebitis is in question. (Link)

The normal Hb is at least 13g/dL in the first month of life, then declines to a nadir at 2-3 months where the lower limit of normality is 9g/dL. It then rises again and should be > 11g/dL by 12 months. (link)

Alveolar echinococcus is caused by Echinoccus multilocularis and is potentially life threatening. It is becoming increasingly common due to invasion of cities in Europe and Japan by red foxes, the main definitive hosts. It is endemic only in the Northern hemisphere but could occur in travellers to Australasia, especially as there is an asymptomatic phase of 5-15 years.

Imaging features that distinguish it from cystic echinococcus (mostly benign disease) include; involvement of the right lobe of the liver; local extension into the abdomen, retroperitoneum or diaphragm; infiltrative, alveolar-like pattern; numerous vesicles (<1 mm -15 cm in diameter); dense surrounding connective tissue; absence of cyst fluid; and occasionally central necrosis. (link)

Despite it’s name, alevolar echinococcus is almost completely confined to the liver. The reason it is called ‘alveolar’ is that it has an alveolar like spreading pattern through the liver in active disease. (link)

Venlafaxine is considered intermediate risk as it achieves clinically significant levels (≥ 10% of maternal concentrations) in the breast feeding infant. Other agents of intermediate risk include  bupropion, clomipramine, diazepam, fluoxetine, doxepin, citalopram, lamotrigine, fluvoxamine, mirtazepine, sertraline, olanzepine, nortriptyline and thiazide diuretics. The other agents listed are considered safe in lactation. (link)

Thiopentone, propofol and etomidate are all considered safe in lactation. There is limited information about ketamine in lactation, so should be considered a higher risk than the other agents until more information is known. (link)

Pertussis and parapertussis are clinically indistinguishable. Culture of a nasopharyngeal aspirate is only about 20% sensitive, although 100% specific, within first 3 weeks of cough in children. PCR is the investigation of choice and is 3 times more sensitive than culture in the first few weeks of cough. The sensitivity of PCR decreases with longer duration of symptoms and in older patients. (link)

Audit C tool is a 3 question screening tool that asks about alcohol frequency, quantity and binge drinking. Up to 4 points can be allocated for each response, making a maximum score of 12. Hazardous drinking present if the score is >4 in males or > 3 in females. CAGE is a 4 question screening tool that asks about thoughts of cutting down, annoyance at criticism of their drinking, guilt about drinking and drinking to cure a hangover. (link)