New content quiz August 2015

Serum IgE is most useful for the detection of sensitisation, not confirmation of anaphylaxis. As of December 2014 there was no jumper ant venom IgE assay available, and the sensitivity of IgE for the detection of latex sensitisation was only about 60%. The sensitivity and specificity of peanut IgE are around 95%. (link)

The key elements of the onsite response to a major casualty incident are: C – Command and Control; S – Safety; C – Communications; A – Assessment; T – Triage; T – Treatment, T – Transport. (link)

Septal haematomas are usually bilateral with nasal obstruction present in 95% and rhinorrhoea in 25% of cases. The haematoma is usually soft when (gently) probed with a cotton bud, whereas a deviated septum is hard. (link)

In distinction to mania, the increased activity in hypomania is goal directed, rather than aimless. Hypomanic episodes usually only last for weeks. The presence of psychosis or flight of ideas suggests mania. (link)

Factitious disorder is an intentional production or feigning of physical or psychological signs or symptoms associated with identified deception. The motivation for the behaviour is to assume the sick role. External incentives for the behaviour (e.g. economic gain, avoiding legal responsibility, or improving physical well-being, as in malingering) may be absent i.e. no secondary gain present (as occurs with conversion disorder). The behaviour is not better accounted for by another mental disorder. Munchausen’s syndrome is considered only as a subform of the disorder. (link)

Active listening skills include: making eye contact; giving your complete attention;  asking questions; summarising frequently; checking understanding; acknowledging statements (e.g. ‘uh-hum’); appearing interested. Interrupt only when necessary, and never at the beginning. (link)

Repair is best performed using continuous subcutaneous suturing with rapidly absorbable polyglactin suture material. (link)

A CSF lactate of 3.0mmol/L in a 24 year old man with a headache and fever is approximately 90% sensitive and 95% specific. (link)

Clot retrieval in acute stroke usually requires advanced perfusion imaging and is appropriate for the minority of patients with acute stroke. It is of proven benefit in large vessel anterior circulation stroke, but not proven in posterior circulation stroke (although likely to be of benefit). Thrombolytics are given concomitantly and clot retrieval may be effective up to 8 hours following stroke onset. (link)

A CRP can be used to determine whether antibiotics should be given in cases when the diagnosis is in doubt. < 20mg/L – do not routinely offer antibiotic therapy; 20-100mg/L – consider a delayed antibiotic prescription; >100mg/L – prescribe antibiotics. < 100 mg/L has high NPV for severe illness and mortality. (link)

Patients usually suitable for discharge with CAP have a suitable psychosocial situation and no more than one of the following: temperature higher than 37.5°C; respiratory rate ≥ 24 breaths per minute; heart rate > 100 beats per minute; sBP ≤ 100 mm Hg; SpO2< 90% on room air; abnormal mental status; inability to eat without assistance. (link)

Colonic involvement in ulcerative colitis begins at the rectum and proceeds proximally in a continuous fashion. The rectum involved in 95% of cases and there are no skip lesions. At the time of diagnosis 30–50% confined to the rectum or the sigmoid colon (distal colitis), 20–30% left-sided colitis, 20% have pancolitis. (link)

There are many anatomical variants of the aortic arch. The most common is separate origins of the innominate, left common carotid, and left subclavian arteries. The second most common is a common origin for the innominate and left common carotid arteries. Another variant is when the left common carotid artery originates separately from the innominate artery. A single brachiocephalic trunk originating from the aortic arch that divides into subclavian arteries or each side and a bicarotid trunk that then divides into the right and left common carotid is called a bovine arch. (link)

These features are most suggestive of acute porphyria. The presence of localised neurological features does not suggest cyclical vomiting syndrome, Wilson’s disease or lead poisoning. (link)

The most common cause of meningitis in children 30-90 days of age is enterovirus, with Gp B Strep. being the second most common. (link)

Any number of colony forming units on urine culture from a suprapubic aspirate is considered indicative of UTI. (link)

Indications for renal USS in UTI include: first UTI and no prior antenatal renal tract US; concurrent bacteraemia; < 3 months of age; urine culture with atypical organisms (e.g. Staphlococcus aureus or Pseudomonas); lack of clinical response to 48 hours of antibiotic if sensitive organism; renal impairment or significant electrolyte derangement; abdominal mass; poor urinary stream. (link)

The Powers ratio is the distance between basion and spinolaminal line at C1 divided by the distance between the middle of the anterior interspinal line at the middle of the anterior arch of C1 to the posterior margin of the foramen magnum. The normal ratio is approximately 1, however an abnormal ratio is only 60% sensitive for fracture detection. A ratio > 1 indicates anterior subluxation and a ratio < 1 suggests: posterior atlanto-occipital dislocation; and odontoid fracture; an atlas ring fracture. (link)

Normal atlanto-occipital alignment in an adult is characterised by: a line drawn along the clivus (Wachenheim’s line) normally just intercepts the posterior tip of the dens; continuation of the spinolaminar line crosses the posterior margin of the foramen magnum (opisthion); the posterior axial interval (perpendicular distance between the basion (anterior border of foramen magnum) and posterior axial line (cranial extension of posterior intervertebral line) should be < 12mm when the basion is anterior to posterior axial line or < 4mm when posterior to posterior axial line. (link)

The normal basiodental interval (distance from basion to tip of dens) on a lateral Cx spine radiograph in an adult should be < 13 mm (link)