New content quiz August 2013

There is some conflicting evidence regarding the seriousness of mechanism of injury alone (i.e. without obvious evidence of physiological disturbance) with it being unclear whether the death of an occupant or being a pedestrian hit by a car are associated with a sufficient degree of injury to warrant trauma centre / ICU level care.

However falls of < 6m (< 3m in children) have a low yield for serious injury and motorcycle crashes with separation of rider and motor vehicle roll overs have low need for trauma centre or ICU care. Ejection from vehicle and extrication time >20 minutes, are more strongly associated with the need for trauma centre care. (Link)

SJS, Haemolytic anaemia and DRESS following penicillin therapy are all absolute contra-indications to  re-challenging. Patients with reported type 1 hypersensitivity reactions who have a negative skin test for penicillin allergy can be safely re-challenged with oral penicillins, as can patients with mild, delayed symptoms. (Link)

The ‘Sepsis six’  items are :deliver high-flow oxygen; take blood cultures; administer empiric antibiotics IV, measure arterial lactate and FBE; commence IV fluid resuscitation and commence urine output measurement. Establishing a CVP of 8-12mmHg does not need to occur within the first hour.(Link)

CT usually only finds another cause of the patient’s symptoms in about 5% of cases. In another 5% it finds incidental abnormalities, most of which require further follow up. (Link)

Cryptogenic septic shock is defined as the presence of an arterial lactate of 2.0-3.9 mmol/L, but without hypotension or the need for assisted ventilation. It progresses to requiring ICU level care in approximately 25% of cases and mortality is about 12.5%. Unfortunately there appear to be no useful initial predictors of progression to requiring ICU level care (other than monitoring progress closely). (Link)

A corresponds to the S2 dermatome. C is S3, D is S4 and E is S5. (Link)

Benign acute childhood myositis usually affects school age children with males more commonly affected than females. It often occurs in clusters a few days after onset of viral type URTI (Influenza A and B especially). It usually affects calf muscles bilaterally and muscular tenderness is usually present. Limb or muscle pain during the acute phase of a febrile illness should raise the possibility of meningococcaemia or other causes of septicaemia. (Link)

Third universal definition (August 2012) of an MI as defined by the ESC/ACCF/AHA/WHF Task Force is determined by a value of troponin T or I exceeding the 99th percentile of a normal reference population and at least one of the following: symptoms of ischaemia; new (or presumed new) significant ST-T wave changes or LBBB (NOT RBBB); development of pathological Q waves on ECG; evidence of new loss of viable myocardium or regional wall-motion abnormality on imaging; intracoronary thrombus at angiography or autopsy.The BNP level is not, on it’s own, a criteria for the diagnosis of MI (Link).

F is subfalcine herniation of the cingulate gyrus under the falx. D is downward transtentorial (uncal) herniation of the temporal lobe which is associated with truncation of the suprasellar cistern. E is cerebellar tonsillar herniation where the cerebellar tonsils are visualised > 5mm below the foramen magnum in adults and > 7mm in children. C is upward transtentorial herniation of the cerebellum, (Link)

A fixed transfusion ratio is associated with a lower mortality following haemorrhagic shock. The correct ratio is 1 unit packed cells: 1 unit FFP: 1/5th unit adult dose platelets (or 1 unit of platelets in countries that do not have adult dose platelets). Crystalloids do not form part of the ratio and higher volumes of them are associated with increased mortality in this situation. Traditional and laboratory testing of coagulation using INR and APTT do not effectively measure the clotting derangements associated with haemorrhagic shock (although an INR > 1.2 is associated with increased mortality risk), and results are too slow to come back to direct immediate therapy. Bedside INR  is not adequately sensitive to be useful. The Hb and platelet counts do not change rapidly in response to haemorrhage (they measure concentrations not amounts) so are not good for guiding initial therapy.The amount of products transfused should be guided by the best measures of perfusion available (eg lactate, urine output, haemodynamic parameters). And finally, don’t forget to add 1g tranexamic acid IV whenever using a massive transfusion. (Link)

EPSS is the most easily learnt standard echocardiographic method of those listed. Subjective visual impression(not listed) is the most rapid, but the least reproducible. Simpson’s method takes about 15 minutes to perform and stroke volume and systolic tissue velocity of the mitral annulus requires good apical views and operator skill to perform. (Link)

Vaginal examination adds little to diagnostic accuracy in minor first trimester bleeding (in the absence of trauma, severe pain, shock or hypotension) when pelvic US and follow up within 24 hours is available. However in the shocked patient it may be therapeutic (removal of products of conception from os) as well as diagnostic (complete miscarriage). Delaying vaginal examination in case of a placenta praevia is not relevant in the first trimester. (Link)

Logistic regression is also known as multivariate analysis and it investigates the association between a dependent variable and one or more predictor variables simultaneously. The outcome needs to be a dichotomous variable (e.g. died or alive) but the predictor variables can be any mixture of continuous, binary, or categorical variables. As it provides the ability to adjust for multiple predictors (and baseline differences between groups), the results are usually reported as an adjusted odds ratio. Comparison of the adjusted odds ratio with the unadjusted odds ratio indicates the degree of baseline differences between the groups compared. It is not a measure of agreement such as a Kappa score or a Bland Altman plot. (Link)

Microscopic haematuria is usually initially present in at least 85% of patients with ureteric calculi. A high urinary pH suggests infection with a urea splitting organism such as Proteus. The presence of > 5 WBCs/high-power field is about 85% sensitive (and 80% specific) for UTI. The presence of > 20 WBCs/high-power field is 95% specific (70% sensitive) for infection and only a little less in the absence of infective symptoms – so is strongly predictive of infection.(Link)

The AIMS65 score is generated from the presence of the following factors, each of which generate one point: serum albumin <30 g/L; INR > 1.5; altered mental state; systolic BP < 90mmHg; and age > 65 years. A urea < 6.5mmol/L is a component of the Glasgow Blatchford score, not the AIMS 65 score (Link).