August 2014 update quiz

Phlegmasia cerulea dolens is due to complete occlusion of deep and superficial venous systems and is characterised by a cyanotic or dusky appearance of the leg. Severe venous congestion leads to increased hydrostatic pressure and tissue ischaemia whch may progress to frank gangrene. Phlegmasia alba dolens is characterised by extensive swelling without tissue ischaemia due to preservation of superficial collateral veins.

Erythema chronica migrans (ECM) usually affects a patch of skin > 5 cm diameter and is present in 80% of cases of Lyme disease. It starts as a small macule or papule at the site of the tick bite 1-2 weeks following the bite (range 3-32 days) and may expand over days/weeks to cover a large area. It may have centrally located vesicles or necrotic areas and central clearing of the lesion may occur. It is occasionally itchy and rarely painful and lasts for 3-4 weeks before spontaneously resolving.

Ascitic fluid contains low levels of complement and reduced opsonic activity and when protein levels are < 1 g/dL, opsonic activity is negligible, therefore low-protein ascites > risk than high protein ascites. Protein ≥ 1 g/dL is close to 100% sensitive for SBP, with a WCC > 250/microL or ascitic/serum LDH ratio ≥ 0.5 approximately 80% sensitive and a positive Gram stain only 10 – 50% sensitive.

According to the International League Against Epilepsy 2014 definition, epilepsy is no longer considered present when a patient has outgrown an age-dependent epilepsy syndrome or has had 10 years seizure free and off anti-convulsants for 5 years.

IV sodium valproate is usually administered in a dose of 10-20mg/kg. It is contra-indicated in children < 2 years of age and in patients with known urea cycle disorders. It is not indicated for the treatment of seizures secondary to drug toxicity

IV levetiracetam is usually administered at a dose of 10mg/kg in children, 15-20mg/kg in adults. It is compatible with 5% dextrose, saline and Hartmann’s solution and administered over 15 minutes. Maintenance dose should be reduced in patients with renal impairment.

In patients with renal impairment high sensitivity troponin is elevated in nearly all patients with a creatinine of > 200 μmol/L. A single elevated HsTNT level in patients with an eGFR < 60mL/min with chest pain or shortness of breath is approximately 70% sensitive and 30% specific for MI. Troponin is > 200 ng/L in 50% of dialysis patients and TnI is more likely to be lower as it is more effectively dialysed than TnT.

In patients < 40 years of age with chest pain and who have no cardiac risk factors and a normal ECG the risk of ACS is approximately 1%.

In patients < 40 years of age with chest pain and who have no cardiac risk factors and a normal ECG exercise testing results in a true positive rate for ACS of < 1:1000. Exercise stress testing does not appear to further assist risk stratification in this group as the test is equivocal in 11% and has a false positive rate 2-3 times the true positive rate.

Desirable features of a clinical indicator include: the measurement of patient oriented outcomes, not surrogate markers; there is astrong link between performance and patient outcome based on methodologically sound research; it is precise and reliable; those proposing the indicator have no conflicts of interest; it is accepted as a valid measure of performance by the end users; the relevant data is available and the desired performance is possible.

Monitoring of the heart rate in patients with ventricular assist devices is still useful as HR is still an important factor in determining cardiac output in these patients.
BP is best measured by using a manual sphygmomanometer and Doppler ultrasound over the brachial or radial artery- a constant sound indicates the mean arterial pressure (normally 70–90 mmHg). Invasive arterial pressure monitoring will nearly always require catheter placement under US guidance due to the reduced pulse pressure and pulse oximetry is often unreliable for the same reason.

Stable patients with traumatic intra-cranial haematomas who have no clinical deterioration do not require a repeat CT head at 24 hours unless they are intubated or taking anti-coagulants or anti-platelet agents.

The rotational technique for insertion of an LMA is best described by rotating the device 90 degrees anti-clockwise after insertion into the oropharynx then rotation 90 clockwise once it is advanced past the tongue. This technique is associated with a 10% higher success rate and slightly shorter time to insertion than the standard insertion technique.

Allergic pulmonary aspergillosis is one of the Aspergillus related lung diseases, that also include chronic necrotizing Aspergillus pneumonia and aspergilloma. It occurs in approximately 1% of patients with asthma, usually in those with moderate or severe persistent disease. It should be considered in this group of patients who do not respond to standard therapy. Common features include: cough productive of mucous plugs or haemoptysis; migratory pulmonary opacities; central bronchiectasis; serum Ig E levels > 1000 IU/dL; eosinophilia; and a positive skin test for A. fumigatus.

PERC criteria include: < 50 years of age; pulse rate < 100 beats/min; SpO2 > 94% on air; no unilateral leg swelling; no haemoptysis; no surgery or trauma within 4 weeks; no previous DVT or PE; and no oral hormone use. It does not include other risk factors for PE (or detection of PE) such as family history of VTE, inherited thrombophilia, factors limiting increases in heart rate, malignancy or pregnancy.