New content quiz July 2014

Features suggestive of a central cause for vertigo include: neck pain or headache (+LR 3.2); skew deviation of eyes (30% sensitive, 98% specific); imbalance and gait unsteadiness as part of the presenting complaint (+LR 3.71). Hearing loss and other ear symptoms suggest a peripheral cause. (link)

Primary erythrocytosis is characterised by a high Hb, PCV and platelet count. Secondary erythrocytosis (of which Polycystic kidney disease is a cause) does not usually cause an increase in the platelet count. Severe dehydration could cause the haematological changes due to haemoconcenttration, however the albumin would be expected to be significantly increased.(link)

All the potential causes produce a microcytic anaemia, however iron deficiency anaemia is the most likely givne the features on FBE (and prevalence in the community). Thalassaemia minor would be expected to have a lower MCV for the Hb noted, sideroblastic anaemia and myeloma would not be expected to have a raised serum transferrin level. (link).

Teardrop cells are present in extra-medullary haemopoiesis so would be the least expected finding. Macrocytosis may be present due to an increased number of reticulocytes. Heinz bodies may be see in drug induced haemolytic anaemias (one of the more common causes). The RCDW can be elevated in anaemia of many causes, but is usually normal in acute haemorrhage or anaemia of chronic disease.(link)

Approximately half of all ED chest pain patients can probably be safely discharged for early outpatient follow up if they have a EDAC score <16 and no new features of ischaemia on ECG and a negative troponin at 0 and 2 hours. Any male ≥ 61 years of age or female ≥ 76 years of age who has pain that is not worse on inspiration or reproduced by palpation are not considered low risk, hence will not be suitable for outpatient evaluation. Any male (and any female >55 years of age without known CAD or ≥3 risk factors) who has pain radiating to the arm or shoulder and sweating is not considered low risk. The presence of known coronary artery disease or multiple risk factors for CAD are only helpful in predicting ACS in younger patients. Patients with scores ≤ 5 may not require serial troponin testing. (link)

A serum lactate may be useful to confirm the diagnosis or monitor therapy. Other therapeutic aims include: a CVP of 8-12 mmHg, within 6 hours,(at least 12mmHg in patients mechanically ventilated); a MAP > 65 mmHg; a urine output > 0.5 mL/kg/hour; a mixed venous oxygen saturation > 70%, within 6 hours. However outcomes may be no better than when CVP or CVO2 are not measured so they are the least essential things to measure.(link)

High flow nasal cannula therapy (HFNC) is used in patients < 2 years of age (2 L/kg/minute flow delivered via nasal cannula connected to a heated humidifier) and in apneoic oxygenation prior to intubation in adults. It is increasingly used in paediatric intensive care units and in inter-hospital transport. It may reduce the work of breathing, provides continuous positive airway pressure and may reduce anatomical dead space. (link)

Transfusion when the Hb is > 9g/dL is usually inappropriate unless significant acute haemorrhage is occurring as it is associated with a 5% absolute higher rate of infection than when a more restrictive strategy is used (i.e. transfusion at Hb < 7-9g/dL). This risk does not appear to be different when leukocyte depleted products are used. (link)

Submersion in cold water (> 2C) is highly unlikely to influence survival. However immersion in/under ice has produced occasional survivors despite prolonged immersion. (link)

Early intubation is most likely harmful as some interruption of CPR is usually required so it is best deferred until the patient fails to respond to initial CPR and defibrillation attempts or demonstrates ROSC. Chest compressions should only be ceased at the time the intubator is about to insert the laryngoscope into the patient’s mouth. Intubation should be completed within 10 seconds of interruption of chest compression,and compressions recommenced as soon as the ETT has passed the cords. Advanced airway techniques reduce periods of ineffective chest compression by approximately 10% absolute as ventilation is easier to perform in synchrony with chest compression. (link)

Renal failure would first be expected to contribute to anaemia once the creatinine is greater than 200 micromol/L. It would be expected to be severe once the creatinine was > 500micromol/L. (link)

Antiviral therapy reduces duration of illness by about 14 hours (zanamivir) and 17 hours (oseltamivir) when started within 36-48 hours of onset in influenza. It appears to have little effect on rates of hospital admission or pneumonia. (link)

A damage control laparotomy is performed in the haemodynamically unstable trauma patient and is aimed to be rapid (<1 hour) in duration. It may include: a full length midline incision; four-quadrant packing of the abdomen; major blood vessel tears are tied off or bypassed; bleeding liver lacerations are packed; small bowel penetrations are stapled over; large bowel perforations are tied shut with tape; spillage of bowel contents is copiously washed out; the abdomen is temporarily closed, often with a sterile plastic sheet. (link)

Vomiting is often of undigested food and should not be bloody in uncomplicated cases, and should not be bilious.It is more prominent in early onset food poisoning and viral causes and rarely prominent in dysentry. (link)

The external jugular vein may accurately reflect venous pressure if it has a wave form, changes with respiration, or fills on compression and falls on release of compression. An elevated venous column in the EJV may be due to the valves in the vein and not due to elevated venous pressure. (link)