New content quiz April 2014

The delayed recurrence of symptoms following an anaphylactic reaction had previously been reported to occur in 3-20% of cases. A more recent ED series reported the incidence of clinically significant delayed reactions in about 0.4% of cases of anaphylaxis and 0.1% of cases of allergy – and 90% of delayed recurrence occurring within 4 hours. The bottom line is that patients who adequately respond to treatment for anaphylaxis do not require a prolonged period of observation. (link)

MRI/MRA reliably detects aneurysms > 3 mm diameter and has a sensitivity of approximately 95% and specificity of 90% overall. False-negative and false-positive aneurysms are mostly located at the skull base and middle cerebral artery and overall accuracy is higher with 3-dimensional reconstructions and 3 Tesla machines. It is less sensitive than CT for detecting blood, more time consuming and rarely sufficient for surgical planning. (link)

Risk factors for litigation include: previous litigation or complaints by the patient; higher (not lower) socioeconomic status; and unrealistic expectations. Also, as outcomes improve, so do expectations – hence the rate of negligence actions increases as the overall standard of care does. (link)

A stenosis of > 80% is usually required to cause significant reduction in renal function. It had previously been thought that balloon angioplasty +/- stent was of benefit, however medical therapy now appears to be equal, if not superior in stenoses of at least 60%. The value of stenting in more severe/critical stenoses is currently unknown. (link)

The five factor score is used to help determine need for aggressive immunosuppression in patients with vasculitis of various causes. One point is scored for each of: proteinuria >1 g/day; creatinine >140μmol/L; cardiomyopathy; severe gastrointestinal involvement (e.g., bleeding or infarction); and CNS involvement. The number of joints involved or skin involvement are not part of the score. Glucocorticoids alone are usually used in patients with a score of 0 (e.g.prednisolone 60 mg/day for 2 weeks) and cyclophosphamide, initially at 2 mg/kg daily, is used in severe progressive disease. (link)

Although serum K+ concentrations as low as 2.5mmol/L are asymptomatic in approximately half of patients, the ECG is abnormal in approximately 70% at this level. About half of patients have muscle pain or weakness when the K+ drops below 2.5mmol/L, but frank paralysis does not usually occur until the K+ is < 2mmol/L. Rhabdomyolysis does not occur unless the serum potassium is < 3.0 mmol/L (link)

Although serum K+ concentrations as low as 2.5mmol/L are asymptomatic in approximately half of patients, the ECG is abnormal in approximately 70% at this level. About half of patients have muscle pain or weakness when the K+ drops below 2.5mmol/L, but frank paralysis does not usually occur until the K+ is < 2mmol/L. Rhabdomyolysis does not occur unless the serum potassium is < 3.0 mmol/L (link)

The ECG features of hypokalaemia (in decreasing order of frequency) are: U waves; flattening of T waves; peaking of p waves; ST depression; and ventricular extrasystoles. The Q-Tc and J-T intervals are not prolonged, however U waves are often mistakenly identified as a lengthening of the T wave. (link)

Approximately 10% of GDP was spent on health in Australia (and NZ) during 2017-18, which is above the OECD average (and UK, Spain and Norway) but a smaller percentage than USA, France, Germany and Japan. This corresponds to about AUD$ 7,500 per person. About 70% of health spending is by Government and this is approximately 25% of total taxation revenue. 95% is recurrent spending and 5% capital spending. The health inflation rate was about 3.0%, a little above the inflation rate in the non-health sector. (link)

False positives for free intraperitoneal gas can rarely occur when the colon is interposed between the liver and the diaphragm (Chiliaditi’s sign). This is present in less than 0.3% of otherwise normal people. The presence of the haustral pattern of the colon may indicate that this is a normal variation, however due to Chiliaditi’s sign being so rare, it is safer to assume that any gas under the diaphragm is pathological. (link)

The features of ST  depression in ACS are: ST depression of 1 mm or more at the J point which is flat or down sloping in 2 or more contiguous leads and is usually regional rather than general. The leads involved does not localise the area of ischaemia as the changes may represent reciprocal changes. ST depression may represent: non STEMI (where it is associated with more left main, proximal left anterior descending, 3-vessel coronary artery disease and increased mortality than other non STEMI ECG findings); posterior AMI; reciprocal changes of ischaemia; or myocardial ischaemia without infarction.

(link)

ERCP is indicated within 24 hours if cholangitis suspected or within 72 hours if dilated common bile duct visualised on US or CT or jaundice present (bilirubin > 85 μmol/L). Fasting for 6-8 hours prior to procedure is usually required and the procedure takes 20-60 minutes to perform. Antibiotic prophylaxis with a quinolone or cephalosporin is required and sedation given for the procedure. Endoscopic sphincterotomy and stone extraction (if < 1cm diameter) if lodged in the lower common bile duct are the aims of therapy. Alternatively, a stent may be passed through any obstructing lesion if all the stones in the CBD are unable to be removed or there are known additional stones in the gallbladder and a cholecystectomy is planned for the next few days. (link)

Cases where contact antibiotic prophlyaxis is not indicated include: kissing on the cheek or lips; food, drink, cigarette sharing contacts; communion cup, lip balm, wind instrument, referee’s whistle sharing; contacts of contacts; and casual nightclub contacts. Contacts requiring antibiotic prophylaxis include: Immediate family and household members in contact with the index case in the 7 days preceding onset of disease; those exposed to oral secretions during the 7 days preceding onset of disease; sexual partners during the 7 days preceding onset of disease; passengers seated in the seat immediately adjacent to the index case on any journey > 8 hours duration; those who performed mouth to mouth resuscitation or intubation and were not wearing face masks; health care workers who are in prolonged contact with the infected patient; children in a day-care centre, preschool class, play group or school class which the patient attends who were in the same room for ≥4 hours in the 7 days preceding the onset of the index case’s illness; and those who have slept in the same room. (link)

Indications for ICU admission for traumatic intracranial bleeding include; GCS <15; non isolated head injury; age ≥ 65 years; swelling or shift on initial CT brain. In the absence of any of these features, critical care interventions only occur in about 2% of cases. (link)

Ulcers < 1cm in diameter are classified as aphthous minor and usually heal spontaneously within 5-10 days without scarring. Treatment might include: chlorhexidine 0.2% mouthwash 10 mL 8 hourly; topical glucocorticoid creams or ointments (e.g. betamethasone 0.05% 8 hourly); diphenhydramine; or combinations of the above with sucralfate or antacid. Systemic steroids are only used for severe disease. usually as a 5 day course, and may be combined with steroid injection into the ulcer base. (link)