A great analysis of the evidence (or lack there of) for stress testing in low risk chest pain has been performed in a comprehensive smartem podcast previously. Now seemingly the largest prospective study (PMID 23689690) of this to date has been released and a great summary is on Dr Andy Neill’s blog.

Essentially of the 4000 odd patients who underwent stress testing, only 0.7% had a lesion at angiogram that may benefit from coronary revascularisation under current AHA guidelines. For those true positives who received medical management instead, the benefit is harder to quantify (and is not done in the study) but based on the Framingham risk data, the number placed on medical therapy and the implied false positive rate, the overall absolute benefit for the cohort is likely substantially less than 1% over a 5 year period of medical therapy.

Against this are the harms of the various stress tests (including the very low risks of test induced arrhythmia and radiation from stress myocardial perfusion imaging), the angiogram risks (eg stroke/MI) as well as the risks of the coronary revascularization interventions and medical management provided to the large numbers of false positives.

Worth reading the whole article.

During an informed consent process, it is becoming increasingly hard to sell the stress test to trop negative low risk ED patients.

Dr Simon Carley published a good approach to recreational drug induced hyperthermia on the St Emlyn’s blog. Nice brief summary on the topic of drug induced hyperthermia generally with the focus on the recreational drug user who comes in hot.

The HINTS exam is a 3 part exam (Head Impulse test, Nystagmus evaluation, Test of Skew, that has been developed by neurologist Dr David Newman-Toker (not to be confused with Dr David Newman of smartem) as an interesting tool for detecting posterior strokes amongst the mass of patients with Acute Vestibular Syndrome (AVS). Most patients with AVS have benign causes such as labrynthitis/vestibular neuritis but some have posterior strokes that we worry about.

HINTS was promoted previously in an emcrit podcast with a video demonstrating the techniques.

A more recent study of the HINTS exam has just been reviewed by EM Nerd and makes interesting reading.

The HINTS exam is appealing but most of the data seems to be generated in a higher risk cohort where the test is performed by neurologists highly experienced in the techniques. It remains unclear how useful it will be when applied in a lower risk cohort by the average ED doc whose has just watched a how-to video. In particular the head impulse testing is difficult to do and the fear is that within this cohort a “normal” exam which is easy to find in unskilled hands (which supposedly suggests a central cause of AVS) may potentially send more benign patients down an imaging route then necessary. Still, it may be a useful weapon to add to the arsenal and in fact could be particularly beneficial in patients who are initially negative on imaging, as HINTS picked up some initial MRI negative patients as  posterior strokes, later confirmed on delayed MRI. This may be even more true when you only have access to a sub-optimal test such as CT initially.

Important to note, this HINTS exam is not for your BPPV patients. It is designed for AVS only e.g. the patient with persistent vertigo that you think is labrynthitis/vestibular neruonitis but can’t be sure.