Sep 15, 2017

Cough drop

The story

Like hunting for edible scraps in the cafeteria after 3PM, finding resistant tuberculosis cases is harder than you'd otherwise expect. A new rapid assay hopes to speed things up. 

The resistance

About 5% of the 10.4 million cases of incident tuberculosis (TB) in 2015 were multi-drug resistant (MDR), according to the WHO. Yet only about a quarter of cases are identified upfront and receive appropriate treatment. The dreaded extensively-drug resistant (XDR) TB adds another wrinkle to the fold, as these patients need longer treatment courses and a broader array of antibiotics to achieve cure. Current rapid sputum testing with a platform called GeneXpert can screen for resistance to first-line treatment agent rifampin, but offers nothing about resistance to other first and second-line agents.

The cartridge

A new testing cartridge that can be used with existing GeneXpert infrastructure can screen for resistance to first and second-line TB treatment regimens. Following sputum testing in 300 East Asian patients with tuberculosis, the cartridge was able to accurately identify resistance to isoniazid, fluoroquinolones, and aminoglycosides within two hours. Conventional culture-based methods can take weeks. The assay was about 90% sensitive for MDR TB and 88% sensitive for XDR TB.

The takeaway

The new cartridge can help clinicians select shorter (MDR) vs. longer (XDR) treatment regimens for resistant tuberculosis, sparing patients the morbidity of delayed diagnosis. Similar to other public health tools, distribution and uptake will be a challenge.

Say it on rounds

When two consult services give opposite recommendations

Can't we all agree? The debate over hormone replacement therapy (HRT) has always been fickle. Here's a new data point: long-term follow-up from the Women's Health Initiative, which randomized over 27,000 women to combination HRT, estrogen-only therapy or placebo for 5 - 7 years, found no difference in all-cause, cardiovascular or cancer-related mortality at 18 years following therapy. When stratified by age group, younger women (ages 50 - 59) fared better on HRT both during treatment and after follow-up, suggesting that initiating therapy soon after menopause is important. 

When you're wondering if you're going to pony up for the iPhone X

Stretching the wallet brings pain. But stretch therapy for resistant hypertension may be more tolerable. A first-in-human study of the MobiusHD, a device that amplifies the baroreceptor stretch reflex in the carotid artery, found that the device reduced blood pressure by an average of 24 / 12 mm Hg in 30 patients with inadequate blood pressure control despite therapy with 3 or more agents. The device, placed percutaneously in one of the carotid arteries, produced durable responses at 6-month follow up. Adverse effects included dizziness, musculoskeletal pain, and hypotension. Stay tuned for additional trials.

When you just can't remember the password to your I-STOP account

Opioids are tough on patients and prescribers. With the opioid misuse epidemic swelling to ever-greater proportions, a government-funded survey found that almost 40% of adults used prescription opiates in 2015. About 1 in 20 adults self-reported opiate misuse within the past year, most commonly to relieve physical pain. And the role of health care providers in all of this? About 40% of misusers attributed their most recent episode of opioid use to free opioid scripts they obtained from friends or relatives.

Brush up

Cryptogenic stroke

About a quarter of strokes have no cause identified after standard workup and are termed cryptogenic. Most are embolic in origin, but consider atherosclerotic arteriopathies and coagulation disorders in your work up. While occult atrial fibrillation is increasingly recognized as a source of cryptogenic strokes in the elderly, half of cryptogenic strokes in young adults are due to patent foramen ovale (PFO). Despite its role in stroke, PFO, which allows venous embolisms to enter the arterial circulation with devastating consequences, is present in almost a quarter of healthy persons.

What's the evidence

For PFO closure in cryptogenic stroke? 2017's RESPECT trial randomized 1,000 patients between ages 18 - 60 with cryptogenic stroke and patent foramen ovale to PFO closure or medical management with either anti-platelet agents or anticoagulation. Over 6-year follow-up, PFO closure decreased the rate of recurrent stroke by 45%, though event rates were low in both groups and those who had PFO closure were at increased risk for venous thromboembolism. Patients with large PFOs and atrial septal aneurysms were most likely to benefit from closure.

What your lawyer friends are talking about

We're just docs, but a deal in which pharmaceutical giant Allergan licensed a drug patent to a Native American tribe to seek immunity from legal challenges seems way sketch. And we're talking about drug companies.

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