Thursday, February 26, 2015

Occult bacteremia

These are the people who get sent home from the ER then have to be called back because their blood cultures turn positive. In this study from a single institution it appeared to be a benign entity:

Methods
This is a retrospective cohort study (September 2010 to September 2012), in adult patients discharged from the ED in whom blood cultures turned positive. Patients were evaluated according to a preestablished protocol.

Results
We recorded 4025 cases of significant BSI in the ED and 113 patients with adult occult BSI. In other words, the incidence of occult BSI in the ED was 2.8 per 100 episodes. The predominant microorganisms were gram-negative bacteria (57%); Escherichia coli was the most common (41%), followed by gram-positive bacteria (29%), anaerobes (6.9%), polymicrobial (6.1%), and yeasts (0.8%). The most frequent suspected origin was urinary tract infection (53%), and most infections were community acquired (63.7%). Of the 105 patients that we were able to trace, 54 (42.5%) were asymptomatic and were receiving adequate antibiotic treatment at the time of the call, and 65 (51.2%) had persistent fever or were not receiving adequate antibiotic treatment.

Conclusions
Occult BSI is relatively common in patients in the adult ED. Despite the need for readmission of a fairly high proportion of patients, occult BSI behaves as a relatively benign entity.

Tuesday, February 24, 2015

When is permanent pacing indicated for AV block?

I'm working through MKSAP 16's section on cardiovascular disease. As much as I hate to be immodest, it's a content area I think I know just a little something about, particularly in the area of electrophysiology. I was drawn to their statement on permanent pacing after acute MI (AMI). Sprinkled throughout MKSAP are sets of high value care recommendations for various specialties, apparently their own version of Choosing Wisely.

The pacing recommendation, which is to wait several days after the occurrence of AV block (AVB) before inserting a permanent pacemaker (PPM) in order to see if the block persisted, struck me as awfully simplistic. Pacing recommendations for AVB have strong underpinnings in physiology which have withstood evidence based scrutiny. The relevant electrophysiology, far more often than not, can be assessed at the bedside via simple electrocardiography. Well, maybe I should qualify that by saying it's true provided adequate skill in interpretation of the ECG is brought to the bedside.

Things have changed through the years. Clinical skills in this area have deteriorated, in part because AVB complicating AMI is much less common in today's reperfusion era than it once was. The question of what to do with AVB after AMI seldom comes up anymore. Before the reperfusion era it was routine. The guiding principle back then was that, at least in acute anterior MI, when the block was subjunctional, that is true type II block, permanent pacing was indicated no matter how transient the block. (Caveat: the atypical situation of block arising in the common bundle of His is a nuanced topic, beyond the scope of this post).

So what about the current guidelines? The STEMI guidelines refer this topic to the device therapy guidelines which say in part:

CLASS I
1. Permanent ventricular pacing is indicated for persistent second-degree AV block in the His-Purkinje system with alternating bundle-branch block or third-degree AV block within or below the His Purkinje system after ST-segment elevation MI. (Level of Evidence: B) (79,126 –129,131)

2. Permanent ventricular pacing is indicated for transient advanced second- or third-degree infranodal AV block and associated bundle-branch block. If the site of block is uncertain, an electrophysiological study may be necessary. (Level of Evidence: B) (126,127) 


For patients in general with acquired AVB the guidelines include the following, listed under the class IIa category:

4. Permanent pacemaker implantation is reasonable for asymptomatic type II second-degree AV block with a narrow QRS.

When type II second-degree AV block occurs with a wide QRS, including isolated right bundle-branch block, pacing becomes a Class I recommendation. (See Section 2.1.3, “Chronic Bifascicular Block.”) (Level of Evidence: B) (70,76,80,85)

The recommendation summary is much more extensive but this small sample illustrates the complexity of decision making and the reliance on assessment of the anatomic site of block via electrocardiography (bedside electrophysiology). When it comes to pacing decisions post MI there's considerably more to it than the MKSAP recommendations would indicate.

Monday, February 23, 2015

Opiate withdrawal: usually benign but not always

The main problem is when opiate withdrawal is precipitated (such as with naloxone) in a narcotic tolerant patient. Here is a case report and review.

Sunday, February 22, 2015

PVCs can help in the diagnosis of myocardial ischemic syndromes

Here is a case presented at Dr. Smith's ECG blog and a link to several more. As Barney Marriott was fond of saying, PVCs pay diagnostic dividends. Know them!

Saturday, February 21, 2015

Admission HgbA1C to help determine discharge diabetes regimen

From a study in Diabetes Care:

RESEARCH DESIGN AND METHODS This was a prospective, multicenter open-label study aimed to determine the safety and efficacy of a hospital discharge algorithm based on admission HbA1c. Patients with HbA1c less than 7% (53.0 mmol/mol) were discharged on their preadmission diabetes therapy, HbA1c between 7 and 9% (53.0–74.9 mmol/mol) were discharged on a preadmission regimen plus glargine at 50% of hospital daily dose, and HbA1c greater than 9% were discharged on oral antidiabetes agents (OADs) plus glargine or basal bolus regimen at 80% of inpatient dose. The primary outcome was HbA1c concentration at 12 weeks after hospital discharge.

RESULTS A total of 224 patients were discharged on OAD (36%), combination of OAD and glargine (27%), basal bolus (24%), glargine alone (9%), and diet (4%). The admission HbA1c was 8.7 ± 2.5% (71.6 mmol/mol) and decreased to 7.3 ± 1.5% (56 mmol/mol) at 12 weeks of follow-up (P less than 0.001). The change of HbA1c from baseline at 12 weeks after discharge was −0.1 ± 0.6, −0.8 ± 1.0, and −3.2 ± 2.4 in patients with HbA1c less than 7%, 7–9%, and greater than 9%, respectively (P less than 0.001). Hypoglycemia (less than 70 mg/dL) was reported in 22% of patients discharged on OAD only, 30% on OAD plus glargine, 44% on basal bolus, and 25% on glargine alone and was similar in patients with admission HbA1c less than or equal to 7% (26%) compared with those with HbA1c greater than

CONCLUSIONS Measurement of HbA1c on admission is beneficial in tailoring treatment regimens at discharge in general medicine and surgery patients with type 2 diabetes.

From commentary in the ACP Hospitalist Weekly:

Measuring HbA1c at admission can help with tailoring a postdischarge treatment regimen for type 2 diabetes patients, the study authors concluded. The observed rate of hypoglycemia was acceptable, which should reassure any hospital clinicians who avoid intensifying outpatient regimens out of fear of hypoglycemia, the authors noted. The findings also support recent guidelines recommending insulin treatment during hospitalization, but resumption of oral medications at discharge for patients with acceptable control. Improving postdischarge glucose control could potentially reduce revisits to the emergency department or hospital, the authors suggested.
Measuring HbA1c at admission can help with tailoring a postdischarge treatment regimen for type 2 diabetes patients, the study authors concluded. The observed rate of hypoglycemia was acceptable, which should reassure any hospital clinicians who avoid intensifying outpatient regimens out of fear of hypoglycemia, the authors noted. The findings also support recent guidelines recommending insulin treatment during hospitalization, but resumption of oral medications at discharge for patients with acceptable control. Improving postdischarge glucose control could potentially reduce revisits to the emergency department or hospital, the authors suggested.

It's important to note that patients in the study had telephone contacts every 2 weeks in the 2 months after discharge and follow-up visits at 1 and 3 months, which could have contributed to their improved glycemic control.
It's important to note that patients in the study had telephone contacts every 2 weeks in the 2 months after discharge and follow-up visits at 1 and 3 months, which could have contributed to their improved glycemic control.