Modification of an evidence-based protocol for advanced appendicitis in children

Introduction

We previously developed an evidence-based clinical pathway for children with advanced appendicitis. The pathway standardized the choice and duration of antibiotic therapy and established discharge criteria. Initially, the pathway led to a 50% decrease in the rate of superficial and deep surgical site infections and a significant decrease in hospital length of stay. Four years after implementation, we noted an increase in the infectious complication rate and the emergence of resistant bacteria to commonly used antibiotics. In this study, we prospectively collected peritoneal fluid cultures at the time of appendectomy in an effort to optimize our antibiotic therapy and decrease complication rates.

Methods

Microbiology analysis of peritoneal fluid cultures obtained at the time of appendectomy was performed in patients with an intraoperative diagnosis of advanced appendicitis. Clinical information, including demographics, laboratory data, and postoperative outcomes were collected and compared to the historic cohort. X², Student’s t-test, and Fisher exact test were used where appropriate.

Results

The historic and prospective cohorts were similar with respect to clinical and demographic data. The postoperative intra-abdominal abscess rate remained unchanged (28% from 24%, P = 0.603). Escherichia coli and Pseudomonas aeruginosa were the most commonly isolated aerobic bacteria from peritoneal fluid in the prospective cohort. Thirty-two percent of these patients had Pseudomonas spp., and 12% had Enterococcus spp. or Escherichia coli resistant to cefoxitin in their peritoneal fluid cultures.

Discussion

A significant proportion (40%) of children with advanced appendicitis had organisms either not susceptible or resistant to our first line antibiotic in their peritoneal fluid cultures. Our clinical pathway now recommends piperacillin-tazobactam as the most effective empiric therapy for advanced appendicitis in children. Microbiologic analysis of peritoneal fluid at appendectomy may be used to tailor antibiotic therapy in advanced appendicitis.     

Migrainous phenomenon precipitated by lumbar puncture headache

This case report describes a patient without personal or family history of migraine or other recurrent headaches who developed a typical lumbar puncture headache leading to a characteristic migrainous visual field deficit. There was no history of analgesic or other medication use or other precipitant, and neither symptom recurred in years of follow-up. The sequence of symptoms suggests that mechanical distortion or irritation of cranial pain-sensitive structures can precede and precipitate the migrainous cortical dysfunction.     

Use of MR imaging for quantitative evaluation of resection for temporal lobe epilepsy

The postoperative magnetic resonance imaging studies of 40 patients who underwent surgery for medically refractory temporal lobe epilepsy were reviewed. A method for quantifying the resection of four specific medial temporal lobe structures--amygdala, uncus, hippocampal formation, and parahippocampal gyrus--was used to correlate postoperative seizure control with the degree to which those structures had been resected. Satisfactory postoperative seizure control was found to be strongly dependent (P less than .01) on the performance of at least partial resection of all four medial temporal lobe structures. The total amount of tissue removed did not necessarily correlate with the clinical outcome in individual cases, however, as long as some portion of all four medial structures had been resected. Two complicating factors--the presence of posterior or bilateral independent electroencephalographic foci and a history of meningoencephalitis--each negatively influenced surgical outcome (P less than .01). In cases with a complicating factor and inadequate medial resection, the outcome was invariably poor.     

RELATIONSHIP BETWEEN NIFEDIPINE SENSITIVITY OF AORTAE AND BLOOD PRESSURE OF STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

1. We have previously described an increased sensitivity to inhibition by nifedipine of noradrenaline-induced contractures of blood vessels in hypertension. In this study we have investigated whether changes in blood pressure (BP) change the sensitivity to nifedipine and K⁺ of aortic rings from normotensive (Wistar-Kyoto rats, WKY) and stroke-prone spontaneously hypertensive rats (SHRSP). 2. SHRSP were treated with: hydralazine plus hydrochloro-thiazide; captopril plus hydrochlorothiazide; hydralazine plus guanethidine; or captopril alone. WKY rats were treated with deoxycorticosterone acetate (DOCA) and NaCl. Treatment commenced from 5 weeks of age and continued until 13–15 weeks. 3. The SHRSP treatments produced similar reductions in BP, and the BP of all the treated groups were significantly lower than the mean BP of untreated SHRSP (201.0 ± 7.7 mmHg). The mean BP of the treated WKY rats (134.2 ± 7.6 mmHg) was significantly higher than the mean BP of the untreated WKY rats (86.8 ± 7.4 mmHg). 4. An area-under-curve (AUC) analysis of the inhibitory effects of nifedipine on responses of aortae to noradrenaline showed no differences between treated and untreated SHRSP groups (overall mean 40.6 ± 1.9% and 43.4 ± 3.4% inhibition of control AUC, respectively), or between DOCA-salt treated WKY and untreated WKY groups (58.8 ± 5.9 and 64.8 ± 2.3, respectively). Noradrenaline-induced contractures of aortae from all SHRSP groups were significantly more sensitive to inhibition by nifedipine than aortae from both WKY groups. 5. The molar concentration of agonist required to evoke 50% of the maximum response (EC₅₀) values for potassium chloride (KCI) were significantly increased in the aortae of all treated SHRSP groups in comparison to those from untreated SHRSP (treated SHRSP groups, 15.53 ± 0.68 mmol/L vs untreated SHRSP group, 11.36 ± 1.10 mmol/L). The EC₅₀ values for KC1 for the aortae from the DOCA-treated WKY rats were significantly less than those from aortae of the untreated WKY (11.80 ± 0.80 and 17.08 ± 1.50 mmol/L, respectively). 6. We conclude that reduction (in SHRSP) or increase (in WKY) of the BP has no effect on the sensitivity of aortic smooth muscle to the inhibitory effects of nifedipine on responses to noradrenaline, suggesting that alterations in voltage-dependent Ca²⁺ mechanisms may be a primary phenomenon in the SHRSP. In contrast, the fact that sensitivity to KC1 changes in the treated SHRSP and WKY aortae suggests such sensitivity is secondary to the BP and thus a separate phenomenon from voltage-dependent Ca²⁺ mechanisms.     

Selective posterior cerebral artery Amytal test for evaluating memory function before surgery for temporal lobe seizure

Selective testing for memory function with Amytal (amobarbital) in the posterior cerebral artery (PCA) is a promising modification of that test in the internal carotid artery (ICA). This new technique, performed with a Tracker catheter system, was completed successfully in 17 of 20 patients being examined before planned surgery for refractory temporal lobe seizure. The PCA test overcomes three major problems with the ICA technique. First, with the PCA technique, memory testing is begun immediately after injection, when the drug has its peak effect. Second, when the speech-dominant hemisphere is being tested with the PCA test, patients do not become aphasic. Third, injection into the PCA delivers the drug more effectively to the target, the ipsilateral hippocampal formation.