Nocardiosis in the Tropical Northern Territory of Australia, 1997-2014

BACKGROUND

Nocardia is an opportunistic pathogen that can cause life-threatening disease. We aimed to characterize the epidemiological, microbiological, and clinical features of nocardiosis in the tropical north of Australia.

METHODS

We conducted a retrospective cohort study of nocardiosis diagnosed between 1997 and 2014. Population-based incidences were calculated using district population data.

RESULTS

Clinically significant nocardiosis was identified in 61 patients. The unadjusted population-based annual incidence of nocardiosis was 2.02 (95% confidence interval [CI], 1.55-2.60) per 100000 people and was 1.7 (95% CI, .96-2.90) fold higher in Indigenous compared with non-Indigenous persons (P = .027). Of 61 patients, 47 (77%) had chronic lung disease, diabetes, and/or hazardous alcohol consumption; 22 (36%) were immunocompromised; and 8 (13%) had no identified comorbidities. Disease presentations included pulmonary (69%; 42 of 61), cutaneous (13%; 8 of 61), and disseminated nocardiosis (15%; 9 of 61). The most commonly identified species were Nocardia asteroides and Nocardia cyriacigeorgica (each 11%). Linezolid was the only antimicrobial to which isolates were universally susceptible; 89% (48 of 54), 60% (32 of 53), and 48% (26 of 54) of isolates were susceptible to trimethoprim-sulfamethoxazole, ceftriaxone, and imipenem, respectively. Eighteen patients (30%) required intensive care unit (ICU) admission, and 1-year mortality was 31%.

CONCLUSIONS

The incidence of nocardiosis in tropical Australia is amongst the highest reported globally. Nocardiosis occurs in both immunocompromised and immunocompetent hosts, and it is associated with high rates of ICU admission, 1-year mortality, and resistance to commonly recommended antimicrobials. Diagnosis should be considered in patients with consistent clinical features, particularly if they are Indigenous or have chronic lung disease.

Epilepsy surgery in children with tuberous sclerosis complex: presurgical evaluation and outcome

PURPOSE

Children with tuberous sclerosis complex (TSC) benefit from excisional surgery if seizures can be localized to a single tuber. We evaluated the role of noninvasive studies to localize the epileptogenic tuber/region (ET/R) and the outcome of focal resection.

METHODS

We identified 21 children with TSC, ages 3 months to 15 years (mean 4.8 years). All had video-(electroencephalogram) EEG and magnetic resonance imaging (MRI) scans, and 18 also had ictal single photon emission-computed tomography (SPECT) studies. An ET/R was localized in 17 patients. Thirteen patients underwent resection guided by intraoperative electrocorticography (n = 7) or subdural monitoring (n = 6).

RESULTS

Interictal EEG revealed a principal spike focus (PSF) that corresponded to the ET/R in 14 children. In seven, PSFs occurred in rhythmic runs. PSFs were not observed remote from the ET/R. Focal polymorphic slowing and attenuation occurred in the region of the PSF in 11 patients. Sixteen patients demonstrated an ictal focus corresponding to the ET/R. Ictal SPECT revealed focal hyperperfusion correlating with the ET/R in 10 patients. Although the MRIs in all children revealed multiple tubers, the ET/R corresponded to a large discrete tuber in 8 patients and a calcified tuber in 13 patients. Patchy calcified tubers were also seen elsewhere in six patients. At a mean follow-up of 26 months, 9 of the 13 children who underwent surgery were seizure-free, one had greater than 75% reduction in seizures, two were unchanged, and one was lost to follow-up. New seizures developed in one child from a contralateral tuber.

CONCLUSIONS

Surgical resection of an ET/R alleviates seizures in most children with TSC and intractable epilepsy. The scalp EEG and MRI help define the ET/R and improve case selection when ictal SPECT is nonlocalizing.

Active immunization with vasoactive intestinal peptide in turkey hens

Active immunization of turkey hens against vasoactive intestinal peptide (VIP) has been shown to inhibit incubation behavior and to increase egg production in second-cycle hens. The objective of this study was to compare the effect of VIP immunization on first- and second-cycle turkey hens during a 27-wk production period. First- (25-wk-old) and second- (54-wk-old) cycle hens were intermixed, distributed among 16 pens, and subjected to a photoperiod of 6 h of light and 18 h of darkness for 10 wk. The first-cycle hens were divided into two groups: keyhole limpet hemocyanin (KLH)-immunized controls (n = 16) and VIP-immunized (n = 18). Second-cycle hens were divided into four groups: 1) unimmunized controls (n = 19), 2) KLH-immunized controls (n = 18), 3) VIP-immunized (n = 19), and 4) VIP-preimmunized (immunized during first cycle; n = 16). Each hen received four antigen injections beginning the day of photostimulation (4-wk intervals), except for the preimmunized hens, which received three injections beginning 4 wk after photostimulation. The maximum titer of VIP antibodies in first-cycle, second-cycle, and preimmunized hens was 17.2+/-2.2, 20.9+/-2.9, and 21.7+/-3.2%, respectively. After photostimulation, plasma prolactin of first- and second-cycle control hens peaked between 484 +/-105 and 630+/-118 ng/mL. In contrast, prolactin changed very little in VIP-immunized turkeys. The average number of daily nest visits was less in first- and second-cycle VIP-immunized hens (1.68+/-0.23 and 1.09+/-0.15 visits per hen per day, respectively) than in their respective KLH-immunized controls (2.47+/-0.36 and 2.65+/-0.45 visits per hen per day). Expression of incubation behavior was 50.0 and 52.6% in first- and second-cycle control hens, respectively, upon termination of the study. In contrast, only 11.1% first-cycle and 5.2% second-cycle VIP-immunized turkeys exhibited the hormonal and behavioral characteristics of incubating hens. Average weekly egg production of first- and second-cycle VIP-immunized turkeys was similar (3.58+/-0.19 vs. 3.63+/-0.14 eggs per hen per wk). First- and second-cycle control hens laid 2.63+/-0.25 and 2.41+/-0.20 eggs per hen per wk, respectively. The present results show that comparable egg production was attained in first- and second-cycle hens by active immunization with VIP.

Ketogenic diet in the treatment of refractory epilepsy in childhood

There has been renewed interest in the ketogenic diet in the treatment of medically refractory seizure disorders in childhood. This article reports the results of a retrospective chart review of 52 patients who were treated with the ketogenic diet. The vast majority (49 of 52) were treated with the classic 4:1 diet. Seizure control improved in 67.3% of patients with complete abolition of seizures in six. Adverse reactions were uncommon and included the development of renal stones, gall bladder stones, and hypoproteinemia in one patient each. Routine biochemical screening during the diet did not identify or prevent adverse events. The authors' experiences with the diet emphasize the need for close ongoing medical and dietary supervision.

Epilepsy surgery in the posterior cortex

Fourteen (74%) of 19 patients obtained a significant reduction in seizures after posterior corticectomy; 6 (32%) were seizure-free over a median follow-up of 3.7 years (range, 1 to 14 years). Surgery included limited resections of the occipital lobe in 16 patients, posterior temporal region in 11, and posterior portion of parietal lobe in 7. Surgical failure related to probable multiple areas of epileptogenesis (4 patients), or limited resections (2 patients) to preserve visual fields (2 patients) and to avoid dyslexia (1 patient). Of 14 patients without a complete hemianopia preoperatively, 6 (43%) developed a new or increased visual field deficit, 2 (14%) of which were hemianopia. Four (36%) of 11 occipital lobe resections resulted in a new or increased visual field deficit: quadrantanopia in 3 and hemianopia in 1. Visual phenomena were the most common initial ictal symptoms, occurring in 13 (68%) of the 19 patients. Twelve patients had complex partial seizures: in 2, always without warning; in 7, always following an aura, usually visual; and in 3 patients, with or without warning. Scalp electroencephalography identified the origin of most recorded seizures in 12 (63%) of the 19 patients. A principal interictal spike focus appeared in 15 patients (79%), and always correlated with the epileptogenic lobe as defined by scalp and/or subdural-recorded seizures (14 patients) or by clinical analysis and computed tomography (1 patient).

An evaluation of perceptual retraining

A group of head injury and stroke patients with impairment of visual perception were randomly allocated to receive either perceptual retraining or conventional occupational therapy. No significant differences were found between the groups, either before or after 4 weeks of treatment, on measures of visual perception or on activities of daily living scale.