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Potisek NM, Morrison J, St Ville ME, Westphal K, Wood JK, Lee J, Combs MD, Berger S, Lee C, Van Meurs A, Halvorson EE. Time to Positive Blood and Cerebrospinal Fluid Cultures in Hypothermic Young Infants. Hosp Pediatr 2024; 14:e6-e12. [PMID: 38062772 DOI: 10.1542/hpeds.2023-007391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2024]
Abstract
BACKGROUND AND OBJECTIVE Hypothermia in young infants may be secondary to an invasive bacterial infection. No studies have explored culture time-to-positivity (TTP) in hypothermic infants. Our objective was to compare TTP of blood and cerebrospinal fluid (CSF) cultures between pathogenic and contaminant bacteria in hypothermic infants ≤90 days of age. METHODS Secondary analysis of a retrospective cohort of 9 children's hospitals. Infants ≤90 days of age presenting to the emergency department or inpatient setting with hypothermia from September 1, 2017, to May 5, 2021, with positive blood or CSF cultures were included. Differences in continuous variables between pathogenic and contaminant organism groups were tested using a 2-sample t test and 95% confidence intervals for the mean differences reported. RESULTS Seventy-seven infants met inclusion criteria. Seventy-one blood cultures were positive, with 20 (28.2%) treated as pathogenic organisms. Five (50%) of 10 positive CSF cultures were treated as pathogenic. The median (interquartile range [IQR]) TTP for pathogenic blood cultures was 16.8 (IQR 12.7-19.2) hours compared with 26.11 (IQR 20.5-48.1) hours for contaminant organisms (P < .001). The median TTP for pathogenic organisms on CSF cultures was 34.3 (IQR 2.0-53.7) hours, compared with 58.1 (IQR 52-72) hours for contaminant CSF organisms (P < .186). CONCLUSIONS Our study is the first to compare the TTP of blood and CSF cultures between pathogenic and contaminant bacteria in hypothermic infants. All pathogenic bacteria in the blood grew within 36 hours. No difference in TTP of CSF cultures between pathogenic and contaminant bacteria was detected.
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Affiliation(s)
- Nicholas M Potisek
- Department of Pediatrics, University of South Carolina School of Medicine Greenville, Prisma Health Children's Hospital-Upstate, Greenville, South Carolina
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - John Morrison
- Division of Pediatric Hospital Medicine, Johns Hopkins All Children's Hospital, St. Petersburg, Florida
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Kathryn Westphal
- Division of Hospital Medicine, Nationwide Children's Hospital, Columbus, Ohio
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio
| | - Julie K Wood
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Jennifer Lee
- Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons and New York-Presbyterian, New York, New York
| | - Monica D Combs
- Department of Pediatrics, Keck School of Medicine of USC, Children's Hospital Los Angeles, Los Angeles, California
| | - Stephanie Berger
- Department of Pediatrics, University of Alabama Heersink School of Medicine, Birmingham, Alabama
| | - Clifton Lee
- Department of Pediatrics, Children's Hospital of Richmond at Virginia Commonwealth University, Richmond, Virginia
| | - Annalise Van Meurs
- Department of Pediatrics, Oregon Health and Science University, Doernbecher Children's Hospital, Portland, Oregon
| | - Elizabeth E Halvorson
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, North Carolina
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Combs MD, Liberman DB, Lee V. Decreasing Blood Culture Collection in Hospitalized Patients with CAP, SSTI, and UTI. Pediatr Qual Saf 2023; 8:e705. [PMID: 38058473 PMCID: PMC10697617 DOI: 10.1097/pq9.0000000000000705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 09/29/2023] [Indexed: 12/08/2023] Open
Abstract
Background Blood culture collection in pediatric patients with community-acquired pneumonia (CAP), skin and soft tissue infections (SSTI), and urinary tract infections (UTI) remains high despite evidence of its limited utility. We aimed to decrease the number of cultures collected in children hospitalized for CAP, SSTI, and UTI by 25% over 11 months. Methods Quality improvement initiative at a children's hospital among well-appearing patients aged 2 months or more to 18 years diagnosed with CAP, SSTI, or UTI. Our primary and secondary outcomes were blood culture collection rate and positivity rate, respectively. Interventions focused on three key drivers: academic detailing, physician awareness of personal performance, and data transparency. Results Over the 2-year study period, there were 105 blood cultures collected in 223 hospitalized patients. Blood culture collection rates demonstrated special cause variation, decreasing from 63.5% to 24.5%. For patients with UTI, 86% (18/21) of blood cultures were negative, whereas 100% were negative for CAP and SSTI. All three patients with bacteremic UTI had a concurrent urine culture growing the same pathogen. Balancing measures remained unchanged, including escalation to a higher level of care and return to the emergency department or hospital within 14 days for the same infection. Conclusions A multifaceted quality improvement approach can reduce blood culture collection for hospitalized patients with CAP, SSTI, and UTI without significant changes to balancing measures. Despite the reduction achieved, the near-universal negative culture results suggest continued overutilization and highlight the need for more targeted approaches to blood culture collection.
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Affiliation(s)
- Monica D Combs
- From the Division of Hospital Medicine, Children's Hospital Los Angeles, Los Angeles, Calif
- Department of Pediatrics, Keck School of Medicine of University of Southern California, Los Angeles, Calif
| | - Danica B Liberman
- Department of Pediatrics, Keck School of Medicine of University of Southern California, Los Angeles, Calif
- Division of Emergency and Transport Medicine, Children's Hospital Los Angeles, Los Angeles, Calif
- Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, Calif
| | - Vivian Lee
- From the Division of Hospital Medicine, Children's Hospital Los Angeles, Los Angeles, Calif
- Department of Pediatrics, Keck School of Medicine of University of Southern California, Los Angeles, Calif
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Combs MD, Mitchell M, Molas-Torreblanca K, Lee C, Raffaele JL, Sharma M, Berger S, Morrison J, Prasad M, Wood JK, Van Meurs A, Mullin R, Doraiswamy V, Ingram E, Banker SL, Lee J, Tan X, Potisek NM, Halvorson EE. Variation in Care of Well-Appearing Hypothermic Young Infants: A Multisite Study. Hosp Pediatr 2023:e2023007199. [PMID: 37503559 DOI: 10.1542/hpeds.2023-007199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
BACKGROUND AND OBJECTIVES Numerous decision tools have emerged to guide management of febrile infants, but limited data exist to guide the care of young infants presenting with hypothermia. We evaluated the variation in care for well-appearing hypothermic young infants in the hospital and/or emergency department setting between participating sites. METHODS This is a retrospective cohort study of well-appearing infants ≤90 days old across 9 academic medical centers from September 1, 2016 to May 5, 2021. Infants were identified via billing codes for hypothermia or an initial temperature ≤36.0°C with manual chart review performed. Primary outcomes included assessment of variation in diagnostic evaluation, disposition, empirical antimicrobial therapy, and length of stay. RESULTS Of 14 278 infants originally identified, 739 met inclusion criteria. Significant interhospital variation occurred across all primary outcomes. Across sites, a full serious bacterial illness evaluation was done in 12% to 76% of hypothermic infants. Empirical antibiotics were administered 20% to 87% of the time. Performance of herpes simplex viral testing ranged from 7% to 84%, and acyclovir was empirically started 8% to 82% of the time. Hospital admission rates ranged from 45% to 100% of patients. CONCLUSIONS Considerable variation across multiple aspects of care exists for well-appearing young infants presenting with hypothermia. An improved understanding of hypothermic young infants and their risk of infection can lead to the development of clinical decision tools to guide appropriate evaluation and management.
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Affiliation(s)
- Monica D Combs
- Department of Pediatrics, Keck School of Medicine of USC, Children's Hospital Los Angeles, Los Angeles, California
| | - Meredith Mitchell
- Department of Pediatrics, Children's Hospital of Richmond at Virginia Commonwealth University, Richmond, Virginia
| | - Kira Molas-Torreblanca
- Department of Pediatrics, Keck School of Medicine of USC, Children's Hospital Los Angeles, Los Angeles, California
| | - Clifton Lee
- Department of Pediatrics, Children's Hospital of Richmond at Virginia Commonwealth University, Richmond, Virginia
| | - Jennifer L Raffaele
- Department of Pediatrics, University of South Carolina School of Medicine Greenville, Prisma Health Children's Hospital-Upstate, Greenville, South Carolina
| | - Meenu Sharma
- Department of Pediatrics, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama
| | - Stephanie Berger
- Department of Pediatrics, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama
| | - John Morrison
- Division of Pediatric Hospital Medicine, Johns Hopkins All Children's Hospital, St Petersburg, Florida
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Madhuri Prasad
- Division of Pediatric Hospital Medicine, Johns Hopkins All Children's Hospital, St Petersburg, Florida
| | - Julie K Wood
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Annalise Van Meurs
- Department of Pediatrics, Oregon Health and Science University, Doernbecher Children's Hospital, Portland, Oregan
| | - Rachael Mullin
- Department of Pediatrics, Oregon Health and Science University, Doernbecher Children's Hospital, Portland, Oregan
| | - Vignesh Doraiswamy
- Division of Hospital Medicine, Nationwide Children's Hospital, Columbus, Ohio
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio
| | - Evan Ingram
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio
| | - Sumeet L Banker
- Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons and New York-Presbyterian, New York, New York; and
| | - Jennifer Lee
- Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons and New York-Presbyterian, New York, New York; and
| | - Xiyan Tan
- School of Mathematical and Statistical Sciences, Clemson University, Clemson, South Carolina
| | - Nicholas M Potisek
- Department of Pediatrics, University of South Carolina School of Medicine Greenville, Prisma Health Children's Hospital-Upstate, Greenville, South Carolina
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Elizabeth E Halvorson
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, North Carolina
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Raffaele JL, Sharma M, Berger S, Mitchell M, Lee C, Morrison J, Prasad M, Combs MD, Molas-Torreblanca K, Wood JK, Van Meurs A, Westphal K, Sawani A, Banker SL, Lee J, King C, Halvorson EE, Potisek NM. Prevalence of Invasive Bacterial Infection in Hypothermic Young Infants: A Multisite Study. J Pediatr 2023; 258:113407. [PMID: 37023947 DOI: 10.1016/j.jpeds.2023.113407] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 03/03/2023] [Accepted: 03/25/2023] [Indexed: 04/08/2023]
Abstract
OBJECTIVE To determine the prevalence of bacteremia and meningitis (invasive bacterial infection [IBI]) in hypothermic young infants, and also to determine the prevalence of serious bacterial infections (SBI) and neonatal herpes simplex virus and to identify characteristics associated with IBI. STUDY DESIGN We conducted a retrospective cohort study of infants ≤90 days of age who presented to 1 of 9 hospitals with historical or documented hypothermia (temperature ≤36.0°C) from September 1, 2017, to May 5, 2021. Infants were identified by billing codes or electronic medical record search of hypothermic temperatures. All charts were manually reviewed. Infants with hypothermia during birth hospitalization, and febrile infants were excluded. IBI was defined as positive blood culture and/or cerebrospinal fluid culture treated as a pathogenic organism, whereas SBI also included urinary tract infection. We used multivariable mixed-effects logistic regression to identify associations between exposure variables and IBI. RESULTS Overall, 1098 young infants met the inclusion criteria. IBI prevalence was 2.1% (95% CI, 1.3-2.9) (bacteremia 1.8%; bacterial meningitis 0.5%). SBI prevalence was 4.4% (95% CI, 3.2-5.6), and neonatal herpes simplex virus prevalence was 1.3% (95% CI, 0.6-1.9). Significant associations were found between IBI and repeated temperature instability (OR, 4.9; 95% CI, 1.3-18.1), white blood cell count abnormalities (OR, 4.8; 95% CI, 1.8-13.1), and thrombocytopenia (OR, 5.0; 95% CI, 1.4-17.0). CONCLUSIONS IBI prevalence in hypothermic young infants is 2.1%. Further understanding of characteristics associated with IBI can guide the development decision tools for management of hypothermic young infants.
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Affiliation(s)
- Jennifer L Raffaele
- Department of Pediatrics, University of South Carolina School of Medicine Greenville, Prisma Health Children's Hospital-Upstate, Greenville, NC.
| | - Meenu Sharma
- Department of Pediatrics, University of Alabama Heersink School of Medicine, Birmingham, AL
| | - Stephanie Berger
- Department of Pediatrics, University of Alabama Heersink School of Medicine, Birmingham, AL
| | - Meredith Mitchell
- Department of Pediatrics, Children's Hospital of Richmond at Virginia Commonwealth University, Richmond, VA
| | - Clifton Lee
- Department of Pediatrics, Children's Hospital of Richmond at Virginia Commonwealth University, Richmond, VA
| | - John Morrison
- Division of Pediatric Hospital Medicine, Johns Hopkins All Children's Hospital, St. Petersburg, FL; Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Madhuri Prasad
- Division of Pediatric Hospital Medicine, Johns Hopkins All Children's Hospital, St. Petersburg, FL
| | - Monica D Combs
- Department of Pediatrics, Keck School of Medicine of USC, Children's Hospital Los Angeles, Los Angeles, CA
| | - Kira Molas-Torreblanca
- Department of Pediatrics, Keck School of Medicine of USC, Children's Hospital Los Angeles, Los Angeles, CA
| | - Julie K Wood
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Annalise Van Meurs
- Department of Pediatrics, Oregon Health and Science University, Doernbecher Children's Hospital, Portland, OR
| | - Kathryn Westphal
- Division of Hospital Medicine, Nationwide Children's Hospital, Columbus, OH; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH
| | - Ali Sawani
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH
| | - Sumeet L Banker
- Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons and New York-Presbyterian, New York, NY
| | - Jennifer Lee
- Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons and New York-Presbyterian, New York, NY
| | - Coleton King
- Department of Psychology, Clemson University, Clemson, SC
| | - Elizabeth E Halvorson
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, NC
| | - Nicholas M Potisek
- Department of Pediatrics, University of South Carolina School of Medicine Greenville, Prisma Health Children's Hospital-Upstate, Greenville, NC; Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, NC
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Combs MD, Edwards SH, Scherpenhuizen JM, Narayan EJ, Kessell AE, Ramsay J, Piltz J, Raidal SR, Quinn JC. Treatment with potassium bromide mitigates ataxia and reduces tremor in lambs with perennial ryegrass toxicosis. N Z Vet J 2019; 67:287-294. [PMID: 31248334 DOI: 10.1080/00480169.2019.1637300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Aims: To assess the use of potassium bromide (KBr) as a therapeutic intervention for perennial ryegrass toxicosis (PRGT) in lambs fed ryegrass seed containing lolitrem B. Methods: Male lambs aged 10-12 months (n = 43) were assigned to receive ryegrass seed containing lolitrem B, at a dose of 0.16 mg/kg/day (Groups 2, 3 and 4), or lucerne chaff and molasses (Groups 1 and 5). Lambs in Groups 2 and 3 were observed for clinical signs and gait changes until defined signs of PGRT were observed, when they were transferred, with lambs in Group 1, to the Testing phase of the trial. Lambs in Group 3 were then treated with a single oral dose of 300 mg/kg bromide. Lambs in Groups 4 and 5 received KBr daily from the start of the trial (540 mg/kg bromide over 3 days then 20 mg/kg daily) and were transferred to the Testing phase after 18 days. Clinical examination and gait assessment, and surface electromyography of the triceps muscle, measuring root-mean-square (RMS) voltages, were carried out on Days 0, 1 and 2 of the Testing phase followed by necropsy, histopathology, measurement of concentrations of bromide in serum and CSF and faecal cortisol metabolites (FCM). Results: In Group 3 lambs, mean composite gait scores decreased between Testing phase Day 0 and Days 1 and 2 (p < 0.001), but increased in lambs in Group 2 between Day 0 and Day 2 (p = 0.015). Scores for lambs in Group 3 on Day 2 were lower than for lambs in Group 2 (p < 0.001). Mean RMS voltages on Day 2 were higher in lambs in Group 2 than Group 3 (p = 0.045). Mean concentrations of bromide in serum were >800 µg/mL in lambs in Groups 3 and 4 on Day 2. Concentrations of FCM were higher in lambs from Group 2 than in Groups 1 or 5, but were similar in Groups 2, 3 and 4. Histopathological findings in the cerebellum of lambs from Groups 2, 3 and 4 were similar, showing pyknosis of neurons within the granular layer of the cerebellum and Purkinje neuron proximal axonal spheroid formation. Conclusions and clinical relevance: A single oral dose of 300 mg/kg bromide in lambs with neurological signs of PRGT resulted in reduced composite gait scores and reduced RMS voltages, indicating a significant improvement in clinical signs of ataxia, movement disorder and muscle tremor associated with the neurotoxic effects of lolitrem B.
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Affiliation(s)
- M D Combs
- School of Animal and Veterinary Sciences, Charles Sturt University , Wagga Wagga , Australia
| | - S H Edwards
- School of Animal and Veterinary Sciences, Charles Sturt University , Wagga Wagga , Australia
| | - J M Scherpenhuizen
- School of Animal and Veterinary Sciences, Charles Sturt University , Wagga Wagga , Australia
| | - E J Narayan
- School of Science and Health, Western Sydney University , Penrith , Australia
| | - A E Kessell
- Veterinary Diagnostic Laboratory, City University of Hong Kong , Hong Kong
| | - J Ramsay
- School of Animal and Veterinary Sciences, Charles Sturt University , Wagga Wagga , Australia
| | - J Piltz
- New South Wales Department of Primary Industries , Wagga Wagga , Australia
| | - S R Raidal
- School of Animal and Veterinary Sciences, Charles Sturt University , Wagga Wagga , Australia
| | - J C Quinn
- School of Animal and Veterinary Sciences, Charles Sturt University , Wagga Wagga , Australia
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Combs MD, Hamlin A, Quinn JC. A single exposure to the tremorgenic mycotoxin lolitrem B inhibits voluntary motor activity and spatial orientation but not spatial learning or memory in mice. Toxicon 2019; 168:58-66. [PMID: 31254599 DOI: 10.1016/j.toxicon.2019.06.228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/19/2019] [Accepted: 06/25/2019] [Indexed: 10/26/2022]
Abstract
The indole diterpenoid toxin lolitrem B is a tremorgenic agent found in the common grass species, perennial ryegrass (Lolium perenne). The toxin is produced by a symbiotic fungus Epichloë festucae (var. lolii) and ingestion of infested grass with sufficient toxin levels causes a movement disorder in grazing herbivores known as 'ryegrass staggers'. Beside ataxia, lolitrem B intoxicated animals frequently show indicators of cognitive dysfunction or exhibition of erratic and unpredictable behaviours during handling. Evidence from field cases in livestock and controlled feeding studies in horses have indicated that intoxication with lolitrem B may affect higher cortical or subcortical functioning. In order to define the role of lolitrem B in voluntary motor control, spatial learning and memory under controlled conditions, mice were exposed to a known dose of purified lolitrem B toxin and tremor, coordination, voluntary motor activity and spatial learning and memory assessed. Motor activity, coordination and spatial memory were compared to tremor intensity using a novel quantitative piezo-electronic tremor analysis. Peak tremor was observed as frequencies between 15 and 25Hz compared to normal movement at approximately 1.4-10Hz. A single exposure to a known tremorgenic dose of lolitrem B (2 mg/kg IP) induced measureable tremor for up to 72 h in some animals. Initially, intoxication with lolitrem B significantly decreased voluntary movement. By 25 h post exposure a return to normal voluntary movement was observed in this group, despite continuing evidence of tremor. This effect was not observed in animals exposed to the short-acting tremorgenic toxin paxilline. Lolitrem B intoxicated mice demonstrated a random search pattern and delayed latency to escape a 3 h post intoxication, however by 27 h post exposure latency to escape matched controls and mice had returned to normal searching behavior indicating normal spatial learning and memory. Together these data indicate that the tremor exhibited by lolitrem B intoxicated mice does not directly impair spatial learning and memory but that exposure does reduce voluntary motor activity in intoxicated animals. Management of acutely affected livestock suffering toxicosis should be considered in the context of their ability to spatially orientate with severe toxicity.
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Affiliation(s)
- M D Combs
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, 2560, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, New South Wales, 2560, Australia
| | - A Hamlin
- School of Science and Technology, University of New England, Armidale, NSW, 2351, Australia
| | - J C Quinn
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales, 2560, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, New South Wales, 2560, Australia.
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Combs MD, Edwards SH, Scherpenhuizen JM, Narayan EJ, Kessell AE, Piltz J, Raidal SR, Ramsay J, Quinn JC. Development of a model for investigation of perennial ryegrass toxicosis in sheep. N Z Vet J 2018; 66:281-289. [PMID: 29949720 DOI: 10.1080/00480169.2018.1492986] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
AIMS To develop a clinical model of perennial ryegrass toxicosis (PRGT) based on feeding a known dose of lolitrem B and ergotamine, and to produce a consistent clinical presentation for assessment of disease pathophysiology, neurological changes and neurohistopathology. METHODS Male lambs, aged between 10-12 months, were randomly assigned to either Treatment (n=9) or Control (n=9) groups. Lambs in the Treatment group received feed containing a novel endophyte-infested perennial ryegrass seed, commencing on Day 0 of the Feeding phase with a low induction dose, then increasing after 3 days to provide 0.16 mg/kg live bodywight (LBW)/day of lolitrem B and 0.054 mg/kg LBW/day ergotamine. Lambs were examined daily and when defined signs of PRGT were observed they were transferred to the Testing phase. Neurological examinations, assessment of gait, surface electromyography (EMG) and mechanosensory nociceptive threshold testing were carried out and blood samples collected during both phases of the trial, with a full necropsy, histopathological examination and measurement of faecal cortisol metabolites (FCM) performed on Day 2 of the Testing phase. RESULTS Typical clinical signs of PRGT, including ataxia of vestibulocerebellar origin leading to stumbling, were observed in all Treatment lambs. The median interval from the start of the Feeding phase to entry into the Testing phase was 21 (min 18, max 34) days. Histopathological characterisation of neurological lesions included the presence of Purkinje cell vacuolation, pyknotic granular layer neurons and proximal axonal Purkinje cell spheroids. Lesions were most apparent within the vestibulocerebellum. Mean root-mean-square voltages from triceps EMG increased in Treatment lambs between Feeding phase Day 0 and Testing phase Day 2 (p<0.001). Daily water intake during the Testing phase for the Treatment group was less than in Control group lambs (p=0.002), and concentrations of FCM at necropsy were higher in Treatment compared to Control lambs (p=0.02). CONCLUSIONS AND CLINICAL RELEVANCE Lolitrem B and ergotamine dosing in feed on a live weight basis combined with neurological/gait assessment provides an effective model for investigation of PRGT and potential therapeutics. Assessment of gait changes using defined criteria and RMS voltages from EMG appear to be useful tools for the assessment of the severity of neurological changes.
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Affiliation(s)
- M D Combs
- a School of Animal and Veterinary Sciences , Charles Sturt University , Wagga Wagga , NSW , 2560 , Australia
| | - S H Edwards
- a School of Animal and Veterinary Sciences , Charles Sturt University , Wagga Wagga , NSW , 2560 , Australia
| | - J M Scherpenhuizen
- a School of Animal and Veterinary Sciences , Charles Sturt University , Wagga Wagga , NSW , 2560 , Australia
| | - E J Narayan
- b Gribbles Pathology , Adelaide , SA , 5065 , Australia
| | - A E Kessell
- c School of Science and Health , Western Sydney University , Penrith , NSW , 2751 , Australia
| | - J Piltz
- d New South Wales Department of Primary Industries , Wagga Wagga Agricultural Institute, Wagga Wagga , NSW , 2560 , Australia
| | - S R Raidal
- a School of Animal and Veterinary Sciences , Charles Sturt University , Wagga Wagga , NSW , 2560 , Australia
| | - J Ramsay
- a School of Animal and Veterinary Sciences , Charles Sturt University , Wagga Wagga , NSW , 2560 , Australia
| | - J C Quinn
- a School of Animal and Veterinary Sciences , Charles Sturt University , Wagga Wagga , NSW , 2560 , Australia
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Quast TA, Combs MD, Edwards SH. Pharmacokinetics of bromide in adult sheep following oral and intravenous administration. Aust Vet J 2015; 93:20-5. [DOI: 10.1111/avj.12285] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2013] [Indexed: 11/29/2022]
Affiliation(s)
- TA Quast
- School of Animal and Veterinary Science; Charles Sturt University; Wagga Wagga New South Wales Australia
| | - MD Combs
- School of Animal and Veterinary Science; Charles Sturt University; Wagga Wagga New South Wales Australia
| | - SH Edwards
- School of Animal and Veterinary Science; Charles Sturt University; Wagga Wagga New South Wales Australia
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Abstract
BACKGROUND Previous work has suggested factors such as gender, smoking behavior, dose, and age affect the amount of drug a patient requires to achieve a desired plasma concentration of clozapine. Plasma clozapine concentrations ranging from 350 to 504 ng/mL in treatment-refractory schizophrenics and schizoaffective patients produce response rates ranging approximately 55-80%. Without the aid of clozapine plasma concentration monitoring, 3-6 months are recommended for a therapeutic clozapine trial. Data suggest that the lag time to response can be reduced by administering a dose that produces a therapeutic clozapine concentration. METHODS To generate a clozapine dosing nomogram to predict clozapine steady-state plasma concentrations, a cohort of 71 patients was collected via retrospective chart review and/or patient interview. Clozapine steady-state plasma concentrations and demographic variables were obtained. Multiple-linear regression was utilized to examine the relationship between the plasma clozapine concentration and the independent variables. RESULTS The dosing model that optimally predicted steady-state clozapine plasma concentrations included the variables dose (mg/day), smoking (yes = 0 and no = 1), gender, and a dose-gender interaction variable. The model explained 47% of the variance in the clozapine concentrations (F = 14.42, p < .001, r2 = .47). Two equations, one for male subjects, i.e., clozapine (ng/mL) = 111 (smoke) + 0.464 (dose) + 145, and one for female subjects, i.e., clozapine (ng/mL) = 111 (smoke) + 1.590 (dose)-149, were derived to predict clozapine steady-state plasma concentrations to serve as a clozapine dosing guide for clinicians. CONCLUSIONS A clozapine dosing nomogram was constructed as a clinical aid to facilitate clozapine dosing.
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Affiliation(s)
- P J Perry
- Department of Psychiatry, College of Medicine, University of Iowa, Iowa City 52242, USA
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Combs MD, Perry PJ, Bever KA. N-desmethylclozapine, an insensitive marker of clozapine-induced agranulocytosis and granulocytopenia. Pharmacotherapy 1997; 17:1300-4. [PMID: 9399615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We reviewed the charts of 58 patients with treatment-refractory schizophrenia who were receiving clozapine, to determine if the drug's active metabolite, N-desmethylclozapine, is a biologic marker for impending clozapine-induced granulocytopenia and agranulocytosis. No significant correlation between granulocyte counts and patient demographic variables of clozapine and N-desmethylclozapine steady-state plasma concentrations, clozapine:N-desmethylclozapine ratio, age, gender, clozapine dosage, smoking status, and race were found. We believe N-desmethylclozapine is not a clinically useful marker for monitoring the effect of clozapine on granulocyte integrity. On the contrary, its plasma concentrations correlated positively with granulocyte counts.
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Affiliation(s)
- M D Combs
- College of Pharmacy, University of Iowa, Iowa City 52246, USA
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