Background
Detailed descriptions of clinical signs associated with radiological findings of the caudal cervical vertebral column are not available.
Objectives/Hypotheses
Describe the clinical ...features associated with neck pain or stiffness, neck‐related thoracic limb lameness, proprioceptive ataxia consistent with a cervicothoracic spinal cord or nerve lesion, and their frequency of occurrence compared with control horses.
Animals
A total of 223 Warmblood horses.
Methods
Case‐control study. Controls and cases were recruited prospectively. All horses underwent predetermined lameness and neurologic examinations. The frequency of occurrence of each clinical feature was compared between cases and controls and relative risk (RR) were calculated.
Results
Ninety‐six cases and 127 controls were included. Forty‐seven (49%) of the cases were classified as neurologic, 31 (32.3%) had thoracic limb lameness, and 18 (18.7%) had neck stiffness or pain or both. Focal caudal cervical muscle atrophy (46, 47.9%), hypoesthesia (38, 39.6%), patchy sweating (16, 16.7%), hyperesthesia (11, 11.5%), and pain upon firm pressure applied over the caudal cervical articular process joints and transverse processes (58, 60.4%) were only observed in cases (P < .001). Sideways flexion of the neck was restricted in a higher proportion of cases (47/96, 49%) compared with controls (40/127, 31.8%; P = .009, RR 1.5). Hopping‐type thoracic limb lameness was only observed in cases, (30, 31.6%). Deterioration in lameness after diagnostic anesthesia occurred in 13/31 (41.9%) cases.
Conclusions and Clinical Importance
Systematic clinical evaluation using the methods described should enable clinical differentiation between horses with caudal cervical lesions and horses with other causes of gait abnormalities.
Background
Juvenile idiopathic epilepsy (JIE) is categorized as a generalized epilepsy. Epilepsy classification entails electrocortical characterization and localization of epileptic discharges (ED) ...using electroencephalography (EEG).
Hypothesis/Objectives
Characterize epilepsy in Egyptian Arabian foals with JIE using EEG.
Animals
Sixty‐nine foals (JIE, 48; controls, 21).
Methods
Retrospective study. Inclusion criteria consisted of Egyptian Arabian foals: (1) JIE group diagnosed based on witnessed or recorded seizures, and neurological and EEG findings, and (2) control group of healthy nonepileptic age‐matched foals. Clinical data were obtained in 48 foals. Electroencephalography with photic stimulation was performed under standing sedation in 37 JIE foals and 21 controls.
Results
Abnormalities on EEG were found in 95% of epileptic foals (35 of 37) and in 3 of 21 control asymptomatic foals with affected siblings. Focal ED were detected predominantly in the central vertex with diffusion into the centroparietal or frontocentral regions (n = 35). Generalization of ED occurred in 14 JIE foals. Epileptic discharges commonly were seen during wakefulness (n = 27/37 JIE foals) and sedated sleep (n = 35/37 JIE foals; 3/21 controls). Photic stimulation triggered focal central ED in 15 of 21 JIE foals.
Conclusions and Clinical Importance
Juvenile idiopathic epilepsy has a focal onset of ED at the central vertex with spread resulting in clinical generalized tonic‐clonic seizures with facial motor activity and loss of consciousness. Electroencephalography with photic stimulation contributes to accurate phenotyping of epilepsy. Foals with this benign self‐limiting disorder might serve as a naturally occurring animal model for self‐limited epilepsy in children.
Background
Irreversible sensorineural auditory loss has been reported in humans treated with aminoglycosides but not in horses.
Objective
Investigate if auditory loss occurs in horses treated using ...the recommended IV daily dosage of gentamicin for 7 consecutive days.
Animals
Ten healthy adult horses (7‐15 years; females and males, 5 each).
Methods
Prospective study. Physical and neurological examinations and renal function tests were performed. Gentamicin sulfate was administered at a dosage of 6.6 mg/kg via the jugular vein on alternating sides for 7 days. Gentamicin peak and trough concentrations were measured. Horses were sedated using detomidine hydrochloride IV to perform brainstem auditory evoked responses (BAER) before the first dose, immediately after the last dose, and 30 days after the last dose. Peaks latencies, amplitudes, and amplitude ratios were recorded. Data from the second and last BAER were compared to results at baseline. Bone conduction was performed to rule out conduction disorders.
Results
Seven horses had auditory loss: complete bilateral (N = 1), complete unilateral (N = 2), and partial unilateral (N = 4). Based on physical examination and BAER results, sensorineural auditory loss was suspected. Absent bone conduction ruled out a conduction disorder and further supported sensorineural auditory loss in horses with completely absent BAER. Auditory dysfunction was reversible in 4 of 7 horses.
Conclusions and Clinical Importance
Gentamicin at recommended doses may cause sensorineural auditory loss in horses that might be irreversible. Follow‐up studies are needed to investigate if other dosing protocols present a similar risk.
Background
Comprehensive descriptions of equids with granulocytic anaplasmosis (EGA) with neurologic or muscle disease and other atypical presentations are scarce in the literature.
Objective
...Describe the clinical signs, laboratory findings, treatment, and outcome of equids with EGA with emphasis on neurologic and muscle disease.
Animals
Thirty‐eight horses, 1 donkey.
Methods
Retrospective study. Equids with EGA were included. The electronic data base was searched from January 2000 to December 2022 using the words anaplasmosis, ehrlichiosis, granulocytic, and rickettsia. Signalment and clinical data were reviewed. Data were evaluated for normality using Shapiro‐Wilk test. Parametric and nonparametric statistics were used for normally and non‐normally distributed data.
Results
Common (41%) and other (59%) presentations were seen in horses ≥ 4 years of age (median, 14 years) with an overrepresentation of males (77%). Neurologic disease was common (41%), mainly presenting as diffuse symmetrical proprioceptive ataxia. Brain disease was less common manifesting as obtundation and cranial nerve deficits. Muscle disease was less common, with QH breeds with the variant causing myosin heavy chain myopathy (MYHM) having severe disease. Cavitary effusion, cardiomyopathy and disseminated intravascular coagulation (DIC) were uncommon. Clinical laboratory results varied depending on disease stage. Muscle enzyme activities were significantly higher in horses with muscle disease. Outcome was favorable with prompt tetracycline treatment. Death and long‐term sequelae were not reported.
Conclusions and Clinical Importance
Common and atypical presentations of EGA have a favorable outcome with prompt tetracycline treatment. Quarter horse breeds with muscle disease should be genotyped for MYHM.
Background
A standardized protocol for electroencephalography (EEG) under standing sedation for the investigation of epilepsy in foals is needed.
Hypothesis/Objectives
To evaluate a modified ...standardized EEG protocol under standing sedation using sublingual detomidine hydrochloride in Egyptian Arabian foals.
Animals
Nineteen foals (controls, 9; juvenile idiopathic epilepsy JIE, 10).
Methods
Descriptive clinical study. Foals were classified as controls or epileptic based on history or witnessed seizures and neurological examination. Foals were sedated using sublingual detomidine hydrochloride at a dosage of 0.08 mg/kg to avoid stress associated with injectable sedation. Once foals appeared sedated with their heads low to the ground and with wide base stance (30 minutes), topical lidocaine hydrochloride was applied at the determined locations of EEG electrodes. Fifteen minutes were allowed for absorption and electrodes were placed, protected, and EEG recording performed.
Results
Level of sedation was considered excellent with no need of redosing. The EEG recording lasted from 27 to 51 minutes and provided interpretable data. Epileptic discharges (ED) were noted predominantly in the central‐parietal region in 9 of 10 epileptic foals. Photic stimulation triggered ED in 7 of 10 epileptic foals and in none of the controls. Foals were not oversedated and recovered uneventfully.
Conclusions and Clinical Importance
Sublingual detomidine hydrochloride is a safe, painless, simple, and effective method of sedation for EEG recording in foals. Sublingual sedation allowed the investigation of cerebral electrical activity during states of sleep and arousal, and during photic stimulation for the investigation of epilepsy in foals.
Background
Transient hypothalamic‐pituitary‐adrenal axis dysfunction occurs in critically ill foals with sepsis and neonatal maladjustment syndrome (NMS). Cortisol is the most commonly measured ...steroid. However, a complex interaction of various steroid compounds might play a role in pathophysiology of this disorder.
Objective
To identify steroid compounds present at high concentrations at birth that rapidly and steadily decrease within the first 7 days of life in healthy foals and that might be supportive diagnosis of NMS and other neonatal disorders.
Animals
Ten healthy neonatal Quarter Horse foals (5 females and 5 males).
Methods
Prospective study. Blood was collected in heparinized tubes within 30 minutes after birth, and at 12, 24, 48, 72, 96, 120, 144, and 168 hours of age. Plasma was separated and a panel of steroid compounds was analyzed using liquid chromatography‐mass spectrometry. A nonlinear regression model was used to determine decay concentrations over time. Confidence intervals (CIs) were calculated and significance was set a P ≤ .05.
Results
Five compounds were identified: pregnenolone, progesterone, deoxycorticosterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate. Pregnenolone and progesterone concentrations rapidly decreased by 24 hours of age and remained low throughout the first 7 days of life. Their half‐life (95% CI) was short at 3.7 (3.4, 4.0) and 4.5 (2.8, 6.1) hours, respectively. No statistical differences in the concentrations of these compounds were found between males and females.
Conclusions and Clinical Relevance
Progesterone might be a useful marker for identifying continuous endogenous production of neuroactive steroids in foals with suspected NMS and other neonatal diseases.
Background
Rapid and accurate markers to aid diagnosis of sepsis are needed in neonatal foals. The CBC variable red blood cell distribution width (RDW) to platelet ratio (RPR) is associated with ...inflammatory response and linked to poor outcomes of sepsis in human patients.
Hypothesis
Explore the correlation of RPR with sepsis in neonatal foals and evaluate RPR predictive and prognostic value.
Animals
Three hundred seventeen hospitalized neonatal foals ≤7 days of age that had a CBC and physical exam performed at admission between 2012 and 2021.
Methods
Retrospective case‐control study. Clinical records were used to calculate sepsis scores and define groups. Red blood cell distribution width to platelet ratio was calculated and compared between groups (septic vs nonseptic) based on Kruskal‐Wallis and Wilcoxon signed‐rank tests. A multivariate logistic regression model to predict sepsis was created. The cutoff for RPR was obtained based on the maximal Youden Index. The Kaplan‐Meier method and the log‐rank test were used to estimate survival curves and compare survival rates based on RPR.
Results
Red blood cell distribution width to platelet ratio was significantly higher in septic foals (Median = 0.099, confidence interval CI 0.093; 0.108) than in sick nonseptic (0.085, CI 0.083; 0.089) and healthy foals (0.081, CI 0.077; 0.086; P < .0001). Red blood cell distribution width to platelet ratio was able to predict sepsis with high accuracy (AUC = 82.1%). The optimal RPR cutoff for sepsis was 0.09.
Conclusions and Clinical Importance
Red blood cell distribution width to platelet ratio calculation is practical, inexpensive, and based on CBC‐derived data. Calculation of RPR along with CBC can aid in the diagnosis of sepsis and estimation of outcome.
In this work, we present the incorporation of a laser doped selective emitter into the i-PERC platform at Imec using large area magnetically confined boron-doped Czochralski grown silicon wafers. ...Cells were fabricated with self-aligned plated n-type contacts with a comparison between the use of a homogenous emitter with contact openings formed by picosecond laser ablation and a selective emitter formed by laser doping with a mode-locked UV laser using various processing speeds. Without modification to other processes in the i-PERC platform, improvements in efficiency of approximately 0.4% absolute were obtained with the inclusion of the selective emitter structure through improvements in open circuit voltage, fill factor and reduced series resistance. This resulted in peak efficiencies of 20.5% using a processing speed for laser doping of 5m/s.
•0.4% absolute efficiency enhancement by the incorporation of a laser doped selective emitter into a PERC cell structure.•Peak efficiency of 20.5% obtained.•Faster processing speeds (>2m/s) observed to cause less bulk damage than slower processing speeds.
Summary
Regional and systemic disorders of myopathic or neurogenic cause affecting the masticatory muscles have been reported or suspected in horses. The primary masticatory muscles include the ...masseter, temporalis, lateral and medial pterygoid muscles. The masseter muscle is the largest of the primary masticatory muscles and the most affected based on sporadic reports. This is a brief review of disorders involving the masseter muscle.
Background
In 2020, a novel neurologic disease was observed in juvenile Quarter Horses (QHs) in North America. It was unknown if this was an aberrant manifestation of another previously described ...neurological disorder in foals, such as equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM).
Hypothesis/Objectives
To describe the clinical findings, outcomes, and postmortem changes with Equine Juvenile Spinocerebellar Ataxia (EJSCA), differentiate the disease from other similar neurological disorders, and determine a mode of inheritance.
Animals
Twelve neurologically affected QH foals and the dams.
Methods
Genomic DNA was isolated and pedigrees were manually constructed.
Results
All foals (n = 12/12) had a history of acute onset of neurological deficits with no history of trauma. Neurological deficits were characterized by asymmetrical spinal ataxia, with pelvic limbs more severely affected than thoracic limbs. Clinicopathological abnormalities included high serum activity of gamma‐glutamyl transferase and hyperglycemia. All foals became recumbent (median, 3 days: 0–18 days), which necessitated humane euthanasia (n = 11/12, 92%; the remaining case was found dead). Histological evaluation at postmortem revealed dilated myelin sheaths and digestion chambers within the spinal cord, most prominently in the dorsal spinocerebellar tracts. Pedigree analysis revealed a likely autosomal recessive mode of inheritance.
Conclusions and Clinical Importance
EJSCA is a uniformly fatal, rapidly progressive, likely autosomal recessive neurological disease of QHs <1 month of age in North America that is etiologically distinct from other clinically similar neurological disorders. Once the causative variant for EJSCA is validated, carriers can be identified through genetic testing to inform breeding decisions.
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