Sensory nerve conduction stimulus threshold measurements of the infraorbital nerve and its applicability as a diagnostic tool in horses with trigeminal-mediated headshaking.

BACKGROUND: To determine whether sensory nerve conduction stimulus threshold measurements of the infraorbital nerve are able to differentiate horses with idiopathic trigeminal-mediated headshaking (i-TMHS) from healthy horses and from horses with secondary trigeminal-mediated headshaking (s-TMHS). In a prospective trial, headshaking horses were examined using a standardized diagnostic protocol, including advanced diagnostics such as computed tomography and 3-Tesla-magnetic resonance imaging (MRI), to differentiate s-TMHS from i-TMHS. Clinically healthy horses served as controls. Within this process, patients underwent general anesthesia, and the minimal sensory nerve conduction stimulus threshold (SNCT) of the infraorbital nerve was measured using a bipolar concentric needle electrode. Sensory nerve action potentials (SNAP) were assessed in 2.5-5 mA intervals. Minimal SNCT as well as additional measurements were calculated. RESULTS: In 60 horses, SNAP could be recorded, of which 43 horses had i-TMHS, six had suspected s-TMHS, three horses had non-facial headshaking, and eight healthy horses served as controls. Controls had a minimal SNCT ≥ 15 mA, whereas 14/43 horses with i-TMHS and 2/6 horses with s-TMHS showed a minimal SNCT ≤ 10 mA. Minimal SNCT ≤ 10 mA showed 100% specificity to distinguish TMHS from controls, but the sensitivity was only 41%. CONCLUSION: A minimal SNCT of the infraorbital nerve ≤ 10 mA was able to differentiate healthy horses from horses with TMHS. Nevertheless, a higher minimal SNCT did not exclude i-TMHS or s-TMHS and minimal SNCT does not distinguish s-TMHS from i-TMHS.

Behavioral Changes Under Levetiracetam Treatment in Dogs.

In veterinary medicine levetiracetam (LEV) is a well-tolerated antiepileptic drug (AED) with only mild to moderate side effects. Behavioral changes are rarely reported in animals. In contrast, in human medicine the impact of LEV on behavior has frequently been described. Since in the Clinic for Small Animals at the University of Veterinary Medicine Hannover single canine patients were observed with behavioral abnormalities after LEV treatment, it was hypothesized that levetiracetam induces behavioral changes or causes an intensifying of pre-existing behavioral abnormalities in dogs with epileptic seizures. This monocentric retrospective study evaluated the incidence of behavioral changes in epileptic dogs treated with the antiepileptic drug LEV based on information obtained in a questionnaire completed by dog owners. Eighty-four client-owned dogs with recurrent seizures receiving LEV as monotherapy, add on treatment or pulse therapy met inclusion criteria. Approximately half of the dogs in the study population were reported to have preexisting behavioral changes before treatment with LEV, and some of these dogs were reported to experience a worsening of behavioral changes (14/44) or the emergence of new behaviors after initiation of LEV therapy (4/44). One quarter of the dogs without pre-existing behavioral abnormalities developed behavioral changes associated with the administration of LEV (10/40). Based on these results, the authors conclude that behavioral changes can occur in dogs being administered LEV, and this should be taken into consideration when discussing treatment options with owners.

Hypernatremia and Coagulopathy May or May Not Be Useful Clinical Biomarkers in Dogs with Head Trauma: A Retrospective Study.

This study was performed to evaluate clinical biomarkers as prognostic values in dogs with traumatic brain injury (TBI) based on findings in human patients. Sodium levels of 158 dogs with TBI and 169 patients with trauma without involvement of the head except head trauma (EHT) were examined. TBI patients with hypernatremia had a slightly higher risk of dying (22.03 %) than dogs with normal sodium levels (19.76%). However, there was no significant correlation between sodium levels and outcome in TBI patients (p = 0.6357). Dogs with sodium levels >160 mmol/L were non-survivors. In dogs with late-onset post-traumatic epilepsy (PTE) more often hyponatremia was measured, and in dogs with immediate PTE mild hypernatremia or normal sodium levels were measured after the trauma. Evaluation of coagulation parameters in a subpopulation of dogs showed a strong correlation between partial thromboplastin time/prothrombin time (PTT/PT) and the Modified Glasgow Coma Scale (MGCS) (p = 0.0006; p = 0.0306). In conclusion, unlike in human patients, sodium levels displayed no significant correlation with survival in dogs with TBI in the current study. However, in cases with severe TBI, dog owners often elect euthanasia before severe hypernatremia can be measured. Late PTE was observed in cases with initial hyponatremia. Because of a significant correlation between PTT/PT and MGCS, coagulopathy might be considered as a prognostic clinical biomarker in canine TBI patients.

The relation between hypointense core, microvascular obstruction and intramyocardial haemorrhage in acute reperfused myocardial infarction assessed by cardiac magnetic resonance imaging.

BACKGROUND: Intramyocardial haemorrhage (IMH) and microvascular obstruction (MVO) represent reperfusion injury after reperfused ST-elevation myocardial infarction (STEMI) with prognostic impact and "hypointense core" (HIC) appearance in T2-weighted images. We aimed to distinguish between IMH and MVO by using T2 (*)-weighted cardiovascular magnetic resonance imaging (CMR) and analysed influencing factors for IMH development. METHODS AND RESULTS: A total of 151 patients with acute STEMI underwent CMR after primary angioplasty. T2-STIR sequences were used to identify HIC, late gadolinium enhancement to visualise MVO and T2 (*)-weighted sequences to detect IMH. IMH(+)/IMH(-) patients were compared considering infarct size, myocardial salvage, thrombolysis in myocardial infarction (TIMI) flow, reperfusion time, ventricular volumes, function and pre-interventional medication. Seventy-six patients (50%) were IMH(+), 82 (54%) demonstrated HIC and 100 (66%) MVO. IMH was detectable without HIC in 16 %, without MVO in 5% and HIC without MVO in 6%. Multivariable analyses revealed that IMH was associated with significant lower left ventricular ejection fraction and myocardial salvage index, larger left ventricular volume and infarct size. Patients with TIMI flow grade ≤1 before angioplasty demonstrated IMH significantly more often. CONCLUSIONS: IMH is associated with impaired left ventricular function and higher infarct size. T2 and HIC imaging showed moderate agreement for IMH detection. T2 (*) imaging might be the preferred CMR imaging method for comprehensive IMH assessment. KEY POINTS: Intramyocardial haemorrhage is a common finding in patients with acute reperfused myocardial-infarction. T 2 (*) imaging should be the preferred CMR method for assessment of intramyocardial haemorrhage. Intramyocardial haemorrhage can be considered as an important influencing factor on patient's outcome.

Assessment of sub-clinical acute cellular rejection after heart transplantation: comparison of cardiac magnetic resonance imaging and endomyocardial biopsy.

OBJECTIVE: Comparing the diagnostic value of multi-sequential cardiac magnetic resonance imaging (CMR) with endomyocardial biopsy (EMB) for sub-clinical cardiac allograft rejection. METHODS: One hundred and forty-six examinations in 73 patients (mean age 53 ± 12 years, 58 men) were performed using a 1.5 Tesla system and compared to EMB. Examinations included a STIR (short tau inversion recovery) sequence for calculation of edema ratio (ER), a T1-weighted spin-echo sequence for assessment of global relative enhancement (gRE), and inversion-recovery sequences to visualize late gadolinium enhancement (LGE). Histological grade ≥1B was considered relevant rejection. RESULTS: One hundred and twenty-seven (127/146 = 87 %) EMBs demonstrated no or mild signs of rejection (grades ≤1A) and 19/146 (13 %) a relevant rejection (grade ≥1B). Sensitivity, specificity, positive predictive, and negative predictive values were as follows: ER: 63 %, 78 %, 30 %, and 93 %; gRE: 63 %, 70 %, 24 %, and 93 %; LGE: 68 %, 36 %, 13 %, and 87 %; with the combination of ER and gRE with at least one out of two positive: 84 %, 57 %, 23 %, and 96 %. ROC analysis revealed an area under the curve of 0.724 for ER and 0.659 for gRE. CONCLUSION: CMR parameters for myocarditis are useful to detect sub-clinical acute cellular rejection after heart transplantation. Comparable results to myocarditis can be achieved with a combination of parameters. KEY POINTS: • Magnetic resonance imaging is useful for the assessment of cardiac allograft rejection. • CMR has a high negative predictive value for exclusion of allograft rejection. • Diagnostic performance is not yet good enough to replace endomyocardial biopsy.

Systemic right ventricles rarely show myocardial scars in cardiac magnetic resonance delayed-enhancement imaging.

OBJECTIVES: To test the hypothesis that myocardial scars cause systolic dysfunction in patients with transposition of the great arteries and a systemic right ventricle. METHODS: We retrospectively analyzed 20 consecutive patients (10 male, mean age 27.3 years) with a systemic right ventricle who underwent cardiac magnetic resonance imaging with 1.5 T. Cine steady-state free-precession sequences were performed to obtain volumes and function. Phase-sensitive inversion-recovery (PSIR) delayed-enhancement imaging was performed to detect myocardial scars. Tricuspid insufficiency was detected with echocardiography. Furthermore, the presence of arrhythmias and New York Heart Association (NYHA) class were assessed. RESULTS: Mean ejection fraction of systemic right ventricles was 43 ± 11 %, mean end-diastolic volume index was 111 ± 37 ml/m(2). Delayed-enhancement imaging revealed only one myocardial scar in the wall of a right ventricular aneurysm. All patients but one (95 %) presented with tricuspid insufficiency. Clinically relevant arrhythmias were present in 13/20 patients (65 %). The majority of patients (90 %) were NYHA class I or II. Arrhythmias, tricuspid insufficiency and NYHA class were not associated with right ventricular ejection fraction. CONCLUSIONS: Although right ventricular function was clearly impaired in our patient cohort, there was only one myocardial scar. Our results show that myocardial scarring assessed by PSIR delayed-enhancement imaging is not the underlying pathology of systemic right ventricular failure.