IBD and Vitamin D

Hello Summarians!

The interactions between nutrient absorption and function in disease are always fascinating—the ultimate chicken/egg dilemma. One of these studies helps to determine what that relationship might be.

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Head Shaking and Trigeminal Issues in Horses

Headshaking (HS) affects approximately 1% to 4.6% of horses, with idiopathic trigeminal-mediated headshaking (ITMHS) being the most common cause. ITMHS typically affects adult geldings of various breeds and disciplines, causing facial pain and reducing quality of life. The underlying cause remains unclear, but there is evidence of trigeminal nerve (TN) dysfunction, including reduced stimulation thresholds suggesting sensory hyperexcitability. Diagnosis is one of exclusion, supported by characteristic clinical signs, and treatment remains inconsistently effective. 

In humans, trigeminal neuralgia—a condition sharing clinical similarities with ITMHS—is often associated with structural abnormalities of the TN visible on MRI. Inspired by these parallels, the current study aimed to determine whether TN asymmetry, particularly side-to-side differences in trigeminal nerve cross-sectional area (TNCSA), could be detected on high-field MRI in horses with ITMHS. 

The study found that horses with ITMHS had significantly greater TNCSA asymmetry than control horses, suggesting a unilateral morphological alteration of the TN. This aligns with the episodic and sometimes unilateral presentation of clinical signs and resembles the unilateral atrophy seen in human trigeminal neuralgia. However, the direction of the morphological change in horses—whether it represents atrophy, swelling, or other changes—remains unclear. Electrophysiological and histopathological data from previous studies show bilateral nerve dysfunction but do not confirm morphological changes. This study's findings of asymmetry suggest that one side may be more affected than the other, possibly representing varying disease severity or subtypes of ITMHS. 

Not all ITMHS horses showed marked TN asymmetry, which may reflect different disease stages, pathophysiological mechanisms, or individual anatomical variability. No focal lesions were identified, and it remains uncertain whether observed differences result from nerve fiber pathology or perineural changes. The study also notes anatomical variations in the subarachnoid space that might influence MRI measurements. 

Among the measured points (MPs), MP 2 showed the greatest discriminatory power between ITMHS and control horses. Balanced gradient echo MRI sequences provided the best contrast for nerve visualization, though some regions were more susceptible to imaging artifacts. The TN was clearly identifiable in all horses, confirming the feasibility of MRI-based assessment. 

The study found no significant effect of ITMHS duration, bodyweight, or age on TNCSA asymmetry, supporting the use of intra-individual side-to-side comparisons to control for these variables. While heavier horses had larger absolute TNCSA, asymmetry remained independent of weight. Age influenced TNCSA at some MPs but did not confound asymmetry findings. 

Limitations include the small sample size, retrospective design, use of control horses with unrelated intracranial diseases, and lack of histopathological confirmation. Additionally, all measurements were performed by a single non-blinded examiner, limiting reproducibility and generalizability. 

In conclusion, the study provides the first evidence of measurable TN asymmetry in horses with ITMHS, suggesting unilateral morphological changes consistent with TN involvement. MP 1, 2, and 4 are recommended for future clinical assessments, with MP 2 being the most promising. These findings reinforce the role of the TN in ITMHS pathogenesis and support the potential for unilateral therapeutic approaches. Further studies are needed to validate these findings and clarify their clinical significance. 

 F. Heun, J. Delarocque, K. Feige, and M. Hellige, “ Trigeminal Nerve Asymmetry in Horses With Idiopathic Trigeminal-Mediated Headshaking: A Retrospective Case-Control Magnetic Resonance Imaging Study,” Journal of Veterinary Internal Medicine 39, no. 5 (2025): e70196, https://doi.org/10.1111/jvim.70196. 

Bottom line — Can play a role and be visible on imaging.

Mentorship for the Spectrum of Care

The transition from veterinary student to practicing veterinarian is an exciting but challenging time, especially when early-career veterinarians encounter ethical dilemmas related to client financial limitations. One of the most common and distressing situations for new graduates is having to navigate cases where clients cannot afford the recommended standard of care. A spectrum-of-care (SOC) approach—offering a range of diagnostic and treatment options—can help veterinarians provide the best possible care within a client’s limitations, while still meeting professional obligations. However, many veterinary students have limited exposure to SOC training during school, largely due to the predominance of tertiary care models and instruction by specialists who rarely work in primary care. As a result, early-career veterinarians may feel unprepared and unsupported when managing financially constrained cases. 

Mentorship plays a critical role in addressing this training gap. While it traditionally focuses on developing technical skills, effective mentorship also helps early-career veterinarians build communication, decision-making, and leadership skills. Mentors can normalize SOC practice, model it in their own cases, and create safe spaces to discuss liability concerns and fears of professional judgment. These fears—often based on misunderstandings about standard of care—can prevent new veterinarians from embracing SOC approaches. Mentors can reassure mentees by clarifying legal definitions and helping them develop tools like templates, medical record documentation strategies, and communication frameworks to protect against liability and build confidence. 

A structured mentorship framework can further support SOC development by helping mentees identify barriers to care—whether client-related, patient-specific, or systemic. Relationship-centered communication is vital for SOC and includes open-ended questions, reflective listening, transparency, and nonjudgmental engagement. By using these techniques, veterinarians can better understand the client’s context and collaboratively build treatment plans. 

Clinical decision-making is another area where mentors are essential. Early-career veterinarians often struggle with decisions when they can’t rely on full diagnostic workups. Mentors can guide mentees through prioritizing tests and treatments based on clinical reasoning, patient needs, and client limitations. Shared decision-making, where clients actively participate in choosing a treatment path, is also emphasized as a best practice, leading to better outcomes and stronger trust. 

Importantly, SOC practice can positively impact the mental health of early-career veterinarians. Ethical dilemmas, especially when they lead to moral distress, are a significant source of psychological strain in this group. Mentorship provides a crucial outlet to discuss these situations, recognize signs of distress, and support the veterinarian’s evolving professional identity. Veterinarians whose identities align with a challenge-focused mindset may thrive with SOC, while diagnosis-focused individuals may find it more difficult. Awareness of these identities can inform mentorship strategies and even help match veterinarians with clinics that align with their values and expectations. 

Ultimately, SOC is becoming increasingly necessary in clinical practice due to the growing prevalence of financial limitations among clients. As veterinary education continues to evolve, mentorship remains a key mechanism for bridging the training gap. Through thoughtful guidance and support, mentors can empower early-career veterinarians to provide compassionate, effective care while maintaining their well-being and professional satisfaction. 

Boatright, K. M. (2025). Mentorship supports early-career veterinarians in developing the skills necessary for successful spectrum-of-care practice. Journal of the American Veterinary Medical Association  https://doi.org/10.2460/javma.25.06.0362 

Bottom line — results support that this is beneficial.

IBD and Vitamin D

Protein-losing enteropathy (PLE) in dogs, most commonly caused by chronic inflammatory enteropathy (CIE) or intestinal lymphangiectasia (IL), is frequently associated with decreased serum vitamin D concentrations. The pathogenesis of this hypovitaminosis D is likely multifactorial, involving malabsorption, systemic inflammation, and possibly direct loss. Vitamin D deficiency in humans with inflammatory bowel disease (IBD) has been linked to disease severity, and supplementation has shown some benefits, although results have been inconsistent. Similar data are lacking in dogs with PLE. 

This prospective, randomized, double-blinded, placebo-controlled clinical trial evaluated whether oral cholecalciferol (vitamin D3) supplementation in dogs with PLE and serum 25-hydroxyvitamin D (25OHD) concentrations below the reference interval could safely increase 25OHD levels and improve clinical or biochemical outcomes. Thirty dogs were enrolled and randomized to receive either cholecalciferol (400 IU/kg/day) or placebo in addition to standard therapy. Dogs receiving cholecalciferol had significant increases in serum 25OHD concentrations at weeks 2 and 4, without developing hypercalcemia. However, no significant improvements in clinical signs or serum biochemical variables were observed compared to the placebo group. 

Serum albumin levels showed a moderate positive correlation with 25OHD concentrations throughout the study, whereas no consistent correlation was found with vitamin D binding protein (VDBP) or C-reactive protein (CRP). This suggests that improvements in albumin may coincide with improvements in vitamin D status, though causality remains uncertain. Interestingly, many placebo-treated dogs also showed normalization of 25OHD concentrations over time, indicating that standard treatment for PLE may be sufficient to resolve vitamin D deficiency in many cases. 

Cholecalciferol was chosen for its availability and affordability, though previous studies suggest that 25(OH)D3 may be a more potent and efficient form of vitamin D supplementation in dogs. Some variability in 25OHD response was noted, and a few dogs developed elevated 25OHD concentrations, suggesting the need for dose adjustment and monitoring. Persistent or elevated parathyroid hormone (PTH) levels in some dogs despite normalized 25OHD and calcium remain unexplained. 

Study limitations included assay changes mid-study, lack of control over diet type and vitamin D content, and variability in concurrent treatments such as glucocorticoids. Additionally, the study did not assess whether vitamin D deficiency contributes to PLE pathogenesis. Ultimately, while cholecalciferol effectively increased serum 25OHD levels, it did not confer a measurable clinical benefit. Monitoring and reserving supplementation for dogs with persistently low vitamin D despite standard PLE treatment appears to be a reasonable clinical approach. 

Jablonski, S.A., Shropshire, S.B., Watson, V.E., Manchester, A.C., Cridge, H., Lennon, E.M. and Tolbert, M.K. (2025), Treatment of Hypovitaminosis D With Cholecalciferol in Dogs With Protein-Losing Enteropathies: A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial. J Vet Intern Med, 39: e70147. https://doi.org/10.1111/jvim.70147 

Bottom line — Did not show an effect in this study.

Just putting things in perspective …