Increased Digital Pulse Cases in Equine Lameness

Introduction to Increased Digital Pulse Cases

• Increased digital pulse is a significant indicator of various underlying conditions affecting equine health. Understanding the causes, implications, and diagnostic approaches is crucial for veterinarians and horse owners alike.

Key Questions Addressed

• Why does the digital pulse increase?
  Increased digital pulse can occur due to inflammation, increased blood flow, or pain in the hoof or distal limb, often due to injury or disease.

• Where do I palpate it?
  Palpation is typically performed over the fetlock and the pastern on the medial and lateral aspects of the leg, focusing on the digital arteries.

• How do I know if it's raised?
  A raised digital pulse feels firmer and ‘bounding’ compared to the normal pulse. It requires careful comparison to the opposite leg to identify abnormalities.

• What is the systematic approach for examination and diagnosis?
  A comprehensive approach involves a thorough history, static and dynamic examination, and targeted diagnostic tests.

• How do I use hoof testers?
  Proper technique involves using consistent pressure on marked areas of the hoof to elicit pain, helping to identify the source of lameness.

• How do I determine the location of pathology based on physical findings?
  Identify areas of swelling, heat, or pain and correlate these with the horse's behavior during motion and response to hoof testers.

• What are the differential diagnoses?
  A systematic approach to identify all potential conditions that could cause increased digital pulse.

• How does disease cause increased digital pulses?
  Various diseases induce vascular changes and inflammation, leading to increased pulse strength as blood flow is affected.

Palpation of Digital Pulse

• Normal Digital Pulse:

• This pulse can be faint and challenging to detect, particularly in horses with thick skin, feathered limbs, or significant muscle mass. It often requires practice to achieve proficiency in detecting a subtle pulse.

• Raised Digital Pulse:

• A raised digital pulse is noticeably more pronounced and is often described as ‘bounding’ or thumping. Comparative assessment to other legs is crucial for determining the relative severity of the condition.

• Assessment of Number of Affected Limbs:

• The number of limbs affected provides insight into the potential spread of disease and assists in forming a differential diagnosis, helping to ascertain if the issue is localized or systemic.

Static Examination

• Observe the Horse's Posture and Movement:

• Determine if the horse is recumbent or standing, as this can indicate varying states of pain or distress. Look for signs like generalized distal limb swelling or localized heat and pain in specific joints, such as the digital flexor tendon sheath, fetlock, or coffin joints.

• Check Hoof Temperature:

• Assess temperature variations in the hooves, as increased warmth can signify inflammation or infection. Also check for wounds, hoof cracks, abnormal hoof rings, defects in the sole, and the type and integrity of the hoof shoe, as these can all provide clues to underlying issues.

Hoof Testers

• Purpose:

• Hoof testers are used to apply pressure to specific areas of the hoof to elicit a pain response, which can be generalized or localized, helping to pinpoint the source of lameness.

• Technique:

• Secure the horse's leg using your own to effectively use both hands, applying gradual pressure on four quadrants of the hoof. Systematically work from one heel to the other and corroborate findings with percussion techniques.

• Tip:

• Examination can often yield more accurate results when shoes are removed if appropriate, allowing for a thorough evaluation of the hoof capsule and surrounding structures.

Dynamic Examination

• Evaluate Movement:

• Assess the horse's locomotion at both walk and trot, particularly during turns as this can exacerbate lameness. Grading of lameness is crucial for establishing its severity:

  • Grade 0: Sound

  • Grade 1: Mild inconsistent lameness

  • Grade 2: Mild consistent lameness

  • Grade 3: Moderate consistent lameness

  • Grade 4: Severe consistent lameness

  • Grade 5: Unable to bear weight

• Further Assessment:

• To enhance diagnosis, consider removing shoes and re-evaluating with hoof testers, as well as using hoof knives to pare the foot and check for discolouration, discharge, or white line deviation which may indicate specific pathologies.

Differential Diagnosis List

• Common Conditions Associated with Digital Pulse Increase:

• Laminitis

• Subsolar abscess

• Fracture

• Bruising

• Corns

• Keratoma

• Septic pedal osteitis

• Thrush in frog clefts

Definitive Diagnosis

• Achieved Through:

• A detailed history of the horse’s health, noting any recent changes in behavior, diet, or environment.

• A comprehensive clinical examination combining both static and dynamic assessments.

• Use of diagnostic imaging such as radiography or MRI/CT when needed, although use of advanced imaging techniques may be rare.

• Conclusion:
  Understanding these factors and processes is essential for veterinarians to accurately diagnose increased digital pulse cases in equines, allowing for timely and effective treatment that can improve outcomes and horse welfare.