page_title: Hypertrophic osteodystrophy
section_title: Clinical Features
hierarchical_section_title: Hypertrophic osteodystrophy / Clinical Features
caption_attribution_description: English: Photograph showing characteristic roaching of 4-month-old puppy with Hypertrophic Osteodystrophy.
context_page_description: Hypertrophic Osteodystrophy is a bone disease that occurs in fast-growing large and giant breed dogs. The disorder is sometimes referred to as metaphyseal osteopathy, and typically first presents between the ages of 2 and 7 months. HOD is characterized by decreased blood flow to the metaphysis leading to a failure of ossification and necrosis and inflammation of cancellous bone. The disease is usually bilateral in the limb bones, especially the distal radius, ulna, and tibia.
  The Weimaraner, Irish Setter, Boxer, German Shepherd, and Great Dane breeds are heavily represented in case reports of HOD in the veterinary literature, but the severity of symptoms and possible etiology may be different across the breeds. For example, familial clustering of the disease has been documented in the Weimaraner, but not in other breeds. The disease in the Weimaraner and Irish Setter can be particularly severe, with significant mortality observed in untreated dogs. The classical age of onset is typically 8 to 16 weeks of age, with males and females equally affected.
context_section_description: A primary characteristics of the condition is lameness.  This is generally due to the swelling of the metaphysis of the long bones that is observed.  Other bones may be affected, particularly the ribs, the metacarpal bones, the mandible, and the scapula.   Lameness may present as mild limping or more severely as a reluctance or inability to stand.  In some breeds and/or individuals, the stance of an HOD puppy as observed from behind has sometimes been described as “cow-hocked.”  Shaking of limbs and a reluctance to put full body weight on the front legs is often observed.  Sometimes the puppy will exhibit a characteristic “roaching” or arching of the spine when standing (see Figure 2).
  Lameness is accompanied by pain upon palpation of affected bones, warmth in the limb as felt by the inside of the clinician's wrist, depression, and loss of appetite.  Limb involvement is usually bilateral, typically involves the distal radius and ulna, and may be episodic.  There is evidence to suggest that most dogs recover after one episode, but some relapse.  Dogs suffering systemic manifestations of the disorder often have poorer prognoses.  Systemic manifestations include fever, multiple body organ inflammation, nasal and ocular discharge, Diarrhea, hyperkeratosis of the foot pads, pneumonia, and tooth enamel hypoplasia (many of these symptoms overlap with symptoms of CDV).  Because early diagnosis must be based on clinical signs, to the extent possible, other disorders should be ruled out (e.g., nutritional bone disease, and osteochondrosis).
caption: Figure 2:  Characteristic roaching in 4-month-old Weimaraner puppy with HOD.
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