“Head-down syndrome” in a rabbit
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onset of “head-down syndrome”, also referred to floppy head syndrome or
dropped head syndrome, has been observed in rabbits. The head is tilted
forward and rabbits seem unable to lift it. The forward flexion is caused by
weakness or contraction of the extensor muscles in the neck, which leads to
the inability to hold the head upright and against the force of gravity.
There is no tilting to the side. It may be accompanied by reluctance to move,
decrease of appetite and pain.
It is important to differentiate between muscle
weakness in the neck region, and excessive contraction of the muscles. Typically,
necks weakness relates to one of these categories: motor neuron disease,
auto-immune muscle disorder (myasthenia gravis-like), inflammatory muscle
disease (polymyositis-like) or idiopathic, while contracted neck muscles
relate to torticolis or neurotoxins. Since the flexion of the head is forward
and not to the side, it is unrelated to an active infection by Encephalitozoon
cuniculi or middle/inner ear infection.
spite of a complete physical examination and diagnostic tests such as blood
tests, radiography, and the history of the rabbits, the etiology of this
disorder remains uncertain. Veterinarian were
puzzled by this health disorder. What could it be ?
few years ago, rabbit presented the exact same clinical features and blood
chemistry results and vets were amazed about his condition too: Twilight.
analysis of the blood chemistry panel of Midnight and Twilight
indicates high liver values (AST, ALT, Alk
Phosphatase) and a low level phosphorus (hypophosphatemia). Hypophosphatemia
has typically been associated with fulminant hepatic failure as well as
increased metabolism of phosphorus during hepatic function recovery and
hepatocyte regeneration. A working hypothesis is that these rabbit may have
suffered hepatic encephalopathy as a consequence of fulminant liver
failure and a raised level of blood ammonia.
Affected rabbits were given antibiotics,
fenbendazole and metacam. Treatment consists of supportive care, antibiotics,
control of pain, force-feeding when necessary. Most animals recover between 7
to 14 days. If needed, subcutaneous fluids and feeding with a syringe should
be started. Prognosis is guarded to good. All
affected rabbit recovered within a week.
The following table’s list causes related to difficulties to hold the head high as observed in other herbivorous animals, horses, cattle, sheep and goats. Further causes cannot be excluded.
on the cause, the inability to hold the head upright is reversible or
irreversible. Recovery may be fast, within a week, or take weeks to months. Prognosis
is guarded to good. Treatment consists of supportive care, antibiotics, fluid
management, control of pain, force-feeding when necessary.
Many thanks to Kathleen Bourdelais, Suzanne Trayhan
and Bonnie Salt for sharing the information about Midnight
and for the permission to use the pictures and videos.