The pediatric neurological examination (Proceedings)
The neurological examination of puppies and kittens can be challenging. Pediatric patients can be uncooperative and their various stages of development lead to different expectations of normalcy compared to adults. Understanding the normal neurologic development of puppies and kittens enhances our ability to identify neurological abnormalities, correctly localize the abnormalities and generate an appropriate list of differential diagnoses.
Signalment and a thorough history are the first part of any examination. Information regarding problematic parturition, affected littermates, health of the parents, feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) status, nutrition, and vaccination history should be obtained. Time of onset of signs as well as their progression may help to rule in or rule out inherited, developmental, and acquired disorders. Identifying where the patient was obtained may be helpful, because certain animal shelters or regions may have a high incidence of distemper or panleukopenia. Catteries may have a high incidence of feline infectious peritonitis (FIP).1
Puppies and kittens mostly either sleep or nurse during the first two weeks of life. Kittens transition directly from waking to REM sleep2 and may have considerable motor activity during sleep during their first week.3 Until 3 weeks of age EEG patterns in puppies are similar during periods of sleep and waking. EEG patterns become adult like by 8 weeks of age.4Vestibular function is present at birth and is important during positioning with nursing.5 The head can be raised at birth and may be used to right them self. Initially movement is swim-like with coordination improving to reach the ability to maintain an upright posture at about 10-14 days of age.4 At about 5-6 days of age stepping movements in the thoracic limbs may be made if weight is supported. Pelvic limb steps may be made at 7-10 days with support.6 At 18-21 days of age an uncoordinated gait begins.5 Adult posture and balance develops between 6 and 8 weeks of age. Breed variation does exist.4 Histologically the spinal cord is mature by 6 weeks of age.17 The cerebellum develops until 10 weeks of age.8
Tactile placing reactions begin as early as early as 2 days in the thoracic limb and 5 days in the pelvic limbs,9 however these are not consistent until about 5 weeks of age. Hopping reactions may be detected from 6-8 weeks of age with the thoracic limbs developing first.4,6 Extensor postural thrust can be seen by 12-14 days in puppies10 and 14-16 days in kittens.3