CASE REPORT

SPINA BIFIDA WITH SYRINGOMYELIA AND MENINGOCOELE

LEIGH CLARK, B.V.Sc., Ph.D., M.Sc., and CAROL H. CARLISLE, M.V.S., D.V.R.

Veterinary School, University of Queensland, St. Lucia, Queensland, 4067

IN A SHORT-TAILED CAT

Introduction Congenital abnormalities of the lower spine and

spinal cord are well known in Manx cats, which frequently show physical disabilities such as hind- limb paralysis and incontinence of urine and faeccs, and have a high mortality rate (James et a1 1969; Martin 1971). Recently we had the oppor- tunity to study a congenitally short-tailed cat, similar to the Manx “stumpy” form (Kerruish 1964), which had spina bifida in the proximal coccygeal rcgion and a meningocoele which had opened to the exterior. The clinical, radiological and pathological findings arc presented.

Clinical History Thc cat camc from Western Queensland, and

was the only one of its litter affected. Its mother was normal, regularly producing healthy litters, and no deformed cat had been seen in the district previously. The animal’s tail had flaccid paraly- sis, was 6 cm long and kinked. When the cat was castrated at 6 months most of the tail was am- putated to prevent its continual soiling with faeccs. This involved sawing through fused coccygeal vcrtebrae in the region of about the sixth. At that time, and at subsequent examina- tions, the cat exhibited a slightly incoordinated hindquarter gait and strained to urinate and de- faecate evcn when bladder and rectum were

Figure 1. Spinal needle inserted in the lumbar region and fluid exuding from the sinus opening above the third coccygeal vertebra.

392

empty. The meningocoele was not noted when the tail was amputated.

About 3 months later the cat was presented at the clinic of the University of Queensland Veter- inary School because clear fluid was exuding from a mid-dorsal open sinus in the anterior coccygeal region. Two small areas free of hair were present in the midline. The most cranial, just behind the sacrum, was 0.5 cm in diameter, raised, and soft to touch. When this swelling was depressed, clear fluid was expressed from an opening in a similar smaller area immediately caudal to the first. Gentle probing through the opening revealed that beneath the skin the two lesions were confluent, forming a cystic cavity. Fluid removed from the subcutaneous cystic dilatation was examined in the laboratory, and its composition was consistent with normal cere- brospinal fluid. Spinal meningocoele was diag- nosed, and permission for euthanasia given.

Radiographic Fiodhp The cat was anaesthetised and a 22 gauge

spinal needle was inserted into the intervertebral space dorsally between the fifth and sixth lumbar vertebrae. One ml of diluted sodium methiodal* (Funkquist 1962), with additional methylene blue, was introduced into the subarachnoid space until methylene blue-stained fluid flowed from the sinus opening (Figure 1). Radiographs were taken in the lateral and the dorsoventral positions prior to euthanasia with barbiturate. The contrast medium was evident dorsally and ventrally in the neural canal, and extended both cranially and caudally from the site of injection. There was pooling over the second, third and fourth coccygeal ver- tebrae (Figure 2). Lateral radiographs showed that the sinus tract extended to the skin surface over the third coccygeal vertebra. In addition, a wedging of lumbar vertebrae 6 and 7 was illus- trated, with consequent loss of intervertebral disc space. Scoliosis at this site produced curvature to the right.

After autopsy, radiographs were made of separated sacral vertebrae and of the first coccy-

“Skiodan Winthrop Laboratories. New York.

Aitstralian Veterinary Journal, Vol. 5 1, August, 1975

SRNlS N3dO’

Discassion Spina bifida is a well recognised congenital

abnormality in a number of species, and is char- acterised by the failure of the neural arches to unite above the spinal canal (Innes and Saunders 1962). It is a particularly well known defect in Manx cats, where abnormalities affecting lumbar, sacral and coccygeal vertebrae have been des- cribed by James et a1 (1969) and Martin (197 1). Spina bifida extending from thorax to sacrum has also been described in a crossbred Siamese kitten with a tail of normal length (Frye and McFarland 1965).

The condition of meningocoele is part of the spina bifida complex, and describes a non-fusion of the dorsal vertebral laminae with protrusion of the meningcs. Both dura mater and arachnoid form the wall of a meningeal sac (Morison 1970) which is distended with cerebrospinal fluid (Figure 5). Presumably in our case necrosis at 1 point of the wall of the sac and overlying skin allowed escape of fluid onto the skin surface.

Syringomyelia, or tubular cavitation in the spinal cord, has been reported in association with spina bifida in Manx cats (Martin 1971). Although a number of theories have been put for- ward to explain the development of these abnor- malities, their pathogenesis is still not understood (Emery and Lendon 1973).

There were 2 unusual features of the present case; firstly, unlike in the Manx variety of cat (Kerruish 1964), there was no evidence that the developmental defect was inherited, and therefore its cause remains obscure. Secondly, it is unusual that thc meningocoele had opened to the exterior

allowing escape of cerebro-spinal fluid. The latter was the main reason for destroying the ani- mal, because it was considered that the risk of its contracting spinal meningitis was high. The re- maining clinical signs attributable to the spinal defect were a slightly incoordinated hindquarter gait, paralysis of the tail and defective control of urination and defaecation.

&Immng Spina bifida of the proximal coccygeal verte-

bral column with an associated meningocoele is described in a male, mixed breed, congenitally short-tailed cat. The meningocoele had opened onto the skin of the tail allowing periodic escape of cerebrospinal fluid. Other clinical signs ex- hibited by the animal were an abnormal hind- quarter gait, paralysis of the tail and defective control of urination and defaecation.

References Crouch, J . E. (1969)-in “Text-Atlas of Cat Anatomy”.

Emer J L. and Lendon, R. G. (1973)A. Parhd.

Frye, F. i. and McFarland, L. Z. (1965)A. Am. vet. mcd. Ass. 146: 481.

Funkquist, B. ( 1 9 6 2 ) J . small Anim. Pract. 3: 53. Innes, J-. R. M. and Saunders, L. 2. (1962)-in “Com-

parative Neuropathology”. Academic Press; New York.

Lea & Febiger; Philadelpbia.

112 83-

~ - .~~.

James, C. C. M.. Lassman, L. P. and Tomlinson, B. E. Kerruish, D. W. (1964)4 . Cat Generics 1: 16. Martin, A. H. (1971)--Vet. Puthul. 8: 232. Morison. J. E. (1970I-in “Foetal and Neonatal

(196914. Purhol. a?. 269.

Patboiogy”. Butkrwoiths; 3rd cdn.. London. (Received for publication 16 October 1974)

BOOK REVIEW SHEEP ON TELEVISION

This book* is one of a series derived from a popular English television program. It is directed primarily towards animal owners and specifically deals with ani- mal health problems under English conditions. It is not certain whether the unnamed author is a veterinary scientist; 1 suspect not.

The book, liberally illustrated with black and white photographs of questionable value (“over 300 action pictures”), discusses the major diseases of sheep and

*The Tv vet S ~ W D book Recognition and treatment of cum- l v ve.. Iusw c . dhto k. B ,Q..

includes a substantial section on obstetrics and preven- tive medicine.

The book may be acceptable for sheep raisers in Britain, but cannot be recommended for Australian veterinary graduates or undergraduates. It abounds in typographical errors and incorrect statements - a few examples will suffice - scrapie is consistently spelt scrapei (p 161 and index) the pustules of conta~ous pustular dermatitis are said to be due to secondary in- fection of ulcers (p .l55), an! even wope Derma!o- philus congalemsis (sic) infdon (mycotrc dennati!is) lumpy wool, is said to be due to a fungus susceptable to griseofulvin (p 154). At $9.95 t b ~ ~ book is a ”np O f f . J. R. Egerton

394 Australian Veterinary Journal, Vol. 51, August, 1975