ADVANCED STRONG ION CALCULATIONS ANDADVANCED STRONG ION CALCULATIONS ANDTHEIR IMPLICATIONS IN ADVANCEDTHEIR IMPLICATIONS IN ADVANCED

RADIOLOGIC DIAGNOSESRADIOLOGIC DIAGNOSES

or TEACHING YOUNG DOGSSTRANGE TRICKS

BY MASON YATES SAVAGE, DVMBased on case #131636

Luna• 6 year old female spayed Miniature Schnauzer

• Presented to the Soft Tissue Surgery Service on 8/4/2011 for surgical repair of a non-healing gastrotomy stoma site

• G-tube was placed in 11/2007 and was non-invasively removed on 9/2010

• Since removal, patient would regularly leak gastric contents from the stoma site

Surgical Removal• Surgical repair proceeded without incident

• Patient recovered well with no immediate post-operative complications

• Histopathology consistent with moderate, chronic, focally extensive ulcerative dermatogastritis

• Largely unremarkable procedure... save for peri-operative blood-work

Not to worry...Luna’s historical

bloodwork is largely similar

Not to worry...Luna’s historical

bloodwork is largely similar

So, perhaps we should discuss Luna’s original reason for g-tube

placement...

• The greatest power transfer in the history of man occurred...

The Year Was 2007

• A young man embarked on an epic path towards becoming a veterinarian...

The Year Was 2007

• And Luna presented to the NCSU ER Service for recumbency, collapse, and mental dullness

• Most significant finding on bloodwork was marked hypernatremia (190 on admission)• Pseudohypernatremia - dehydration• Excessive water loss - consider panting, renal

losses (as with diabetes insipitus and lack of ADH)• Inadequate water intake - primary adipsia

The Year Was 2007

Imaging Results• Abdominal Ultrasound

• Questionable cholecystitis• Questionable left glomerulonephritis• Questionable hepatic nodule, non-specific

• Echocardiogram • Normal

• MRI...

SULLIVAN, S.A., HARMON, B.G., PURINTON, P.T., GREENE, C.E., GLERUM, L.E. (2003) Lobar holoprosencephaly in a Miniature

Schnauzer with hypodipsic hypernatremia. Journal of the American Veterinary Medical Association 223, 1783–1787

Holoprosencephaly• Embryologic defects arising from defective

development of the floor plate of the prosencephalon

• The floor plate is essential for aiding in the development of overlying structures• Defective floor plate causes aplasia or hypoplasia of median

and paramedian forebrain structures

• Key Features• Aplasia/hypoplasia of midline structures• Incomplete separation of normal paired structures• Commonly see single forebrain ventricle, absence or

hypoplasia of corpus callosum and septum pellucidum

SULLIVAN, S.A., HARMON, B.G., PURINTON, P.T., GREENE, C.E., GLERUM, L.E. (2003) Lobar holoprosencephaly in a Miniature Schnauzer with hypodipsic hypernatremia. Journal of the American

Veterinary Medical Association 223, 1783–1787

Miller’s Anatomy of the Dog - 4th Edition

Holoprosencephaly• Three degrees:

• Alobar - complete lack of separation of cerebral hemispheres

• Semilobar - rostral hemispheres fuse, occipital lobes are distinct

• Lobar - mildest with well formed cerebral hemispheres and less extensive fusion of midline structures, especially caudally

• Cause commonly unknown• In lambs exposure to Veratrum californicum on day 14 of

gestation can cause malformation

Holoprosencephaly• Previous Reports

• Stillborn puppy with cyclopia• Two reports of dogs with hypodipsic

hypernatremia• Absent septum pellucidum and septal neuclei, enlarged

lateral ventricles, and absent corpos callosum on post• Cat with hypodipsic hypernatremia

• CT images strongly resembled described holoprosencephalic changes

Holoprosencephaly• Adipsia pathogenesis

• Osmoreceptor cells (osmostats) located in anterior wall of 3rd ventricle

• A dysfunction of the osmostats is suspected in these patients

• However dysfunction of of other forebrain mediators of thirst and drinking behavior cannot be ruled out

Luna’s Story• G-tube was placed as she was adipsic in

hospital and for fear of continued hypodipsia or adipsia

• Recovered well from procedure and was discharged uneventfully

• Within 1 year, learned to drink on command and no longer needed water administration by g-tube

• Continues to do well at home post-operatively

Lightning Round

• Name that malformation

Name that Malformation

• Increased volume of intracranial cerebrospinal fluid

• Can occur within the ventricular system (internal _____) or surrounding the brain (external ______)

HYDROCEPHALUS

Hydrocephalus

• Categories• Internal or External• Obstructive or Non-

obstructive (compensatory)

Name that Malformation

• Cerebrum is destroyed in utero and replaced by CSF-filled cavity with no residual neural parenchyma

HYDRANENCEPHALY

Name that Malformation

• CSF-filled cavity within the brain that communicates with the ventricular system or subarachnoid space

PORENCEPHALY

Name that Malformation

• Failure of the forebrain to bifurcate into 2 discrete cerebral hemispheres

• Exists in 3 forms• A_____• Semi_____• and ______

PROSENCEPHALY

Name that Malformation

• Disorder of cortical neuronal migration

• Brain fails to form normal surface convolutions

• Smooth surface appearance

LISSENCEPHALY

Lissencephaly• Has been reported in

dogs and cats• Clinical signs include

abnormal mentation, behavioral abnormalities, delayed postural reactions, and seizures

• Bonus Question:• Thought to be

hereditary in this breed of dog?• Lhasa Apso’s

Name that Malformation

• Rare malformation of cerebrum

• Excessive number of small, histologically anomalous gyri

POLYMICROGYRIA