Transcranial Doppler Ultrasound Examination in Dogs with Suspected Intracranial Hypertension Caused by Neurologic Diseases

Background

Transcranial Doppler ultrasound examination (TCD) is a rapid, noninvasive technique used to evaluate cerebral blood flow and is useful for the detection of intracranial hypertension in humans. However, the clinical usefulness of TCD in diagnosing intracranial hypertension has not been demonstrated for intracranial diseases in dogs.

Objectives

To determine the association between the TCD variables and intracranial hypertension in dogs with intracranial diseases.

Animals

Fifty client‐owned dogs with neurologic signs.

Methods

Cross‐sectional study. All dogs underwent TCD of the basilar artery under isoflurane anesthesia after magnetic resonance imaging (MRI). Dogs were classified into 3 groups based on MRI findings: no structural diseases (group I), structural disease without MRI evidence of intracranial hypertension (group II), and structural disease with MRI evidence of intracranial hypertension (group III). The TCD vascular resistance variables (resistive index [RI], pulsatility index [PI], and the ratio of systolic to diastolic mean velocity [Sm/Dm]) were measured.

Results

Fifteen, 22, and 13 dogs were classified into groups I, II, and III, respectively. Dogs in group III had significantly higher Sm/Dm (median, 1.78; range, 1.44–2.58) than those in group I (median, 1.63; range, 1.43–1.75) and group II (median, 1.62; range, 1.27–2.10). No significant differences in RI and PI were identified among groups.

Conclusions and Clinical Importance

Our findings suggest that increased Sm/Dm is associated with MRI findings of suspected intracranial hypertension in dogs with intracranial diseases and that TCD could be a useful tool to help to diagnose intracranial hypertension.     

ULTRASONOGRAPHIC DIAGNOSIS OF CANINE HYDROCEPHALUS

The brains of 23 canine patients and six random-source dogs were examined ultrasonographically through the bregmatic fontanelle or a surgical craniotomy. Fifteen dogs had abnormal neurologic signs; the others were normal on neurologic examination. Untrasound results were compared with signalment, clinical signs, electroencephalography, computed tomography, radiology and histopathology. The purposes of the study were to demonstrate the use of ultrasound for the diagnosis of canine hydrocephalus and to determine whether there is a relationship between ventricular size and clinical signs. Lateral ventricles were considered enlarged if lateral ventricular height, ventricle-mantle ratio, or ventricle-hemisphere ratio, at the level of or caudal to the interthalamic adhesion in the transverse plane, exceeded 0.35 cm, 0.25 or 0.19, respectively. Of the 29 dogs examined, 14 had enlarged lateral ventricles and abnormal neurologic signs. Five dogs had enlarged lateral ventricles but appeared neurologically normal (occult hydrocephalus). Correlation was poor between ventricular size and clinical signs.     

Acute encephalitis and hydrocephalus in dogs caused by canine parainfluenza virus

Gnotobiotic puppies were inoculated intracerebrally with a strain of canine parainfluenza virus (CPI-78-238). Four of eight dogs developed histological evidence of acute encephalitis. Clinical signs of encephalitis were seen in two of these four dogs; one had signs and lesions of interstitial pneumonia. Of six inoculated dogs observed for six months after infection, five developed internal hydrocephalus. Virus was reisolated from two dogs with acute encephalitis but not from dogs with hydrocephalus. Hemagglutination-inhibition antibodies persisted throughout the observation period of six months at high levels in the serum and cerebrospinal fluid of hydrocephalic dogs.     

Surgical technique, postoperative complications and outcome in 14 dogs treated for hydrocephalus by ventriculoperitoneal shunting

Objective: To report frequency and type of complications, and outcome in dogs with severe neurologic signs secondary to internal, suspected obstructive hydrocephalus treated by ventriculoperitoneal (VP) shunting. Study Design: Case series. Animals: Dogs (n=14). Methods: Medical records (2001–2006) was reviewed for dogs that had VP shunting. Inclusion criteria were complete medical record, progressive forebrain signs unresponsive to medical treatment, normal metabolic profile, negative antibody titers and/or cerebrospinal PCR for Toxoplasma gondii, Neospora caninum, and canine distemper virus, magnetic resonance images of the brain, confirmed diagnosis of VP shunting, and follow‐up information. Results: Hydrocephalus was idiopathic in 5 dogs and acquired (interventricular tumors, intraventricular hemorrhage, inflammatory disease) in 9 dogs. Four dogs developed complications 1 week to 18 months postoperatively, including ventricular catheter migration, infection, shunt under‐drainage, kinking of the peritoneal catheter, valve fracture, and abdominal skin necrosis. Three of these dogs had 1 or more successful revision surgeries and 1 dog was successfully treated with antibiotics. All, but 1 dog, were discharged within 1 week of surgery, and had substantial neurologic improvement. Median survival time for all dogs was 320 days (1–2340 days), for dogs with idiopathic hydrocephalus, 274 (60–420) days and for dogs with secondary hydrocephalus, 365 (1–2340) days. Conclusions: VP shunting was successful in relieving neurologic signs in most dogs and postoperative complications occurred in 29%, but were resolved medically or surgically.     

MAGNETIC RESONANCE IMAGING FINDINGS ASSOCIATED WITH LATERAL CEREBRAL VENTRICULOMEGALY IN ENGLISH BULLDOGS

Multiple congenital or developmental anomalies associated with the central nervous system have been reported in English Bulldogs. The purpose of this retrospective study was to identify and describe the prevalence and MRI characteristics of these anomalies and their association with presence and degree of cerebral ventriculomegaly. Magnetic resonance imaging studies of 50 English Bulldogs were evaluated. Forty‐eight dogs had some degree of cerebral ventriculomegaly, 27 of which had an otherwise normal brain. Presence of lateral ventriculomegaly was not significantly associated with presence of another intracranial lesion. Appearance of the septum pellucidum was variable, ranging from intact to incomplete or completely absent. The corpus callosum was subjectively thinned in all but three dogs, two of which had normal lateral ventricles. Fusion of the rostral colliculi was not found in any dog. A persistent craniopharyngeal canal was identified in one dog. Aqueductal stenosis caused by fusion of the rostral colliculi was not identified in any dog. Findings indicated that cerebral ventriculomegaly is a common finding in English Bulldogs with or without other intracranial lesions, aqueductal stenosis caused by fusion of the rostral colliculi is unlikely to be a common etiology leading to obstructive hydrocephalus, and a large craniopharyngeal canal is a rare finding that has unknown clinical significance at this time.     

COMPARISON BETWEEN ULTRASONOGRAPHIC AND CLINICAL FINDINGS IN 43 DOGS WITH GALLBLADDER MUCOCELES

Cholecystectomy is the current standard recommended treatment for dogs with gallbladder mucoceles. However, medical management with monitoring has also been recommended for asymptomatic dogs. The purpose of this retrospective study was to compare ultrasonographic patterns of gallbladder mucoceles with clinical disease status in a group of dogs. For each included dog, the ultrasonographic pattern of the mucocele was classified into one of six types: type 1, immobile echogenic bile; type 2, incomplete stellate pattern; type 3, typical stellate pattern; type 4, kiwi like pattern and stellate combination; type 5, kiwi like pattern with residual central echogenic bile; and type 6, kiwi like pattern. A total of 43 dogs were included. Twenty‐four dogs, including 11 dogs with gallbladder rupture, were symptomatic. Nineteen dogs were asymptomatic. Cholecystectomy (n = 19), medical therapy (n = 17), or monitoring (n = 6) treatments were applied according to clinical signs and owners’ requests. One dog suspected of having gallbladder rupture was euthanized. Frequencies of gallbladder mucocele patterns were as follows: type 1 = 10 (23%), type 2 = 13 (30%), type 3 = 5 (12%), type 4 = 11 (26%), type 5 = 4 (9%), and type 6 = 0. In dogs with gallbladder rupture, type 2 (8/13) was the most common. No significant correlations were found between ultrasonographic patterns of gallbladder mucoceles and clinical disease status or gallbladder rupture. Findings indicated that ultrasonographic patterns of gallbladder mucoceles may not be valid bases for treatment recommendations in dogs.     

Clinical and imaging findings,treatments, and outcomes in 27 dogs with imaging diagnosed trigeminal nerve sheath tumors: A multi‐center study

The clinical behavior of canine trigeminal nerve sheath tumors and benefits of previously reported treatments are incompletely defined. Aims of this retrospective, multicenter, observational study were to describe clinical signs, tumor localization characteristics, treatments, and clinical outcomes in a group of dogs with this neoplasm. Databases at four hospitals were reviewed for dogs with a trigeminal nerve sheath tumor diagnosis, magnetic resonance imaging (MRI) studies, and presentation between 2004 and 2014. A single observer recorded medical record findings and two observers recorded MRI characteristics by consensus. A total of 27 dogs met inclusion criteria (15 treated with stereotactic radiation therapy and 12 unirradiated). Two unirradiated dogs were excluded from outcome analyses. The most common presenting signs were masticatory muscle atrophy (26 dogs), neurologic signs referable to intracranial disease (13), and ocular disease (12). Based on MRI findings, all dogs had disease extending centrally at the level of the brainstem. The most commonly affected trigeminal nerve branches were the mandibular (26 dogs), maxillary (22), and ophthalmic (10). Of 15 dogs treated with stereotactic radiation therapy, one had improved muscle atrophy, and six had poor ocular health after treatment. Neurologic signs improved in 4/5 dogs with intracranial signs. Overall median survival time for the 10 unirradiated dogs with available follow‐up was 12 days and 441 days for the 15 stereotactic radiation therapy dogs. Mean survival times between these groups were not significantly different (mean 95% CI for unirradiated dogs was 44–424 days and mean 95% CI for stereotactic radiation therapy dogs was 260–518 days).     

MORPHOLOGY OF THE CAUDAL FOSSA IN CAVALIER KING CHARLES SPANIELS

Chiari malformations and syringohydromyelia are an important disease complex in Cavalier King Charles Spaniels. Although abnormalities in caudal fossa morphology are considered major contributors to the development of this disease, limited information exists on the range of morphologies in Cavalier King Charles Spaniels and on the relationship of these to clinically evident disease. Sixty-four Cavalier King Charles Spaniels were studied. Each underwent a neurologic examination and magnetic resonance imaging of the cervical spine and brain. T2-weighted sagittal images were used to determine both the morphologic characteristics and volume of the caudal fossa in each dog. This volume was also analyzed as a percentage of total cranial cavity volume. Each attribute was correlated with neurological grade and presence of syringohydromyelia. Fifteen dogs had neurologic signs, and 59 had morphologic abnormalities of the craniocervical junction. While 27 dogs had syringohydromyelia, 13 of these were clinically normal. Cerebellar herniation and occipital dysplasia were common findings but were not associated with syringohydromyelia. Dorsal compressive lesions were noted at the first and second cervical vertebral junction. Factors associated with the presence of neurologic signs included syringohydromyelia and the ratio of caudal fossa/total cranial cavity volume; dogs with signs had significantly larger syringohydromyelia than asymptomatic dogs. Caudal fossa size was not associated with syringohydromyelia. A positive association was identified between foramen magnum size and length of cerebellar herniation. The prevalence of craniocervical junction abnormalities is high in Cavalier King Charles Spaniels. While several factors are associated with neurologic signs, occipital hypoplasia appears to be the most important factor.     

Evaluation of transformation growth factor beta1, interleukin-10, and interferon-gamma in male symptomatic and asymptomatic dogs naturally infected by Leishmania (Leishmania) chagasi

The aims of this study were to evaluate the immunomodulatory role of TGF-β₁, IL-10, and INF-γ in spleen and liver extracts and supernatant cultures of white spleen cells from male symptomatic and asymptomatic dogs, naturally infected by Leishmania (Leishmania) chagasi. Thirty dogs from Araçatuba, São Paulo, Brazil, an endemic leishmaniosis area, were selected by positive ELISA serological reaction for Leishmania sp. and divided into two groups: asymptomatic (n = 15) and symptomatic (n = 15) consisting of animals with at least three characteristic signs (fever, dermatitis, lymphoadenopathy, onychogryphosis, weight loss, cachexia, locomotion problems, conjunctivitis, epistaxis, hepatosplenomegaly, edema, and apathy). After euthanasia, spleen and liver fragments were collected for ex vivo quantification of TGF-β₁, IL-10, and INF-γ. Naturally active in vitro produced TGF-β₁ was also evaluated in spleen cell culture supernatant. Spleen and liver extract of asymptomatic dogs had higher mean TGF-β₁ levels than symptomatic dogs. High concentrations of IL-10 were found in spleen, and mainly in liver extract of both groups. Higher INF-γ concentrations were found in spleen extracts of symptomatic dogs, and in liver extracts of asymptomatic dogs. Extract of this cytokine was lower in spleen extract. Although INF-γ is being produced in canine infection, mean levels of TGF-β₁ and IL-10 from spleen and liver extracts were quantitatively much higher; suggesting that immune response in both asymptomatic and symptomatic dogs was predominantly type Th2.     

ASSOCIATIONS BETWEEN CARDIOPULMONARY VARIABLES AND THE CEREBROSPINAL FLUID SIGNAL-VOID SIGN IN SMALL-BREED DOGS

The cerebrospinal fluid (CSF) signal-void sign is a CSF signal loss, especially on T2-weighted magnetic resonance (MR) images. The CSF signal-void sign is often seen in small dogs with hydrocephalus and syringomyelia. In people, this sign is attributed to high velocity or turbulent CSF flow resulting from normal arterial pulsations, but is more pronounced in hydrocephalic patients with reduced intracranial compliance. If dogs are similar, then detection of this sign might be influenced by cardiovascular variables affected by anesthesia or related to intracranial compliance (e.g., blood pressure) or that affect CSF flow (e.g., heart rate). Therefore, the purpose of this study was to investigate whether the CSF signal-void sign is associated with these cardiovascular variables. The sample population consisted of 53 small-breed (<15 kg) anesthetized dogs undergoing spin echo, T2-weighted MR imaging of the neurocranium. Heart rate, blood pressure (systolic, mean, diastolic, pulse), and end-tidal CO₂ were recorded and dogs were grouped as having a CSF signal-void sign in the mesencephalic aqueduct (19/53) or not (34/53). Normality was confirmed and t -tests used. No statistical difference was detected between groups for any of the cardiovascular variables. However, the sample size was too small to accept the null hypothesis that no difference existed between groups for any of the variables assessed. Therefore, although it is uncertain whether the investigated variables alter the frequency of detecting a CSF signal-void sign, any possible relationship does not appear strong.     

T2‐WEIGHTED MAGNETIC RESONANCE IMAGING MEASUREMENTS OF OPTIC NERVE SHEATH DIAMETER IN DOGS WITH AND WITHOUT PRESUMED INTRACRANIAL HYPERTENSION

Intracranial hypertension is a cause of cerebral ischemia and neurologic deficits in dogs. Goals of this retrospective study were to test interobserver agreement for MRI measurements of optic nerve sheath diameter and associations between optic nerve sheath diameter, signalment data, and presumed intracranial hypertension status in a cohort of dogs. A veterinary radiologist interpreted scans of 100 dogs and dogs were assigned to groups based on presence or absence of at least two MRI characteristics of presumed intracranial hypertension. Two observers who were unaware of group status independently measured optic nerve diameter from transverse T2‐weighted sequences. Mean optic nerve sheath diameter for all dogs was 3 mm (1–4 mm). The mean difference between observers was 0.3 mm (limits of agreement, ?0.4 and 1.0 mm). There was no correlation between optic nerve sheath diameter and age for either observer (r = ?0.06 to 0.00) but a moderate positive correlation was observed between optic nerve sheath diameter and body weight for both observers (r = 0.70–0.76). The 22 dogs with presumed intracranial hypertension weighed less than the 78 dogs without (P = 0.02) and were more often female (P = 0.04). Dogs with presumed intracranial hypertension had a larger ratio of optic nerve sheath diameter to body weight for each observer‐side pair (P = 0.01–0.04) than dogs without. Findings indicated that the ratio of MRI optic nerve sheath diameter relative to body weight may be a repeatable predictor of intracranial hypertension in dogs.     

Polymorphism,coupling interval and prematurity index in dogs with degenerative mitral valve disease and ventricular arrhythmias

Ventricular arrhythmias (VA) are a recognized concern in dogs with degenerative mitral valve disease (DMVD). The coupling interval (CI) and the prematurity index (PI) have been shown to accurately differentiate between benign and malignant VA in people, where ventricular arrhythmias are known to be associated with an increased risk of development of signs of heart failure or sudden death. In this study, we characterized ventricular arrhythmias in dogs with symptomatic and asymptomatic DMVD. Seventy dogs with naturally-occurring DMVD and ventricular arrhythmias were retrospectively studied. A cross-sectional investigation including dogs with either symptomatic (stages C/D; n?=?41) or asymptomatic (stages B1/B2; n?=?29) DMVD was performed. Electrocardiographic tracings were reviewed to calculate both the CI and PI. In eight dogs these indices were compared with those obtained from both a Holter recording and a standard ECG tracing and no statistical differences were found (CI, p?=?0.97; PI, p?=?0.17). Even though CI and PI were determined in all animals enrolled in the study, VPC characteristics were only compared between symptomatic and asymptomatic dogs when a 24-h Holter recording was available (n?=?49). The PI was different (p?=?0.01) between symptomatic (0.65?±?0.17) and asymptomatic (0.56?±?0.18) dogs, but CI was considered similar (p?=?0.91). Also, the symptomatic dogs had more polymorphic VPC (p?=?0.002) and supraventricular arrhythmias (p?=?0.0002) than the asymptomatic animals. Polymorphism, and repeating patterns of ventricular premature complexes, were characteristics frequently present in overtly symptomatic animals affected by mitral endocardiosis.     

IDENTIFICATION OF ARACHNOID CYSTS IN THE QUADRIGEMINAL CISTERN USING ULTRASONOGRAPHY

The ultrasonographic findings in three small breed dogs with intracranial arachnoid cysts are described. Ultrasound images were obtained via the foramen magnum, temporal window and persistent bregmatic fontanelle (when possible). In transverse, dorsal and sagittal transcranial ultrasound images there was marked dilation of the lateral ventricles and a well-defined, oval to triangular-shaped anechoic area between the caudal aspect of the occipital lobes, dorsal to the midbrain, and rostral to the cerebellum. These findings were consistent with a diagnosis of concurrent hydrocephalus and an arachnoid cyst within the quadrigeminal cistern.     

Clinical signs, magnetic resonance imaging features, and outcome after surgical and medical treatment of otogenic intracranial infection in 11 cats and 4 dogs

Brainstem dysfunction resulting from central extension of infection is a life-threatening complication of otitis media/interna (OMI) that has been described infrequently in dogs and cats. We review the clinical signs of disease, diagnostic findings, and results of surgical and medical treatments of brainstem disease attributable to otogenic intracranial infection in cats and dogs. Eleven cats and 4 dogs were examined because of acute, subacute, or chronic clinical signs of brain disease including central vestibular signs, altered mentation, abnormal posture/gait, cranial nerve deficits, and seizures. Results of a minimal database (CBC, serum biochemical panel, urinalysis, thoracic radiographs, and abdominal ultrasonographic images or radiographs) were within reference intervals in all animals. Magnetic resonance (MR) images of the head were acquired for all animals, and cisternal cerebrospinal fluid (CSF) from 9 of 11 cats and 3 of 4 dogs was examined. Surgical exploration and ventral bulla osteotomy were done for 12 of 15 animals, followed by 1–3 months of antibiotic therapy; the remaining animals were euthanized before treatment. In all animals, MR imaging was effective in characterizing the location and extent of the pathologic changes intracranially as well as within middle/inner ear structures. Results of CSF analysis were characteristic of bacterial infection in most of the animals with acute or subacute disease. Since long-term outcome in all treated animals was very good to excellent, it was concluded that dogs and cats with intracranial disease secondary to extension of otitis media/interna have a good-to-excellent prognosis when the condition was diagnosed and was treated by surgical exploration and appropriate antibiotic therapy.     

Canine prostate specific esterase (CPSE) as an useful biomarker in preventive screening programme of canine prostate: CPSE threshold value assessment and its correlation with ultrasonographic prostatic abnormalities in asymptomatic dogs

Due to the increased attention that pet‐owners devote to their animals and to the improved veterinary care, investigations regarding methods to early detect prostatic disorders that might affect canine life quality have been performed. Canine prostate specific esterase (CPSE) concentration was reported to be higher in dogs suffering from prostatic diseases. This study aimed to estimate the CPSE threshold as a biomarker to early identify prostatic diseases in asymptomatic dogs. The ultrasonographic examination of the prostate was performed in 19 dogs (6–40 kg; 1–5 years) with no symptoms of prostatic diseases. Dogs were grouped according to the presence (Group A) or absence (Group B) of prostatic disorders at the ultrasound (altered appearance, the presence of cysts or irregular borders). For each dog, a venous blood sample was collected to measure serum CPSE and the ratio between calculated and normal expected prostatic volume was assessed for each dog. The CPSE data were statistically analysed (t test, p < .05), and the CPSE threshold in blood serum between groups was calculated by ROC. In 11 dogs, ultrasonography showed signs of prostatic abnormalities (Group A, 2–5 years), while no signs were detected in eight dogs (Group B, 1–3 years). The calculated/estimated volume ratio resulted greater than 1.5 in Group A dogs. The CPSE was statistically different between groups (p < .0001): higher in Group A (mean = 184.9, SD = 126 ng/ml) than in Group B (38.9 ± 22.1 ng/ml). The cut‐off CPSE threshold was 52.3 ng/ml (ROC, AUC = 0.974, SE 95.6%, SP 89.2%). This study suggests that CPSE serum concentration higher than 50 ng/ml in asymptomatic dogs is associated with ultrasonographic alterations and increased the prostatic size (volume by 1.5 times greater than the normal size). As the onset of prostatic disorders often remains asymptomatic, the rapid assessment of CPSE could be suitable for selecting preventively those animals that would require further accurate evaluation.     

Neurologic, endocrinologic, and pathologic findings associated with large pituitary tumors in dogs: eight cases (1976-1984)

Invasive tumors of the pituitary gland were diagnosed in 8 dogs. Seven of the dogs had been treated for pituitary-dependent hyperadrenocorticism before the onset of neurologic signs. All 8 dogs had behavior abnormalities and similar neurologic signs: 6 dogs had rotary nystagmus and 7 dogs had symmetric tetraparesis. Once neurologic signs developed, the clinical course in all 8 dogs had a mean duration of 4.7 +/- 2.0 months before death or euthanasia; 5 dogs had a clinical course of less than or equal to 2 months. Necropsy was performed in 7 dogs. The histologic diagnosis was malignant pituitary adenocarcinoma in 2 dogs and pituitary adenoma in 5 dogs.     

Neurologic dysfunction in hypothyroid, hyperlipidemic Labrador Retrievers

BACKGROUND: Hypothyroidism has been associated with a variety of neurologic signs, but the mechanism for this association is not completely understood. Hypothyroidism also is associated with hyperlipidemia that predisposes to atherosclerosis, increased blood viscosity, and thromboembolic events. OBJECTIVE: The objective is to characterize neurologic signs potentially associated with hyperlipidemia and atherosclerosis in canine hypothyroidism. ANIMALS: This study used dogs referred to North Carolina State University Veterinary Teaching Hospital for evaluation of neurologic signs. MATERIALS AND METHODS: A retrospective study was conducted in which medical records of dogs with neurologic signs and a diagnosis of hypothyroidism and hyperlipidemia were reviewed. Details of the history, presenting signs, results of routine blood tests, thyroid tests, cerebrospinal fluid (CSF) analysis and diagnostic imaging, and response to therapy were compiled. RESULTS: Three Labrador Retrievers and one Labrador Retriever cross fit the inclusion criteria. All dogs were hypothyroid and severely hyperlipidemic. Neurologic signs included tetraparesis, central and peripheral vestibular signs, facial paralysis, and paraparesis. Two dogs had an acute history and rapid resolution of signs consistent with an infarct, the presence of which was confirmed in 1 of the dogs by magnetic resonance imaging. Two dogs had chronic histories of cranial neuropathies and paraparesis. One of these dogs had evidence of iliac thrombosis and atherosclerosis on ultrasound examination. All dogs improved with thyroid hormone supplementation. CLINICAL RELEVANCE: Labrador Retrievers may be predisposed to the development of severe hyperlipidemia in association with hypothyroidism. One possible consequence of severe hyperlipidemia is the development of neurologic signs due to atherosclerosis and thromboembolic events.     

IMAGING DIAGNOSIS—TRANSCRANIAL COLOR‐CODED DUPLEX SONOGRAPHY IN A DOG WITH HEPATIC ENCEPHALOPATHY

We report the use of transcranial Doppler ultrasonography in a dog with hepatic encephalopathy secondary to a congenital portosystemic shunt. A severe increase in the pulsatility index was measured in the right middle cerebral artery, left middle cerebral artery, and basilar artery. These values returned to normal following medical stabilization of the patient and resolution of the neurologic signs. Transcranial Doppler ultrasonography appears to have value for monitoring the status of intracranial hypertension in patients with hepatic encephalopathy.     

Pituitary tumor size, neurologic signs, and relation to endocrine test results in dogs with pituitary-dependent hyperadrenocorticism: 43 cases (1980-1990).

Pituitary neoplasm was identified in 43 dogs with pituitary-dependent hyperadrenocorticism via necropsy (n = 33), diagnostic imaging with computerized tomography or magnetic resonance imaging (n = 5), or diagnostic imaging and necropsy (n = 5). All dogs had clinical signs and clinicopathologic test results typical of hyperadrenocorticism. Thirty-seven dogs had grossly visible pituitary tumors, and 6 dogs had microscopic pituitary tumors. Fifteen dogs had developed neurologic signs typical of those resulting from an enlarging pituitary mass. Twenty-three dogs had pituitary tumors greater than or equal to 1 cm in diameter. Provocative testing of the pituitary-adrenocortical axis was performed on all dogs. Dogs with grossly visible pituitary tumors and dogs with neurologic signs had significantly (P less than 0.05) higher mean plasma endogenous ACTH concentrations, compared with values from dogs with microscopic tumors and dogs without neurologic signs, respectively. Dogs with grossly visible pituitary tumors and dogs with tumors greater than or equal to 1 cm in diameter had significantly (P less than 0.05) lower adrenocortical responsiveness to exogenous ACTH, compared with dogs with microscopic pituitary tumors and dogs with tumors less than 1 cm in diameter, respectively. Despite these differences, there was overlap between test results among dogs. On the basis of endocrine test results, it would appear difficult to distinguish dogs with pituitary-dependent hyperadrenocorticism and large pituitary tumors from those with pituitary-dependent hyperadrenocorticism and microscopic pituitary tumors prior to onset of neurologic signs.     

Survival, neurologic response, and prognostic factors in dogs with pituitary masses treated with radiation therapy and untreated dogs

BACKGROUND: Pituitary masses in dogs are not uncommon tumors that can cause endocrine and neurologic signs and, if left untreated, can decrease life expectancy. HYPOTHESIS: Dogs with pituitary masses that received radiation therapy (RT) have more favorable neurologic outcomes and longer survival times compared with untreated dogs. ANIMALS: Nineteen dogs with a pituitary mass identified on CT or MR imaging were irradiated with 48 Gy given in 3 Gy daily-dose fractions. Twenty-seven untreated control dogs had pituitary masses. METHODS: Medical records of dogs with pituitary masses were retrospectively reviewed for clinical signs, mass size, and outcome. RESULTS: Median survival time was not reached in the treated group. Mean survival time in the treated group was 1,405 days (95% confidence interval [CI], 1,053-1,757 days) with 1-, 2-, and 3-year estimated survival of 93, 87, and 55%, respectively. Median survival in the nonirradiated group was 359 days (95% CI, 48-916 days), with a mean of 551 days (95% CI, 271-829 days). The 1-, 2-, and 3-year estimated survival was 45, 32, and 25%, respectively. Dogs that received RT for their pituitary tumors had significantly longer survival times than untreated dogs (P = .0039). Treated dogs with smaller tumors (based on maximal pituitary-to-brain height ratio or area of tumor to area of brain) lived longer than those with larger tumors (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: When compared with untreated dogs, RT increased survival and controlled neurologic signs in dogs with pituitary masses.