Biomedical subjects
Publications and source records attributed to T K Graves.
Until recently, the diagnosis of hyperthyroidism in cats was thought to be simple; however, not all cases of the disease are straightforward. Although single resting serum thyroid-hormone determinations may well be adequate to confirm the diagnosis, in many cases, the diagnosis of feline hyperthyroidism requires more extensive investigation.
We measured glomerular filtration rate (GFR) estimated by plasma disappearance of 99mTc-labeled diethylenetriaminepentaacetic acid, serum concentrations of thyroxine (T4), creatinine, and urea nitrogen, and urine specific gravity in 13 cats with naturally acquired hyperthyroidism before and 30 days after treatment by bilateral thyroidectomy, and in a group of 11 control cats. Mean (+/- SD) serum T4 concentration decreased from a pretreatment value of 120.46 (+/- 39.21) nmol/L to a posttreatment value of 12.15 (+/- 6.26) nmol/L (P < 0.0001; reference range, 10 to 48 nmol/L). Treatment of hyperthyroidism resulted in a decrease in mean (+/- SD) glomerular filtration rate, from 2.51 (+/- 0.69) ml/kg of body weight/min to a posttreatment value of 1.40 (+/- 0.41) ml/kg/min (P < 0.0001). Mean serum creatinine concentration increased from 1.26 (+/- 0.34) mg/dl to 2.05 (+/- 0.60) mg/dl (P < 0.01). Mean serum urea nitrogen concentration increased from 26.62 (+/- 6.83) mg/dl to a mean postthyroidectomy concentration of 34.92 (+/- 8.95) mg/dl (P < 0.01). All changes were significant. Two cats developed overt renal azotemia after treatment of hyperthyroidism. Our results provide further evidence that treatment of hyperthyroidism can result in impaired renal function. In addition, our results suggest that, in some instances, thyrotoxicosis might mask underlying chronic renal insufficiency.
A Holstein fetus was delivered by Caesarean section at a gestational age of 441 days. The pituitary pars distalis was aplastic and the adrenal and thyroid glands were severely hypoplastic. Arrested or retarded cartilage cell maturation resulted in absence or minimal development of epiphyseal ossification centers, delayed ossification of carpal bones, and arrest of longitudinal growth of bones. The pathophysiology of prolonged gestation and of skeletal pathology is discussed.
As expertise among small animal practitioners grows, feline hyperthyroidism is being diagnosed earlier in the course of the disease. There are, in fact, a growing number of cats with clinical signs of hyperthyroidism and palpably large thyroid glands whose serum total thyroxine (T4) and triiodothyronine (T3) concentrations are within the normal or borderline range. This condition can be referred to as "occult" hyperthyroidism. Early detection and treatment of feline hyperthyroidism presents an obvious advantage in avoiding some of the deleterious effects of chronic thyroid hormone excess (eg, cardiomyopathy). Recent advances have been made in the diagnosis of occult hyperthyroidism in cats. It has been found, for instance, that serum thyroid hormone concentrations can fluctuate in and out of the normal range in some cats with hyperthyroidism. Recent work also has laid the groundwork for use of a T3 suppression test as an aid in the diagnosis of early, mild, or occult hyperthyroidism in cats. The purpose of this chapter is to discuss these and other developments, as well as to discuss some of the problems confronted in diagnosing occult hyperthyroidism in cats.
The oral and intravenous disposition of the anti-thyroid drug propylthiouracil (PTU) was determined in six clinically healthy cats and four cats with naturally occurring hyperthyroidism. Compared with the normal cats, the mean plasma elimination half-life of PTU was significantly (P less than 0.001) shorter in the hyperthyroid cats (77.5 +/- 5.8 minutes compared with 125.5 +/- 3.7 minutes) and the total body clearance of PTU was significantly (P less than 0.05) more rapid in the cats with hyperthyroidism (5.1 +/- 0.8 ml kg-1 min-1 compared with 2.7 +/- 0.2 ml kg-1 min-1). Following oral administration, both the bioavailability (59.7 +/- 4.9 per cent compared with 73.3 +/- 3.7 per cent) and peak plasma concentrations (14.5 +/- 1.6 micrograms ml-1 compared with 18.9 +/- 0.9 micrograms ml-1) of PTU were significantly (P less than 0.05) lower in the hyperthyroid cats than in the control cats. No difference was noted, however, between the apparent volume of distribution for PTU in the two groups of cats. Overall, results of this study indicate that the oral bioavailability of PTU is decreased and PTU disposition is accelerated in cats with hyperthyroidism.
The suppressive effects of three different low dosages of dexamethasone (5, 10 and 15 micrograms kg-1) on serum cortisol concentrations were evaluated in 10 normal cats. On four different days, serum was collected before and at two, four, six and eight hours after the intravenous administration of saline or dexamethasone. Following the administration of saline, no significant difference in mean serum cortisol concentrations was noted between the basal or postinjection values. In contrast, mean serum cortisol concentrations decreased significantly (P less than 0.05) by two hours and remained significantly below mean basal values eight hours after injection of all three dosages of dexamethasone. The degree of cortisol suppression became progressively greater as the dosages of dexamethasone were increased. After administration of the highest dose of dexamethasone (15 micrograms kg-1), serum cortisol decreased to below 5 ng ml-1 by two to four hours and remained suppressed (under 5 ng ml-1) eight hours after injection in all cats. In contrast, two of the 10 cats showed a slight escape from cortisol suppression by eight hours after injection of dexamethasone at the dosage of 10 micrograms kg-1, whereas a dosage of 5 micrograms kg-1 failed to suppress cortisol concentrations below 10 ng ml-1 at any of the sampling times in one cat and was associated with increasing serum cortisol concentrations at eight hours after injection in three cats.(ABSTRACT TRUNCATED AT 250 WORDS)
Quality of life and outcome assessments are particularly critical for nurses in assessing clinical care for diseases such as cancer because of potential mortality and the exacting modalities of treatment. The 278 study participants were patients at the M.D. Anderson Cancer Center Orlando. The respondents were assessed with the Health Status Questionnaire (HSQ; D. M. Radosevich, H. Wetzler, & S. M. Wilson, 1995). Prostate cancer patients scored higher (had a higher quality of life) on average (6.08%) than breast cancer patients on all subscales except Physical Functioning. The diagnostic center patients scored higher (9.68%) than breast cancer patients and prostate cancer patients (3.47%). Breast cancer respondents scored 16.61% lower than the normative values for individuals less than 65 years of age, whereas prostate cancer respondents scored 10.91% higher than the normative values for those older than 65. The data analysis confirmed that breast cancer and prostate cancer patients have statistically different scores on the HSQ, implying different quality of life concerns for each group.
OBJECTIVE: The purpose of this study was to determine the signalment, history, clinical signs, diagnosis, treatment, outcome, and factors affecting outcome of dogs and cats surgically treated for bile peritonitis. STUDY DESIGN: Retrospective study. ANIMALS OR SAMPLE POPULATION: Twenty-four dogs and two cats surgically treated for bile peritonitis. METHODS: The medical records of dogs and cats surgically treated for biliary effusions at the Ohio State University and Michigan State University between 1987 and 1994 were reviewed. Statistical analysis was performed to compare factors affecting outcome. RESULTS: The cause of the biliary effusion was determined in 24 animals, and resulted from disruption of the biliary tract secondary to trauma (n = 13) or necrotizing cholecystitis (n = 11). Determination of the bilirubin concentration of the abdominal effusion was the only diagnostic test that was 100% effective in diagnosing bile leakage before surgical intervention. The bilirubin concentration of the effusion was consistently at least two times higher than the serum bilirubin concentration. Bacteriologic culture and sensitivity revealed that a septic, biliary effusion was usually associated with multiple types of gram-negative bacteria. The overall survival rate was 50% (13 of 26). The peripheral white blood cell count was significantly lower in survivors (mean 20,608/uL) compared with nonsurvivors (mean 35,712/uL). The immature neutrophil count was also significantly lower in survivors (mean 686/uL) than in nonsurvivors (4,852/uL). Only 27% (3 of 11) of the animals with a septic biliary effusion survived. In contrast, 100% (6 of 6) of the animals in which no bacteria were isolated from the abdominal effusion survived. Open abdominal drainage was not a successful treatment for 7 of 9 animals with septic biliary effusions. Survival was not significantly affected by the distribution of the peritonitis, cause of biliary effusion, or duration of clinical signs before surgical intervention. CONCLUSIONS: Patients with sterile biliary effusions have a much lower mortality rate than those with septic biliary effusions. The successful treatment of sterile biliary effusions does not require open abdominal drainage, and is not affected by the duration of the effusion. CLINICAL RELEVANCE: This retrospective study provides information that may aid the surgeon in the diagnosis and treatment of bile peritonitis.
We measured serum thyroxine (T4) and 3,3',5-triiodothyronine (T3) concentrations in hyperthyroid cats (hourly for 10 hours in 14 cats, and daily for 15 days in seven cats) to assess fluctuation in thyroid hormone levels. Over the 10-hour study period the coefficient of variation (CV) for serum T4 and T3 concentrations ranged from 6.4-22.6% (mean = 12.0 +/- 4.8%) and from 9.6-33.1% (mean = 17.5 +/- 6.3%), respectively. During the 15-day study period, CV for serum T4 ranged from 6.6-34.8% (mean = 18.4 +/- 9.3%), while CV for serum T3 ranged from 7.8-31.0% (mean = 20.1 +/- 8.6%). These CV values were significantly higher than the expected intra-assay CVs (T4 assay, 5.1%; T3 assay, 7.7%). In addition, some of the cats with mild hyperthyroidism showed one or more normal serum T4 and T3 values during the course of the respective study periods. There was no specific time during the 10-hour study period at which the cats consistently showed peak serum T4 or T3 concentrations. These results suggest that serum thyroid hormone concentrations are subject to a degree of fluctuation that exceeds the usual assay variation, and that cats with mild hyperthyroidism can, at a given time, exhibit normal serum T4 and T3 values. Therefore, a diagnosis of feline hyperthyroidism should not be excluded on the basis of the finding of a single normal serum T4 or T3 value in a cat with clinical signs and physical examination findings consistent with the disease.
We evaluated three reflectance meters (Accu-Chek II, Glucometer II, and Glucoscan 2000) and two reagent strips (Chemstrip bG and Glucostix) for accuracy and precision in determining blood glucose concentrations in the dog. To evaluate accuracy, we compared results of blood glucose determinations performed on 95 samples using the various strips and meters vs. the glucose concentrations obtained using the glucose-oxidase method on a Beckman Glucose Analyzer. Accuracy was evaluated statistically using least squares regression analysis. To evaluate precision, samples in various ranges of blood glucose concentration were tested repeatedly (20 times within a 1-hour period) on the same reflectance meter. Coefficient of variation (CV) was determined to evaluate reproducibility of results. Overall, there were significant correlations (P less than 0.001) between the laboratory glucose values and the blood glucose concentrations obtained with Chemstrip bG (r = 0.976), Glucostix (r = 0.904), Accu-Chek II (r = 0.986), Glucometer II (r = 0.911) and Glucoscan 2000 (r = 0.944). In the precision study, all three meters had excellent CVs in the normal range (3.6% to 4.9%). However, Accu-Chek II was found to be more precise in the hypoglycemic and hyperglycemic ranges (3.6% and 2.6%, respectively) than either Glucometer II (8.8% and 5.4%) or Glucoscan 2000 (7.8% and 8.2%). The results of this study indicate that all of the meters and reagent strips tested are highly accurate in determining blood glucose concentrations in the dog. However, both in terms of accuracy and reproducibility of results, Accu-Chek II and Chemstrip bG, gave the highest correlation coefficients and, as such, are probably of the greatest clinical value.
The Doppler ultrasonic recording technique was used to measure systolic and diastolic blood pressures indirectly in 28 cats with naturally occurring renal failure, 39 cats with hyperthyroidism, and 33 clinically normal cats. The mean systolic and diastolic blood pressures in the normal cats were 118.4 +/- 10.6 mm Hg and 83.8 +/- 12.2 mm Hg, respectively. In the cats with chronic renal failure, both the systolic (146.6 +/- 25.4 mm Hg) and diastolic (96.6 +/- 15.2 mm Hg) blood pressures were significantly higher (P less than 0.0001 and P less than 0.01, respectively) than in the normal cats. Elevations in systolic and/or diastolic blood pressure were recorded in 17 (61%) of the 28 cats with chronic renal failure. In the 39 untreated hyperthyroid cats, both the mean systolic (167.9 +/- 28.9 mm Hg) and diastolic (111.6 +/- 21.5 mm Hg) pressures also were significantly higher (P less than 0.0001) than normal. Increased systolic and/or diastolic blood pressure was recorded in 34 (87%) of the 39 hyperthyroid cats. In seven cats with hyperthyroidism that were reevaluated two to four months after successful treatment of the hyperthyroid state, there was a significant fall in mean systolic pressure (P less than 0.05) from a pretreatment value of 159.5 +/- 15.4 mm Hg to a posttreatment value of 132.0 +/- 1.62 mm Hg. Overall, the results of this study indicate that mild to moderate hypertension is common in cats with chronic renal failure and in cats with untreated hyperthyroidism. In addition, the hypertension appears to be reversible following successful treatment of the hyperthyroid state.
The purpose of this study was to develop a T3 suppression test to help in the diagnosis of mild hyperthyroidism in cats. We evaluated the response in circulating T4 concentrations to exogenous T3 (liothyronine) administration in 44 clinically normal cats, 77 cats with hyperthyroidism, and 22 cats with nonthyroidal disease. The test was performed by first collecting blood samples for basal serum T4 and T3 determinations, administering liothyronine at an oral dosage of 25 micrograms three times daily for seven doses, and, on the morning of the third day, again collecting serum samples for T4 and T3 determinations 2 to 4 hours after the seventh dose of liothyronine. The mean basal serum concentrations of T4 (53.1 nmol/L) and T3 (1.8 nmol/L) were significantly higher in the cats with hyperthyroidism than in the normal cats (T4 = 25.3 nmol/L, T3 = 1.3 nmol/L) and the cats with nonthyroidal disease (T4 = 29.5 nmol/L, T3 = 1.4 nmol/L); however, there was a great deal of overlap of basal values between the three groups of cats. Of the 77 cats with mild hyperthyroidism, 41 (53%) had serum T4 values and 55 (71%) had T3 values that were within the established normal ranges. After administration of liothyronine, mean serum T4 concentrations fell much more markedly in the normal cats and the cats with nonthyroidal disease than in the hyperthyroid cats.(ABSTRACT TRUNCATED AT 250 WORDS)
We measured plasma concentrations of cortisol and aldosterone before and after administration of adrenocorticotropin (ACTH) in dogs with trichuriasis. These dogs had physical examination, historical, and serum electrolyte findings suggestive of hypoadrenocorticism; trichuriasis-associated pseudohypoadrenocorticism has been reported previously. We found normal basal and ACTH-stimulated plasma cortisol concentrations. Basal and ACTH-stimulated plasma aldosterone concentrations were normal in 2 dogs and increased in 3 dogs, suggesting that the electrolyte abnormalities seen in this clinical syndrome are not due to aldosterone deficiency.
A nine-year-old, castrated male golden retriever had lethargy, fever, massive peripheral lymphadenomegaly, hepatosplenomegaly, and pale mucous membranes. There was a marked leukocytosis (456.3 x 10(3) cells/microliter) with 99% blasts; a moderate, nonregenerative anemia; and marked thrombocytopenia. A tentative diagnosis of acute lymphocytic leukemia was made pending results of cytochemical staining. Despite the severity of the laboratory and clinical findings, the dog exhibited a partial response to an induction chemotherapy protocol commonly used for lymphoma. Subsequent cytochemical staining of the original blood and bone-marrow samples resulted in a revised diagnosis of acute myelomonocytic leukemia (AML-M4). Clinicopathological findings, response to treatment, and clinical outcome in this case of canine AML-M4 are discussed.