Case Studies Flashcards
What is a disease that is commonly vaccinated against that can cause neurological signs in dogs?
Distemper
What is paraparesis?
paraplegia? hypalgesia? paresis?
* paraparesis- bilateral motor dysfunction of the pelvic limbs
* paraplegia- loss of motor function the pelvic limbs
* hypalgesia- decreased sense of pain
* paresis- deficit of motor function
The muscle of the external bladder sphincter is smooth muscle and contraction is initiated by sympathetic fibres of the pelvic nerve. True or false?
false
Lesions affecting the bladder at S1-S3, could cause?
Flaccid bladder and dribbling urine
Which drugs would be used in the treatment of disorders of micturition… which drugs may be used in this scenario: upper motor neuron bladder?
which drug would be used with urinary incontinence?
Phylpropanolamine= sympathomimetric
What is discospondylitis?
Inflammation of an intervertebral disc with osteomyelitis of the adjacent vertebrae (usually caused by haematogenous bacterial infection or sometimes a haematogenous fungal infection) e.g. Aspergillus species in German shepherd dogs or due to migrating foreign body (mainly grass awns) contaminated with bacteria
Thoracolumbar spine depicting calcified intervertebral discs and a protruded intervertebral disc
What is a hemilaminectomy?
Surgery to help alleviate the symptoms of an impinged or irritated nerve root in the spine. During this procedure, surgeons remove part of a vertebra called a lamina. this removal of bone creates more space in the spinal canal and is meant to release nerve tissue from pressure.
Cervical fractures most commonly affect the axis. Animals typically present with neck pain. Which combo of signs might be seen if the fracture site becomes unstable and compresses the spinal cord?
Non-ambulatory tetraparesis (muscular weakness affecting all four extremities), increased muscle tone and normal spinal reflexes in all limbs
Simply staring into an animal’s eyes and observing carefully will allow you to (sub)consciously assess which cranial nerves?
2, 3, 4, 5, 6, 7, 8, parasympathetic pathway
What is myringotomy and bulla osteotomy?
Myringotomy- Incision into the tympanic membrane
Bulla osteotomy- opening the middle ear
What part of the brain is each associated with?
Match each Cranial Nerve up with the part of the brain it is associated with?
Where is the lesion?
* lethargic 6 months ago
* aggression 2 weeks ago
* indoors- dog lies quietly
* outdoors- appears to be blind
* gait is normal
* pupils are large, symmetric and unchanging in light and dark
* PLR absent bilaterally
Optic chiasm
cat suddenly falls off armchair, ataxic, unable to walk, repeatedly falls to the left, left head tilt, nystagmus with a horizontal fast phase to the right
Left vestibular apparatus to account for all the signs
Disease of the inner ear may result in the development of Horner’s syndrome as a result of the sympathetic innervation of the eyes. Postganglionic sympathetic fibres travel through the inner ear on their way to the eye. Which of the following are symptom’s?
* Pupillary constriction (miosis)
* Retratction of the eye (enophthalmos)
* Narrowing of the palpebral fissure (ptosis)
* Prolapse of the third eyelid
Alpha two agonists are contraindicated in heart failure patients, why?
Alpha two agonists cause profound bradycardia as a result of central (medullary) inhibition of cardiac rate– and possibly due to the increased reflex vagal activity as well by the initial pressor effect on blood vessels. Bradycardia may result in reduced cardiac output, accompanied by AV block, which can increase the risk of arrythmias
What is the most significant side effects of exogenously administered opioids related to binding of which receptor?
* Mu 2 (holy grail– develop a specific mu 1 agonist– with powerful analgesic effects and NO mu2 side effects)
Why does Butorphanol have fewer side effects than morphine?
* As most of the opiod side effects are mu 2 mediated, since butorphanol is a mu antagonist it will have fewer side effects
What do the sedative actions of benzodiazepines relate to?
Allosteric modulation of the GABA receptor
What do the phenothiazine derivative sedatives such as acepromazine do?
Alpha blockers- so will cause a hypotension, that results in reflex tachycardia
Which of the following conditions would use of an opioid drug be contra- indicated?
Asthma (bronchoconstrictive tendency)
Do opioids cause pupillary dilation?
No.
What are the analgesic effects of NSAID’s related to?
Peripheral inhibition of prostaglandin synthesis but also through inhibition of COX-2. Some NSAIDs inhibit LOX pathway, which may also result in inhibition of prostaglandin synthesis.
Termination of anaesthetic effect of alfaxalan is due to redistribution to adipose tissue- true or false?
False– neurosteroids are metabolized by the liver very rapidly so that their duration of action is short
What is ketamine?
An NMDA receptor antagonist with therapeutically useful analgesic properties
True or false: propofol is less cardiodepressant than thiopentone?
False. It does have a shorter duration of action and rapid recovery due to metabolism by the liver. The cardiodepressant effect of propofol has been shown to outlast its anaesthetic effects.
Why should a shocked individual receive a smaller induction dose of an IV anesthetic?
As CO falls, the proportion of the induction dose reaching the brain increases
True or false: Induction of anesthesia will be more rapid if a gaseous anaesthetic is less soluble in blood. What’s an example of an anaesthetic agent with a very low solubility in blood?
* True
* Sevoflurane
What situation might result in prolonged duration of anaesthesia following administration of a standard dose of thiopentone?
The patient is thin
What anaesthetic agent does not act by binding to GABA receptors? What are the actions of propofol?
* Ketamine
* Propofol actions are also at the GABA receptor
What is the bioavailability of an IV drug?
100%
A drug with a bioavailability of 50% is likely to require a higher dose when given orally then when given by injection- true or false?
True
A drug with a volume of distribution of 3L/kg bodyweight is likely to distribute throughout the body with extensive tissue binding- t or f?
true
True or false- a more lipid soluble anaesthetic will be eliminated from the body more rapidly?
False
Why will an obese patient recover from repeated doses of thiopentone more slowly than a thin dog?
Blood levels are maintained by thiopentone released from adipose tissue
At the peak of the plasma concentration curve. What are the rates of absorption and rates of elimination?
Equal.
What data do you need in order to calculate the loading dose of a drug?
Volume of distribution, bioavailability, and target plasma concentration
What will more frequent administration of smaller boluses of drug result in?
Decrease in fluctuation around the mean steady state concentration
Recovery from thiopentone induced anaesthesia occurs as a result of?
Redistribution of drug to a second compartment
A loading dose may be required if
A drug has a narrow therapeutic range
What is the general rule of thumb for how much water a dog should drink? A cat?
* Dog about 100 mL per kg
* Cat about 60-70 mL per kg
What simple test may give you an indication that a dog is drinking excessively?
Measure urine specific gravity
With a glucose concentration of 8.9 mmol/l (3.3-6.7). What might this indicate?
* Stress, post prandial sampling, hyperadrenocorticism
If alkaline phosphatase (ALP) is high, what could this indicate?
* Cholestasis, recent administeration of corticosteroids, hepatic neoplasia
If alanine aminotransferase (ALT) is increased, what could this indicate?
* Hepatic neoplasia, congestive heart failure, severe anaemia, acute hepatitis
A high cholesterol, could be a result of?
Nephrotic syndrome or hyperadrenocorticism
Abnormalities?
Enlarged liver
Which parts of the adrenal gland produce cortisol?
Zona fasciculata and Zona reticularis
The urine cortisol: creatinine ratio is commonly used as a screening test for hyperadrenocorticism. It allows you to exclude a diagnosis of hyperadrenocorticism if the result is within the normal range, but does not allow you to confirm a diagnosis if the result is above the normal range. Such a test might be described as– what sensitivity and what specificity?
Low specificity, and high sensitivity
What would the endogenous ACTH be in a dog with pituitary dependent hyperA? What about adrenocortical tumour?
* PDH: Increased
* Adrenocortical tumour: decreased
Why might you see dyspnoea in a dog with hyperA?
Hypercoaguable state
Why do you see PU/PD in a dog with hyperA?
* Increase glomerular filtration rate
* Inhibit ADH activity on distal convoluted tubule
Why do you see polyphagia with hyperA?
* Inhibition of glucose uptake by peripheral tissues
What class of drug do you treat Addison’s disease? One reason why?
Mineralocorticoid
An increase in potassium and decrease in sodium
What is the most likely cause of elevated blood glucose?
Diabetes mellitus
Which hormone is largely responsible for reducing blood glucose concentrations?
Insulin
What is the approximate renal threshold for blood glucose (the value for blood glucose which results in incomplete reabsorption of glucose from the glomerular filtrate)?
In normal dogs glucose is reabsorbed by the renal tubules, but if levels rise above 10- 12 mmol/l, these tubular reabsorptive mechanisms are overwhelmed and glucosuria results
What type of acid base disturbance is present based upon the results of the (venous) blood gas analysis?
Metabolic acidosis with respiratory compensation
What does ketoacidotic diabetes mellitus (DKA) result from?
Develops from an uncontrolled Diabetes mellitus
What is diabetes mellitus?
A complex disorder of carbohydrate, protein, and lipid metabolism that is caused by a lack of insulin or by factors that oppose the action of insulin.
What are the actions of insulin?
* assists with cellular uptake of glucose from the bloodstream= hypoglycaemic effect
* Within cells, insulin promotes anabolism (synthesis of glycogen, fatty acids, and proteins) and counters catabolic effects (reduces gluconeogenesis and inhibits fat and glycogen breakdown)
Diabetogenic hormones counteract the effects of insulin and raise blood glucose. Which diabetogenic hormone is most likely to be associated with the development of diabetes mellitus?
Progesterone
What is the principal underlying mechanism for the polyuria seen in diabetes?
Osmotic diuresis secondary to glucosuria
What are the main causes of weight loss seen with diabetes mellitus?
* loss of glucose in the urine
* Reduced peripheral tissue anabolism
FIB: Lack of insulin results in reduced utilasation of _____, ______ and _______ by peripheral tissues. What does all of this result in?
Glucose, amino acids, and fatty acids
** accumulation of glucose in the blood which is freely filtered through the glomeruli
What causes the polyuria in diabetes mellitus?
Glucose exerts an osmotic diuritic effect (brings the water with it)
Diabetic ketoacidosis (DKA) is a serious complication of uncontrolled diabetes mellitus. How does it result?
Generation of ketone bodies occurs as free fatty acids are oxidized to form acetoacetate. Ketone bodies are substrates used for energy metabolism used by most tissues, but excessive production results in acumulation of ketone bodies in the circulation and ketoacidosis. Ketone bodies also spill over into the urine contributing to osmotic diuresis.
What causes polyphagia in diabetes mellitus? Why does weight loss still occur?
Polyphagia occurs due to the circulating glucose not entering the cells of the satiety centre in the hypothalamus, which is a mechanism of insulin. The satiety centre fails to inhibit the hunger centre which results in an increased appetite.
* Weight loss occurs despite increased food intake due to caloric loss associated with glucosuria and reduced anabolic processes in the peripheral tissues.
What does DKA result in?
A critically ill patient. Osmotic diuresis (from glucose and ketone bodies) causes electrolyte loss, dehydration, hypovolaemia, and decreased perfusion of tissues. When ketones are produced by the liver, an equivalent number of hydrogen ions are produced and those overwhelm the buffering capacity of the body resulting in metabolic acidosis. Hypovolaemia contributes to the acidosis with under perfusion of the kidneys and decreased glomerular filtration resulting in pre-renal azotaemia.
What can high phosphate levels result in?
Haemolytic anaemia
What are some of the clinical signs of hypoglycaemia?
Shaking, disorientation, and seizures
