Pathophysiology Flashcards
What is the modified Bernouli equation?
Change in pressure = 4v2
If a dog has a peak tricuspid regurgitant jet velocity of 1.96 m/s, what is the pulmonary arterial pressure and is the pulmonary arterial pressure normal or abnormal (if abnormal, what severity)?
15 mmHg (normal is <30mmHg)
If a dog has a tricuspid regurgitant jet of 4.3 m/s, what is the pulmonary arterial pressure? Is it normal or abnormal (if abnormal, what is the severity)?
74 mmHg - moderate severity (51-80mmHg)
What are the normal systolic pressures in the heart and great vessels?
Nickel - Dime - Quarter - Dollar
Right atrium - 5
Left atrium - 10
Right ventricle and MPA - 25
Left ventricle and Ao - 100
Cushing’s reflex
Maintenance of intracranial pressure
CPP = MAP - ICP
If MAP drops below ICP –> hypothalamus initiates ischemic reflex –> sympathetic nervous system induces vasoconstriction and increased CO until MAP is restored. Baroreceptors on carotid bodies sense hypertension –> reflex bradycardia
CSF production
Ependymal lining (pia and arachnoid) in ventricles and central canal
Choroid plexus in lateral, third, and fourth ventricles
Produced by ultrafiltration of plasma
T/F: The rate of CSF production depends on osmotic pressure, but not hydrostatic pressure (blood pressure)
True
What is the primary mechanism for CSF resporbtion?
Through the arachnoid villi outpouchings in the dorsal sagittal sinus
What is the most common digital neoplasm in the dog?
SCC
T/F: digital SCC has a worse survival time than digital malignant melanoma
False. The survival time is not dependent on histopathologic type of neoplasia; it is dependent on the tumor stage
Regarding canine digital neoplasia, which prognostic factor is associated with survival time:
- Tumor type
- Presence of metastatic disease
- Local tumor stage
- Age and sex
Only the local tumor stage is associated with survival time
Regarding dogs with appendicular bone neoplasia, which of the following are associated with pathologic fracture?
- Width of the lesion
- Length of cortical involvement
- Age
- Lytic appearance
Lytic appearance
T/F: The radius is associated with a reduced frequency of pathologic fracture due to primary bone neoplasia
True; possibly due to splint effect from the ulna. This was not seen with the tibia/fibula.
Which factors are associated with shorter survival time in urinary bladder TCC?
- Heterogeneous mass
- Trigonal location
- Wall involvement
Telangiectatic osteosarcoma
- Medium dogs
- Aggressive lesion of the tibia
- Shorter survival time than osteogenic osteosarcoma
Is the survival time between telangiectatic osteosarcoma and hemangiosarcoma significantly different?
No. tOSA (7mo) and HSA (10mo)
T/F: Amputation and chemotherapy prolong the survival time in dogs with bone HSA, but not for dogs with bone tOSA
False. Amputation and chemotherapy prolong survival for both
What is the incidence (low, medium, high) for presence of pulmonary metastasis at the time of diagnosis of tOSA? HSA?
High for both
What pathology contributes to degenerative lumbosacral stenosis?
- Hansen type 2 disc degeneration
- Subluxation of the S1 vertebral and misalignment of the facet joints
- Concurrent congenital vertebral anomalies
- Transitional lumbar vertebra
- Supernumerary lumbar vertebra
- Soft tissue and bone proliferation
- Interarcuate ligaments
- Joint capsule
- Epidural fibrosis
- Spondylosis
- Sacral osteochondrosis
- Vascular compromise to the blood supply of spinal nerves
Cats with spinal lymphoma
- Younger at time of diagnosis compared to other tumors
- Shorter duration of clinical signs
- More lesions in the CNS
- Many cats also have extra-CNS disease
Radiographic findings with leptospirosis and pathophysiology
Diffuse or caudodorsal, reticulonodular interstitial pattern
Due to hemorrhage secondary to endothelial damage and vasculitis caused by spirochete replication in the blood vessels
Ultrasonographic findings with leptospirosis
Kidneys
- Cortical and/or medullary hyperechogenicity
- Decreased corticomedullary distinction
- Pyelectasia
- Thickened cortices
- Medullary rim sign
Liver
- Hypoechoic, heptomegaly
Insulinoma metastasis
Metastasize to liver and lymph nodes (high); rarely to bone or lungs
Pathophysiology of insulinoma
Arise from B cells in the islets of Langerhans (endocrine pancreas); neoplastic cells release insulin independent of the normal suppressive effects of hypoglycemia
Medium to large breed, older dogs
Pathophysiology of IMPA
Type 3 hypersensitivity reaction where antigen-antibody immune complexes accumulate in a joint space –> complement activation –> cytokine release –> neutrophils attracted –> neutrophils release cytokines and lysosomal enzymes –> tissue damage
Erosive (rheumatoid) - also has antibody attack against collagen
Non-erosive
What joints are most commonly affected with erosive IMPA?
Stifles and carpi; digits can also be affected
Signalment for erosive IMPA versus idiopathic non-erosive IMPA
Erosive - small breed, middle aged
Idiopathic non-erosive - sporting to large breed, young
8 yo MN DSH presents for several month history of depression and acute blindness. What is your diagnosis (GRE image provided)
Pituitary apoplexy - hemorrhagic infarction within a pituitary tumor. Patients usually have acute onset blindness and a history of altered mentation
What influences outome after trans-sphenoidal hypophysectomy in dogs?
- Larger pituitary mass size (pituitary-brain ratio; normal <0.31)
- Contacting the interthalamic adhesion (Grade 3)
- Invasion of the cavernous sinus or circle of Willis (Type B)
According to Sato paper, Grade 3B, 4, and 5 are not suitable for this surgery
Metastasis of urinary bladder TCC
Regional lymph nodes +/- lung
Sensitivity and specificity of prostatic mineralization for neoplasia in a castrated dog
High sensitivity
High specificity (100%)
T/F: degree of prostatic mineralization on ultrasound, but not radiographs correlates to diagnosis of prostatic neoplasia
True. Increased mineral on US correlates with a diagnosis of neoplasia, but the amount of mineral on rads does not
What is the most common congenital portosystemic shunt in the cat?
EHPSS - Left gastric to CVC
Splenosystemic shunts in cats
- Different age distribution (older, spayed F) compared to congenital
- Unclear if they are congenital or acquired; many cats had hepatopathy with potential for portal hypertension
- No clinical signs associated with shunt
- Shunts did not resolve when rechecked
Feline hepatic lipidosis
- Most common hepatic disorder in cats
- Due to lipid metabolism imbalance –> accumulation of triglicerides in hepatocytes (>50% of hepatocytes are filled)
- Anorexia –> hormone-sensitive lipase –> lipolysis –> excessive number of fatty acids sent to liver for oxidation –> accumulation of fat in hepatocytes
- Obese, middle aged cats with anorexia x 2-14d
Sublingual ectopic thyroid neoplasia
- Younger than dogs with thyroid neoplasia at other locations
- Less likely to have metastatic disease
- Less agressive biologic behavior
- Prolonged survival time even without treatment
Major hormone for triggering gallbladder contraction
Cholecystokinine secreted by duodenal mucosal under influence of fat or protein; gallbladder contracts over 1-2 hours and is incompletely, variably emptied following a meal
Bile acids
- Produced by the liver from cholesterol –> major route of cholesterol excretion
- Conjugated prior to secretion so that they are hydrophilic
- Active secretion of bile acids by the hepatocytes into canaliculi
- In the intestines the conjugated bile acids are transformed by enteric bacteria in 2 ways:
- hydroxylation to secondary bile acids (conjugated) –> resorbed in the ileum
- deconjugation –> absorbed in the duodenum andj ejunum by passive diffusion
T/F: Enterohepatic circulation of bile acids is efficient, but absorption of bilibrubin is not efficient
True. 98% of bile acids resporbed by intestine and 90% are cleared by the liver (high concentration in portal blood, but not systemic); bilirubin is not as efficiently removed from the systemic circulation.
Explains the difference in bilirubin and bile acid profiles with different liver diseases. Cholestasis - bilirubin and bile acids in circulation; PSS - bile acids in circulation, but bilirubin normal
Normal portal blood pressure
0 to 5 mmHg
Broad causes of portal hypertension
- Increased delivery of blood (AV malformation)
- Increased resistance to passage of portal blood (pre-hepatic, intra-hepatic, or post-hepatic)
Phases of degluttination
- Oral (voluntary) - tongue forces bolus caudodorsally against hard palate into the pharynx
- Pharyngeal (1-2 s)
- Reflex controlled by brainstem and triggered by food at base of tongue; respiratory center in medulla is inhibited during this time
- Bolus transported from oropharynx into esophagus
- Esophageal (8-10s)
- Food transported through esophagus to stomach
Esophageal phase of degluttination
- Continuation of pharyngeal peristaltic wave
- Begins with relaxation of the cranial sphincter allowing movement of bolus into esophagus
- Cricopharyngeal muscle contracts to prevent cranial reflux
- Primary peristaltic wave
- If food remains in esophagus after primary wave, a secondary peristaltic wave is initiated by intraluminal distention
- Relaxation of caudal sphincter (really just a zone of high pressure
Pharyngeal phase of degluttination
- Initiated by presence of bolus at base of tongue at the end of the oral phase
- Pharyngeal peristalsis –> bolus moved to the laryngopharynx
- Breathing stops momentarily –> soft palate elevated closing nasopharynx
- Tongue pressed against hard palate –> oral opening of oropharynx close
- Pharyngeal contraction assisted by craniodrosal movement of hyoid apparatus and larynx –> glottis pulled under epiglottis –> closes laryngeal opening
- Arytenoid cartilages close –> prevent movement of food into respiratory system
- Pharyngeal contraction progressive manner and UES (cricopharyngeal muscle) relaxed to accept the bolus
Gastric emptying in cats
- Liquid - 15 min to 2 hours
- Solid - 10-12 hours
There is the least change in transit time with ket/val sedation
Dog gastric emptying
- Liquid - 30 min to 2 hrs
- Solid - 8 hours
Upper GI study in the dog - transit times
- Gastric emptying - 30 min to 2 hrs (minimal residual in stomach)
- Contrast in duodenum - 15 min
- SI transit time - 30 min to 2 hrs
- SI emptying time - 3 hrs to 5 hrs
Upper GI study in the cat - transit times
- Gastric emptying - 15 min to 1-2 hours
- Contrast in duodenum - 10 min
- Contrast in jejunum - 30 min
- SI transit time - 1.5 to 2 hours
- SI emptying time 3-5 hours
Transit time of barium in the foal
Reaches large intestine by 8 hours
Most common intraoral tumor in the dog? cat?
Dog - melanoma > SCC > fibrosarcoma
Cat - SCC > fibrosarcoma
Common sites of metastasis of oral malignant melanoma in the dog
Regional lymph nodes
Lung
Metastatic pattern of oral SCC
Locally invasive. Metastasizes to regional lymph nodes; lung metastasis is rare
Oral fibrosarcoma metastatic pattern
Locally invasive. Metastasis is rare
Canine EPI
- Loss of pancreatic acinar cells (islets intact) –> inadequate production of digestive enzymes
- Characteristic gray feces, weight loss, increased volume of feces
- Low serum TLI is highly sensitive and specific
Ventricular Pressure-Volume Loop
B - mitral valve opens
B-C - diastole (stroke volume)
C - mitral valve closes
C-D - isovolumetric contraction
D - aortic valve opens
D-A - systole
A - aortic valve closes
Gallbladder sludge in dogs
- Older dogs and dogs with Cushings or hypothyroidism have more sludge
- Biochemical changes not correlated with presence of sludge
- May be associated with altered gallbladder contractility
- Incidental
- Rarely resolves, but may change consistency
Slipped capital epiphysis
In cats, growth plate should close between 7 and 9 months
Cats with slipped capital epiphyses are older (12-24 mo), obese, and neutered males
Neutering may delay physeal closure, however, there is also dysplasia of the physis resulting in persistently open, disorganized growth plate that cannot resist normal forces
May be bilateral
Major risk factor for adjacent segment disease
number of vertebrae incorporated into the fused segment –> the longer the fused segment, the greater the fulcrum effect from the fused segment and the greater the biomechanical stress at the remaining adjacent mobile segment
Spondylosis deformans
- Noninflammatory, degenerative process
- Boxer and German shepherd
- most common in the thoracolumbar and lumbosacral vertebral column, (L2–L3) and (L7–S1) affected most commonly
Diffuse idiopathic skeletal hyperostosis (DISH)
- Affects both the appendicular and axial skeleton
- Severe, contiguous bone formation along ventral longitudinal ligament
- Diagnosis
- flowing calcification 4 contiguous vertebral bodies
- no degenerative intervertebral disc disease (including vacuum phenomena and vertebral body marginal sclerosis)
- absence of articular process, joint bony ankylosis and sacroiliac joint erosion, sclerosis, or intra‐articular osseous fusion.
Fusion of >/= ______ consecutive intervertebral disc spaces is correlated with adjacent segment disease at the neighboring, unfused disc space
2
Feline DJD
- High prevalence
- Can be associated with decreased mobility
- Misamatch between radiographic signs and presence of pain response
Most frequent site of axial DJD in the cat? Most severe site?
Most frequent - T7-10
Most severe - lumbar or LS
Most commonly affected joints in feline DJD
Hip and elbow
What joints are most likely to have cartilage damage without radiographic evidence of DJD?
Stifle > coxofemoral joints and elbow > tarsus
What radiographic findings correlate with cartilage degeneration in cats?
Presence of osteophytes
Joint-associated mineralization (stifle)
Subjective radiographic DJD score
Meniscal mineralization in cats
- Mineralization always located in cranial horn of medial meniscus
- Strongly associated with medial compartment stifle DJD
PSS in cats
- EHPSS most common; left gastric to CVC
- IHPSS are rare; left divisional is most common
- DSH, Persian, Himalayan, Siamese
- Ptyalism and copper irises
When performing cystography, the patient should be in _____ recumbency?
Left lateral recumbency –> this traps any gas that obtains entrance to the venous system (via exposed capillary beds (ulceration) or via ureterovesicular reflux)
Physeal closure times
- Atlas
- Humeral condyle (intercondylar physis)
- Anconeal process
- Capital epiphysis
- Tibial tuberosity
- Atlas - 115 days
- Humeral condyle - 6 - 8wks
- Anconeal process - 150 days (5 mo)
- Capital epiphysis - 12mo
- Tibial tuberosity - 9-12mo
Normal pituitary measurements on CT in DOGS
- 4.5 mm in height and 6 mm in width
- Pituitary height-to-brain area (P:B) <0.3
