Canine II Flashcards
What is hemangiosarcoma (HSA)?
A malignancy of endothelial cells that line blood vessels.
What is the most common site of hemangiosarcoma in dogs?
The spleen.
What are other common sites of hemangiosarcoma?
Right atrium (auricle)
Which dog breeds are predisposed to hemangiosarcoma?
German Shepherds
What is the most common tumor to metastasize to the brain?
Hemangiosarcoma.
What are the typical emergency presentations of visceral hemangiosarcoma?
Acute hemoabdomen with hypovolemic shock
What history is often associated with visceral hemangiosarcoma?
Intermittent ‘good days’ and ‘bad days’ due to small bouts of internal hemorrhaging and reabsorption of blood.
How does hemangiosarcoma metastasize?
Via blood vessels and direct contact seeding within the abdomen if the tumor ruptures.
What is the median survival time for visceral hemangiosarcoma?
Generally less than 1 year
What imaging modality is most useful for diagnosing hemangiosarcoma?
Abdominal ultrasound to identify cavitary
Why is fine needle aspirate cytology often unrewarding for hemangiosarcoma?
Samples are often filled with blood
What is the preferred method for diagnosing splenic hemangiosarcoma?
Surgical biopsy and splenectomy if cavitary or fluid-filled lesions are present.
What radiographic findings suggest hemangiosarcoma?
Pulmonary metastasis or pericardial effusion on thoracic radiographs.
What hematologic abnormalities are common in hemangiosarcoma?
Anemia (with or without regenerative response)
What coagulation abnormality is associated with hemangiosarcoma?
Prolonged clotting times if in disseminated intravascular coagulation (DIC).
What is the first step in stabilizing a dog with hemoabdomen due to hemangiosarcoma?
IV fluids and blood transfusions as needed.
What surgical procedure is commonly performed for splenic hemangiosarcoma?
Splenectomy with biopsy of abnormal tissues.
What chemotherapy is recommended to delay metastasis in hemangiosarcoma?
Adriamycin-based chemotherapy.
What is the median survival time for hemangiosarcoma with surgery alone?
3 weeks to 3 months.
What is the median survival time for Stage I hemangiosarcoma treated with surgery and chemotherapy?
9 months.
What is the median survival time for Stage II hemangiosarcoma with hemorrhage
treated with surgery and chemotherapy?
What is the median survival time for Stage III metastatic hemangiosarcoma treated with chemotherapy?
3.5 months.
What is the primary cause of cutaneous hemangiosarcoma?
Chronic sun exposure.
Which dog breeds are predisposed to cutaneous hemangiosarcoma?
Fawn-colored Pit Bulls
What are common sites of cutaneous hemangiosarcoma?
Ventral abdomen
How does cutaneous hemangiosarcoma differ from visceral forms?
It has a lower metastatic rate
What is the recommended treatment for cutaneous hemangiosarcoma?
Surgical removal of problematic (bleeding
What is the prognosis for cutaneous hemangiosarcoma?
Dogs may live for years
What preventive measures can reduce the risk of cutaneous hemangiosarcoma?
Applying sunblock or keeping dogs indoors during peak sunlight hours.
What is hip dysplasia?
A polygenic
Which dog breeds are predisposed to hip dysplasia?
German Shepherd
What gait abnormality is strongly indicative of hip dysplasia?
Bunny hopping gait.
What is the Ortolani test used for?
Detecting hip laxity by eliciting a ‘pop’ as the femoral head returns to the acetabulum.
What radiographic findings are associated with hip dysplasia?
Less than 50% coverage of femoral head
At what age can juvenile hip dysplasia typically be diagnosed?
Between 3-8 months of age.
What two radiographic screening methods are used to diagnose hip dysplasia?
OFA Hip and PennHIP.
What is the primary difference between OFA Hip and PennHIP?
OFA is subjective and requires dogs to be 2 years old
What is the primary conservative management for hip dysplasia?
NSAID therapy
What NSAIDs are commonly used for hip dysplasia?
Carprofen
What are examples of chondroprotective agents used for hip dysplasia?
Glucosamine
What type of exercise is recommended for hip dysplasia management?
Low-impact walking and swimming to maintain muscle tone.
What is Juvenile Pelvic Symphysiodesis (JPS)?
A procedure that cauterizes or staples the pubic symphysis to improve acetabular coverage.
At what age is JPS performed?
14-20 weeks of age.
What is the Triple Pelvic Osteotomy (TPO) procedure?
A surgery involving three cuts in the pelvis to increase femoral head coverage by rotating the acetabulum.
At what age is TPO performed?
6-12 months
What is a Total Hip Replacement (THR)?
Placement of prosthetic acetabular and femoral components to replace the diseased joint.
What are the two types of Total Hip Replacement systems?
Cemented and Cementless.
What is the success rate of THR?
Approximately 90%
At what age can THR be performed?
Any time after growth plates are closed.
Why is THR not commonly performed in very young dogs?
Uncertainty about the longevity of implants; humans require revision surgery in 10-15 years.
What is a Femoral Head and Neck Ostectomy (FHO)?
A salvage procedure where the femoral head and neck are removed to form a pseudo-joint.
Which patients benefit most from FHO?
Small animals weighing less than 20-30 lbs
What is a possible side effect of FHO?
Mechanical lameness due to limb shortening.
What is the purpose of denervation of the hip joint capsule?
To eliminate pain perception while hip dysplasia progresses.
What nutritional factor is associated with a higher incidence of hip dysplasia?
Over-nutrition during growth.
What are two breeding programs aimed at reducing hip dysplasia?
PennHIP and OFA Hip Certification.
What is the most common cause of hypothyroidism in dogs?
Lymphocytic thyroiditis.
What is a rare congenital form of hypothyroidism called?
Cretinism.
What is the most common cause of misdiagnosed hypothyroidism?
Euthyroid sick syndrome (suppressed TSH due to illness).
What are the primary thyroid hormones?
Thyroxine (T4) and triiodothyronine (T3).
What is the main function of thyroid hormones?
Increase metabolic rate
What are the most common clinical signs of hypothyroidism?
Weight gain
What is the classic alopecia distribution in hypothyroid dogs?
Bilaterally symmetric alopecia over the lateral trunk
What cardiovascular abnormalities are associated with hypothyroidism?
Bradycardia
What are the two most common laboratory abnormalities in hypothyroidism?
Mild non-regenerative anemia and hypercholesterolemia.
What is the preferred screening test for hypothyroidism?
Serum total T4 level.
What does a normal T4 level indicate?
The dog is not hypothyroid.
Why should low T4 levels be confirmed with additional testing?
Illness or other factors may lower T4 without true hypothyroidism.
What additional endocrine tests can confirm hypothyroidism?
cTSH and free T4 by equilibrium dialysis
What are the expected lab results in a hypothyroid dog?
Increased cTSH and low free T4.
What is the response in a TSH stimulation test for a hypothyroid dog?
Low T4 even after TSH administration.
What is the treatment for hypothyroidism?
Oral levothyroxine administration.
How should levothyroxine dosing be determined?
Based on the dog’s ideal body weight.
How should T4 levels be monitored after starting therapy?
Evaluate T4 levels periodically to adjust dosing.
What is the most common cause of laryngeal paralysis?
Idiopathic disease in older dogs.
Which breeds are most commonly affected by idiopathic laryngeal paralysis?
Labrador Retrievers
What is the key muscle responsible for arytenoid abduction?
Cricoarytenoideus dorsalis muscle.
Which nerve innervates the cricoarytenoideus dorsalis muscle?
Recurrent laryngeal nerve.
What are the possible causes of laryngeal paralysis?
Idiopathic
Which form of laryngeal paralysis is more common: congenital or acquired?
Acquired.
What are the hallmark clinical signs of laryngeal paralysis?
Voice change
What are additional clinical signs that may be observed?
Coughing
What is the gold standard for diagnosing laryngeal paralysis?
Laryngeal examination under light anesthesia.
Why is doxapram used during laryngeal exams?
It stimulates respiration
What finding on laryngeal examination confirms paralysis?
Failure of arytenoids to abduct on inspiration.
What is the most common surgical treatment for laryngeal paralysis?
Cricoarytenoid lateralization (‘laryngeal tie-back’).
What percentage of dogs develop pneumonia after laryngeal tie-back surgery?
10-28%.
What percentage of dogs with postoperative pneumonia may die from it?
Up to 14%.
What is a major complication of partial laryngectomy?
Laryngeal webbing (50% complication rate).
What surgical treatment is considered for dogs at high risk of aspiration pneumonia?
Permanent tracheostomy.
Why is reinnervation of laryngeal muscles not commonly performed?
It takes a long time for function to resume
What surgical procedure is associated with severe postoperative bleeding and edema?
Castellated laryngofissure.
What newer surgical technique has shown promise for treating laryngeal paralysis?
Video and laser-assisted unilateral partial arytenoidectomy.
What is the most common dermal malignancy in dogs?
Mast cell tumor (MCT).
Which dog breeds are predisposed to mast cell tumors?
Boxers
How do mast cell tumors behave in brachycephalic breeds?
They frequently develop multiple MCTs
What substances are released when mast cells degranulate?
Histamine
What systemic effects can mast cell degranulation cause?
GI ulcers
Why are mast cell tumors called ‘The Great Pretender’?
They can mimic any skin lesion
What is the preferred initial diagnostic method for mast cell tumors?
Fine needle aspirate (FNA) cytology.
What common cytologic finding supports a diagnosis of mast cell tumor?
Abundant eosinophils.
Why can’t the grade of a mast cell tumor be determined by cytology?
Histologic evaluation of a biopsy is required to assess grade.
What additional diagnostics are indicated for aggressive MCTs?
Fine needle aspirate of regional lymph nodes
What is the purpose of buffy coat analysis or bone marrow aspirate in MCT cases?
Rarely performed due to low diagnostic yield.
What is the most commonly used grading system for MCTs?
The Patnaik system.
What three factors are evaluated in the Patnaik grading system?
Cell differentiation
What are the three grades in the Patnaik system and their prognostic significance?
Grade 1: Least aggressive
What percentage of Grade 1 mast cell tumors metastasize?
<10%.
What percentage of Grade 3 mast cell tumors metastasize?
50-90%.
What survival time is associated with Grade 3 mast cell tumors?
6 months to 3 years.
How does tumor location affect prognosis?
Visceral MCTs have a poor prognosis; mucosal and mucocutaneous MCTs are more aggressive.
What mitotic index is associated with poor prognosis?
> 5 mitoses per 10 high power fields.
What are additional proliferation markers used for prognosis?
Ki-67
What is the significance of KIT mutation in MCTs?
Associated with a worse prognosis.
Which breeds tend to have less aggressive mast cell tumors?
Boxers and Pugs.
What is the treatment of choice for mast cell tumors without metastasis?
Surgical excision with wide margins (2-3 cm lateral and 1 fascial plane deep).
What is the role of radiation therapy in MCT treatment?
Used as an adjuvant when complete surgical margins cannot be achieved.
What chemotherapeutic agents are commonly used for mast cell tumors?
Vinblastine
When is chemotherapy indicated for MCTs?
If metastasis is present
What corticosteroid is used in MCT treatment?
Prednisone.
Why is prednisone beneficial for mast cell tumors?
It is cytotoxic to mast cells
What H1 blocker is commonly used for MCTs?
Diphenhydramine (Benadryl).
What H2 blockers are used to manage MCT-associated GI ulcers?
Famotidine
What is the first FDA-approved tyrosine kinase inhibitor for MCTs?
Toceranib (Palladia).
How does Toceranib (Palladia) work?
Inhibits aberrant cell signaling pathways in MCTs
What is the most common malignant oral tumor in dogs?
Oral malignant melanoma (OMM).
Which dog breeds are overrepresented for oral melanoma?
Chow Chows
What type of tumor is melanoma?
A tumor of melanocytes.
What percentage of oral melanomas are amelanotic?
About 1/3 of cases.
Why can amelanotic melanomas be difficult to diagnose?
They lack melanin and can resemble sarcomas
What is the metastatic rate of oral melanoma?
Up to 80% of cases.
Where does oral melanoma commonly metastasize?
Local lymph nodes first
Besides the oral cavity
where else can melanoma occur?
What is needed for definitive diagnosis of oral melanoma?
Biopsy.
What other oral tumors must oral melanoma be distinguished from?
Squamous cell carcinoma
What staging tests should be performed after diagnosis?
Minimum database
What imaging modalities are useful for assessing bone involvement?
CT or MRI.
What is the treatment of choice for the primary tumor?
Surgical excision with wide margins.
What surgical procedures are often required for complete excision?
Partial mandibulectomy or maxillectomy.
What role does radiation therapy play in oral melanoma treatment?
Used for tumor shrinkage or slowing growth if surgery is not feasible.
What chemotherapy agents have shown mild efficacy in shrinking oral melanoma lesions?
Carboplatin and cisplatin.
What makes melanoma a good candidate for immunotherapy?
It is often an immunogenic tumor.
What is the commercially available DNA vaccine for canine oral melanoma?
A xenogeneic human DNA vaccine encoding tyrosinase.
How does the melanoma vaccine work?
The injected DNA encodes human tyrosinase
Is the melanoma vaccine used for prevention or treatment?
Treatment after diagnosis.
What is the current efficacy of the melanoma vaccine?
Early reports show promise
What tumor size is associated with a better prognosis?
Tumors <2 cm have a median survival of about 17 months.
What is the median survival time for tumors >2 cm?
About 5.5 months.
How does tumor location affect prognosis?
Rostral oral cavity tumors have better survival rates than caudal ones.
What surgical factor improves prognosis?
Complete margins obtained in the first surgery.
What is the most common primary bone tumor in dogs?
Osteosarcoma (OSA).
Which type of dog is most commonly affected by osteosarcoma?
Large and giant breed dogs.
What skeletal region is most commonly affected by osteosarcoma?
Metaphyseal region of the appendicular skeleton.
What are the most common locations for appendicular osteosarcoma?
Distal radius
What are common clinical presentations of osteosarcoma?
Chronic progressive lameness or acute lameness after trauma (e.g.
Where does osteosarcoma most commonly metastasize?
Lungs (primary site)
What percentage of dogs with osteosarcoma eventually develop metastasis?
0.9
What are the characteristic radiographic findings of osteosarcoma?
Lytic and productive lesion at the metaphysis
What finding on radiographs suggests metastasis rather than primary bone cancer?
A diaphyseal lesion.
Why is fine needle aspiration (FNA) preferred over biopsy for diagnosing osteosarcoma?
FNA is less invasive and avoids pathologic fractures.
What laboratory abnormality is associated with a poor prognosis in osteosarcoma?
Elevated alkaline phosphatase (ALP).
What imaging modality can help detect bone metastases?
Bone scan (nuclear scintigraphy) or full-body radiographs.
What is the most effective way to alleviate osteosarcoma-associated pain?
Limb amputation.
Why is amputation considered palliative rather than curative?
Because most dogs develop metastasis even after surgery.
What is a limb-sparing procedure for osteosarcoma?
Surgical removal of the tumor with placement of a prosthetic implant.
What are complications associated with limb-sparing surgery?
Chronic infections
What is the role of radiation therapy in osteosarcoma treatment?
Pain palliation
What is the main chemotherapy drug used for osteosarcoma?
Cisplatin or carboplatin
What is the role of bisphosphonates in osteosarcoma?
They inhibit osteoclasts and help reduce bone pain in non-surgical cases.
What is the median survival time for osteosarcoma with amputation alone?
4-6 months.
What is the median survival time for osteosarcoma with surgery and chemotherapy?
10-12 months.
What is the median survival time for osteosarcoma with metastatic disease?
1-3 months.
What percentage of osteosarcomas affect the axial skeleton?
0.25
Which dog size is more commonly affected by axial osteosarcoma?
Small to medium-sized dogs.
What are common locations for axial osteosarcoma?
Mandible
Which axial osteosarcoma location has the best prognosis?
Mandible (70% 1-year survival with surgery alone).
How does axial osteosarcoma compare to appendicular osteosarcoma?
Generally considered aggressive
What is the difference in presentation of pancreatitis between dogs and cats?
Dogs often present with acute severe episodes
What are common risk factors for canine pancreatitis?
Obesity
What is a unique diagnostic clue for pancreatitis in dogs?
Hunched posture (‘praying position’).
What are the typical clinical signs of pancreatitis in dogs?
Vomiting
What are the typical clinical signs of pancreatitis in cats?
Lethargy
Which two diagnostic tests are the most useful for pancreatitis?
Ultrasound and pancreatic-specific lipase immunoreactivity (cPLI for dogs
Why are serum amylase and lipase levels unreliable for diagnosing pancreatitis?
They are nonspecific and can be elevated due to other causes.
Why is mild pancreatitis particularly difficult to diagnose in cats?
Cats often do not show significant clinical signs
What is the primary treatment approach for acute pancreatitis in dogs?
Supportive care including IV fluids
Why is delaying feeding sometimes recommended in canine pancreatitis?
To reduce pancreatic stimulation and prevent vomiting.
When are antibiotics indicated for pancreatitis in dogs?
Only if pancreatic necrosis or sepsis is suspected.
What additional treatments may be used for severe pancreatitis?
Plasma or heparin administration in severe cases.
What is the main treatment for feline pancreatitis?
Supportive care with pain management
Why is identifying and treating underlying disease critical in feline pancreatitis?
Pancreatitis in cats is often secondary to other diseases such as hepatic lipidosis or inflammatory bowel disease.
Which breeds are predisposed to EPI?
German Shepherds
What are the hallmark clinical signs of EPI?
Polyphagia
What is the most common cause of EPI in dogs?
Pancreatic acinar atrophy.
What is the most common cause of EPI in cats?
Chronic pancreatitis.
What test is used to diagnose EPI?
Trypsin-like immunoreactivity (TLI)
What is the cornerstone of EPI treatment?
Exogenous pancreatic enzyme supplementation (powdered pancreatic extracts).
What other supplements are often needed for EPI patients?
Parenteral cobalamin (B12)
What dietary modifications are recommended for EPI patients?
Highly digestible
What is pericardial effusion?
An uncommon but life-threatening condition where excessive fluid accumulates in the pericardial space
What is cardiac tamponade?
A condition where intrapericardial pressure equals or exceeds right atrial pressure
How does the rate of fluid accumulation affect clinical signs?
Rapid accumulation causes acute severe signs
What is the most common neoplastic cause of pericardial effusion in dogs?
Hemangiosarcoma.
What other neoplasms can cause pericardial effusion in dogs?
Chemodectoma
What are non-neoplastic causes of pericardial effusion in dogs?
Right-sided heart failure
What are common causes of pericardial effusion in cats?
Congestive heart failure
What is the most common cause of pericardial effusion in horses?
Idiopathic pericardial effusion.
What is the most common cause of pericardial effusion in cattle?
Traumatic reticuloperitonitis (hardware disease).
What are the general clinical signs of pericardial effusion?
Lethargy
What are specific cardiovascular signs of pericardial effusion?
Jugular vein distension
What is pulsus paradoxus?
An exaggerated decrease in systolic blood pressure during inspiration
What is the gold standard diagnostic test for pericardial effusion?
Echocardiography
What are common radiographic findings in pericardial effusion?
Enlarged cardiac silhouette with a rounded appearance
What ECG abnormalities are seen with pericardial effusion?
Sinus tachycardia
What is electrical alternans?
A pattern of alternating variation in R-wave amplitude
What is the first-line treatment for pericardial effusion with cardiac tamponade?
Pericardiocentesis.
What are possible complications of pericardiocentesis?
Ventricular premature complexes
What is the definitive treatment for idiopathic pericardial effusion?
Pericardiectomy.
What additional treatment is used for neoplastic causes of pericardial effusion?
Chemotherapy
How is idiopathic pericardial effusion in horses treated?
Indwelling chest tube with drainage and lavage
Why is treatment of traumatic pericarditis in cattle usually unrewarding?
It is often severe
What is a portosystemic shunt (PSS)?
An abnormal blood vessel allowing portal blood to bypass the liver and enter systemic circulation.
What are the primary categories of portosystemic shunts?
Congenital vs. acquired
What is the most common type of portosystemic shunt in dogs?
Single
What breeds are predisposed to extrahepatic shunts?
Yorkshire Terriers
What type of shunts are more common in large-breed dogs?
Intrahepatic shunts.
What classic ocular sign is sometimes seen in cats with congenital PSS?
Copper-colored irises.
What are common clinical signs of PSS?
Failure to thrive
What neurological signs are associated with hepatic encephalopathy?
Head pressing
Why do clinical signs of PSS often worsen after meals?
Increased ammonia absorption from protein metabolism.
What CBC findings are associated with PSS?
Initially normocytic
What chemistry abnormalities are seen with PSS?
Low BUN
What is the most useful blood test for diagnosing PSS?
Pre- and post-prandial bile acids.
How do bile acid levels appear in a dog with a PSS?
Dramatically elevated post-prandial bile acids.
What other blood test can support PSS diagnosis?
Elevated fasting ammonia levels.
What urine abnormality is associated with PSS?
Ammonium biurate crystals.
What is the most common radiographic finding in PSS?
Microhepatia (small liver).
What is the most reliable imaging modality for diagnosing PSS?
Ultrasound (though sensitivity is ~60%).
What contrast study confirms PSS by visualizing abnormal blood flow?
Mesenteric portovenography or transcolonic scintigraphy.
How does transcolonic scintigraphy diagnose PSS?
In a normal dog
What is the goal of medical management for PSS?
Reduce ammonia production and manage hepatic encephalopathy.
What antibiotics are used to reduce ammonia-producing bacteria?
Metronidazole or Neomycin.
What is the function of Lactulose in PSS treatment?
It acidifies the colon
Why is a low-protein diet recommended for PSS patients?
Reduces ammonia production from protein metabolism.
What additional medications are used for managing hepatic encephalopathy?
Potassium bromide (if seizuring)
What is the expected outcome of medical management alone?
Shortened lifespan; surgery is recommended if possible.
What is the preferred surgical treatment for PSS?
Gradual occlusion of the shunting vessel using an ameroid constrictor or cellophane band.
Why is complete ligation of a shunt rarely performed?
It can cause severe portal hypertension and high complication rates.
What is the mortality rate associated with PSS surgery?
Approximately 20%.
What complications should be monitored for postoperatively?
Hypoglycemia
Why is a liver biopsy recommended during PSS surgery?
To rule out microvascular dysplasia
