Small Animal Internal Medicine Flashcards

A 12-year-old, male neutered Domestic Shorthair cat presents with a 3-month history of weight loss despite a ravenous appetite, polyuria, polydipsia, and recent episodes of vocalizing at night. On physical examination, you note a heart rate of 240 bpm, a palpable thyroid nodule (goiter), and a BCS of 3/9. Which of the following is the most definitive and often curative treatment for this condition?

Answer: Radioactive iodine (I-131) therapy

Radioactive iodine (I-131) therapy is considered the gold standard and most definitive curative treatment for feline hyperthyroidism. It works by concentrating radioactive iodine in the hyperactive thyroid tissue, which destroys the abnormal cells. Methimazole requires lifelong administration and can have side effects. Surgical thyroidectomy is also a curative option but carries anesthetic and surgical risks, including potential damage to the parathyroid glands. An iodine-restricted diet can manage the condition but is not curative and requires strict dietary adherence.

A 7-year-old Miniature Schnauzer is brought to the clinic with a 2-day history of anorexia, vomiting, and apparent abdominal pain (prayer position). Bloodwork reveals lipemia, neutrophilia, and elevated amylase and lipase. Which of the following diagnostic tests is most specific for diagnosing pancreatitis in this dog?

Answer: Canine pancreatic lipase immunoreactivity (cPLI)

Canine pancreatic lipase immunoreactivity (cPLI), often run as a Spec cPL test, is the most specific blood test for diagnosing canine pancreatitis. Unlike general serum lipase and amylase, which can be elevated due to other conditions (e.g., renal disease, other gastrointestinal issues), cPLI specifically measures lipase originating from the pancreas. Abdominal radiographs may show secondary signs like a loss of serosal detail or a mass effect in the cranial abdomen, but these findings are not specific to pancreatitis.

Which of the following scenarios is the primary indication for using an ACTH stimulation test over a low-dose dexamethasone suppression test (LDDST) when diagnosing hyperadrenocorticism (Cushing's disease) in a dog?

Answer: The dog has a history of recent, high-dose corticosteroid administration.

The ACTH stimulation test is the test of choice for diagnosing iatrogenic hyperadrenocorticism, which is caused by the administration of exogenous corticosteroids. In this situation, the adrenal glands will be atrophied and will show a blunted or minimal response to ACTH stimulation. The LDDST is unreliable in these cases. While both tests can be affected by concurrent illness like diabetes, the LDDST is generally preferred for screening naturally occurring Cushing's due to its higher sensitivity. The LDDST, not the ACTH stim test, can sometimes help differentiate between pituitary and adrenal causes.

A 9-year-old Golden Retriever presents with chronic small bowel diarrhea, significant weight loss, and peripheral edema. Bloodwork reveals panhypoproteinemia (both albumin and globulin are low). After ruling out other causes of protein loss (e.g., kidney, liver disease), a diagnosis of protein-losing enteropathy (PLE) is suspected. Which of the following is NOT a common underlying cause of PLE in dogs?

Answer: Exocrine pancreatic insufficiency (EPI)

While Exocrine Pancreatic Insufficiency (EPI) causes malabsorption, weight loss, and diarrhea, it does not typically cause the significant intestinal protein loss that defines PLE. The primary pathophysiology in EPI is a lack of digestive enzymes. Common causes of PLE involve diseases that damage the intestinal wall, leading to protein leakage, such as severe inflammatory bowel disease, intestinal lymphangiectasia (dilated lymphatic vessels), and intestinal cancer.

According to the International Renal Interest Society (IRIS) guidelines for staging Chronic Kidney Disease (CKD) in a cat, what is the primary initial parameter used for staging?

Answer: Fasting blood creatinine concentration

The IRIS staging system for CKD is primarily based on fasting blood creatinine concentration in a stable, well-hydrated patient. While Symmetric dimethylarginine (SDMA) is a valuable biomarker incorporated into the guidelines, especially for early detection and in cases of low muscle mass, creatinine remains the foundational parameter for the initial staging into one of the four stages. Urine specific gravity and blood pressure are used for sub-staging the disease, not for the primary staging.

A 6-year-old, spayed female Labrador Retriever is diagnosed with diabetes mellitus. The owner has started insulin therapy. Which clinical sign is the most reliable indicator for the owner to monitor at home to assess for hypoglycemia?

Answer: Lethargy, weakness, or ataxia

Lethargy, weakness, ataxia, and in severe cases, seizures, are classic clinical signs of hypoglycemia (low blood sugar) resulting from an insulin overdose. While polyuria, polydipsia, and weight loss are signs of uncontrolled diabetes (hyperglycemia), they are not indicative of an acute hypoglycemic event. An increased appetite can be seen with both hyperglycemia and early hypoglycemia, but weakness and neurologic signs are more specific and urgent indicators of low blood glucose.