Lecture 8 2/13/25 Flashcards
What is a paraneoplastic syndrome?
alteration in structure/function occurring distant to the tumor
What are the causes of paraneoplastic syndromes?
-production of small molecules released into circulation
-immune cross-reactivity between malignant and normal tissues
How are PNS treated?
treating the tumor
What are the characteristics of hypercalcemia?
-one of the most common PNS in dogs
-total calcium is the screening test
-iCa is the active portion
What are the clinical signs of hypercalcemia?
-lethargy
-weakness
-anorexia
-vomiting
-diarrhea
-constipation
-PU/PD
-AKI
-dehydration
-muscle tremors
What are the characteristics of hypercalcemia of malignancy?
-involves release of PTHrP, which has similar biologic effects to PTH
-cancer is the most common cause in dogs; less common cause in cats
Which tumors are associated with hypercalcemia of malignancy in dogs?
-lymphoma
-AGASACA
-multiple myeloma
-thymoma
-other carcinomas
Which tumors are associated with hypercalcemia of malignancy in cats?
-lymphoma
-squamous cell carcinoma
What are first steps of a work up for a patient with suspected hypercalcemia?
-physical exam with focus on lymph node palpation and rectal exam
-minimum database (CBC/chem/UA)
-iCa to confirm ionized hypercalcemia
If the initial workup in a patient with suspected hypercalcemia does not provide answers, what can be done next?
thoracic and abdominal imaging looking for:
-cranial mediastinal mass
-enlarged lymph nodes
-abnormal liver or spleen
What is the normal physiology of iCa and PTH?
elevated iCa provides negative feedback that shuts off PTH production/release
What are the characteristics of a malignancy panel?
-usually not needed
-can diagnose hyperparathyroidism
-absence of PTHrP does NOT mean pet does not have cancer
When should hypercalcemia be treated?
-iCa greater than 1.8 mmol/L
-Ca x Phos > 70; risk of dystrophic mineralization
-clinical signs, azotemia, dehydration
What are the treatment options for hypercalcemic patients?
-rehydration and diuresis with 0.9% NaCl sol.
-furosemide once rehydrated
-bisphosphonates to inhibit osteoclasts
-calcitonin
-prednisone (after getting a diagnosis)
What are the causes of hypercalcemia in felines?
-spurious
-hyperparathyroidism
-idiopathic
-renal dz
-tumors
What are the clinical signs of GI ulceration?
-vomiting
-lethargy
-anorexia
-melena
What are the lab findings with GI ulceration?
-anemia
-increased BUN
-decreased albumin
What are the characteristics of GI ulceration?
-mast cell degranulation leads to excess histamine
-only occurs with large disease burden or high grade tumors
-want to treat the tumor and provide omeprazole and sucralfate
What are the characteristics of hyperviscosity syndrome?
-increased blood components leads to increased blood viscosity
-causes end-organ damage at the brain, arteries, retina, kidney, and heart
What are the characteristics of multiple myeloma?
-cancer of the plasma cells that results in excess Ig production
-highly increased TP, increased globulins
-uncommon in dogs
What are the clinical signs of multiple myeloma?
-lameness
-epistaxis
-PU/PD
-kidney dz
-neuro. signs
-cytopenias
-increased calcium
What are the criteria for multiple myeloma diagnosis?
-must have 2/4 of the following:
–monoclonal gammopathy
-light chains
-osteolysis
-marrow plasmacytosis
What is monoclonal gammopathy?
a monoclonal increase in globulins that can be seen on a serum protein electrophoresis
What are the characteristics of light chains?
-light chains spill over into urine
-can be detected on urine electrophoresis
-CANNOT be detected on routine dipstick
What are the treatment options for multiple myeloma?
-chemotherapy; CHOP or melphalan and prednisone protocols
-IV fluids
-blood products
What are the signs of hyperestrogenism?
-bone marrow hypoplasia
-alopecia
-+/- feminization syndrome
What are the characteristics of hyperestrogenism?
-occurs in cryptorchid patients with sertoli cell tumors
-treatment is removal of tumor
-bone marrow recovery is not guaranteed if pet had tumor for a longer duration
What are the characteristics of IMHA and immune-mediated thrombocytopenia?
-seen in lymphoma and leukemia cases
-treat with removal/treatment of tumor +/- immunosuppressant treatment
What are the characteristics of DIC?
-coagulopathy that occurs when patient has an initial hypercoagulable state that later becomes a hypocoagulable state
-seen in 10% of dogs with malignant tumors
-most common with hemangiosarcoma
-must remove tumor; otherwise grave prognosis
What are the characteristics of myasthenia gravis?
-antibodies to AchR block transmission at the neuromuscular junction
-associated with thymoma
-diagnosed with an AchR antibody test
What are the clinical signs of myasthenia gravis?
-intermittent muscle weakness
-exercise intolerance
-regurgitation
-megaesophagus
-dysphagia
What are the characteristics of thymoma?
-seen in older dogs and cats
-cranial mediastinal mass
-local invasive but does not usually spread beyond that
How is thymoma diagnosed?
ultrasound-guided FNA
What is the treatment for thymoma and myasthenia gravis?
-surgical removal of tumor
-radiation therapy
-cholinesterase inhibitors and supportive care for MG
What are the characteristics of hypertrophic osteopathy?
-overproduction of periosteum
-causes lameness, soft tissue swelling, ocular discharge, +/- fever
-preferentially affects long bones
How is hypertrophic osteopathy diagnosed?
radiographs
What are the causes of hypertrophic osteopathy?
-neoplastic causes such as primary lung tumor or pulmonary metastasis
-non-neoplastic causes
What is the treatment for hypertrophic osteopathy?
-remove underlying cause
-multimodal pain control
-euthanasia if underlying cause cannot be controlled
