Midterm Flashcards
What are the causes of a non-regenerative anemia?
-pre-regenerative
-chronic renal disease
-inflammation
-bone marrow disease
-hypothyroidism or cushings
-iron deficiency
-precursor targeted IMHA
What are the causes of neutrophilia?
-Inflammation
-stress
-physiologic
-chronic leukemia
-paraneoplastic
What are the causes of a monocytosis?
-inflammation
-stress
-acute or chronic leukemia
What are the causes of thrombocytosis?
-essential thrombocythemia
-splenic contraction/splenectomy
-inflammation
-iron deficiency
What is commonly seen with anemia of chronic disease?
Mild normocytic, normochromic, non-regenerative anemia
T/F: Reactive thrombocytosis secondary to inflammation is a common cause of thrombocytosis in animals
True
What are the different methods for sampling the respiratory system?
-nasal swab/nasal biopsy (often polyps are connected to a tumor)
-paranasal trephination
-transtracheal aspiration (culture/cytology)/endoscopic tracheobronchial aspiration (allows for visualization)
-bronchioalveolar lavage (for asthma or infectious bronchitis)
-lung biopsy
-thoracocentesis (pleural fluid evaluation, cytology, bacterial/fungal culture)
-necropsy
What are the most common diseases of the nasal cavity?
-viral (herpesvirus in cats)
-bacterial (atrophic rhinitis in pigs or actinomycosis in cows)
-fungal (aspirgillosis in dogs and horses, crypto in cats)
-cancer (adenocarcinoma, SCC, mesenchymal tumors (chrondro or osteosarcoma) or tooth related tumors
What causes atrophic rhinitis in pigs?
Coinfection with bordatella bronchiseptica (not normal flora) and pasteurella multocida (normal flora)
If there is a large granulomatous lesion compressing the cribriform plate and the brain in a cat, what is the likely diagnosis?
Cryptococcus
-can see similar lesions in horses
Why are ethmoid hematomas in horses so difficult to treat?
They will continuously regrow
- causes profuse bleeding from the nares
What is the most common bacterial isolate from the respiratory tract in horses?
Strep equi ssp zooepidemicus
- normal flora bacteria
- also most common bacteria with pneumonia
Describe subepiglottal ulcers?
Common in racing horses
- causes inflammation in larynx causing them to not breath normally
What causes fibronecrotic laryngitis in cows?
Fusobacterium necrophorum and histophilus somni
- focally extensive lesions
What are some other pathologies that histophilus somni can cause?
Thromboembolic meningoencephalitis in pigs
-BRD in cattle
What is the cause of diffuse fibronecrotic pharyngitis and tracheitis? What is the cause of this in horses?
Infectious bovine rhinotracheitis virus
- in horses caused by equine herpesvirus 1
What are all the agents associated with BRDC?
Viruses: BRSV, PI3, BVD, IBR, coronavirus
Bacteria: Pasteurella multocida, mannheimia haemolytica, mycoplasma bovis, histophilus somni, truparella pyogenes
What is the Lungworm agent?
Dictyocaulus viviparus
If you get a cuture from a cow with BRDC and you just have trueparella, what does this mean?
You have to keep digging
- this is an opportunistic infection, something else caused the damage initially
How does mycoplasma cause disease?
Attaches itself to the cilia as it wants to be one, which slows down the mucociliary apparatus
-can cause bronchiectasis
If you see fibrinous bronchopneumonia in a cow with suspected shipping fever, what agent is likely involved?
Mannheimia hemolytica
- part of normal flora
What are the main respiratory defenses?
Nasal colonization and shedding
-mucociliary clearance
-host defense factors in epithelial lining
-inflammatory response of epithelial cells
-alveolar macrophages
-recruited neutrophils
T/F: viral infections always come before bacterial in BRDC infections
False
-usually the case but can also be due to cold air, dehydration, vitamin D deficiency, stress, steroid use, and many other causes
What is fog fever?
Atypical interstitial pneumonia of cattle
- occurs during spring with lush pastures
- lush pastures contain a large amount of Tryptophan which is converted to 3-methyl indole in the rumen
What is the reportable disease that you should have on the top of your differential list if you see granulomatous lung abscesses in a cow?
Tuberculosis
- Mycobacterium bovis
- the US is currently free of this disease
What is vena cava syndrome in cattle?
Acidosis causes ruminal papilla sloughing allowing for bacterial translocation from rumen to the liver
- after the liver it can travel through the vena cava and heart and make its way to the lungs where it results in pulmonary thromboemboli
- emboli can also result in jugular thrombosis and deep vein thrombosis
Describe the agents responsible for ovine enzootic pneumonia
-environmental factors: crowding, humidity, temperature, air quality, stress
-viral infections: RSV, BPIV-3, adenovirus
-bacterial infections: mannheimia hemolytica, pasteurella multocida, mycoplasma ovipneumonia (big killer of bigborn sheep), histophilus somni
Describe OPP and CAE
Small ruminant lentiviruses
-results in progressive interstitial pneumonia, encephalitis, arthritis and mastitis
What is the one condition that does not follow the rules and causes caudodorsal distribution of fibrinous bronchopneumonia in pigs?
Actinobacillus pleuropneumonia
Why is interstitial pneumonia hard to diagnose on necropsy?
It is diffuse
- if you dont have normal lung to compare it to you may think it looks normal
What is the main clinical sign of retroviral pulmonary carcinomatosis (ovine pulmonary adenocarcinoma)?
When you tilt their head down, gravity causes a large amount of fluid to flow out of nares
What does diffuse interstitial pneumonia with multifocal lobar atelactasis look like in pigs? What are some conditions that can cause it?
Looks like a checkerboard
- caused by PRRSV and porcine influenza virus
What are the different causes of fibrinous polyserositis in pigs?
Mycoplasma hyorhinis, **glaeserella parasuis (glassers disease), streptococcus suis, Ecoli
What area of the lungs are most affected by suppurative bronchopnuemonia in horse?
- only affects cranioventral aspect of the diaphragmatic lobe of lungs
What is the most common cause of pneumonia in horses?
Strep equi ssp zooepidemicus
What is the cause of equine nodular pulmonary fibrosis?
EHV-5
- usually located on dorsal aspect of diaphragmatic lung lobes
What is commonly seen on histopath of a foal with rhodococcus equi?
Giant cell macrophages
-also can cause ulcerative colitis, lymphadenitis, or osteomyelitis
What are the common agents responsible for bronchopneumonia in dogs and cats?
Usually secondary
- pasteurella
-streptococcus
-Ecoli
-klebsiella
-bordatella bronchiseptica
What are the main causes of interstitial pneumonia in dogs and cats?
Dogs: canine distemper (main one), canine parainfluenza, canine adenovirus, canine influenza, canine herpesvirus 1 (usually only in young animals)
Cats: feline rhinotracheitis (feline herpesvirus 1), feline calcivirus
What can cause diffuse granulomatous pneumonia in dogs and cats?
Histoplasmosis
-can also be seen with blastomyces or cryptococcus in some cases
What are the features of heart muscle on histopath?
Striations, intercalated discs, branching, central nucleus
What are some congenital malformations of the heart?
VSD(most are high in the ventricle),ASD, PDA, persistent right aortic arch (along with megaesophagus), tetrology of fallot
When does PDA become a problem?
If it doesnt close by 2 weeks
- wont see lesions for months however
-causes continuous washing machine murmur
Where does pulmonic stenosis or subaortic stenosis occur?
Pulmonic- right at level of the valve
Subaortic stenosis - right below the valve
What tumors affect the heart?
Hemangiosarcoma, chemodectoma (heart base tumors) and lymphoma
What are the classic locations of hemangiosarcoma?
Right auricle, spleen, skin
-neoplasia of endothelial cells (causes poorly formed blood vessels)
What is cardiac tamponade?
Excessive pressure in the pericardium preventing the heart from contracting effectively or fill effectively
What is the common clinical presentation of chemodectomas?
Effusion in pericardial sac
- tumor itself is usually benign
What species most commonly gets lymphoma in the heart?
Cows
-also get it in heart, abomasum, uterus, spinal cord, lymph node (retrobulbar most commonly)
-associated with bovine leukosis virus (though very few cows develop lesions)
What are the main types of cardiomyopathy in vet med?
Hypertrophic, dilated, restrictive, boxer
What is the common signalment for DCM?
Large breed dogs
-results in decreased contractility, dilation is due to volume overload
-can also occur as a result of grain free diets
-can be seen in cats due to taurine deficiency
Who gets HCM?
Cats
- can be primary or secondary (associated with hyperthyroidism)
-concentric hypertrophy is due to pressure overload
-heart should weight 18 grams or less (if more, it is sus)
-on histopath will see fibrous infiltrates and disorganization of fibers and lipid deposits
In boxer cardiomyopathy, what is the heart wall replaced with?
Lipid
- over 75% of the wall replaced
Who gets myxomatous mitral valve disease?
Small breed dogs (Cavaliers mostly)
- valves look thin and shiny
What can cause myocardial necrosis in a puppy?
Parvo
What do horses get that causes myocardial necrosis?
Ionophore toxicity
-often occurs when horses get into cattle feed
-causes sudden death
What is white muscle disease a result of?
Selenium or vitamin E deficiency
-selenium is a cofactor for glutathione reductase which helps to break down free radicals
-shows up most commonly in heart, tongue, and diaphragm and masseter muscles
-always take sample of papillary muscle (most frequently affected)
What can occur with death of heart muscle
Fibrosis of heart muscle
- flow of blood to lung will be affected (hemosiderin in macrophages)
- necrosis around central vein of liver +/- fat accumulation
T/F: sepsis can lead to endocarditis, myocarditis and pericarditis
True
What are some physical exam findings that would point one towards an infectious/inflammatory differential?
-fever
-generalized lymphadenopathy
-multisystemic disease
What on a CBC points towards inflammation?
Let shift, leukocytosis, toxic changes, lymphopenia (could be due to acute inflammation or stress)
If the HCT is low, and RBCs are normal, can you still categorize the patient as anemic?
YES
What are the 3 things that can cause a selective
and severe hypoalbuminemia?
-Protein losing nephropathy
-Liver failure
-Inflammation
With PLE, what changes do you expect to see to the proteins?
Hypoalbuminemia + hypoalbuminemia
How can you rule out hepatic failure as a differential?
If all of the markers of liver function are normal
- Glucose
-BUN
- cholesterol
How can you rule out a protein losing nephropathy?
Look at urine protein
- if negative, this can be ruled out
What are the causes of hyperglobulinemia?
Inflammation
Neoplasia (lymphoma and plasma cell)
Dehydration
How can you rule out renal causes of azotemia?
Adequately concentrated urine
What electrolyte changes may be seen with urinary bladder rupture?
Hyponatremia, hypochloremia, and hyperkalemia
Why may you have a decreased anion gap?
Hypoalbuminemia
- albumin is an unmeasured anion (have to increase other anions- chloride and bicarb- in order to maintain electroneutrality)
What is the equation for anion gap?
(Sodium + potassium)- (chloride + bicarb)
What does an elevated TCO2 indicate?
A metabolic alkalosis
If alkalosis is due to vomiting, what would you expect the electrolyte values to look like?
Chloride would be lower than sodium (corrected chloride)
T/F: foals < 6 months have lower MCV than adult horses
True
What does MCH tell you?
The amount of iron in each RBC
- if RBCs are smaller there will be less iron
- low MCHC is more definitive for diagnosing an iron deficiency anemia
What are the causes of hyperglycemia?
Glucocorticoid stress, sepsis (can cause hyper or hypoglycemia), epinephrine excitement
When is there a risk of tissue mineralization
When Ca X P >80
What are some causes of hyperphosphatemia?
Decreased GFR, diffuse intestinal disease, rhabdomyolysis
What are some potential causes of an elevated GGT in horses?
Cholestasis, biliary hyperplasia, intestinal disease
What is the most common cause of a hyperbilirubinemia due to elevated indirect bilirubin?
Fasting/anorexia
When should you calculate a corrected chloride?
When there is a hyponatremia along with a hypochloremia
How do you calculate corrected chloride?
(middle of Na reference/measured Na) X cl
What are some causes of a hyponatremia and hypochloremia?
-volume overload
-excessive water intake
-hypertonic fluid loss (secretory diarrhea)
-hypotonic fluid loss (GI, renal, 3rd space)
What is an elevated anion gap by definition?
A titrational metabolic acidosis
- can be due to ketones, lactate, uremic acids, or ethylene glycol
What do the cranial mediastinal, sternal, and hilar lymph nodes drain?
Mediastinal: 2nd stop for lymph nodes that drain head and forelimbs, also drains ribs and thoracic vertebrae, some of caudal lungs
Sternal: abdominal cavity and body wall, mammary glands
Hilar: drain the lungs
What can significant enlargement of the hilar lymph nodes lead to?
Ventral deviation of the carina
What are the two main differentials for a miliary interstitial or nodular structured interstitial pattern?
Fungal pneumonia: blasto, histo, coccidiomycosis (valley fever)
Less likely: neoplasia (lymphoma or metastatic disease)
-more likely to have variety in sizes
Where is blastomycosis typically found
in wet soils enriched with organic matter
- endemic areas include mississippi, ohio, st lawrence river and the atlantic states of the US
Describe the pathogenesis of blastomycoses
Nasal cavity–> alveolar spaces–> phagocytized by macrophages –> pathogenic yeasts distributed throughout lymphatic and hematogenous routes–> most commonly travel to skin and bone
- the cutaneous form occurs in 20-50% of all patients with blasto, with a predilection for the nasal plane, face and plantar cushions
How is blasto diagnosed?
-historically based on direct detection in tissues and fungal culture
-histopath allow for observation but not identification
-fungal culture is the most robust and irrefutable technique, but fungal growth is slow which delays diagnosis and treatment
-molecular tests are the main method of quick diagnosis today
T/F: blasto is zoonotic
TRUE
- should where PPE if you suspect this
Describe the features and pathogenesis of rhodococcus equi
-gram positive, facultative intracellular pathogen ubiquitous in soil
-VapA gene allows the bacteria to survive within macrophages
-inhibits fusion of the phagosome-lysosome, bacteria replicate within and eventually rupture macrophages (similar to pathogenesis of mycobacterium)
-young foals are at risk due to waning of passive humoral activity. Failure of passive transfer of colostrum is also a predisposing factor
How can you diagnose rhodococcus? What are some other differentials?
Gross and histological findings
-bacterial culture and/or PCR amplification combined with cytologic examination of the transtracheal aspiration
-radiographic evidence of lung abscesses/granulomas, ultrasonography
Differentials for granulomatous pneumonia: aspergillus, histoplasma, Blastomyces, cocciodioises, cryptococcus, mycobacterium
T/F: rhodococcus equi infections can be seen in a variety of other species besides horses
True
Describe the pathogenesis of fibrinous bronchopneumonia as a result of Ecoli infections in cats
- Ingestion and/or inhalation
- Adherence and colonization
- VF CNF-1 reduces arrival of inflammatory cells and evades neutrophils
- CNF-1 induces edema and necrosis of the blood vessels and pulmonary parynchema
What are the hallmark features of a stress leukogram?
Mild leukocytosis (mature neutrophilia and mild monocytosis), lymphopenia and eosinopenia
What is seen on bloodwork with a titrational metabolic acidosis?
-Elevated anion gap
- low TCO2
What bloodwork changes would you expect to see with primary hyperparathyroidism?
-high calcium, low phosphorus
*primary hyperparathyroidism is rare
What changes would you expect to see with the chemistry with addisons disease?
Changes in sodium, chloride and potassium
What bloodwork changes would you expect to see with vitamin D toxicosis?
Elevated calcium and phosphorus
What bloodwork changes would you expect to see with osteolytic disease?
Elevated calcium (only when very widespread) and phosphorus
What test should you run if you want to determine if a hypercalcemia is idiopathic or due to cancer?
iCa, PTH, PTHrp
- PTHrp would be elevated if cancerus
What are some causes of a pleural modified transudate?
- Heart failure
- Obstruction of caudal vena cava or hepatic vein (GDV, heartworm)
- Neoplasia
- Lung disease of torsion
- Diaphragmatic hernia
- Long standing transudates
What are the differentials for eosinophilia?
Worms, wheezes and weird diseases (eosinophilic bronchopneumonia, hypereosinophilic syndrome, neoplasia, specifically mast cell and lymphoma)
Describe what the most important values to look at are on blood gas and what elevations/decreases indicate
pH: if decreases=primary acidemia, if increased=primary alkalemia
pCO2: if decreased= respiratory alkalosis, if increased =respiratory acidosis
TCO2 (HCO3): if decreased = metabolic acidosis, if increased=metabolic alkalosis
T/F: If pH is normal, there is not a compensatory reaction
True
- compensatory responses never get you back to normal pH
-may indicate a mixed acid base reaction
What should you look at when interpreting acid-base on CBC/chem? What do changes indicate?
Na:
Cl: Decreases in corrected chloride =hypochloremic metabolic alkalosis (occurs with vomiting), increases in corrected chloride =”hyperchloremic” secretional metabolic acidosis (occurs a lot with diarrhea and loss of bicarb)
K: Acidosis causes increases (leaves cells as H enters), alkalosis causes decreases (enters cells as H leaves)
TCO2: Increased=metabolic alkalosis, decreased= metabolic acidosis
Anion Gap: Increased= titrational metabolic acidosis, decreased doesn’t matter clinically
T/F: Gallop rhythm is an arrythmia
False- it is an auscultated sound
- not necessarily associated with an arrythmia
What radiographic changes are seen with pleural effusion?
Increase in soft tissue opacity in periphery of thorax with conforms to the thorax margins
- retraction and rounding of lung lobe margins
- less gas within lung parenchyma–> increased opacity
- pleural fissure lines are widened (more separation between lung lobes)
-border effacement of heart and diaphragm
Describe how you take a vertebral heart score
Take measurements of top dimesion of the long and wide view, line up with the cranial aspect of T4 vertebral body
-count vertebral bodies that the measurements span and determine the sum of the 2
What is seen on radiographs with left sided heart enlargement?
Lateral: increased length of the heart mainly due to left atrial enlargement (looks like the heart is wearing a backpack)
DV: widening of the cranial heart due to left atrial and left auricular enlargement, left ventricular hypertrophy maintains a normal apex
What is the consequences of HCM?
Disease of diastolic dysfunction
-causes left ventricular hypertrophy, and backup of fluid into the left atrium and eventually the pulmonary veins leading to cardiogenic pulmonary edema
Where does pulmonary edema tend to occur in dogs with left sided congestive heart failure?
Perihilar
- more random distribution in cats
Where do the pulmonary veins lie in relation to the arteries?
Ventral and central
What happens to the pulmonary vasculature with right sided vs left sided disease?
Left sided: pulmonary venous distension
Right sided: pulmonary arterial enlargement
What thoracic changes are commonly seen with heartworm disease in cats?
-increased lung opacity due to acute and chronic parenchymal inflammation and thromboembolism secondary to inflammatory reactions to arriving and dead adult heartworms
-enlarged caudal pulmonary arteries (right often moreso than left)
-cats tend to not get pulmonary hypertension or right heart changes
-Cats with feline asthma can look very similar in terms of the lung changes- bronchial pattern
*in dogs you can see right heart enlargement - increased sternal contact, reverse D appearance
What is the MAIN difference between heartworm disease in dogs and cats?
Cardiac disease in dogs, respiratory disease in cats
-most cats with heartworm clear the infection on their own (aberrant host), they are more resistant
-cats have infections with fewer worms, but a few worms is still considered a heavy infection
-one third of cases are worms of the same sex
-microfilaria are very rare, and if present exist very transiently
T/F: in cats, no single test will detect all of the heartworm cases
True
Describe the use of serology in diagnosing heartworm
Antigen test: gold standard in dogs, not in cats. High specificity, but in cats will not detect male only infections
Antibody test: can detect antibodies 2 months post infection, but not all cats produce antibodies (just indicates exposure)
-if a cat is suspected of having heartworm, both tests are recommended (false negatives can still occur)
How do you diagnose heartworm in cats?
Combo of diagnostics: antibody test, antigen test, thoracic radiographs, echocardiography
-repeat tests if you suspect infection and you keep getting negatives
What occurs with DCM?
Functional deficit in contractility
- causes enlarged lumen of the left ventricle
Why are hyperthyroid cats at a higher risk of developing HCM?
Due to increased catecholamine releases
- leads to hypertension and increased force required to contract the heart
- can also be primary and not associated with hyperthyroidism
What does DCM predispose to? HCM?
DCM: Ascites
HCM: thrombus formation
T/F: heart muscle can regenerate
False
- damage to heart is therefore a big deal
What species are the most affected by white muscle disease?
Cow, sheep, pig > horse and goat > dog, cat, bird
- usually affects neonates
How can you diagnose white muscle disease?
GPX in blood in living animals
-Se/vitamin E in liver of dead animals
What is the last tissue type to lose fat?
The bone marrow
What direction do thrombi build?
Retrograde
- opposite to the direction of blood flow
- towards heart in artery, away from heart in vein
For all species except for the pig, how does flow through the lymph node occur?
Afferent lymphatic vessels come in through the capsule, lymph then percolates through the subcapsular sinuses, then down through cortex and medulla and out through the efferent lymphatics
- lymphoid follicles exist in the cortex, can tell how antigenically stimulated a lymph node is based on the density of the follicles and whether they are primary or secondary
What can cause lymph nodes to be too small?
- developmental disorders such as SCID
-lack of antigenic stimulation (pathogen free animals)
-cachexia/malnutrition (mainly decreases production of T lymphocytes)
-aging/senile atrophy (generalized depression of the immune system–> loss of lymphocytes –> lymph node atrophy)
-viral infections (destruction of lymphoid tissue, BVDV, Canine distemper)
What is the term for enlarged lymph nodes? What are the 3 main differentials for this?
Lymphadenopathy
-can be due to lymphoid hyperplasia, lymphadenitis or neoplasia
What can cause lymphoid hyperplasia?
-due to secondary lymphoid follicles reacting to anitgenic stimulation
Can be due to generalized lymph node hyperplasia (systemic inflammatory disease/infection) or localized lymph node hyperplasia (draining regional area of inflammation or antigenic stimulation)
How can you differentiate hyperplasia vs neoplasia on necropsy?
Hyperplasia: will have a mottled appearance on the cut surface, retention of the cortical and medullary architecture, painful on palpation
Neoplasia: homogenous white/tan cut surface, loss of normal architecture, non-painful on palpation
How is lymphadenitis different than lymphoid hyperplasia?
Lymphadenitis is a nidus of inflammation/infection within the lymph node itself vs just antigenic stimulation from an infection elsewhere
Define lymphadenitis and describe the different morphological patterns associated with it
-regional lymph nodes drain a site of nearby infection and become infected themselves
Patterns:
- suppurative (strep)
-caseous (corynebacterium pseudotuberculosis)
-granulomatous (intracellular pathogens: histoplasma capsulatum, leishmania, mycobacterium)
What are some less frequent manifestations of CL?
Ulcerative lymphangitis in cattle/horses
-pectoral abscesses in horses
What is the pathogenesis of CL in sheep?
Skin wounds allow for bacteria to enter through the skin, bacteria then drain to the regional lymph nodes and form abscesses which is enclosed by a fibrous capsule
-repeated cycles of abscess formation and encapsulation can occur leading the cut surface to look like an onion (termed lamination)
What is the classic presentation of granulomatous inflammation on histology?
Giant cell macrophages containing bacteria surrounded by lymphocytes and plasma cells
What is primary neoplasia of the lymph node?
Lymphoma
- arise from lymphoid tissue outside the bone marrow
Classification guides treatment:
- anatomic location: multicentric, alimentary, mediastinal, cutaneous, etc
- immunophenotype: T cell, B cell, non B/non T
- cell morphology: size, nuclear features, mitotic rate
- histological pattern: diffuse vs follicular
- biologic behavior: low, intermediate, high grade
What percentage of dogs with lymphoma will develop hypercalcemia?
15%
- due to PTHrp (comes from neoplasia itself)- AGASACA is the other neoplasm that does this
In what species can viral infections contribute to the development of lymphoma?
Cats
- feline leukemia virus
- can cause mediastinal and multicentric forms, affects younger cats
Cattle
- bovine leukemia virus
- causes a lymphocytosis which can progress to lymphoma
- long latency period (more likely to find this in old cattle), young cattle more likely to be sporadic lymphoma
Why do lymphomas so often metastasize? What tumor types are most likely to metastasize to the lymph node?
The two most common routes of metastasis are through the bloodstream and the LYMPHATICS
- usually found near the subcapsular sinus
- often poorly differentiated
Tumor types: SCC (late in course of disease), mammary carcinoma, gastric carcinoma, pulmonary carcinoma, osteosarcoma, melanoma
What are the two main components of the spleen?
Red pulp: removes RBCs and microbes, stores RBCs
White pulp: secondary lymphoid tissue
What is one of the main functions of the spleen?
To remove senescent erythrocytes
What can trauma to the spleen result in?
Trauma can cause rupture and fibrosis
-can also cause selenosis or accessory spleens that seed into the omentum (must differentiate from hemangiosarcoma by taking biopsy)
What are siderotic plaques?
- common in older dogs
-arise from healing of previous subcapsular hemorrhage - look like mineralization around the border (grey tan plaques)
Why are splenic torsions more common in dogs and pigs?
The gastrosplenic ligament is much longer in these species
- usually occur in combination with gastric torsion in deep chested dogs
-medical crisis
- venous outflow more impaired than arterial supply–> congestion and infarction
What are the two primary causes of splenic infarcts?
Acute vascular occlusion (usually due to thromboembolism)
Vasculitis (due to bacterial/viral infection)
*acute lesions will look red and enlarged, chronic will look grey and fibrosed
What are some causes of small spleens?
-developmental disorders (SCID)
-cachexia/malnutrition (mainly decreases production of T lymphocytes)
-aging/senile atrophy (generalized depression of immune system– > loss of lymphocytes –> splenic lymphoid atrophy)
-splenic contraction (sympathetic activation, heart failure, shock)
What do congestion and cellular infiltration of the spleen look like on necropsy?
Congestion: bloody
Cellular infiltrate: meaty
What are the main causes of splenic congestion?
Barbiturates (most common cause)
Acute septicemia (anthrax, salmonellosis)
What are the main causes of cellular infiltration of the spleen?
-macrophage hyperplasia (hemolytic anemia or chronic infectious disease)
-neoplasia (lymphoma** or leukemia)
-rarely amyloidosis or lysosomal storage disease
*- can also cause nodules
What is the most common cause of splenic nodules in the cat?
Mast cell neoplasia
- in the dog, can be due to nodular hyperplasia (benign- can lead to hematoma formation), hematoma, hemangiosarcoma, lymphoma, or metastatic neoplasia
- in all species can be caused by lymphoma, granulomas or abscesses
What are the 5 causes of loss of serosal detail?
Lack of fat, peritoneal fluid, immaturity, visceral crowding, cellular infiltration
What are the most common tissues of origin of a central abdominal mass?
Spleen, pancreas, intestines, ventral liver mass
What are the most common tissues of origin of a dorsal abdominal mass?
Left kidney, left adrenal gland, mesenteric LN, ovary, intestine
What are the most common tissues of origin of a cranioventral abdominal mass?
Right or left liver lobes, pyloric or antral region of the stomach, pancreas, gall bladder, hepatic lymph nodes
What are the most common tissues of origin of a dorsocaudal abdominal mass?
medial iliac LN, colon/rectum, uterus, periprostatic cysts
What are the most common tissues of origin of a ventrocaudal abdominal mass?
Urinary bladder, prostate, uterus, retained testicle, small intestine
T/F: the center of the mass is usually the origin point
True
What is the most likely differential for a focal splenic mass?
Hemangiosarcoma
- 2/3 of abdominal masses are mid ventral, 2/3 of those are associated with spleen, and 2/3 of those are hemangiosarcoma
-hematoma is the next ruleout
When you see pulmonary nodules of varying sizes, what is the most likely diagnosis?
Pulmonary metastasis
T/F: with generalized hepatomegaly, you will see a shift in the gastric axis
True
- pylorus is pushed caudally and dorsally
What is the most common cause of generalized splenomegaly?
Splenic torsion or round cell infiltrate (will cause spleen to be in abnormal position- C shaped)
What are the round cell tumors?
Lymphoma, mast cell, histiocyte
Describe the pathology of splenic torsions
-spleen rotates on its vascular pedicle
-thin-walled splenic veins become occluded
-thicker walled splenic artery is partially occluded
-blood enters the spleen and cannot leave causing splenic congestion, splenomegaly and free fluid
What will ultrasound of the spleen look like in the case of torsion?
Will look like a course screen compared to normal (lacy or mottled appearance)
-may also see absence of blood flow
-may see splenic vein thrombosis
Treatment is splenectomy
T/F: generalized splenomegaly in a cat is typically benign
False
- this is true in dogs
- in cats, there is usually pathology as they don’t use the spleen as a blood reservoir as dogs do
What is the next step if you suspect lymphoma in a cat?
US with fine needle aspirates
- main differential is mast cell tumor
When can you see anemia as a result of kidney disease?
End stage
- at the point that kidney is so damaged that it is not producing erythropoietin anymore
If you see a mild thrombocytopenia on bloodwork from a cat, what is the first thing you should look at?
The blood smear
- often a result of platelet clumping
*other differential may be splenic sequestration- but rare in cats
What is the only reason for an elevated albumin?
Dehydration
What are the main differentials for an enlarged spleen in a cat?
Neoplasia or infectious disease or torsion
If you see a severe anemia with a moderate reticulocytosis (inadequately regenerative), what may this indicate?
Either there is a chronic anemia with an acute event occurring on top of it or there is a condition targeting the RBC precursors
What are acanthocytes, keratocytes and schistocytes seen in response to?
Acanthocytes: liver disease, erythrocyte fragmentation
Keratocytes: iron deficiency, liver disease, myelodysplastic syndrome, erythrocyte fragmentation
Schistocytes: severe iron deficiency, microangiopathic hemolytic anemia, myelofibrosis, heart failure, glomerulonephritis
T/F: ALT has longer half life than AST
True
- if there is prior injury to the liver, ALT may be elevated for longer than AST
What is the significance of hemosideran presence in peritoneal fluid analysis?
Occurs with chronic breakdown of blood
- indicates that chronic hemorrhage is present
