erythropoietin

stimulates RBC production

phagycytose macromolecules and immune complexes

contract to autoregulate glomerular blood flow

the renal tubules can regenerate provided:

[image]

renal agenesis/aplasia

compensatory hypertrophy

• autosomal dominant
• persian cats
• 3-10yrs old
• >7 yrs old
• the liver
• ultrasound

blood supply anatomy in kidney

red for 2-3 days, then grey/pale/tan with fibrosis

NSAIDS

PGE2 maintains vasodilation; NSAIDS inhibit this, leading to ischemic necrosis

dilation of renal pelvis/calyces/ureter due to obstruction

• circulating immune complexes deposit in or adjacent to glomerular basement membrane or Ab formed against basement membrane
• lattice formation of Ab less phagocytized by body
• complement fixation, inflam mediators, leukocytic infiltration
• filtration barrier compromisedàprotein loss

• viral 
• bacteria 
• parasitic/protozoal 
• autoimmune 
• neoplasia

• systemic reactive amyloidosis 
• SAA
• Sharpei
• Abyssinians
• Logol's iodine

• amorphous to hyaline eosinophilic material in glomeruli, which may be enlarged. 
• Congo red will turn apple green under polarization

• equine: Actinobacillus equuli
• porcine: erysipelothris thusiopathiae
• cattle: truperella pyogenes (Arcanobacterium) from vegetative valvular endocarditis

especially proximal, distal may be affected

glomeruli unaffected

basement membranes not preserved

• hi metabolic activity
• exposed to agents in large volume of ultrafiltrate they resorb
• basement membranes preserved

• heavy metals
• Abx
• plants
• oxalates (ethylene glycol)
• mycotoxins
• endogenous substancces (Hgb, Mgb)
• miscellaneous (canthardin)

•  loss of cellular detail
• karyorrhexis, karyolysis, pyknosis
• increased cytoplasmic eosinophilia
• sloughing of epithelial cells

• increased cytoplasmic basophilia
• piling/crowding of epi cells
• nuclei with open chromatin pattern and prominent nucleoli
• mitotic figures

·         very common to observe chronic interstitial nephritis lesions in older animals, cause not evident

·         acute cases: edema, leuk infiltrate, focal tube necrosis

·         chronic cases: leukocytic infiltrate, fibrosis, atrophy

·         lumpy, bumpy, secondary cysts

e.g. leptospirosis and Encephalitozoon cuniculi

·         ureteritis, cystitis

·         vesicoureteral reflux-retrograde flow up ureters during micturition

• same as those that cause lower UTI's (E. coli, Staph, Strep, Pseudomonas, Proteus, Enterobacter, Coryne, Aranobacter pyogenes in cattle, Actinobaculum suis in swine

• acute lesions have suppurative exudates in pelvis, extending into tubules and interstitium
• medulla most severely affected, but lesions can extend into cortex
• in chronic fibrosis, inflammatory infiltrate more mononuclear

kidney worm in swine, encysts in perirenal tissue and cysts communicate with renal pelvis to allow for passage of eggs

males

sheep, cattle, dogs

chickens and pigs

grey-white to tan, soft masses, may have extensive hemorrhage. histo: primitive glomeruli, stroma, and tubules 

·         gastric ulcers/uremic gastritis

·         ulcerative glossitis/stomatitis,  (lingual ulcers)

·         mineralization of intercostal pleura

·         uremic pneumonitis

·         parathyroid hyperplasia- phosphate retention due to dec GFR,àdec plasma ionized Ca++àstims PTH release

·         anemia-↓erythropoietin, hemolysis due to factors in uremic plasma, GI hemorrhage

ectopic

golden retrievers

patent urachus

foals

• calculi from urethra to renal pelvis
• urine pH, hereditary factors (Dalmatians), dietary factors, UTIs, thick bladder

§  loss of normal voiding mechanisms

§  loss of acidic urine pH (carnivores)

§  glucosuria (great for bac growth)

§  proteinuria

§  mucosal trauma

§  degree of inflam seen on UA does not correlate well with histo inflam

§  females anatomically predisposed- short wide urethra

• rarely seen except in diabetic animals due to bacterial fermentation of urinary glucose into CO2,
• causes tiny bubbles seen on rads

bracken fern 

hematuria, hemorrhagic proliferative cystitis, bladder neoplasms, papillomas, hemangiosarcomas, leiomyosarcomas, fibrosarcomas

botryoid rhabdomyosarcomas occur in _____________ breed dogs 

bladder neck or trigone

50%

• well-differentiated transitional
• undergo malignant transformation

Which of the following is not a stem cell  for epithelial repair in bronchi/bronchioles?

a.      mucous cells

b.      ciliated cells

c.       nonciliated cells

1.      cartilage maintains patency, prevents collapse

2.      thick connective tissue prevents infection spread into surrounding alveolar parenchyma

3.      chronic inflammation results in dilation

4.      changes in diameter increase resistance markedly

• terminally differentiated.
• a.      mucous cells
• b.      basal cells
• c.       other nonciliated cells

1.      ciliated are terminally differentiated

2.      epithelial regen capacity

a.      mucous cells

b.      nonciliated (Clara cells)

1. no cartilage or glands in walls
2.   airway patency maintained by tethering support of interalveolar septa on bronchiolar wall
3.    thin connective tissue in wall allows infection spread to surrounding alveoli
4.  chronic inflam result in stenosis of lumen

a.      type 1

                                                                          i.      thin, large surface area, susceptible to damage, prevents interstitial fluid from leaking out, keeps surface tension low, incapable of division

b.      type 2

                                                                          i.      produce surfactant, cuboidal, produce other mediators, stem cells for repair 

1.      increased airway resistance

a.      airway obstruction

b.      ventilation/perfusion abnormàhypoxemia

2.      decrease mucociliary clearance

a.      predispose to secondary bacterial infection

•Infectious: viral, bacterial, fungal, parasitic

•Toxic: e.g. - 4 -ipomeanol and other plant toxins

• Hypersensitivity

Epithelial Changes

• Degeneration/Necrosis

• Erosion/Hyperplasia

Submucosa/lamina propria

• Edema

• Hyperemia

• Cellular infiltration

Lumen obstruction

• Exudate fills

• Reduced diameter: Wall enlargement and contraction of muscle

1.      chronic infection (usually bac)

2.      neut-mediated tissue destruction

a.      destruction of glands and cartilage

b.      fibrosis

1.      increase in airway resistance (turbulence and luminal obstruction)

2.      poor mucociliary clearance

3.      aspiration of infective material to alveoli

1. Duration: 
Acute, subacute, chronic

2. Distribution: 
Focal, multifocal, diffuse

3. Nature of exudate:
Necrotic, suppurative, eosinophilic, 
erosive, hyperplastic, etc.

Dilation of airway: saccular or cylindrical

2. Thick wall

3. Luminal exudate: grey, green, or tan

thick, mucoid or caseous

obstruction of bronchiolar lumen by fibrous connective tissue      

Atelectasis: collapse of the lung

1.      neonatal (inadequate surfactant)

2.      acquired

a.      compressive

b.      obstructive

What is the most common cause of bronchiectasis?

a. viral infection 

b. chronic dust inhalation
c. chronic bacterial infection

which of the following processes is reversible?

a. bronchiectasis

b. bronciolitis obliterans

c. atelectasis

d. alveolar emphysema

1.      alveolar

a.      incidental in cats, old dogs, more relevant in smokers

Pathophys significance:

1.     decreased alveolar and capillary surface area

2.      loss of radial support for airways: early closure

3.      dec elastic properties, increase complaiance and residual lung capacity

4.      loss of capillary area, pulm hypertension

5.      irreversible

2.      interstitial

a.      common, cattle-gas blown out into loose connective tissue

b.      excess gas in pulmonary interstitium

c.       forced expiration against obstructed airways

d.      gas dissects into interstitial tissue

                                                              i.      interlobular septa

                                                            ii.      perivascular areas

                                                          iii.      subpleural tissues

            e.  pathophys: restrictive lung disease

1. Airway obstruction and inflammation

2. Protease/Antiprotease imbalance

3. Post-obstructive pressure disruption

a. Increased permeability of alveolar epithelial and endothelial cells

b. Increased pulmonary hydrostatic pressure

c. Decreased capillary oncotic pressure

d. Lymphatic obstruction

o   initial deposition of causative agent in terminal bronchioles and alveoli

o   bacteria or aspiration

o   early damage in proximal acinar areas with spread into surrounding alveolar parenchyma

o   cranioventral

o   may intercurrent fibrinous pleuritis

o   may spread to lobular distrib

o   chronicity: fibrosis and lymphadenomegally

o   microscopic: abundant exudate in alveoli (neuts, fibrin, necrotic debris), lesions initially airway oriented

o   airways obstructed

o   infiltration of walls and filling of alveoli makes lung stiffer

o   exudate and alveolar wall thickening creates diffuse barrier

o   primary injury to elements of interalveolar septum  (epi, endothelium)

o   virus (immune-suppressing), protozoa, some fungi, rarely bacteria (assoc with bacteremia)

o   often diffuse or locally extensive firm, large, red, with muscle or liver consistency on cut surface

o   microscopic: early type I epithelial necrosis

o   subacute: type 2 epithelial hyperplasia alveolar septal thickening, mononuclear cells,

o   chronicity marked by fibrosis

o   thickening and infiltration of alveolar walls marked by increased stiffness and decreased compliance: restrictive

o   decreased diffusion capacity: hypoxemia

describe acute viral pneumonia

1. Viruses replicate in respiratory airway and 

alveolar epithelial cells

2. Virus induces inflammatory and immune 

response

3. Inflammation in parenchyma is focused on 

interalveolar septa

4. Viral replication is effectively halted before 

diffuse interstitial pneumonia develops

1. Often associated with viruses that replicate in 

macrophages and/or depress or escape antiviral 

immunologic defense mechanisms

2. Virus spreads throughout the lung and induces 

diffuse interstitial pneumonia

3. Examples: Ovine progressive pneumonia, canine 

distemper virus

1. Colonization of respiratory tract 

2. Depression of pulmonary defense mechanisms

e.g., virus, stress, dehydration, particulates. etc

3. Exponential growth of Mannheimia haemolytica

with leukotoxin production

4. Damage to neutrophils, macrophages, release of 

endotoxin

5. Leukotoxin and endotoxin-mediated tissue 

damage accentuated by neutrophil release of toxic 

molecules

The distribution of pneumonia is cranioventral, it is most likely:

a.      aspiration pneumonia 
b.      fungal pneumonia
c.      viral pneumonia
d.     bronchopneumonia
e.     interstitial pneumonia

If it is bronchopneumonia, the most likely cause(s) is/are:

a.      bacteria
b.      virus
c.      aspiration
d.      A and B
e.      A and  C

If the pneumonia is diffuse, the least likely cause is:

a.      virus
b.      protozoa
c.      toxins
d.      aspiration
e.      bacterial septicemia

1. Ingestion of pneumotoxin

2. Ruminal conversion and/or intestinal absorption

3. Activation of pneumotoxin by pulmonary

     cytochrome P450 monooxygenase 

4 . Covalent binding or free-radical damage by

     metabolites and pulmonary cell death

5. Pulmonary cells most susceptible to toxic injury:

       a. Nonciliated bronchiolar cells

       b. Type 1 alveolar epithelial cells

       c. Capillary endothelial cells

a. Nonciliated bronchiolar cells

       b. Type 1 alveolar epithelial cells

       c. Capillary endothelial cells

a. L-tryptophane/3-methylindole

b. Moldy sweet potatoes (4-ipomeanol)

c. Perilla mint (purple mint)

d. Stinkwood (Ziera arborescens)

• Large surface area
• Susceptible to damage
• Incapable of division

1. Canine Distemper

2. Canine Influenza

3.Canine Adenovirus type 2

4. Parainfluenza type 2 virus

5. Canine respiratory coronavirus

6.Canine herpesvirus 1

1. Respiratory/OropharyngealInoculation
2. Replication in oropharyngeal lymphoid tissue and viremia
3. Replication in lymphocytes, epithelial cells, monocyte/macrophage cell lineages, nervous tissue cells
4. failure of cell/humoral/natural immunity leads to penetration of blood-brain barrier and severe encephalomyelitis

Rhinitis, pharyngitis, tracheitis, bronchitis, bronchiolitis

• Patchy to diffuse interstitial pneumonia (or 

bronchointerstial pneumonia)

*May appear as bronchopneumonia if secondary

bacterial infection

• Cytopathic effects: intranuclear and intracytoplasmic

Inclusions in epithelial cells and macrophages 

(cytoplasmic inclusions predominate); syncytial cells

acute respiratory viral infections often induce pulmonary lesions including:

a. bronchitis

b. bronchiolitis

c. patchy interstitial pneumonia

d. diffuse interstitial pneumonia

e. A, B, & C

what mechanism accounts for some respiratory viruses being able to induce chronic pneumonia and diffuse interstitial pneumonia?

a. replicate in type 1 cells

b. replicate in type 2 cells

c. evade or suppress

which induces the most severe irreversible lung and pleural damage?

a. viral

b. bacterial

which of the following are reversible?

A. acute bronchitis 

B. bronchiectasis

C. alveolar emphysema 

D. bronchiolitis obliterans 

E. Bronchoalveolar carcinoma 

A. acute bronchitis = reversible

B. bronchiectasis = mostly irreversible

C. alveolar emphysema = irreversible

D. bronchiolitis obliterans = mostly irreversible

E. Bronchoalveolar carcinoma = irreversible

• Gastrointestinal

• Lymphoid (lymph nodes, spleen, thymus)

• Dermatitis, Conjunctivitis

• Cystitis, other urinary lesions

• Teeth: enamel hypoplasia

• Nervous tissues; Eyes

• Erosive/hyperplastic tracheitis and bronchitis
• Tracheal / bronchial gland epithelial cell necrosis/hyperplasia  with lymphocytes/ neutrophils
• Severe pulmonary hemorrhage
• Suppurative bronchopneumonia (mild to moderate)
• Mild lymphocytic rhinitis

• Erosive/hyperplastic tracheitis and bronchitis and bronchiolitis
• Tracheal / bronchial gland epithelial cell necrosis/hyperplasia with lymphocytes/ neutrophils
• Suppurative bronchopneumonia (mild to severe)
•  Gram positive and / or negative bacteria in pneumonic lesions 
• Lymphocytic or suppurative rhinitis
•  No Severe pulmonary hemorrhage

1. Blastomycosis

2. Histoplasmosis

3. Coccidioidomycosis

4. Pneumocystosis 

5. Cryptococcosis

Granulomatous pneumonia and 

Pyogranulomatous pneumonia

• Mycelial and yeast forms in lesions

• Yeast forms: 5-25 µm diameter

• Doubly refractile, broad-base

budding

• Stains: PAS and GMS

 Lung lesions of Blastomyces dermatitidis are often confused with what? 

disseminated carcinomas 

(blastomycosis in young dogs:2-5

yrs)

1. Granulomatous pneumonia and

Pyogranulomatous pneumonia

2. Spherules: 20-100 µm diameter

with endospores

3. Ruptured spherules: induce neutrophil

infiltrates 

(pyogranulomouslesions)

4. Extrapulmonary lesions: lymph 

nodes, spleen, bone

1. Diffuse interstitial pneumonia

• Unusual manifestation for fungal disease

2. Associated with immunosuppression

3. Ribosomal RNA sequence: fungal

- most consistent with fungal (controversial)

4. “Trophozoites” (1-4 µm) attach to

type 1 cells, induce damage

5. Cysts (5-7 µm) in alveolar spaces 

are detectable by GMS and PAS

1. More commonly induces

encephalitis and nasal/sinus infections

2. Pneumonia common if

immunosuppression

3. Induces granulomatous pneumonia

4. Organisms 1-7 µm diameter with

1-30 µm diameter capsule (PAS, GMSpositive)

• Dogs: 10-11 years
• Most common breeds reported: Boxer, Doberman Pinscher, Australian shepherd, Irish Setter, Bernese Mountain Dog
• No gender prevalence reported
• 
  
• Cats: 12-13 years 
• No breed or gender predisposition

Veratrum californicum in sheep

poison hemlock in pigs

genetic

• overbite, underbite
• Genetic abnormalities
• Calcium deficiency 
• Chondrodysplasia

• Viral (usual)
• Thermal, toxic (rare)

Viral infection: e.g. calicivirus, BVD

• Toxic disease: e.g., phenybutazone

• Uremia

• Immune mediated disease: e.g., pemphigus, SLE

FMD would likely cause: 

a. vesicular lesions

b. ulcerative lesions

c. proliferative lesions

d. necrotizing lesions

the likely cause of a proliferative stomatitis in a sheep is:

a. FMD

b. BVD

c. contagious ecthyma (parapox virus)

d. Actinobacillus

c. proliferative stomatitis is often caused by parapox viruses e.g. Bovine papularstomatitis- calves

• Contagious ecthyma – sheep, goat

• bacterial (Fusobacterium necrophorum, Actinobacillus lignieresii)
• infarctive (Banamine in horses)

• granulomatous-cryptococcal stomatitis
• pseudomembranous-Candida albicans (thrush)

Age: Usually over 3 years of age; Mean 8.5 years

• Location: Anywhere on the gingiva

• Histologic features: 

• Mesenchymalspindle to stellate cells (periodontal ligament)

• Odontogenic epithelium (cell rests of Malassez)

• Variable matrix with characteristics of bone, dentin or cementum

• Behavior if untreated: 

• Expansile and non-invasive

• Excision is usually curative

Age: Older than three years of age; Mean 8.8 years

• Location: Anywhere on the gingiva

• Histologic features: 

• Interconnecting, invasive sheets of odontogenic

epithelium

• Behavior if untreated: Invasive into bone; No 

metastasis

Age: Mean – 8 years old

• Location: Tonsil, gingiva, lip, tongue, palate, 

pharynx

• Gross features: nodular, firm, often ulcerated

• Behavior if untreated:

• Tonsillar: Metastasis to regional nodes early (98%) with frequent more 

distant metastasis (63%)

• Others: Locally invasive, lower percentage 5-10% metastasize

Most common oral tumor in the cat

• Age: Median – 12 years

• Location: Tongue and gingivamost common

• Gross and histologic features: similar to dog

• Behavior if untreated: Locally invasive and mass 

producing; destructive to bone; 15% metastasis 

rate to local nodes reported in one study

Age: Mean – 11 years

• Location: Gingiva and lips most common

• Behavior if untreated: 70% metastasize to regional 

lymph nodes and 67% to distant sites (lung, brain, 

eyes, liver, kidney)

• May be amelanotic

Age: Mean – 7.2 years

• Location: gingiva, hard/soft palate, lip, tongue

• Behavior if untreated: Local infiltration and tissue 

destruction. Metastasis in 20% to local lymph 

nodes and 10-20% to lungs.

• Persistent right fourth aortic arch
• Idiopathic denervation
• Polymyositis
• Myasthenia gravis
• Hypothyroidism
• Trypanosoma cruzi
• Addison's

• Papilloma
• Leiomyoma/Leiomyosarcoma
• Squamous cell carcinoma

[image]

what is this?

vesicular oral lesions can be induced by all of following except:

a.      FMD

b.      thermal injury

c.       vesicular stomatitis virus

d.      swine vesicular disease virus

e.      bovine papular stomatitis virus

ulcerative oral lesions can be induced by:

a.      chronic uremia

b.      calicivirus

c.       BVDV

d.      FMD

e.      all above

which of the following oral neoplasms in dogs has the greatest probability of metastasis?

a.      tonsillar squamous cell carcinoma

b.      periodontal fibromatous epulis

c.       acanthomatous ameloblastoma

d.      squamous papilloma

e.       leiomyoma

which of the following oral neoplasms in dogs has the least probability of metastasis?

a.      melanoma

b.      periodontal fibromatous epulis

c.       acanthomatous ameloblastoma

d.      fibrosarcomas

e.       leiomyomasarcoma

Carbohydrate overload 

• Lactic acid burn of mucosa 

• Acidosis

• Chronic complications

• Scars

• Mycotic infection

• Bacterial infection -----Hepatitis

• Trauma, chemical injury

• High acidity

• Local ischemia

• Helicobacter spp.

• Neoplastic disease: mast cells and gastrin-producing tumors

May lead to fatal hemorrhage, chronic hemorrhage 

or perforation and peritonitis

[image]

was ist das?

[image]

what is this?

1. Gastric/abomasal volvulus
2.  Intestinal Volvulus/torsion
3. Intestinal external herniation
4. Intestinal internal herniation/ entrapment
5.  Intussusception
6. Intestinal stenosis/atresia
7. Intestinal stricture
8. Enteroliths and impactions

Initial gastric dilation

• Gas accumulation

• Dietary and feeding/exercise may influence

Volvulus that may be associated with:

• Deep chested body configuration

• Relaxation/stretching of gastrohepatic ligament

1. Conditions during first 6 weeks of lactation
2.  High production of volatile fatty acids with diet
3.  GI stasis allowing abomasalstasis and gas accumulation and decrease in size of rumen
4.  Deep body cavity

• Enteritis/altered motility

• Intestinal foreign body

• Intestinal polyp/neoplasm

1. Maldigestion/Malabsorption –Osmotic

    • Epithelial surface area loss via villous atrophy and 

    other mechanisms

2. Secretory mechanisms – Cl Secretion

    • Many infectious agents act at the level of the 

    intestinal crypts 

3. Increased permeability

    • Mucosal epithelial damage 

    • Increase vascular permeability

[image]

what is this including morphologic diagnosis?

• Salmonella
• Enterotoxigenic E coli 
• Clostridium difficile
• Lawsonia intracellularis*

[image]

what is this?

1. Attach to M-cells, enterocytes and goblet cells
2.  Survive in phagosome (neutralize NO through SPI-2)
3. Toxins inducing necrosis: Enterotoxin, Verotoxin, Endotoxin
4. Upregulate chloride ion secretion via PGE2

1. Peracute septicemia

    Vasculitis, thrombosis

2. Acute enteric salmonellosis

    Enterocolitis

    Septicemia: hepatocellular necrosis,       

    lymphadenomegally, splenomegally, fibrinous

    cholecystitis

3. Chronic enteric salmonellosis

    Enterocolitis

    Thrombosis

    Rectal strictures in pigs

• parvovirus replication
• BVD
• rinderpest
• mycotoxins
• radiation

• rotavirus
• coronavirus replication
• cryptosporidium attach, replicate

what is this?

[image]

• Lawsonia intracellularis
• Coccidiosis

Johne's disease: Chronic diffuse granulomatous 

enteritis and lymphangitis

1. Lymphoma
2.  Epithelial tumors
3. Adenoma
4.  Adenocarcinoma
5.  Leiomyoma/Leiomyosarcoma/GIST
6.  Carcinoid

all the following result in decreased size of thymus and lymph node except:

a.      parvo

b.      lymphoma

c.       corticosteroids

d.      K9 distemper

e.       A and D

uniformly enlarged dog spleen that bleeds on cut surface is most likely:

a.      hemangiosarc

b.      hemangioma

c.       lymphoma

d.      congestion

e.       nodular hyperplasia

irregular dark red nodule in spleen that bleeds on cut surface could be all of the following except:

a.      hemagiosarcoma

b.      hemangioma

c.       granulomatous splenitis

d.      hematoma

e.       nodular hyperplasia

Which of the following terms are used synonymously with lymphoma in 

veterinary medicine?

A. Malignant lymphoma

B. Lymphosarcoma

C. Myeloma

D. A,B

E. A,B,C

 The most common anatomic form of lymphoma in dogs is:

A. Multicentric

B. Alimentary

C. Thymic

D. Cutaneous

E. Solitary

The most common cardiac site for lymphoma in cattle is:

A. Right atrium

B. Right ventricle

C. Left atrium

D. Left ventricle

E. Aortic valve

viral infection has been identified as a cause of lymphoma in:

A. Dogs

B. Cats

C. Cattle

D. A,B,C

E. B,C

 The most common anatomic form of lymphoma in cats is:

A. Multicentric

B. Alimentary

C. Thymic

D. Cutaneous

E. Solitary

1.Lymphadenitis

   • Acute to chronic duration

   • Infectious, immune, toxic etiology

2.Neoplasia 

   • Primary (e.g., lymphoma)

   • Metastatic

3. Lymphoid Hyperplasia (Antigen driven)

Primary immunodeficiency 

1. Combined immunodefiency (CID) of Arab foals

- Genetic defect in DNA-dependent protein kinase

- Defective DNA repair

2. X-linked CID in dogs

Basset hounds, Jack Russell terriers, Welsh corgi 

dogs

1. Viruses that replicate in lymphocytes and induce

apoptosis/necrosis:

• Canine distemper virus

• Canine parvovirus

2. Glucocorticoids (endogenous, exogenous)

3. Chemotherapeutic drugs, ionizing radiation,

malnutrition, cachexia

- immunodeficiency, senile atrophy, wasting/cachexia

- lymphoid necrosis alone isn’t enough to decrease

spleen size (usually)

• Uniform splenomegaly
• Splenic nodules and masses 

1. Congestion – terminal (euthanasia associated)

2. Torsion

1. Bacteremia/septicemia

2. Granulomatous splenitis

3. Hemolytic anemia (autoimmune, hemoparasitic)

4. Lymphoma (other lymphoid neoplasm/leukemia)

5. Extramedullary hematopoiesis

6. Amyloidosis, storage disease

1. Hematoma

2. Hemangioma/Hemangiosarcoma

3. Nodular hyperplasia with hyperemia

4. Splenic infarct

5. Incomplete splenic contraction (postmortem finding)

1. Nodular hyperplasia

2. Granulomatous splenitis, Splenic abscess

3. Lymphoma (other lymphoid neoplasm)

4. Metastatic neoplasm

1. spleen
2. liver
3. right atrium
4. lung

a. Cortex  

    Primitive and maturing lymphocytes

b. Medulla

    Thymic epithelial cells and Hassall’s corpuscles

    Myoid cells

    Interdigitating cells and dendritic cells

    Lymphocytes

1. Thymic hypoplasia (e.g., CID)

2. Maturation and Aging (involution)

3. Thymitis (e.g., porcine circovirus 2, epizootic bovine 

    abortion, salmon poisoning in dogs)

4. Thymic atrophy (lymphocyte apoptosis/necrosis)

    a. Viral diseases: FeLV, FIV, canine distemper,

        equine herpesvirus 1, feline panleukopenia, 

        Canine parvovirus

    b. Glucocorticoids (exogenous/endogenous)

    c. Nutritional deficiency (starvation, zinc deficiency, 

        protein deficiency)

d. Toxins – lead, mercury, polychlorinated biphenyls

1. Thymic hemorrhage (young dogs)

2. Lymphoma

3. Thymoma

• Epithelial component is neoplastic

1. Most common in dogs 5-11 years old

2. 10% cases in dogs 1-4 years of age

3. Report of higher incidence in boxer and 

Scottish terrier dogs

4. Gamma herpesvirus associated with some 

B-cell lymphomas

1. Multicentric 

• Generalized lymphadenomegaly

• Liver and spleen

• Kidney, heart, tonsil, bone marrow, CNS

2. Alimentary

• Intestine and mesenteric lymph nodes

• Less common: Generalized lymph node and liver/spleen

3. Thymic

• Concentration in thymus and cranial medistinum

• Commonly associated with hypercalcemia

4. Cutaneous

• Infrequent

• T-cell cutaneous lymphoma in dogs (Mycosis fungoides)

• Cutaneous

5. Other

• Solitary: (brain, lung, etc.)

• Specialized: Lymphomatoid granulomatosis

1. lymphoma

2. Young cats affected by FeLV (>50% 5 years 

old or less)

3. Until recent years, 70% of cats were viremic

with FeLV. Now decreasing percentage of 

lymphoma cats are FeLV positive

1. Alimentary 

• Jejunum / ileum

• Mesenteric nodes

• Liver and kidney

• Often FeLV negative

2. Thymic

• Concentration in thymus and cranial medistinal nodes

• Pleural effusion and compressive atelectasis common

• Often FeLV positive

3. Multicentric

• Generalized lymphadenomegally

• Liver / spleen

• CNS

• Often FeLV positive

4. Solitary

• Often kidneys

1.Multicentric

• Most common BLV association

• Lymph nodes, right atrium, abomasum, kidneys, uterus, spinal 

epidural fat

• Intestine, liver, and spleen less common

2.Cutaneous 

3.Thymic

• Adolescent cows (6-30 months)

• Bone marrow involvement

4.Calf form

• Less than 6 months old

• Generalized nodes, bone marrow, blood, liver, spleen

• 50% involve thymus, heart, kidneys, uterus

5.Alimentary form – Rare

6.Solitary – Spinal canal

Which of the following viruses in cattle commonly induce syncytial bronchiolar epithelial cells following respiratory infection (more than one)?
A. Adenovirus
B. Bovine herpesvirus type 1
C. Rhinovirus
D. Parainfluenza

E. Rinderpest

F. Bovine Syncytial virus