Pathology 2 Mo's notes Flashcards
What is the definition of Infective Endocarditis?
Inflammation of the endocardial surfaces of the heart including heart valves which is caused by certain microorganisms.
Types of endocarditis
- Infective endocarditis: here microbes colonize the heart valves and form friable vegetations. The 2 types of IE are acute and subacute.
- Non-bacterial thrombotic endocarditis aka marantic endocarditis: this variant characteristically occurs in the settings of cancers e.g. adenocarcinomas
- Libman sacks endocarditis: occurs in the settings of cancers e.g. adenocarcinoma
Why rheumatic heart and valve replacement patients are more susceptible to IE?
Blood usually flows smoothly over valves, when these valves are damaged (as in RH) or in valve replacement, there will be an increased chance for bacterial colonization on damaged tissues.
Pathophysiology of rheumatic heart disease?
Leads to what macroscopic changes?
Immune system responds to group strep A but reacts with own tissues.
Combination of antibody and T-cell reactions cause chronic inflammation and damage/thickening of heart valves and cause stenosis.
What are the gross acute and chronic findings in infective endocarditis?
Acute phase: Valvular vegetations
Chronic phase: Commissural fibrosis, valve thickening, and calcification + shortened and fused chordae tendinea
Microscopic findings of infective endocarditis?
Aschoff bodies, a form of granulomatous inflammation which consists of a central zone of degenerating ECM infiltrated
by lymphocytes, plasma cells and Anitschkow cells, found in all 3 layers of the heart – pericardium, myocardium or endocardium
What 7 things to look for in echo for IE?
1) Valvular regurgitation: A regurgitant jet >1 cm in length and peak velocity >2.5 m/s
2) Leaflet: Prolapse, Coaptation failure, Thickening (>4 mm), Reduced mobility, Nodules
3) Annular dilatation
4) Chordal elongation/rupture
5) Increased echogenicity of subvalvular apparatus
6) Pericardial effusion
7) Ventricular dilatation and dysfunction (almost always with significant regurgitation)
Common organisms for IE?
- Viridans Strep. or Staph.
- . Coagulase negative staph.
- . Enterococci
- . Hacek group of microorganisms (oropharyngeal commensals)*
* Haemophilus species,
* Aggregatibacter species,
* Cardiobacterium hominis,
* Eikenella corrodens
* Kingella species
What is used to diagnose IE?
Duke’s criteria
What are Dukes Major criteria for IE?
- Blood cultures positive for endocarditis - typical organisms
- Evidence of endocardial involvement - echo
What are Dukes minor criteria for IE?
1 Risk factors for infective endocarditis (see risk factors section)
2 Fever > 38oC
3 Vascular phenomena: septic emboli, Janeway lesions, conjunctival haemorrhage, intracranial haemorrhage
4 Immunological phenomena: glomerulonephritis, Osler’s nodes, Roth spots, positive rheumatoid factor
5 Microbiological evidence: positive blood cultures which do not meet the major criteria
What are risk factors for IE?
Intrinsic/Extrinsic
Intrinsic risk factors include:
- Valvular stenosis or regurgitation: congenital or acquired
- Hypertrophic cardiomyopathy
- Structural heart disease with turbulent flow (e.g. VSD, PDA): but NOT isolated ASD or fully repaired VSD or PDA
- Prosthetic heart valves: these will require replacement if infected
- Previous infection (infective endocarditis/rheumatic fever) causing structural damage
Extrinsic risk factors include:
- Intravenous drug use (right-sided endocarditis)
- Invasive vascular procedures (e.g. central lines)
- Poor oral hygiene/dental infections
What are complications of IE?
Cardiac/Systemic
Cardiac complications include:
* Valve destruction
* Heart failure (secondary to valve regurgitation)
* Arrhythmias and conduction disorders (e.g. AV block)
* Myocardial infarction
* Pericarditis
* Aortic root abscess
Systemic complications include:
* Emboli (e.g. stroke, splenic infarction)
* Immune complex deposition (e.g. glomerulonephritis)
* Septicaemia
* Death
Whare are some signs and symptoms of IE?
FROM JANE
Signs and symptoms of IE FROM JANE
* Fever
* Roth’s spots
* Osler’s nodes
* Murmur
* Janeway lesions
* Anemia
* Nail hemorrhage
What is the medical treatment of IE?
IV antibiotics depending on culture and sensitivity for 6 weeks (IV ceftriaxone and vancomycin)
Why might antibiotics not work in IE?
- Valves do not have specific blood supply so antibiotics cannot reach
- Organisms lie inside the vegetations
- Bacteria form a biofilm (glycocalyx covering) that shields them from antibiotics
How is IE managed if there is no response to medical Rx?
Valve replacement or heart transplantation
What are the side effects of long term steroids?
- Opportunistic bacterial and viral infections such as EBV, CMV —> leukemia, lymphoma
- Cushingoid features: obesity, muscle weakness, hirsutism, striae
- Cardiovascular: fluid retention, hypertension
- Endocrine: DM
- Musculoskeletal: osteoporosis, AVN, proximal myopathy
Mechanism of action of immunosuppressants? How do immunosuppressants work?
What is the mechanism of action of warfarin?
Which numbers?
Vitamin K antagonist thus inhibiting clotting factors 2,7,9,10
How to reverse warfarin?
- Vitamin k
- FFP
- PCC
In IE if there are right sided vegetations what is the cause?
IV drug abuser
What causes aortic stenosis?
Atherosclerosis: Lipid accumulation, inflammation, calcification →
valve thickening and stenosis
How does heart failure develop in aortic stenosis?
- As the aortic valve progresses from sclerosis to stenosis, the left ventricle encounters chronic resistance to systolic ejection (↑ afterload) → thickening of the left ventricular wall (hypertrophy)
- Effects of high left ventricular afterload include decreased left ventricular myocardial elasticity and coronary blood flow and increased myocardial workload, oxygen consumption, and mortality.
- Late manifestations of LVH include a smaller left ventricular chamber size, which decreases preload and worsens systolic dysfunction. The result is insufficient stroke vol ume, cardiac output, and ejection fraction. Finally, backward transmission of increased left ventricular pressure to the lungs may cause pulmonary venous hypertension and reactive vasoconstriction of the pulmonary vasculature.
Which coagulation pathway is not affected by warfarin?
Intrinsic pathway
What is a thrombus?
a blood clot formed in situ within the vascular system of the body and impeding blood flow
What are surgical options for aortic stenosis?
mechanical valve
tissue valve
TAVI - transarterial valve insertion
Aortic balloon valvulopasty
What is giant cell arteritis?
Inflammatory disease of blood vessels (large and medium) of the head, mainly branches of ECA.
What are 4 histological changes in giant cell arteritis?
intimal thickening
elastic lamina fragmentation
infiltrateof T-cell and macrophages
giant mulitnucliated cells
Why can blindness ocour in giant cell arteritis?
Ophthalmic artery involvement
What is the management for giant cell arteritis?
Corticosteroids. Start prednisolone 60mg/d PO immediately or IV methylprednisolone if evolving visual loss or history of amaurosis fugax. Typically a 2-year course.
What are the pathological changes in osteoporosis?
- Histologically normal bone that is decreased in quantity.
- Postmenopausal osteoporosis the increase in osteoclast activity affects mainly bones or portions of bones that have increased surface area, such as the cancellous compartment of vertebral bodies.
- The trabecular plates become perforated, thinned, and lose their interconnections, leading to progressive micro fractures and eventual vertebral collapse
What four things is osteoporosis characterised by?
- Low bone mass
- Micro architectural deterioration of bone tissue
- Increase bone fragility
- Loss of bone matrix
How do corticosteroids cause osteoprosis?
- Direct inhibition of osteoblast formation
- Direct stimulation of bone resorption
- Inhibition of GIT calcium absorption
- Stimulation of renal calcium losses
- Inhibition of sex steroids
What are primary causes of osteoporosis?
- Idiopathic
- Postmenopausal
- Senile
What are secondary causes of osteoporosis?
Endocrine - addisons, DMT1, HPTH
GI - malabsorption
Drugs - etoh, corticosteroids
Misc - anaemia, immobilisation
What are some causes of pathological fractures?
- Skeletal metastasis
- Paget’s disease
- Multiple myeloma
- Rickets
- Osteomalacia
- Osteogenesis imperfecta
- Radiotherapy
What is multiple myeloma?
It’s a plasma cell neoplasm commonly associated with lytic bone lesions, hypercalcemia, renal failure, and acquired immune abnormalities. It produces large amounts of IgG 55% or IgA 25%. It is the most common primary bone tumor in elderly
What is used to diagnose multiple myeloma?
- Punched-out lytic skull lesions on x-ray
- M spike on protein electrophoresis
- Ig light chains in urine (Bence Jones proteins)
- CRAB:
o HyperCalcemia (corrected calcium > 2.75 mmol/l, > 11 mg/dL)
o Renal insufficiency attributable to myeloma
o Anemia (hemoglobin < 10 g/dl)
o Bone lesions (lytic lesions or osteoporosis with compression fractures)
What is Bence Jones protein?
Are monoclonal globulin proteins or immunoglobulin light chain found in the urine. The proteins are produced by neoplastic plasma cells. Bence Jones proteins are present in 2/3 of multiple myeloma cases.
What are some causes of fat embolism?
- Long bone fracture (closed)
- Major Burns
- Acute pancreatitis
- DM
- Orthopedic surgery (intramedullary nailing, joint reconstruction)
- Decompression sickness
- CPBG (cardiopulmonary bypass graft)
How to manage fat embolism?
- Respiratory (O2/mechanical ventilation)
- Fluid and electrolytes balance
- General (DVT, sepsis, nutrition)
What is gangrene?
Gangrene (or gangrenous necrosis) is a type of necrosis caused by a critically insufficient blood supply
What is necrosis?
Accidental and unregulated form of cell death resulting from damage to cell membranes and loss of ion homeostasis
For necrosis and apoptosis what are the cell size, nucleus, plasma membrane, cellular contents, inflammation, and physiological/pathological role?
What is the pathogenesis of necrosis?
Severe/prolonged ischemia: severe swelling of mitochondria, calcium influx into mitochondria and into the cell with rupture of lysosomes and plasma membrane. Death by necrosis due the release of cytochrome C from mitochondria
What are the differences between wet and dry gangrene?
site/mechanism
/macroscopy
/putrefication
/demarcation/bacteria/prognosis
What is atherosclerosis?
Pathological process of the vasculature in which an artery wall thickens as a result of accumulation of fatty materials such as cholesterol
What are 5 risk factors for atherosclerosis?
- Smoking
- HTN
- DM
- Family history
- Increased LDL
What is a classification of lung cancer?
Small cell v non-smal cell
What are the types of necrosis?
- Coagulative
- Liquefactive
- Caseous
- Fat
- Fibrinoid
- Gangrenous
What is the pathogenesis of clubbing?
high plasma growth hormone
megakaryocytes lodge in peripheral vasculature lead to platelet derived growth factor (PDGF) = increased vascular permeability
How to distinguish the type of cancer?
Immunohistochemistry
If a tumour is epidermal growth factor positive what is the chemotherapy agent?
Tyrosine kinase inhibitor (imatinib)
What is an adenocarcinoma?
Adenocarcinoma is cancer that forms in mucus-secreting glands throughout the body.
What is emphysema?
In people with emphysema, the air sacs in the lungs (alveoli) are damaged. Over time, the inner walls of the air sacs weaken and rupture — creating larger air spaces instead of many small ones and reducing surface area for gas exchange
What is paraneoplastic syndrome?
A paraneoplastic syndrome is a syndrome (a set of signs and symptoms) that is the consequence of a tumor in the body (usually a cancerous one).[1] It is specifically due to the production of chemical signaling molecules (such as hormones or cytokines) by tumor cells or by an immune response against the tumor.[2]
What are the four categories of paraneoplastic syndromes?
What is an example of each? What is it caused by?
endocrine
- Cushing’s - pancreatic cancer
- hypercalcaemia - SCC lung, breast, renal
neurological
- myasthenia - bronchocarcinoma
mucocutaneous
- acanthosis nigricans - lung cancer, gastric
hematological
- VTE - all
Young Indian woman returns from visiting family with weight loss, night sweats and cervical lymphadeompathy.
What are three differentials?
TB
Lung cancer
Hodgkin’s lumphoma
What are the tests for TB?
Sputum - MC&S
* Mantoux test
* PCR to differentiate mycobacteria tuberculosis from other species
* FNAC of lymph node
What oragnisms cause TB?
- Mycobacterium tuberculosis
- Mycobacterium avium intracellulare (MAC) → disseminated infection in immunocompromised patients
- Mycobacterium bovis
What are the culture media for mycobacteria?
- Solid media: Lowenstein Jensen media, Middlebrook media
- Liquid media: BACTEC/MIGT (mycobacteria growth indicator tube)