Week 2 - General Pathological Mechanisms Flashcards
List the types of exudate
- Serous - usually a transudate found in pleural, pericardial or peritoneal spaces
- Fibrinous exudate - fluid rich in fibrin, an exudate due to high protein content - often on serosal surface, meninges
- Suppurative exudate - pus forming, an exudate rich in neutrophil polymorphs (abscess)
- Haemorrhagic - severe vascular injury or depletion of coagulatory factors
- Membraneous - epithelium becomes coated in membrane formed by fibrin, epithelial cells and inflammatory cells
- Psuedomembraneous (ulceration) - surface exudate on mucosal/epithelial sites e.g. C diff colitis
- Necrotising (gangrenous) - high tissue pressure leading to vascular occlusion and thrombosis
List the most frequently occuring causes of death, all ages, in Scotland
- Neoplastic e.g. lung and breast cancer
- Infective e.g. pneumonia
- Vascular e.g. myocardial infarction
- Metabolic e.g. diabetes
- Inflammation e.g. chronic obstructive pulmonary disease
- Traumatic e.g. road traffic collision
- Degenerative e.g. Alzheimer’s disease
- Iatrogenic e.g. intra-operative death
How prevalent is Meckel’s diverticulum?
Occurs in about 2% of the population
What is cytology?
- Study of cells
- Advantages
- Can’t biopsy fluids e.g. pleural effusion
- Less invasive than tissue biopsy
- Limitations - no tissue architecture
Describe the process of fracture healing
- Inflammation
- Haematoma forms at site of fracture
- Prostaglandins recruit neutrophil polymorphs, macrophages, lymphocytes and fibroblasts to the site of injury
- Granulation tissue, ingrowth of vessels, migration of mesenchymal cells occurs
- Nutrients and oxygen are supplied by the exposed bone and muscle
- Repair
- Fibroblasts lay down stroma to support ingrowing vessels
- Collagen matrix is laid down
- Osteoid is secreted and mineralised leading to soft callus formation
- Callus ossified after 4-6 weeks by forming bridge of woven bone between fracture fragments
- Remodelling
- Occurs slowly over months and years
- Returns bone to its original shape, structure and mechanical strength
- Facilitated by mechanical stress
Describe the internal examination performed in post-mortems
- Evisceration
- Single incision from sternal notch to symphysis pubis - allows removal of thoracic, abdominal and pelvic organs
- Second incision around posterior part of the skulls to reflect the scalp, skull is opened and brain removed
- Eviscerations usually performed by APTs
- Organ dissection
- Pathologist inspects each organ then carefully dissects them - MACROSCOPIC ASSESSMENT
- Pathologist may retain small amount of tissue for MICROSCOPIC ASSESSMENT
Define chronic inflammation
- Inflammation is a physiological response to injury, defined as chronic when -
- It is persistent and lacks resolution when the inflamed tissue is unable to overcome the effects of the injurious agent
- It persists for weeks, months or years
- It is characterised by infiltrates of lymphocytes, plasma cells, and macrophages
Describe anaplasia and dysplasia of tumours
- Anaplasia = lack of differentiation of a tumour (synonymous with undifferentiated)
- Dysplasia = disordered growth in which cells fail to differentiate fully, but are contained by the basement membrane, i.e. non-invasive
What are the effects of necrosis?
- Functional
- Depends on tissue/organ
- Inflammation
- Release of cell contents activates inflammation and causes damage
- Either acute with removal of stimulus and then healing and repair or chronic with persistence of stimulus and chronic inflammation
Describe pathological calcification
- Deposition of calcium salts
- May be
- Dystrophic - deposition in abnormal tissue with normal serum calcium
- Metastatic
- Deposition in normal, living tissue with raised serum calcium
- Often in connective tissue of blood vessels
- Can compromise tissue function
What are the hilar points on a chest X-ray?
- Hilar points are angles formed by the descending upper lobe veins and lower lobe pulmonary arteries
- Not always clearly visible
- L usually higher than R
List the factors which influence wound healing
- Local -
- Type, size and location of wound
- Movement within wound
- Infection
- Presence of foreign/necrotic material
- Irradiation - causes formation of many fragile BVs, collagen weak
- Poor blood supply
- Systemic -
- Age
- Nutrition (vitamin C, zinc)
- Systemic disease (e.g. renal failure, diabetes)
- Drugs (esp. steroids)
- Smoking
How is a developmental anomaly different to congenital anomaly?
- Terms often used interchangeably
- Congenital anomalies are anomalies that exist at or before birth regardless of the cause, and may be either:
- Functional/metabolic - how the body works (inborn errors of metabolism, haemophilia, cystic fibrosis)
- Structural - how the body is made up physically/architecturally
- Developmental anomaly = deformity, absence or excess body parts/tissues which occur when normal growth is disturbed
- If growth of an organ or system is disturbed = structural anomaly
- Therefore, developmental anomaly = structural congenital anomaly
Describe the pathogenesis of atherosclerosis
- Foam cells
- Fatty streak
- Intermediate lesion
- Atheroma
- Fibrous plaque
- Complicated lesion/rupture
Progressive endothelial dysfunction
Describe the pathophysiology of coronary artery disease
- Atheromatous arterio-vascular disease
- Development of atheroma/plaques
- Progressive narrowing and stenosis of artery
- Plaque rupture
- Acute thrombus
- Vascular occlusion
- Downstream ischaemia and infarction
How is a post-mortem examination carried out?
- Background information
- From medical notes
- Past medical history
- Summary of clinical events and treatments
- Autopsy
- External examination
- General appearances, external disease etc.
- Medical treatment e.g. drains
- Internal examinations
- Body cavities and systems
- Organs examined in turn
- Further examination
- Samples taken
- Histology, neuropathology
- Bacteriology, biochemistry etc.
What is diverticulum?
- Circumscribed pouch/sac caused by herniation of lining mucosa of an organ through defect in muscular coat
- Classic examples are Meckel’s diverticulum and sigmoid colon diverticula/diverticular disease
How is ACS treated?
- Prevent thrombus extension
- Anti-platelet agent - aspirin, clopidogrel
- Anticoagulant - heparin
- Remove the thrombus
- Thrombolysis - alteplase, tenecteplase
- Remove clot via catheter (PCI)
- Widen the stenotic plaque
- Balloon angioplasty, insert coronary artery stent
- Prevent further thrombus
- Anti-platelet agent, statin
What is granulomatous inflamamtion?
- Distinctive pattern of chronic inflammatory reaction
- Predominant cell types are activated macrophages with a modified appearance (epithelioid macrophages - looks like epithelial cell) and giant cells (formed from fused epithelioid macrophages) (+CD4+ T cells)
- Recognition of the granulomatous pattern and type of giant cells in a biopsy specimen is important because of the limited number of possible conditions that cause it and the significance of the diagnoses associated with the lesions
- Necrosis - often in infective cases, so-called caseous necrosis is characteristic of TB (+ leprosy, blastomycosis)
What is the significance of the costophrenic recess on chest X-ray?
- Costophrenic recess formed by the hemidiaphragm and the chest wall and contains the rim of the lung base which lies over the diaphragm
- Angle formed by the lateral chest wall and the diaphragm is known as the costophrenic angle
- On CXR angles should be sharp - disappears first in pleural effusions
- Infection in base of lung - likely to be seen in recess
What is homeostasis?
- Definition - normal cells in a steady state
- Injury can induce changes in homeostasis
- Injury can be either reversible or irreversible
- Leads to either adaptation or cell death
Describe the final steps in the coagulation cascade, how is this clinically relevant?
Clot dissolved by plasmin to substances e.g. D-dimer
- Typical D-dimer containing fragment contains two D domains and one E domain of the original fibrinogen molecule
- D-dimer has long half life (8 hours) so is best for testing clotting clinically
- Elevated D-dimer - 94% sensitivity, 95% NPV
How are tumours staged?
- Stage of a tumour is based on the size of the primary tumour, the extent of invasion into surrounding tissue, the spread to regional lymph nodes and the presence or absence of metastases
- Essentially, stage = how far a tumour has spread/how advanced a tumour is
- TNM system is used, stands for:
- Tumour - how big? Has it locally invaded?
- Nodes - are nodes involved? How many?
- Metastasis - distant metastases?
- If a tumour has metastasized it is late stage or stage IV
- Each specialty has its own dataset to stage tumours
What causes hypertrophy?
- Increased functional demand
- Hormonal stimulation
Describe the prevalence of VTE
- Increases with age
- Average incidence - 1-1.5/1,000 population per year
Describe the morphology of apoptosis
- Cell shrinkage
- Chromatin condensation (unlike necrosis) - packaging up of nucleus
- Membranes of cell and mitochondria etc. remain intact, unlike necrosis
- Cytoplasmic blebs form and break off to form apoptotic bodies which are phagocytosed by macrophages
Describe the morphology of neutrophil polymorphs
Multilobulated nucleus - 3 lobes
Limited cytoplasm
No granules
Define metaplasia
- Reversible change from one fully differentiated cell type into another
- Adaptation so cells sensitive to a particular stress are replaced by other cells better able to withstand the adverse environment
What is exposure in an X-ray?
Amount of X-ray going through patient, varies which differences in shape/size (smaller - less exposure, larger - more exposure)
What structures are visible on a normal chest X-ray?
Describe reversible and irreversible cell injury
- Cell injury may be reversible or irreversible
- Reversible
- Changes due to stress in environment
- Return to normal once stimulus removed
- Irreversible
- Permanent
- Cell death, usually necrosis, follows
- Reversible
- Continuum between reversible and irreversible
- Threshold (‘point of no return’) depends on type, duration and severity of injury
What are the clinical features of systemic inflammation?
- Increased respiratory rate
- Increased heart rate
- High or low temperature
- Low or raised white cell count
What is a paradoxical embolism?
- Very rare
- Venous drainage to R side of heart, in atrial septal defects blood moves R –> L and clot can form in L
How would the certificate of cause of death be completed from the following history:
- 54 year old man
- Smoker, history of angina
- Collapsed at train station on way to work
- Bystander CPR until ambulance arrival
- 45 minutes of CPR in A&E with no spontaneous return of circulation
- Pronounced dead in A&E
On post-mortem
- Ruptured MI, ruptured aortic root
- Necrosed myocardium - infarction
- Left ascending coronary artery fully occluded
- Disease or condition directly leading to death
a) Cardiac tamponade
b) Due to, or as a consequence of, ruptured MI
c) Due to, or as a consequence of, thrombus of left ascending coronary artery
d) N/A - Other significant conditions contributing to the death, but not related to the disease or condition causing it = smoking
Define hyperplasia
- Increase in the number of cells in an organ or tissue
- Adaptive response in cells capable of replication
- Critical response of connective tissue cells in wound healing
What would you want to know when a 30-year-old female presents to A&E with an 18-hour history of right iliac fossa abdominal pain?
- SOCRATES of the abdominal pain
- Site
- Onset
- Character
- Radiation
- Associated symptoms
- Time
- Exacerbating/relieving factors
- Severity
- Pregnancy? - ruptured ectopic pregnancy is major concern (every woman of childbearing age presenting to A&E needs a urine pregnancy test)
- Bowels - change, diarrhoea, constipation, blood, mucous
- Blood - haematochezia or melena (melena = upper GI bleed), volume
List the risk factors for arteriosclerotic cardiovascular disease
- Smoking
- Hypertension
- Hyperlipidaemia
- Diabetes
- Obesity
- Family history
Give examples of endogenous and exogenous depositions
- Endogenous
- Intracellular
- Melanin
- Haemosiderin
- Bile
- Lipid, including cholesterol
- ‘Storage disease’ especially in liver e.g. alpha-1-antitrypsin
- ‘Degeneration products’ e.g. lipofusion
- Extracellular
- Amyloid
- Fibrosis
- Calcium
- Intracellular
- Exogenous
- Intracellular
- Tattoo pigment
- Carbon (anthracosis)
- Asbestos
- Extracellular
- Exogenous may be extracellular too
- Intracellular
What is the differential diagnosis for a painful swollen leg?
- Trauma
- Fractures, dislocations, muscle strain/rupture or haematoma
- Non-traumatic
- Musculoskeletal causes, osteoarthritis, rheumatoid arthritis, septic arthritis, gout and pseudogout, popliteal (Baker’s) cyst, tenosynovitis, bursitis, myopathies
- Skin/soft tissue infections
- Cellulitis, erysipelas, abscesses, necrotising faciitis
- Vascular causes
- Venous occlusion - DVT, superficial vein thrombosis, venous insufficiency (post-DVT, varicose veins)
- Acute ischaemia - cardiac thromboembolism, peripheral arterial disease, massive DVT
- Lymphoedema
- Causes of bilateral leg swelling
- Systemic oedema - heart failure, cirrhosis, nephrotic syndrome, malnutrition, immobility
How do vascular changes occur in inflammation?
- Vasodilation
- Transient vasoconstriction then vasodilatation
- Starts in arterioles
- Increased blood flow
- Due to histamine (mast cells), prostaglandins (can be produced by all nucleated cells), NO (made by nitric oxide synthase in endothelial cells)
- Arterioles dilate increasing blood flow
- Increased vascular permeability
- Permits escape of protein rich fluid exudate into extravascular tissue
- Contraction of endothelial cells
- Increased interendothelial spaces
- Mediated by histamine, bradykinin, substance P
- Vascular congestion/stasis
- Slower flow, increased concentration
- Endothelial activation
- By mediators produced during inflammation
- Increased levels of adhesion molecules
How can you arrive at a differential diagnosis?
- Location of disease
- Think through different structures - are they normal or abnormal (systematic, like clinical history and examination)
- Abnormality may be of quantity (more or less) or quality (different structure)
- Consider possible causes/nature of disease
List physiological and pathological causes of apoptosis
- Aetiology - Physiological
- Embryogenesis - deletion of cell populations
- Hormone dependent involution - uterus, breast, ovary
- Cell deletion in proliferating cell populations to maintain constant number of cells e.g. epithelium
- Deletion of inflammatory cells after an inflammatory response
- Deletion of self-reactive lymphocytes in thymus
- Aetiology - Pathological
- Viral infection - cytotoxic T-lymphocytes
- DNA damage
- Hypoxia/ischaemia
Describe the hilar structures seen on chest X-ray
- Each hilum contains major bronchi and pulmonary vessels
- Lymph nodes are not visible unless enlarged
What causes cell injury?
- If the stress is more intense, longer-lasting or of a specific type, or if the cell is very sensitive, then there may be cell injury
- Cells directly affected may undergo
- Sub-lethal cell injury
- Cell death
- The body may respond with
- Inflammation - acute or chronic
- Possibly, after many years, affected cells may undergo
- Neoplasia
Define carcinoma in-situ
- Full-thickness (severe) epithelial dysplasia extending from basement membrane to surface epithelium
- Applicable only to epithelial neoplasms, if the entire lesion is no more advanced than CIS (carcinoma in-situ), then the risk of metastasis is zero
- Because there are no blood vessels or lymphatics within the epithelium above the BM
- Why cervical/bowel screening is so important
How does the diaphragm appear on chest X-ray?
- Right hemi-diaphragm is slightly higher than the left
- Liver is located beneath the right and stomach bubble is seen below the left
- Cardiophrenic angles between heart and diaphragm - can have collection of fat here if obese
What is the right paratracheal stripe on a chest X-ray?
- R edge of trachea
- Normally less than 3mm
- Enlargement may represent mass or nodes
- L side of trachea not so well defined
- Tracheobronchial angle - where azygous vein lies
How are histopathology samples prepared?
- Pathologist examine and trim tissue
- Tissue fixed in formalin
- Tissue processing
- Dehydration
- Clearing
- Wax impregnation
- Tissue blocks sectioned, stained (e.g. w/ H&E)
Give examples of cytology samples
- Exfoliative cytology
- Fluid cytology including effusions
- Scrape, smear and brush cytology (including cervical)
- Fine needle aspiration
- Direct e.g. sampling surface lumps on skin, head and neck, breast, lymph nodes
- Under ultrasound guidance, as above plus endoscopic ultrasound (EUS) e.g. LNs, upper gastro-intestinal or respiratory tract, pancreas
Compare the microscopic appearance of a normal appendix vs an acutely inflamed appendix
- Normal appendix wall, layers =
- Mucosa - epithelium (columnar), lamina propria, muscularis mucosa
- Submucosa
- Muscularis propria (pink layer)
- Serosa
- Normal mucosa - uniformly arranged crypts/glands (test tube like arrangement)
- Abnormal appendix wall:
- Muscularis propria thicker, more blue
- Engorged blood vessels
- Increased cellular infiltrate
What molecular testing can be done for pathological diagnosis?
- Immunhistochemistry
- Flow cytometry
How do metastases present?
- Multiple skin lesions
- Brain - CNS lesions
- Lungs - breathlessness/haematemesis
- Liver - jaundice, masses
- Bones - pathological fracture
- Lymph nodes - e.g. neck (gastric, lung cancer)
Give the differential diagnosis for chest pain
- Musculoskeletal
- Rib fracture, muscular, chondritis
- Cardiac
- Angina, myocardial infarction
- Lung
- Pleuritic pain - infection, infarction, malignant
- Vascular
- PE, aortic dissection
- Oesophageal
- Acid reflux, hiatus hernia
How are tumours graded?
- As tumours become more poorly differentiated, the higher the grade becomes
- As tumours look less and less like the original tissue, they are really becoming worse and worse = grade
- Poorly differentiated cancer is a high grade malignancy and a well differentiated cancer is a low grade malignancy
List the phases of wound healing
- Formation of blood clot
- Formation of granulation tissue
- Cell proliferation and collagen deposition
- Scar formation
- Wound contraction
- Connective tissue remodelling
- Recovery of tensile strength
List indications for chest X-ray
- Emergency
- Acute respiratory symptoms
- Chest pain
- Septic screen
- Acute abdomen
- Post central line/chest drain insertion
- Elective
- Persistent/chronic respiratory symptoms
- Pre-operative work up
- Metastatic screen
- TB contacts
What is the function of an exudate?
An exudate allows delivery of nutrients, dilution of toxins, entry of antibodies and stimulates the immune response
How can emboli form?
- Can arise within the body or out with it, including
- Thrombus
- Air
- Fat
- Amniotic fluid
- From thrombus forming
- In the leg veins
- In the carotid arteries
- Inside the heart
- And embolising to
- The lungs
- The brain
- Other tissues
How do defects in the immune system lead to chronic granulomatous disease?
- Defect in NADPH oxidase system within phagocytes (including macrophages)
- Heterogeneous but usually X-linked
- Inability to kill intracellular organisms by respiratory burst
- Patients have repeated and recurrent infections, develop granulomata of lymph nodes, skin, lungs, liver and GI tract
What anatomical structures are located in the right iliac fossa in a female patient which may cause pain?
- Anatomical structures
- Skin - sebaceous cyst
- Subcutaneous fat - lipoma
- Appendix - appendicitis
- Ovary - cyst
- Fallopian tube - ectopic pregnancy
- If there is GI bleeding - aetiology unlikely to be gynaecological
- Gynaecological disease may cause GI upset by impinging bowel
Describe the coagulation cascade
- Tissue injury causes the coagulation system to be triggered by the tissue factor/factor VIIa complex, which activates FIX and FX
- Activated FIX converts small amounts of prothrombin to thrombin, which is sufficient to amplify coagulation by activating factors V and VIII, platelets, and platelet-bound factor XI
- Coagulation is propagated when FIXa binds to FVIIIa on the surface of activated platelets, forming intrinsic tenase, which activates FX
- Activated FX binds to activated factor V to form prothrombinase, which converts prothrombin (factor II) to thrombin (factor Iia)
- In the final step, thrombin converts fibrinogen to fibrin
Describe the covering of the lungs
- Lungs covered by pleura - two layers
- Inner layer = visceral pleura
- Outer layer = parietal pleura
- Fissures formed by invagination of the visceral pleura
- Two layers separated by a potential space which may contain up to 15mls of fluid normally
Give examples of ectopia
- Ectopia cordis = displacement of heart outside of body
- Ectopic thyroid tissue = nodules of mature thyroid tissue located elsewhere in the neck
- Ectopic pregnancy = implantation occurring in fallopian tube rather than endometrium (more often seen in the context of pelvic inflammatory disease or previous surgery)
What is the importance of differentiation in tumours?
- Site of origin in metastatic disease
- E.g. Squamous carcinoma in a lymph node - sites of origin would include lungs, respiratory tract, gynae tract, skin
- Prognosis
- Well differentiated often better prognosis than poorly differentiated (unpredictable)
- Treatment
- Treatment varies e.g. adenocarcinoma vs squamous
Why are mastectomy specimen edges stained?
- When examined under microscope can measure distance between edge of tumour and stained edge of specimen - gives surgical margin
- >1mm clear surgical margin - doesn’t require further treatment (can ensure that all of tumour has been removed)
Describe the gross pathological appearance of the terminal ileum in Crohn’s
- Large BVs - vasodilation due to inflammation
- Stricture - narrowing of the terminal ileum due to fibrosis (from inflammation)
- Opened specimen
- Colour - red due to engorged blood vessels
- Thickness of intestinal of wall - thickened due to inflammation, lumen is narrower (strictures form), causes outflow obstruction
- Strictures - outflow obstruction, perforation, peritonitis (area of stricture has to be removed)
- Appearance of mucosal surface - irregular, cobbled
What are the functions of neutrophil polymorphs?
- Phagocytosis of cells which have been targeted by opsonisation
- Intracellular killing of micro-organisms (bactericidal components)
- Oxygen dependent
- Oxygen independent
- Release lysosomal products, propagating the response
List the types of malignant tumours
- Carcinoma - epithelial origin (squamous cell carcinoma, basal cell carcinoma, renal cell carcinoma, adenocarcinoma)
- Sarcoma - mesenchymal origin (osteosarcoma, liposarcoma, pleomorphic sarcoma)
- Melanoma - melanocytic origin
- Lymphoma - haemopoeitic origin (Hodgkin or non-Hodgkin lymphoma, high grade or low grade)
- Germ cell tumours
What is the significance of the aortic knuckle on chest X-ray?
- Represents the left lateral edge of the aorta as it arches backwards over the left main bronchus, continues as the descending aorta
- Older people - bulging
- Teenagers - small aortic knuckle, big hila
What bloods are done in tumour investigation?
- FBC, U+E, LFTs, calcium
- Protein electrophoresis
- Tumour ‘markers’ as appropriate: AFP, HCG, PSA, CEA, Ca 19.9 (pancreatic Ca), Ca 125 (ovarian Ca) - non-specific
- Clinical context crucial
Which important structres are not visible on a chest X-ray?
- Sternum
- Oesophagus
- Spine - can see spinous processes usually
- Fissures
- Pleura
- Aorta
How is a post-mortem completed?
- All organs returned to patient’s body cavity (minus tiny amount of tissue taken for microscopic assessment)
- If no death certificate has been issued before the PM, the pathologist will write a death certificate
- The report prepared by the pathologist is sent to the PF, or for consented/hospital cases, to the patient’s GP and the clinician in charge of care
- Patient’s body is then reconstructed to permit viewing of the deceased by their family
- Body released for burial or cremation as specified by the deceased/family
Describe the morphology of macrophages
- Elongated, large nucleus
- Voluminous cytoplasm
What is neoplasia?
- Literally = new growth
- An abnormal tissue mass, the growth of which is excessive (i.e. not an adaptation to physiological demands) and uncoordinated compared to adjacent normal tissue
- Persists even after cessation of the stimuli that caused it
How does a normal lymph node aspirate compare to an abnormal lymph node aspirate?
Normal:
- Lymphocytes are pleomorphic
- Vary in size, shape, colour
- Clonal expansion is bad - monomorphic, suggests cancer (lymphoma)
Abnormal:
- Non-Hodgkin’s lymphoma
- Monomorphic cell population (lymphocytes)
- All same colour, size, shape
- Low grade B-cell lymphoma - small to medium lymphocytes
- Very difficult or impossible to distinguish from normal reactive lymph nodes
- Metastatic squamous cell carcinoma
- Squamous epithelial cells are larger than lymphocytes, with more cytoplasm - which is usually pink (keratin)
- Epithelial cells generally cohesive (form protective coverings) so stick together - appear in sheets and lumps rather than dispersed (like lymphocytes)
Give examples of local effects of tumours
- Oesophagus - dysphagia/odynophagia
- Sigmoid colon - altered bowel habit/blood PR
- Bronchus - pneumonia/haemoptysis
- Head of pancreas - obstructive jaundice
What vascular pathology can be seen on post-mortem?
- Thrombosis and infarction
- Dead (necrotic) heart muscle due to infarction - takes 2-3 days to be visible
- Feels soft at first
- Turns yellow/grey
- Bowel infarction
- Cerebral infarct
- Dead (necrotic) heart muscle due to infarction - takes 2-3 days to be visible
- Embolism
- Haemorrhage
How are tumours named based on their tissue of origin?
- Lipo- = fat
- Rhabdo- = skeletal muscle
- Leio- = smooth muscle
- Osteo- = bone
- Chondro- = cartilage
- Adeno = gland
- Meningo- = meninges
- Angio- = vascular
How are post-mortem examinations done in the UK?
- Hospital ‘consented’ PM
- Usually done at the request of clinicians to answer questions about the patient’s pathology or treatment
- Requires specific consent of the family
- Few cases per year (e.g. 40-50 in Glasgow)
- Medico-legal PM
- At the instruction of the Procurator Fiscal (Scotland) or Coroner (England and Wales)
- Does not require consent of the family
- Constitute the vast majority of PMs performed in the UK (110,000 per year in England and Wales, 6500 in Scotland)
List the causes of atrophy
- Loss of innervation
- Diminished blood supply
- Inadequate nutrition
- Decreased workload
- Loss of endocrine stimulation
- Aging (senile atrophy)
What is metastasis? How can metastasis occur?
- Tumour implants discontinuous from the primary tumour
- Spread of tumour to distant sites can occur by:
- Lymphatic spread - most common pathway for dissemination of carcinomas (+ sarcomas). Pattern of lymph node involvement follows the natural routes of drainage.
- Haematogenous spread - typical of sarcomas. Arteries are more difficult for tumour to penetrate than veins. With venous invasion, the blood-borne cells follow the venous flow draining the site of the tumour. Liver and lungs are frequently involved.
- Seeding of body cavities (transcoelomic spread) - occurs when a malignant neoplasm penetrates into a natural ‘open field’ such as peritoneal cavity, pleural space, pericardial cavity etc. Most common examples - ovarian carcinoma, gastric carcinoma.
- Perineural
Describe prevention of DVT thrombus extending or embolism
- Anticoagulation for 3-6 months
- Heparin (LMWH)
- Warfarin (target INR 2.5)
- Direct oral anti-coagulant (direct Xa or IIa inhibitor)
- Remove risk factors - smoking, OCP etc.
- Graduated elastic compression stockings
How sensitive/specific is the Wells clinical score?
- 5.5% of those with score <2 actually had DVT or PE
- 27.9% of those with score >/= 2 had a DVT or PE confirmed
How does the acute inflammatory response terminate?
- Removal of stimulus
- Neutrophils have a short half life
- Variation in cytokine stimuli
- Neural impulses
- Macrophages are activated to perform different functions
What are the affects of acute inflammation?
Beneficial -
- Dilation of toxins by oedema fluid
- Increased entry of antibodies and drug transport
- Fibrin mesh traps microorganisms
- Delivery of nutrients
- Stimulation of immune response
Detrimental -
- Digestion of normal tissue
- Swelling e.g. epiglottitis (bacterial infections, obstructs airways)
- Inappropriate response e.g. type I hypersensitivity response (allergic rhinitis)
What is intussusception? When does it commonly occur?
- Elderly - usually in context of tumour
- Peristalsis of proximal bowel over next part
- –> ischaemic bowel disease, colitis
Describe the pathological appearance of an old cerebellar infarct
- Depressed area - colliquitive necrosis (liquifies)
- Brain has no fibroblasts - glial cells
- Gliosis = cerebral scar
- Indentation, loss of tissue, feels firm
How is MI/ACS diagnosed?
- Suggestive history
- Clinical evidence of cardiac dysfunction
- ECG findings
- Biochemical evidence of myocardial damage (ischaemia)
- Elevated troponin (biochemical marker)
- Visualisation of coronary arteries
- Cardiac catheterisation
Gives examples of atrophy - physiological and pathological
- Uterus - menopause causes atrophy (physiological)
- Brain atrophy seen with age (physiological) or with degenerative conditions e.g. Alzheimer’s (pathological)
- Kidney atropy due to renal artery stenosis e.g. due to high BP (pathological)
- Intestinal villous atrophy in coeliac disease (T cell mediated resposne - pathological)
Describe the deposition of haemosiderin in macrophages
Haemosiderin (iron - brown) may be deposited after haemorrhage or if there is congestion of blood vessels
How do we confirm or exclude the diagnosis of DVT?
- Clinical decision rule
- Determine likelihood of DVT
- Blood tests
- Fibrin D-dimer, a measure of dissolved thrombus
- Image venous system of leg
- Compression ultrasound, venography
List the types of necrosis
- Coagulative
- Firm, tissue outline retained
- Haemorrhagic - due to blockage of venous drainage
- Gangrenous - larger area especially lower leg
- Firm, tissue outline retained
- Colliquitive
- Tissue becomes liquid and its structure is lost e.g. infective abscess, cerebral infarct
- Caseous
- Combination of coagulative and colliquitive appearing ‘cheese-like’ (caseous)
- Classical for granulomatous inflammation esp. TB
- Fat
- Due to action of lipases on fatty tissue
Describe differentiation of tumours
- Tissue type represented by the tumour
- The extent to which the tumour cell resembles the original cell
- Ranges of differentiation - well, moderately, poorly, undifferentiated
- Well differentiated tumours resemble identifiable tissue types
- Undifferentiated tumours do not resemble anything, ICC (immunocytochemistry) may be needed to know where it came from
What histopathology sample types are taken?
- Small biopsies
- Mucosal (e.g. colonic biopsy)
- Needle core (e.g. liver biopsy)
- Incisional (e.g. skin punch biopsy)
- Excision biopsy (e.g. suspected melanoma) - whole thing removed
- Resections
- Small e.g. appendicectomy
- Large e.g. pneumonectomy
Describe prevention of DVT
- Avoid risk factors if possible
- Risk assess at hospital admission or surgery
- Provide thrombo-prophylaxis when appropriate
- Anti-embolism stockings
- Heparin (LMWH daily SC)
- Education of patients on risks and avoidance measures e.g. early mobilisation
What can the outcome of acute inflamamtion be?
- Resolution - complete restoration of tissue to normal
- If minimal tissue damage
- If occurs in tissue with regenerative capacity i.e. skin
- If cause is rapidly removed or destroyed
- If there is good vascular drainage
- Healing by fibrosis
- After substantial tissue damage
- Tissue incapable of regeneration e.g. brain
- Abundant fibrin exudate
- Progression to chronic inflammation
- Persistent stimulus
- Tissue destruction leading to ongoing inflammation
Which cardiac contours are seen on a normal chest X-ray?
- RA and LV cardiac contours seen
- Can’t see RV (front) or LA (back)