Current Flashcards
1
Q
blood cell lineage
A
1st = pleuripotent stem cell
2nd = common progenitor cells
- common lymphoid
- common myeloid
3rd = progenitor cells
- lymphoid
- > B cell progenitor or T/NK progenitor
- mekakaryocyte erythroid progenitor
- > erythrocyte progenitor via EPO
- > megakaryocyte progenitor via TPO
- granulocyte monocyte progenitor
- > monocyte progenitor
- > granulocyte progenitor
4th = precursor (blasts)
- proerythroblast -> erythrocyte
- mekakaryoblast -> mekakaryocyte -> platelet
- myeloblast -> granulocytes
- monoblast -> monocyte
2
Q
ddx AML
A
I AM a BAD MD
- infection
- > mononucleosis (EBV/HIV/CMV)
- ALL
- myelofibrosis
- blast crisis (CML)
- aplastic anaemia
- drugs
- > methotrexate
- > vitamin B12
- MyeloDyslpasia
3
Q
ddx lymphoma
A
- leukemia
- > ALL
- MR HIV SANG
- > mononucleosis
- > rubella
- > hep
- > influenza
- > viral serum sickness like syndrome
- > syphilis
- > autoimmune (SLE)
- > neoplasia (mets to lymph nodes)
- > gonnacoccal disseminated infection
4
Q
TB pathophys
A
Inoculation
- inhalation of droplet nuclei
- from contact with pulmonary TB
- likelihood of transmission
- > infectivity of source
- > degree of exposure
- > immunostatus of recipient
Infection
- deposition in alveoli
- > engulfed by macrophages
- survival/replication in macrophages
- > release
- immune response
- > predominately macrophages
- > mediated by Th1 cells
- options
- > clearance
- > primary disease
- > latency
- greatest risk of progression
- > HIV
- > malnourished
- > immunocompromised (diabetes, ESRD)
- > haematological malignancy
- > cigarrete smokers
latency
- formation of granuloma
- > necrotic core (caseous centre)
- > peripheral granulation tissue with macrophage and lymphocytes
- granuloma contains TB/prevents spread
- clinical
- > non infectious
- > usually negative CXR
- > positive skin test
- reactivation
- > 10% risk over life time
- > higher risk with immunocompromise
- > HIV = 10% per year
primary
- formation of granulomatous structure called tuburcle
- bacterial replication not controlled
- > tubercle enlargement
- > termed Ghon focus on CXR
- bacilli enter local lymph nodes
- > lymphadenopathy
- calcified Ghon focus + local lymphadenopathy
- > Ranke complex on CXR
- bacteraemia
- > miliary TB
- erosion into airway
- > infectivity
5
Q
TB investigations
A
FBC -leukocytosis -anaemia EUC -treatment LFTs -treatment
Sputum
- 3 specimens
- > 8 hours apart
- > cough/induced/bronchoalveolar lavage
- smear
- > acid fast bacilli
- > rapid but low sensitivity
- culture
- > most sensitive and specific
- > solid media = 1-2 months
- > liquid media = 1-3 weeks
- > sensitivity testing
- NAAC
- > rapid
- > high sensitivity/specificity
- > confirms diagnosis in smear positive/negative
HIV serology
Hep serology
CXR
- fibronodular opacities
- > may be cavitating
- > usually in upper lobes
- Gohn focus
- Ranke complex
Latent
- TST
- > uses purified protein derivative to evaluate delayed hypersensitivity response
- > false negative approx 25%
- > cannot distinguish between active/latent/vaccination
- > 15mm in people with no risk factors
- > 10mm for new conversion or risk factors
- > 5mm in HIV, contact, or positive CXR
- IGRA
- > measures response of T cell to TB antigens
- > false neg approx 25%
- > less false positive in vaccination
6
Q
TB treatment
A
Infectivity
- isolated
- > non infectious after 2 weeks of daily therapy
- notifiable disease
Resistance
- PCR resistance testing for isoniozid
- multidrug resistance (isoniozid and rifampicin) less common
Compliance
- education
- case management
- consider directly observed therapy
Standard course
- RIPE daily for 2 months
- > rifampicin
- > isoniozid
- > pyrazinamide
- > ethambutol
- rifampicin + isoniozid daily for 4 more months
- success
- > initial = 98%
- > 1% relapse within 5 years
7
Q
upper (occipital-C2) cervical vertebral injuries
A
atlanto-occipital dislocation
-flexion injury
atlanto-axial dislocation
-flexion rotation
C1 fracture
- burst (jefferson)
- > compression force
- > occipital condyles driven down into C1 lateral mass
- > fracture of anterior/posterior arch
- > transverse ligament may rupture
- > highly unstable
- posterior arch fracture
- > extension force
- > compression of posterior arch between occipital bone and C2 spinous process
- > vertical line through C1 posterior arch on xray
- > stable
C2 fracture
- hangmans
- > fractured pedicle of C2
- > hyperextension of skull, C1 and 2
- > unstable
- odontoid fracture
- > flexion/extension injury
- > type 1 = above transverse ligament (stable)
- > type 2= at dens base (ubstable)
- > type 3= extension into base of C2 (unstable)
8
Q
lower cervical vertebral injuries
A
Anterior wedge
- extreme flexion force
- fracture of anterior portion of vertebral body
- > seen as drop in height on lateral
- usually stable
Teardrop
- flexion teardrop
- > extreme flexion
- > vertebral bodies hit against each other
- > anteroinferior portion of upper body fractured
- > free segmental anteriorly displaced as teardrop
- extension tear drop
- > extreme extension force
- > avulsion of anterior longitudinal ligament
- > gives roughly same appearance as flexion teardrop
Spinous process fracture
- clay shovelers fracture
- usually direct trauma or flexion during MVA
- stable
Facet joint dislocation
- bilateral
- > extreme flexion
- > lower facet of upper vertebra brought over upper facet of lower vertebra
- > highly unstable
- unilateral
- > rotation and flexion
- > gives bow-tie appearance of posterior elements on lateral
9
Q
glaucoma
A
BACKGROUND
peripheral neuropathy of optic nerve
open angle
- blockage of drainage system
- > trabecular meshwork
- > canal of schlemm
- > aqueous veins
- presents with
- > peripheral scotoma
- > chronic progressive
closed angle
- iris blocks anterior chamber drainage
- presents with
- > red eye
- > eye pain
- > headache, nausea, vom
- > halos
INVESTIGATIONS
tonometry -pressure >21mmHg ophthalmoscopy -cup:disc >0.6 -assymetry >0.2 slit lamp -drainage angle open -cornea clear visual field testing -peripheral scotoma
TREATMENT
- all eye drops
- decrease aqueous production
- > beta blockers (timolol)
- > carbonic anhydraze inhibitors (dorzolamide)
- increase outflow
- > prostaglandin analogues (latanoprost)
- > α 2 agonist (brimonidine)
10
Q
inguinal hernia ddx
A
NULLAHS
- neoplasia
- > testicular
- > lymphoma
- undescended testis
- lymphadenopathy
- lipoma of spermatic cord
- aneursym (femoral)
- hydrocele
- sphena varix
