A1 IHS SAQ (2022/2023) Flashcards
Compare the structure and function of compact bone and spongy bone (8)
Spongy vs Compact Bones
* Spongy Bones are also called cancellous bones
* They light, spongy and soft in nature
* They are made up of trabeculae
* They fill the inner layer of most bones
* Bone marrow cavity absent
* Bone marrow produces red corpuscles and white granular corpuscles
* It forms the epiphyses of long bones
* Trabeculae do not contain arteries
- Compact bones are also called cortical bones
- They are heavy, tough and compact in nature
- They are made up of osteons
- They fill the outer layer of most bones
- Bone marrow cavity present in the centre
- Bone marrow stores fat
- It forms the diaphysis of long bones
- Osteons contain arteries
Normocytic anemia causes
Any four:
* Blood loss
* Haemolysis
* Anaemia of chronic disease
* Renal disease
* Mixed nutritional (iron, b12/folate) deficiency
* Bone marrow failure (e.g. drugs, infiltration
List 2 red blood cell abnormalities that are causes of splenomegaly.
Hereditary spherocytosis
Sickle cell anaemia
Identify two metabolites that accumulate in body fluids and are used to confirm an acute
porphyric attack.
d-ALA, PBG
List and briefly describe 3 biochemical parameters by which the laboratory can distinguish
between in vivo and in vitro haemolysis
- Unconjugated bili not raised (no time for haem metabolism)
- Potassium often highly raised (released from red cell cytoplasm)
- Haptoglobin is not decreased
Outline 3 ways to avoid causing haemolysis when performing a venesection
Avoid small needles
Transport tubes carefully
Avoid drawing rapidly
Acute porphoria gene invovled?
PPOX
What should drip contain - porphyric patient
Dextrose
3 Severe malaria symptoms?
Non-ambulant
Jaundice
Impaired mental functioning
Draw interaction between splenic dendritic cell and CD4+ T cell
Dendritic cell:
MHC II presenting peptide antigen
CD80/86
CD4 cell:
TCR
CD28
CD4
List 2 cytokines which would activate the CD4+ T cell to a Th1 phenotype?
IL-12, IFN-y
Name 2 plasma cell disorders other than myeloma
Amyloidosis
MGUS
State the name of the neoplastic cell in Hodgkin lymphoma.
Reed-sternberg
Name in full 3 pathogens that are associated with neutropenic sepsis.
Staph aureus
Escherichia coli
Klebsiella pneumonia
Define positive selection (T cell development)
Binding of TCRs of mature T cells to MHC in the thymus
Define negative selection (T cell development)
Removal of T cells that bind too strongly to self antigen presented on MHC
Why is negative selection of T cells important?
Prevents the formation of self reactive T cells.
Identify any four factors that are used to define the metabolic syndrome.
- Increased waist circumference (Abdominal obesity)
- Elevated triglycerides
- Low HDL cholesterol
- Elevated blood pressure
- Raised blood glucose
List 2 causes for raised reticulocytes
Bleeding, haemolysis
Define hemolytic anemia
Reduced red cell survival, peripheral destruction
List 5 symptoms related to hyperviscosity of blood
Peripheral neuropathy
Gout
Headaches
Blurred vision
Hypertension
Name the enzyme effected for both anemia and neurological disease caused by VitB12 deficiency
Methionine synthase
List 2 malaria chemoprophylactic agents
Malarone
Doxycycline
Define hyperparasitemia
> 5% parasitized RBCs
Is Beta-thalassemia a quantitative or qualitative hemoglobinopathy? Why?
Quantitative. Produces correct structure, but not enough
What is an advantage of being a haemoglobinopathy carrier?
Protection from cerebral malaria
How do haemaglobinoapthies protect against severe malaria?
Ineffective haemopoeisis
Increased hemolysis
What is the inheritence of beta-thalassemia
autosomal recessive
List components of CD8 immunological synapse with liver cell
TCR binding to peptide presented on MHC-I
CD8+ stabilize
Fas on liver cell binding to Fas-ligand on CD8+ cell
ADCC activates which cells?
NK cells
Describe 3 stages in development of haematopoeitc system
Primitive, pro-definitive, definitive stages.
Primitive stage:
Blood islands along yolk sac
produces large nucleated RBCs, megakaryocytes, macrophages - invade embryo
Pro-definitive:
Generates eryhro-myeloid progenitors and lympho-myeloid progenitors
Definitive:
Dorsal aorta cells - produce clusters of HSCs located in lumen of aora through EHT
Pro-definitive and definitive wave progenitors travel to liver - RBCs, megakaryocytes, granulocytes, T/B cells, monocytes formed
What are B symptoms?
temperature >38 degrees C
night sweats
>10% weight loss over 6 months
Outline any three (3) possible clinical presentations caused by the infiltration of blasts into soft tissues and detectable by X-Ray examination.
Mediastinum mass - SOB
Lung parenchyma - SOB
Pleural effusion - SOB
Bone lesions - bone pain
Name the Ph negative neoplasm associated with massive splenomegaly
Primary myelofibrosis
Anele Makhamba is found to have splenomegaly associated with her diagnosis of leukaemia. List any five (5) other causes of splenomegaly
Congestion
Infection
Metastasis of neoplasm
RBC abnormalities
Autoimmunity
Storage disorders
Amyloidosis
Differential diagnosis of generalized lymphoadenopathy
TB
HL
Burkitt lymphoma
Mono
What investigations can be used to invest lymphadenopathy
Sputum
Needle biopsy
How can lab tests assess renal function
Measure plasma creatinine - estimate GFR with equations
Outline progression of acute varicella infection
Skin rash
Lesions at multiple stages of development
Macule - papule - vesicles - scabs
Itchy
List complications of acute varicella infection in child
Secondary bacterial infection
Pneumonia
encephalitis
stroke
hemorrhagic varicella
Outline implications of neonate whose mother had acute varicella infection during pregnancy
If <20 wk:
congenital varicella with microphtalmia, limb hypoplasia, skin scarring
If >20wk:
Risk of zoster early in life
Perinatal:
Neonatal varicella - severe infection.
What class of hormone is cortisol
Steroid hormone, cholesterol precursor
Compare storage of steroid and peptide hormones
Steroid hormones - not stored
Peptide hormones - membrane bound
How would you screen for retinopathy?
Fundoscopy
List three (3) microscopic lesions Kyle may develop in his kidneys as a result of poorly controlled
diabetes and provide a brief explanation of the pathogenesis of each. (6 marks)
Pappilary necrosis - ischemia
Pyelonephritis - glucose in urine cultures bacteria, poor inflammatory response
Glomerulosclerosis - proteinuria
Dipstix of DKA
+++ glucose
+++ ketones
Define non-thyroidal syndrome
Sick euthyroid syndrome - thyroid function changes due to severe illness
What is the worst outcome of hypoglycemia
Coma - death
Why is glucagon raised in diabetics?
No insulin. Insulin usually inhibits glucagon release
Why can insulin and glucagon not enter cells?
Large polypeptides - too large and charged to cross plasma membrane
Requires membrane protein as receptor - second messenger systems
Identify key difference between glycogen stores in liver vs glycogen stores in muscle
Glycogen stores in liver used to maintain constant BLOOD glucose levels in eg. fasted stated
In muscle, in low glucose states, glycogen stores used to replenish glucose to generate energy for muscle itself to use
