OSCE data interpretation Flashcards
What is measured in thyroid function tests?
TSH
T3
T4
What is the ratio of T3 and T4 produced by the thyroid?
T4:T3 is 20:1
T3 is produced by peripheral conversion of T4
Free T4 makes up …….% of total T4, with the rest being bound to thyroid binding globulin.
1%
What clinical features are found in Grave’s disease?
Exophthalmos
Pretibial myxoedema
What will the TFTs be in hypothyroidism?
TSH high
T4 low
(if T4 is normal and TSH is raised, this suggests subclinical hypothyroidism)
What will the TFTs be in secondary hypothyroidism (pathology of pituitary or hypothalamus)?
TSH normal/low
T4 low
What will the TFTs be in Grave’s disease?
TSH low
T3 and T4 high
Why are LFTs ordered?
- Investigate suspected liver injury/disease
2. Distinguish between hepatocellular injury and cholestasis
Which blood tests are included in LFTs?
ALT AST ALP GGT Bilirubin Albumin Prothrombin time (PT)
What are the causes of an isolated rise in ALP?
- Bony metastases/ primary bone tumours eg. sarcoma
- Vitamin D deficiency
- Recent bone fracture
- Renal bone disease (CKD)
If a patient has dark urine and normal stools, what does this suggest about the cause of jaundice?
Hepatic jaundice
If a patient has dark urine and pale stools, what does this suggest about the cause of jaundice?
Post hepatic jaundice (obstructive)
What can cause LOW albumin levels?
- Liver disease
- Inflammation-> acute phase response
- Loss of albumin- nephrotic syndrome
If ALT>AST what does this sugguest?
Chronic liver disease
NAFLD
Drug/ viral hepatitis
If AST> ALT what does this suggest?
Alcoholic hepatitis
Cirrhosis
Cancer
What are common causes of ACUTE hepatocellular injury?
- Poisoning eg. paracetamol overdose
- Hepatitis A and B
- Liver ischemia
What are common causes of CHRONIC hepatocellular injury?
- Alcoholic fatty liver disease
- Non alcoholic fatty liver disease
- Chronic infection (Hepatitis B or C)
- Primary biliary cirrhosis
What are LESS common causes of CHRONIC hepatocellular injury?
- Alpha 1 antitrypsin deficiency
- Wilson’s disease
- Haemochromatosis
What does a typical liver screen involve?
- LFTs
- Coagulation screen
- Viruses- Hepatitis A/B/C, EBV, CMV
- Autoantibodies: AMA, pANCA, ANA, ASMA
- Immunoglobulins: IgM and IgG
- Alpha-1 antitrypsin
- Copper (Wilson’s disease)
- Ferritin (Haemochromatosis)
What blood tests will be done if a patient is confused (confusion screen)?
- FBC (WCC for infection)
- CRP
- U&Es (Uraemia/ hyponatraemia)
- Bone profile (hypercalcaemia/ hypocalcaemia)
- B12 and folate (deficiency)
- TFTs (hypothyroid)
- Glucose (hypogylcaemia)
- LFTs (hepatic encephalopathy)
- Coagulation/ INR
What clinical observations may suggest anaemia due to active bleeding?
Hypotension
Tachycardia
What lab tests should be done to investigate anaemia?
- FBC
- TFTs (hypothyroidism can cause macrocytic anaemia)
- U&Es (CKD can cause anaemia)
- Haematinics: B12, folate, ferritin, iron, TIBC
What blood tests should be done to investigate hyponatraemia?
- U&Es: asses degree of hyponatraemia/ renal function
- Serum/ urine osmolality
- TFTs (hypothyroidism can cause hyponatraemia)
- Serum cortisol (Addison’s)
What lab tests are done in a myeloma screen?
- FBC (anaemia/ neutropenia/ thrombocytopenia)
- U&Es (raised creatinine/ hypercalcaemia)
- ESR (raised)
- Blood film (RBCs stacked ontop of each other)
- Blood and urine protein electrophoresis (paraprotein band)
- Immunoglobulin measurement
- Bone marrow biopsy (increased number of plasma cells)
What imaging is done to screen for myeloma?
Xrays
MRI
look for lytic lesions of skull, axial skeleton, proximal long bones
What is the NORMAL appearance of CSF?
Clear
Colourless
What is a NORMAL CSF WBC count?
0-5cells/uL
NO neutrophils, only lymphocytes
What is a NORMAL CSF opening pressure?
10-20 cm H2O
What is the NORMAL glucose level in CSF?
2.8-4.2 mmol/l