Data Interpretation Flashcards
causes ↓ Na+?
↓ VOL
Fluid loss (D+V)
Addison’s disease
Diuretics (any)
✓ VOL
SIADH
Psychogenic polydipsia
Hypothyroidism
↑ VOL HF RF LF (causing hypoalbuminaemia) Nutritional failure (causing hypo-A-) Thyroid failure (↓thyroidism; can be ✓volaemic too)
causes SIADH
SIADH:
Small cell lung tumours
Infection
Abscess
Drugs (carbamazepine and antipsychotics) Head injury
causes ↑ Na+?
all begin with ‘d’:
- dehydration
- drips (i.e. too much IV saline)
- drugs (e.g. effervescent tablet preparations or IV preparations with a high Na+ content)
- diabetes insipidus (effectively opposite to SIADH)
causes anaemia with low MCV?
Iron deficiency anaemia
Thalassaemia
Sideroblastic anaemia
causes anaemia with normal MCV?
Anaemia of chronic disease
Acute blood loss
Haemolytic anaemia
Renal failure (chronic)
causes anaemia with high MCV?
B12/folate deficiency (‘megaloblastic anaemia’) (incl. pernicious anaemia B12)
Excess alcohol
Liver disease (including nonalcoholic causes)
Hypothyroidism
Haematological diseases beginning with ‘M’: 1) myeloproliferative
2) myelodysplastic
3) multiple myeloma
causes ↓ K+?
DIRE
- Drugs (loop + thiazide diuretics)
- Inadequate intake/intestinal loss (D+V)
- Renal tubular acidosis
- Endocrine (Cushing’s + Conn’s syndromes)
↑ K+?
DREAD
- Drugs (K+ sparing diuretics and ACEi)
- Renal failure
- Endocrine (Addison’s)
- Artefact (very common, due to clotted sample)
- DKA (NB when insulin is given the K+ drops requiring regular (hourly) monitoring +/− replacement)
causes ↑ neutrophils?
neutrophilia
Bacterial infection
Tissue damage (inflammation/infarct/ malignancy)
Steroids
causes ↓ neutrophils?
neutropenia
Viral infection
Chemotherapy or radiotherapy*
Clozapine (antipsychotic)
Carbimazole (antithyroid)
*Patients undergoing chemo or radiotherapy may become neutropenic (or even pancytopenic) in response to infection (‘neutropenic sepsis’). This carries a much higher mortality rate so they must be given urgent IV broad-spectrum Abx (the choice is hospital specific).
causes ↑ lymphocytes?
lymphocytosis
Viral infection
Lymphoma
CLL (chronic lymphocytic leukaemia)
causes ↓ platelets?
thrombocytopenia
↓ production:
- infection (viral)
- drugs (PENICILLAMINE in RA)
- the 3 myelo- s
↑ destruction:
- HEPARIN
- ↑ splenism
- DIC
- ITP
- HUS/TTP
causes ↑ platelets?
thrombocytosis
reactive:
- bleeding
- tissue damage
- post-splenectomy
primary:
- myelo- disorders
causes prerenal AKI?
70%
Urea rise > creatinine rise
e.g.: Urea 19 (3–7.5 mmol/L) Creatinine 110 (35–125 μmol/L)
- Dehydration (or if severe, shock) of any cause, e.g. sepsis, blood loss
- Renal artery stenosis (AKI in RAS often triggered by ACEI or NSAIDs) and effectively causes ↓ perfusion of the kidneys and prerenal picture
Nb: the creatinine can rise with severe prerenal AKI; to differentiate this from intrinsic and obstructive AKI, multiply the urea by 10; if it exceeds the creatinine (showing a relatively greater increase in urea compared to creatinine) then this suggests a prerenal aetiology
causes postrenal AKI?
(20%)
(obstructive)
Urea rise < creatinine rise
(Ex - bladder or hydronephrosis PALPABLE depending on level of obstruction)
e.g.: Urea 9 (3–7.5 mmol/L) Creatinine 342 (35–125 μmol/L)
- in lumen: stone or sloughed papilla
- in wall: tumour (renal cell, transitional cell), fibrosis
- external pressure: BPH, prostate CA, lymphadenopathy, aneurysm
causes intrinsic renal AKI?
10%
Urea rise < creatinine rise
(Ex: bladder or hydronephrosis NOT palpable)
e.g.: Urea 9 (3–7.5 mmol/L) Creatinine 342 (35–125 μmol/L)
“INTRINSIC”:
- Ischaemia (due to prenal AKI, causing acute tubular necrosis)
- Nephrotoxic antibiotics**
- Tablets (ACEI, NSAIDs)
- Radiological contrast
- Injury (rhabdomyolysis)
- Negatively birefringent crystals (gout)
- Syndromes (glomerulonephridites)
- Inflammation (vasculitis)
- Cholesterol emboli
What are the especially nephrotoxic Abx?
can cause intrinsic AKI
gentamicin
vancomycin
tetracyclines
what can cause ↑ urea?
- kidney injury
- upper GI haemorrhage
usually indicates RF, however, because it is a breakdown product of amino acids, it can also reflect an upper GI bleed
where haemoglobin has been broken down by gastric acid into urea, which is subsequently absorbed into the blood
Ix to do if ↑ urea with normal creatinine?
patient who is not dehydrated/have prerenal failure
look at Hb
if ↓
probably upper GI bleed
liver markers of: hepatocyte injury or cholestasis?
bilirubin
ALT (+AST)
ALP
markers of liver’s synthetic function?
- albumin
- vitamin K-dependent clotting factors (II, VII, IX and X) measured via PT/INR
what does a solitary ↑ bilirubin indicate?
(PREhepatic jaundice)
- haemolysis
- Gilbert’s and Crigler-Najjar syndromes
↑ ALP causes?
“ALKPPHOS”
A ny fracture L iver damage (posthepatic) K (Kancer) P aget's disease P regnancy H ↑parathyroid O steomalacia S urgery
↑ bilirubin and ↑ AST/ALT?
INTRAhepatic issue
- fatty liver
- hepatitis + cirrhosis (alcohol, hep A-E, CMV, EBV, AI/PBC/ASC)
(lalso DRUGS - paracetamol, statins, rifampicin) - malignancy
- Wilsons, haemo
- HF (congestion)
↑ bilirubin and ↑ ALP?
POSThepatic issue
- gallstone
- DRUGS: (5)
- cholangioCA
- PBC, PSC
- pressure (pancreatic/gastric CA or lymph node)
drugs that can cause obstructive (POSThepatic) jaundice?
↑ bili and ↑ ALP
1) flucloxacillin
2) co-amoxiclav
3) nitrofurantoin
4) steroids
5) sulphonylureas
what is ↓ T4 and ↑ TSH?
describe thyroid feedback loop?
1’ hypothyroidism
(↓ T4 from thyroid causes compensatory TSH)
- Hashimoto’s
- drug-induced
hypo releases TRH
pituitary releases TSH
thyroid releases T3 + T4
these -ve feedback on hypo and pituitary
what is ↓ T4 and TSH?
2’ hypothyroidism
(↓ TSH from pituitary causing ↓ T4)
- pituitary tumour or damage
what is ↑ T4 and ↓ TSH?
1' hyperthyroidism (T4 from thyroid causes ↓ TSH via negative feedback) - Grave's - toxic nodular goitre - drug-induced
what is ↑ T4 and ↑ TSH?
2’ hyperthyroidism
(↑ TSH from pituitary causing ↑T4)
- pituitary tumour
if asked to change levothyroxine dose according to TFT results, which to look at?
1) when to ↓ dose?
2) when to keep dose?
3) when to ↑ dose?
TSH
- < 0.5
- 0.5-5
- > 5
(bc ↑ TSH levels indicate ↓ T4 levels)
usual projection of CXR so that heart is normal sized?
PA
reading a CXR?
A
● trachea should be central (if not collapse -i.e. towards affected side, or pneumothorax - i.e. away from affected side)
● mediastinum - widened (R upper lobe collapse w/ tracheal deviation)
or aortic dissection (w/t tracheal deviation)
B
● white area= effusion (seen as unilateral and solid)
● pneumonia (seen as unilateral and fluffy)
● oedema (seen as bilateral and fluffy)
● fibrosis (seen as bilateral and honeycomb)
● apices (TB / an apical tumour)
C
● heart should be < 50% width of lungs (PA) (>50 = cardiomegaly)
● triangle behind the heart (i.e. sail sign) - left lower lobe collapse
D
● costophrenic angles (pleural effusion)
● air under R hemidiaphragm (bowel perforation / recent surgery
● (under the L side is gastric air bubble - normal)
E
● bones (rib fractures/lytic lesions usually suggesting mets)
signs of pulmonary oedema on CXR?
“ABCDE”
● Alveolar oedema (bat wings) ● Kerley B lines (interstitial oedema) ● Cardiomegaly ● Diversion of blood to upper lobes (where vessels in upper zone are larger than in lower zone) ● Effusions (pleural)
how to approach ABGs?
● look at O2 (Nb: pt on 60% O2 you would expect PaO2 to be 10 less, i.e > 50kPa) ● look if RF (<8 kPa) type II if ↑ CO2 (COPD) ● check pH (abnormal CO2 = respiratory) (abnormal HCO3- = metabolic) (abnormal both = mixed picture)
causes of resp alkalosis?
rapid breathing
SOB or anxiety
causes of resp acidosis?
COPD
NM failure
restrictive chest wall
(same as type II )RF
causes of metabolic alkalosis?
V
diuretics
Conn’s syndrome (↑ aldosterone therefore ↑ Na+ and ↓ K+)
causes of metabolic acidosis?
lactic acidosis
DKA
renal failure
ethanol/methanol/ethylene glycol intox
what is the PR interval?
beginning of P wave to beginning of QRS
what is ST interval?
end of QRS to end of T wave
what is QT interval?
beginning of QRS to end of T wave
what causes the 1st deflection of QRS to look like:
“W” in V1
“M” in V6
?
“W” i LL ia “M”
LL
left BBB
whats causes 1st deflection of QRS to look like:
“M” in V1
“W” in V6
?
M o RR o W
RR
right BBB
how to approach ECGs?
● rate (300/ large squares between each QRS)
● rhythm (P waves = sinus) (PR interval and QRS indicate heart block or AF)
● QRS complex
(>3 small sq = BBB)
(if V1 height + V6 height = >3.5 large sq = LVH)
● ST segment
(elevated = infarction)
(convex = pericarditis)
(depressed = ischaemia)
(downsloping in all = DIGOXIN)
● T waves
(if >2/3 QRS height throughout, ↑ K+)
(inversion = old infarction/LVH - unless in aVR and I)
PR interval >1 large square but constant =?
1st degree heart block
PR interval increasing, then missed = ?
2nd degree heart block
type 1
two or three P-waves for every QRS?
2nd degree heart block
type 2
random (no relationship between P wave and QRS complex?
3rd degree heart block
complete heart block
if no P-waves (and irregular QRS complexes) then it is?
AF
if T waves are “tented” (> 2/3 of the QRS height) throughout the ECG?
↑ K+
