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