Data interpretation trickery Flashcards
How do you narrow the differentials of low Hb?
Look at the mean cell volume (micro vs macro)
Whats the first rule of assessing hyponatreamia?
Look at the patients fluid status
- Hypovolaemic
- Euvolaemic
- Hypervolaemic
What are the causes of hypernatraemia?
Four D’s
- Dehydration
- Drips (too much IV saline)
- Drugs
- Diabetes insipidus (opposite of SIADH)
What are the causes of a microcytic anaemia?
1* - Iron deficiency
- Thalassemia
- Sideroblastic anaemia
What are the causes of normocytic anaemia?
- Anaemia of chronic disease
- Acute blood loss
- Heamolytic anaemia
- Renal failure (Chronic)
What are the causes of macrocytic anaemia?
B12/folate deficiency
Excess alcohol
Liver disease
Hypothryroidism
Heamotological disease i.e Myeloproliferative, myelodysplastic, multiple myeloma
What causes a neutrophilia?
High neutrophils:
- Bacterial infection
- Tissue damage i.e inflammation, infarction, malignancy
- STEROIDS
What can cause a neutropenia?
Low Neutrophils
- Viral infection
- Chemo or radiotherapy
- CLOZAPINE (Antipsych)
- CARBIMAZOLE (Antithyroid)
What causes lymphocytosis?
- Viral infection
- Lymphoma
- Chronic lymphocytic leukemia
What can cause a thrombocytopenia?
Think mechanism
Low platelets
Reduced production
- infection (usually viral)
- Drugs (i.e pinacliinamine in rheumatoid tx)
- Myelodysplasia, myelofibrosis, myeloma
Increased destruction:
- Heparin
- Hypersplenism
- DIC
- idiopathic thrombocytopenic purpura
- Heamolytic uraemic syndrome
What causes high platelets?
Reactive:
- Bleeding
- Tissue damage (infection/inflammation/malignancy)
- Post splenectomy
Primary
- Myeloproliferative disorders
What causes SIADH?
S - Small cell lung cancer
I - Infection
A - Abscess
D - Drugs i.e carbamazepine and antipsychotics
H - Head injury
What are the causes of hypovolaemic hyponatraemia?
Hypovolaemic:
- Fluid loss (D+V)
- Addisons
- Diuretics (any type)
What are the causes of euvolaemic hyponatraemia?
- SIADH
- Psychogenic polydypsia
- Hypothyroidism
What causes hypokalemia?
DIRE
D - Drugs (loop and thiazide diuretics)
I - Inadequate intake or intestinal loss (D+V)
R - Renal tubular acidosis
E - Endocrine (cushings and crohns disease)
What are the causes of hypervolaemic hyponatraemia?
- Heart failure
- Renal failure
- Thyroid failure
- Hypoalbuminaemia caused by
-> Liver failure
-> Nutritional failure
What causes hyperkalaemia?
DREAD
D - Drugs )K sparring diuretics and ACE-inhibitors)
R - Renal failure
E - Endocrine (addisons disease)
A - Artefact (clotting)
D - DKA
What does a raised urea indicate?
Kidney injury or upper GI bleed
Whats the biochemical disturbance pattern of a pre-renal AKI?
UREA»_space; Creatinine rise
i.e Urea 19mmol (3.5-7.5) and creatinine 110 (35-125)
What are the causes of pre-renal AKI?
- Dehydration (or severe shock) -> sepsis, blood loss etc
- Renal artery stenosis (which when combined with ACEi or NSAIDS results in AKI)
What is the biochemical patter of an intrinsic renal AKI?
Urea «_space;creatinine
Bladder or hydronephroses NOT palpable.
What are the causes of intrinsic AKI?
INTRINSIC
I - Ischemia -> Acute tubular necrosis
N - Nephrotoxic Abx
R - Rad contrast
I - Injury - rabdo
N - Gout crystals
S - Syndromes
I - Inflam i.e vasculitis
C - Cholsterol emboli
What are the common nephrotoxic drugs?
Gentamicin, vancomycin, tetracyclines
What are the comon post renal AKI biochemical pictures?
Urea «_space;Creatinine
Bladder or hydronephroses may be palpable
What are the common causes of post renal AKI?
Lumen: Stone
Wall: Tumor, fibrosis
External: BPH, Aneurysm
What are the markers you look for in hepatocellular injury or cholestasis:
- BIlirubin
- ALT, AST
- ALP and CGT
What are the synthetic markers of liver function?
- Albumin
- Vit K proteins Clotting factors 2,7,9,10 via PT and INR
What can cause a raised ALP?
ALPKPHOS
A - Any #
L - Liver damage (post hep)
K - K for cancer
P - Pagets disease and pregnancy
H - Hyperparathyroidism
O - Osteomalacia
S - Surgery
What marker do you get for prehapatic damage and what are the causes?
Isoalted raised bilirubin
- Heamolysis
What pattern of injury is there for an intrahepatic injury?
- Increased bilirubin
- Increased AST and ALT
Two T’s for inTTrahepatic
What are the common causes of intrahepatic injury?
- Fatty liver
- Hepatitis (alc, virus, drugs; para, statins, rifampacin and autoimmune)
- Cirrhosis
- Malignancy
- Metabolic (wilsons, heamochromatosis)
- HF with hepatic congestion
What is the biochemical pattern of posthepatic injury?
- Raised bilirubin
- Increased ALP and CGT
What are the common causes of post hepatic injury?
Lumen:
- Stones
- Drugs causing cholestasis
Wall
- Cholangiocarcinoma
- 1* biliary cirrhosis
- Sclerosing cholangitis
Extrensic pressure
- Pancreatic or gastric cancer, lymph node
What drugs can cause cholestasis?
- Flucloxacillin
- Co-amoxiclav
- Nitrofurantoin
- Steroids
- Sulphonylureas
Whats the rule of thumb for changing levothyroxine?
- Unless grossly hypo/hyperthyroidism, change by the smallest increment
What are the causes of primary hypothyroidism? Biochemical pattern?
Dec: T4
Inc: TSH
- Hashimotos thyroiditis
- Drug induced hypothyroidism
What are the causes of secondary hypothyroidism? Whats the biochemical pattern?
Dec: T4 and TSH
- Pituitary damage or tumour
What are the causes of primary hyperthyroidism? Biochemical pattern?
Increased T4 and decreased TSH
- Graves
- Toxic nodular goiter
- Drug induced hyperthyroidism
Whats the pattern of secondary hyperthyroidism?
Increased TSH and T4.
Causes
- Pituitary tumor
Describe the range of TSH values and how you would change levothyroxine:
TSH:
<0.5 - Decrease dose
0.5-5 - Increase dose
5+ Increase dose
