Metabolic Medicine Flashcards
(52 cards)
What are some causes of hyperkalemia?
acute kidney injury
drugs*: potassium sparing diuretics, ACE inhibitors, angiotensin 2 receptor blockers, spironolactone, ciclosporin, heparin**
metabolic acidosis
Addison’s disease
rhabdomyolysis
massive blood transfusion
What would you expect the K+ to be in DKA?
Low due to total body loss
When is hyponatraemia considered chronic?
> 48 hours
or
duration of symptoms are not known
What is the serious potential consequence of osmotic demyelination?
Locked in syndrome
How is Hyponatremia treated?
Mild cases/ usually associated with edematous fluid:
- fluid restriction
- diuretics - furosemide
Hypovolaemic
- 0.9% saline
Severe:
- hypertonic saline
SIADH:
- fluid restriction
- Saline
- Tolvaptan - ADH receptor antagonist
when should calcium gluconate be given?
K+ >6.5
or ECG changes
What is the maximum rate K+Cl can be infused at?
20mmol/Hour
or
Max concentration of: 40mmol/L
List come causes of SIADH:
Small cell lung cancer
Subarachnoid bleed
Mycoplasma pneumonia
Meningitis
Drugs
- carbamazepine
- SSRI
Surgery
What are the symptoms of SIADH?
lethargy
headaches
dizziness
Postural Hypotension
ataxia
confusion
Seizures
Coma
How is hypernatremia investigated and treated?
Fluid status
Serum osmolality
Urine Na2+/ osmolarity
Treatment:
Acute - Dextrose 5%
Chronic: slow adjustment <10mmol daily
- fluids
Dehydration
- 0.9% saline
What are some etiologies for diabetes insipidus?
Cranial:
- x-linked condition
- Idiopathic (typically autoimmune)
- Head injury
- Craniopharyngioma
- Infection
- surgical
Nephrogenic:
- Drugs - lithium
- Receptor defect
- Hypercalcaemia
What is the diagnostic investigation into Diabetes insipidus?
Water deprivation test / Desmopressin Stimulation test
Urine osmolarity measured
If someone had hypernatremia and underwent investigations into diabetes insipidus, and their results turned out to be primary polydipsia what would you expect the urine osmolality results to be?
Pre- desmopressin
- high osmolality (trying to reabsorb water)
Post desmopressin
- High osmolality (still trying to reabsorb water)
What things may give an artificially high K+ readying?
Contamination of K from EDTA tubes
- U&Es should be done first
Thrombocythemia
- K+ leaks out as the platelets try to clot
Delayed analysis
- K+ leaks out as cell decay
Poor venipuncture
How should severe hyponatremia be treated?
slow infusion of IV saline if >48 hours
Infusion of IV saline if <48 hours
What is the effect of hypokalemia on the heart?
Increased ventricular ectopics leadign to:
- VT
- VF
- Torsade de point
- decreases repolarisation inducing Early- after depolarisations
- increase ventricular rate
U waves are seen
What is considered severe hypokalemia?
<2.5mmol
What drug can hypokalemia induce severe toxicity in?
Digoxin
What “malignancy” investigations should be done into hypercalcemia?
FBC
- Anaemia
Imaging
- Bone scan
- CXR
- Neck US
Electrophoresis
- myeloma
Alkaline Phosphatase
- Bone mets
What is the management for severe Hypercalcaemia and what daily monitoring should be done?
Dehydration Furosemide Bisphosphonates - Zoledronic acid \+/- Steroids (myeloma, sarcoidosis)
Daily Monitoring:
- Ca2+
- U&Es
- Mg2+
Which drugs cause SIADH?
Cant Concentrate Serum Sodium
- carbamazepine
- cyclophosphamide
- SSRIs
What is first line treatment for hypercalcaemia?
IV fluid
In dehydration what would you expect the haematocrit and serum haemoglobin to be?
Slightly raised
- relative polycythemia
Which commonly used antithrombotic drug can cause a rise in K+?
Heparin
