Endocrinology Flashcards
(47 cards)
What is the pathophysiology of DKA
There is excessive glucose but cannot be taken up by the cells due to a lack of insulin
so the body metabolises proteins and fats into ketones for energy.
Ketones then cause a metabolic acidosis due to an excessive concentration of ketone anions in the blood
How may DKA present?
Gradual drowsiness vomiting and dehydration Polyuria Polydipsia Lethargy Anorexia non-specific abdominal pain Ketotic breath Coma Deep breathing - Kussmaul breathing
What are the triggers for DKA
Infection MI Pancreatitis Chemo antipsychotics Non-compliance Wrong Insulin dose
What are the three criteria needed for diagnosis of DKA
- Acidaemia (pH<7.3)
- Hyperglycemia
- Ketonaemia
What investigations are done in suspected DKA?
Bedside: Capillary blood glucose, urine dipstick, ECG
Bloods: blood glucose, FBC, U+Es, amylase, blood culture (if signs of infection), ketones
Imaging: CXR (may be considered)
ABG - for anion gap and pH
What type of anion gap will someone with DKA have?
High anion gap
How is the anion gap calculated?
(Na + K) - (Cl + HCO3)
shows if acidosis is metabolic
When would a patient with DKA be transferred to ICU?
high blood ketones low bicarb a pH lower than 7.1 Potassium lower than 3.5 GCS <12 Sats <92 Systolic <90 Tachy or Brady Anion gap above 36
Why may potassium drop when insulin is given?
because insulin forces potassium back in the cells by increasing the sodium-potassium channel activity, therefore there is less within the blood causing hypokalaemia
When can ketonuria also occur?
After an overnight fast
Alcohol (if glucose is normal)
how is DKA managed?
if BP is low - 500ml bolus
Find out blood gases for pH, keones, glucose, bicarb, U+Es
50units of actrarapid into 49.5ml of 0.9% saline. Infuse at 0.1unit/kg/hr
Stat dose if infusion is delayed
Assess need for potassium replacement (if potassium falls below 5.5)
Catheterise
Consider NG tube if vomiting or drowsy
What should be considered once insulin is being administered
Glucose level AVOID HYPOGLYCAEMIA once glucose drops below 14, start 10% glucose at 125ml/hr Potassium level 3.5-5.5 - Add 40mmol per litre of fluid <3,5 - Seek help from HDU/ICU
What is the typical fluid deficit in DKA?
100ml/kg
What are the complications of DKA?
Cerebral oedema (if sudden CNS decline get help) - if fluid and insulin given rapidly
Aspiration Pneumonia (drowsy/unconscious and vomiting)
Hypokalaemia - if potassium not replaced once insulin is given
Hypomagnesaemia
Hypophophataemia
Thromboembolism
Why is cerebral oedema a complication of DKA?
The high glucose content of the blood causes fluid to move from ICF to ECF therefore the cells in the brain shrink. If insulin and fluid is given to a patient in DKA too rapidly it cause a rapid reversal of osmolarity and fluid moves into the cells and causes cerebral oedema,
How does a hypoglycaemia present?
Rapid onset
Autonomic - sweating. anxiety, hunger, tremor, palpitations, dizziness
Neuroglycopenic - confusion, drowsiness, visual trouble, seizures, coma
What are the causes of hypoglycaemia?
EXPLAIN
Ex ogenous drugs e.g. insulin, oral hypoglycaemics, alcohol (binge without food) and aspirin poisoning
P ituitary insufficiency
L iver failure
A ddisons disease
I slet cell tumours
N on pancreatic neoplasms, e.g. fibrosarcomas
How is hypoglycaemia investigated?
BM
Bloods: glucose, FBC, U+Es, cortisol, insulin, c-peptide, plasma ketones
Drug history
What are the causes of hypoglycaemic hyperinsulinaemia?
Sulfonylureas, insulinoma, insulin injection (no detectable C peptide - only released with endogenous insulin)
If the insulin is low and the plasma ketones are increased what are the differentials
Addisons disease
Pituitary insufficiency
Alcohol
How is a hypoglycaemic episode treated?
Oral sugar and long acting starch
If cannot swallow - 25-50ml 50% glucose with 0.9%saline flush
Glucagon 1mg IM if not IV access (repeat after 20mins and follow with oral carb)
What is Cushings Syndrome
Chronic state caused by excess glucocorticoids and loss of normal feedback mechanisms of HPA axis
exogenous - oral steroids
endogenous - increased secretion of cortisol (very rare)
How is cortisol excreted
in the urine
What are the causes of Cushings DISEASE?
ACTH secreting pituitary adenoma causing bilateral adrenal hyperplasia
A low dose dexamethasone test leads to no change in cortisol but 8mg may be enough to halve morning cortisol
