DKA Flashcards
DKA
disordered metabolic state that usually occurs in the context of an absolute or relative insulin deficiency accompanied by an increase in the counter-regulatory hormones
ketone bodies
found in the liver mitochondria, are derived from acetyl CoA, which is from ß oxidation of fats
they diffuse into the blood stream and peripheral tissues
under what conditions are ketones formed
no glucose in the tissues - starvation and diabetes
this is because oxaloacetate will not be available for the conversion of acetyl CoA to citric acid
FFA are released from tissues by lipolysis and converted to ketone bodies by ß oxidation
what can high levels of ketones lead to
acidosis
what symptoms does high glucose excretion cause
osmotic diuresis - dehydration - polyuria, polydipsia
when is DKA a danger in T1DM
insulin supplementation missed
biochemical diagnosis of DKA
ketosis - ketonaemia >3mmol/L or significant ketonuria (>2 positives on standard urine stick)
diabetes - BG > 11.1 mmol/L or known diabetes
acidosis - bicarbonate <15 mmol/L or venous pH < 7.3
what are some common precipitants of DKA
infection
illicit drugs and alcohol
non adherence with treatment - not enough insulin
newly diagnosed diabetes
steroids
pancreatitis
how can steroids precipitate DKA
they can induce hyperglycaemia
therefore insulin dose should be increased during steroid treatment
associated conditions
underlying sepsis and gastroenteritis
CF
osmotic related - dehydration: thirst and polyuria
ketone body related - flushing, vomiting, abdominal pain and tenderness, breathlessness (Kussmauls respiration)
NB cannot smell ketones (pear drops) on all patients breath
investigations
ECG, CXR
urine: dipstick and MSU
blood: capillary and lab glucose, ketones, U&Es, amylase, osmolality, ABG, FBC, blood culture
classically, glucose at presentation
median level aroud 40mmol/L, from 10 - 100
euglycamia ketosis is possible
classically, potassium at presentation
>5.5mmol/L
beware of the low normal
classically, creatinine and lactate on presentation
creatinine raised
raised lactate common
sodium levels
- normal presentation
- what does inc/normal Sodium indicate
hyponatraemia is common, hyperglycaemia increases serum osmolality (in blood), resulting in movement of water out of cells and subsequently reduction in Sodium levels by dilution
increased or normal Sodium indicates severe dehydration (water loss)
as treatment commences, Sodium concentration will rise as water enters cells
blood ketones on presentation
>3 mmol/L
ßhydroxybutyrate is the ketone measured in the blood
acetoacetate is measured in the urine
bicarbonate, amylase and WCC on presentation
HCO3: <10
amylase frequently raised - pancreatitis or just salivary in origin
WCC - median around 25, doesnt always infer infection
causes of death from DKA
adults: hypokalaemia, aspiration pneumonia, ARDS and co-morbidities
children: cerebral oedema
inital managment of DKA in HDU
saline or fluids replaced within 30 min with 0.9% saline
tests: venous blood gas for pH, bicarbonate and lab glucose, ketones, U&Es (for Potassium and Sodium) as minimum
insulin within an hour
watch K and replace aggressively to prevent hypokalaemia and cardiac arrest
check U&Es and lab glucose every 2 hours initially
consider catheter if not passed urine by 1 hour. consider NG tube if vomiting or drowsy
prescibe LMWH to all patients
avoid hypoglycaemia (when glucose is <14mmol/L start 10% glucose alongside saline)
why must LMWH be prescribed
risk of thromboembolism
what does insulin do to K+
drives K into cells so levels can drop suddenly
this can drive the patient into cardiac arrhythmia, check wtih ECG
after losses have been replaced in HDU, what is done
follow up: screen eyes, check feet and check urine albumin and bicarbonate
blood ketone testing
ßhydroxybutyrate
<0.6 mmol/L is normal
optimum meter
