Key facts:
Authors: Kate Outterside, Sailesh Sankar, Ateeq Syed
Top Tip: Give a lot of fluids, but don't cause cerebral oedema
Key Differential Diagnoses
- HONK
- Hyperglycaemia + other causes of metabolic acidosis (eg lactic)
- Hyperglycaemia + other causes of drowsiness
Key Investigations
- Glucose (BM) + Capillary Blood Test for ketones
- FBC, ESR, CRP
- U+E, LFT, Bone, Glucose, HbA1C ± Troponin T
- ECG, CXR
- ABG, BC
- Urinalysis (ketones?) ± MSU
Key Treatment
- INSULIN (ACTRAPID, 50 units in 50 mls N saline), start infusion at 0.1 units/kg/hr
- SC ENOXAPARIN 40 mg od
- IV + FLUIDS + K
Key Management Decision
- ITU
Background
80-90% patients are already known to have DM1; for the rest, it may the the first presentation
Introduction
- DKA is one of the most important acute complications of DM (mainly Type 1; occasionally Type 2) and can be the first presentation of Type 1 DM (10-20%); ie more usually patient is known to have Type 1
- Blood glucose does not have to be high (ie euglycaemic DKA can occur)
- Diagnosis requires ketosis and acidosis. To establish a diagnosis, you need to demonstrate: glucose >11.1, ketonuria 2+, pH <7.3, and HCO3 <15
- But, milder metabolic disturbance may be present 'on the way' to 'full DKA'
- Either way, patients are water, sodium and potassium depleted; and acidotic. It can present over hours, though more usually 1-3 days
- Aim for gradual fall in glucose
- Watch out for cerebral oedema esp in pts <30y, with Na that fails to rise with rehydration
- Prognosis: with modern fluid management, mortality rate is about 2%. Before the discovery of insulin in 1922, the mortality rate was 100%
- People with diabetes also have CVAs, take overdoses and have head injuries
Pathophysiology
Definition
- (Ketoacidotic) hyperglycemia, that mainly occurs in Type 1 DM
Aetiology
- 1st presentation of Type 1 DM (10-20%)
- Genetic
- Autoimmune
Precipitants
- Infection
- Surgery
- MI
- Pancreatitis
- Non-compliance
Symptoms
- Polyuria/polydipsia
- Weight loss
- Vomiting/abdominal pain (can present as 'acute abdomen')
- Genital candida
- Visual blurring
- Confusion
Key Questions
- "Have you stopped taking/changed your insulin recently?"
- "Have you had an infection recently?"
Signs
- Fever, dehydration (low BP, tachycardic?)
- Smell of ketosis on breath
- Hyperventilation (Kussmaul's breathing; appears as SOB)
- Genital candida
- Reduced level of consciousness
Investigation
Note: patients with Type 2 DM can also have DKA; ketonuria does not equate with ketosis
Blood
- Glucose (BM) + Capillary Blood Test for ketones (separate ketone test strip)
- FBC (WC can be raised in absence infection), ESR, CRP
- U+E, LFT, Bone, Glucose
Note: glucose usually > 11 mmol/L; but DKA can occur with glucose <10 mmol/L; euglycaemic DKA can even occur - HbA1C, Troponin T (myocardial infarction can precipitate DKA)
- Consider BHCG in women
- BC
- Amylase
Note: pancreatitis can precipitate DKA but amylase can be raised in the absence of pancreatitis (salivary origin?) - ABG (need to make diagnosis; to make diagnosis pH <7.3 ± serum bicarbonate <15 mmol/L)
Note: serial blood gases can be venous blood
Other
- Urinalysis: ketones?; these are notoriously unreliable, with a significant false positive rate; ie there are a lot of old/frail patients with DM, who come in with ketonuria 1+ or 2+ who do not have DKA
Note: ketonuria does not equate with ketoacidosis - ± MSU (infection?)
- ECG (silent MI?; if abnormal, do Troponin T)
- CXR (infection?)
Key Investigations
- Glucose
- Urinalysis
- ABG
- To establish a diagnosis: Glucose >11.1, Ketonuria 2+, pH <7.3, HCO3 <15
Differential Diagnoses
- HONK
- Hyperglycaemia + other causes of metabolic acidosis (eg lactic, salicylate OD)
- Hyperglycaemia + other causes of drowsiness
Treatment
Principles: replace fluid, correct electrolytes, give insulin, look for+Rx infection
Treatment (first line)
Drugs
- INSULIN (ACTRAPID, 50 units in 50 mls N saline)
Start infusion at 0.1 units/kg/hr = 7 units/hr for 70kg person
Blood gluc (mmol/L) Insulin infusion (units/h)
0-4.0 0.5
4.1-7 1
7.1-10 2
10.1-12 3
12.1-16 4
>16.1 6
Measure BM hourly and titrate insulin accordingly
Note: aim for fall in glucose > 3mmol/L/h; and, do not stop insulin infusion, until SC insulin re-established
Note: if on basal bolus regime, continue basal long acting insulin (such as glargine); if patient on an insulin pump, contact diabetologist - SC ENOXAPARIN 40 mg od
- ± BROAD SPECTRUM AB (according to local policy), if infected
Procedures
- BM (hourly), VBG hourly until normal then 2 hrly, lab bloods twice daily, K 2-4 hrly
- NG tube, if drowsy (prevent aspiration)
- IV + FLUIDS + K (N Saline ± K; until BG < 15, then use 5% dextrose)
- 1L in 30 mins; 1L in 1h; 1L in 2h; then 4 hourly until rehydrated (aim approx 8-10L over 48h); keep IV fluids going whilst on insulin infusion
Serum K K added to each litre
<3.5 40 mmol
<3.5-5.0 20 mmol
<5.0, or anuric No supplements
Note: aim to replace approx 8-10L in 48h (less in elderly, or patients with CCF)
Key management decision
- ITU/not
Treatment
(second line)
Drugs
- If cerebral oedema, IV MANNITOL 0.25-2 g over 30-60 mins (usually 100 mls 20%), if cerebral oedema; repeated 1-2x after 4-8 hrs
Procedures
- If hypotensive, start with IV colloids
If unwell, urinary catheter, CVP, arterial line
Prescribing issues
- Keep IV going whilst on insulin infusion
Admit?
- Always
Bed plan
- Medical admission ward
- ± Endocrine
- ± ITU
Referrals
Medical
- Endocrine
- ± ITU
Other
- Hospital DM nurse ± Community DM nurse)
The Rest
Community follow-up is important: ring GP or community DM nurse, or both
Complications
- Of infection
- Hypoglycaemia (over-zealous use insulin)
- Hypokalaemia (insulin causes shift of K into cells)
- Cerebral oedema (especially children; Rx mannitol/dexamethasone)
- Phosphate/magnesium may decrease
- Thromboembolism
Follow-up
- Hospital DM nurse ± Community DM nurse + GP
Prognosis
- With modern fluid management, mortality rate is about 2%. Before the discovery of insulin in 1922, the mortality rate was 100%
- Poorer if shock, oliguria, first presentation Type 1 DM, severe acidosis (pH <7.1), cerebral oedema
2° Prevention
+ Health promotion
- Education
- Encourage compliance
- Seek help if cannot give themselves insulin (or run out), or BG > 20 mmol/L, or if infected
Don't forget
- K may fall rapidly
- Aim for gradual fall in glucose
- Exclude MI and infection
Red flags
- Reduced level of consciousness (cerebral oedema?)
- Severe sepsis/shock
- Severe acidosis (pH <7.1)
Note: if so, manage on ITU
