Diabetic ketoacidosis (DKA)

Key differential diagnoses

HONK
Hyperglycaemia + other causes of metabolic acidosis (eg lactic)

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

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

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

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 Diagnosis

HONK
Hyperglycaemia and other causes metabolic acidosis (eg aspirin overdose and lactic acidosis)

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

Admit?

Always

Bed plan

Medical admission ward
± Endocrine
± ITU

Referrals

Medical:
Endocrine
± ITU

Other:
Hospital DM nurse ± Community DM nurse)

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