T1DM and DKA

T1DM and DKA

Endocrinology series

Dr Azeem Alam, MBBS BSc (Hons)Surgical AFPGuy’s and St. Thomas’ HospitalContent reviewed on the 28/04/2020.

Pathophysiology, differentials, investigations and management.

Cases Quiz

History An 11-year-old boy presents to the emergency department with abdominal pain and vomiting. He reports an ongoing history of frequent urination and extreme thirst.

BM levels are unrecordable and ketones are 4 mmol/L. You notice a fruity smell on his breath.

Observations HR 125, BP 92/65 mmHg, RR 28, SpO2 97%, Temp 38.0

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Case 1

History An 11-year-old boy presents to the emergency department with abdominal pain and vomiting. He reports an ongoing history of frequent urination and extreme thirst.

BM levels are unrecordable and ketones are 4 mmol/L. You notice a fruity smell on his breath.

Observations HR 125, BP 92/65 mmHg, RR 28, SpO2 97%, Temp 38.0.

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Case 1

Pathophysiology

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Pathophysiology

(1)

(2)

Pathophysiology

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Pathophysiology

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Definition: a metabolic disorder characterised by high glucose levels due to absolute insulin deficiency.

Epidemiology• 10-20% of all diabetic patients • Most common form of diabetes in <20 years of age • Highest incidence at 10-14 years old

Risk factors• HLA risk profile: HLA-DR3 and HLA-DR4• Personal / family history of autoimmune disease: e.g Hashimoto’s

Pathophysiology

Pathophysiology

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Clinical features

Symptoms Signs

Polyuria Poor wound healing

Polydipsia

Polyphagia

Weight loss

Fatigue

Pathophysiology

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T1DM vs. T2DM

T1DM T2DM

Frequency 10-20% 80-90%

Pathogenesis Absolute insulin deficiency

Insulin resistance

Genetics HLA association No HLA association; strong genetic predisposition

Presentation Age < 20 years old and often acute with DKA

Age > 40 years and gradual onset

Acute manifestation

DKA Usually HHS

Management Insulin Lifestyle à oral medicationà insulin

Pathophysiology

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Primary investigations:• Random blood glucose: >11mmol/mol with clinical features à same-day referral • Fasting blood glucose: ≥7.0 mmol/L is typical• Oral glucose tolerance test: >11mmol/mol two hours after a 75g oral glucose load• HbA1c: >48 mmol/mol suggests hyperglycaemia over 3 months. Use for monitoring

Investigations to consider:• C-peptide: if atypical features are present e.g. age > 50, or BMI > 25kg/m2

• Autoantibodies: if atypical features are present; e.g. anti-glutamic acid decarboxylase• VBG: if concerned about DKA

Investigations

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Management

Urgent referral to diabetes specialist team

Lifestyle• Diet high in fibre and low in fat, sugar, and salt• Educate regarding carbohydrate counting; allows insulin dose to be matched to intake

Insulin therapy• Basal-bolus: first-line, long-acting regularly (basal) with rapid-acting insulin before meals (bolus)

• Basal: Levemir (Detemir) given twice daily. Lantus (Glargine) once-daily is an alternative• Bolus: Insulin Lispro (Humalog), Insulin Aspart (Novorapid)

• Mixed insulin regimen: mixed insulin comprises a short-acting and long-acting insulin, BD.• Used when unable to tolerate basal-bolus regime

• Continuous insulin infusion: disabling hypoglycaemia or persistent hyperglycaemia (HbA1c >69mmol/mol)

Pathophysiology

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Glucose• HbA1c: measured every 3-6 months with a target of ≤48 mmol/mol• Self-monitoring: check blood glucose levels at least 4 times a day. Targets as follows:

• On waking: 5-7 mmol/L• Before meals and other times of the day: 4-7 mmol/L

Retinopathy• Immediate ophthalmology referral upon diagnosis and annually thereafter• Arrange urgent review thereafter if:

• Acute reduction in acuity• Pre proliferative or proliferative retinopathy• Diabetic maculopathy

Diabetic foot• Should be assessed at least annually; refer urgently to foot protection service if at risk (e.g. ulceration)

Diabetic nephropathy• Annual measurement of eGFR and urinary albumin:creatinine ratio

Monitoring

Pathophysiology

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Complications

System Complication

Cardiovascular • Ischaemic heart disease• Heart failure• PVD

Neurological • Stroke• Carpal tunnel syndrome• Neuropathy

Endocrine • DKARenal • Diabetic nephropathy and

CKDOphthalmology • Diabetic retinopathy

• Macular degeneration• Open-angle glaucoma• Cataracts

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• Metabolic state as a complication of T1DM (predominantly)

• Medical emergency: dehydration and electrolyte imbalances

• Triad: hyperglycaemia, acidosis and ketonaemia

• Mortality rate < 1% in UK

• May be a first presentation of T1DM

• Often a precipitating factor: infection, trauma, surgery, corticosteroid use

Diabetic ketoacidosis

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Diabetic ketoacidosis

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Precipitating factor

Net reduction in insulin

Increase in counter hormones

(e.g. cortisol)

Reduced glucose entry into cells

Metabolism of lipids as an alternative energy

source

? FFA to liver ? Ketogenesis

Acidosis

? Gluconeogenesis ? Glycogenolysis

Hyperglycaemia

Osmotic diuresis

Dehydration and electrolyte

abnormalities

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Pathophysiology

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Clinical features

Symptoms Signs

Abdominal pain Fruity ‘pear drop’ smell of acetone on the breath

Nausea and vomiting Dehydration:• Mild: only just detectable• Moderate: dry skin and mucus membranes; reduced skin

turgor• Shock: tachycardia, hypotension (late), drowsiness,

reduced urine output

Polyuria and polydipsia Kussmaul respiration: deep, laboured breathing

Weight loss

Inability to tolerate oral fluids

Lethargy and confusion

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Bedside• Urine dip: glycosuria and ketonuria• Bedside ketone and capillary glucose

Bloods• ABG/VBG: quickest way to ascertain pH and HCO3 levels• U&Es: electrolyte derangement and acute kidney injury due to dehydration• FBC and CRP: raised inflammatory markers may suggest underlying infection as a precipitant• Infection screen: if an infection is the suspected trigger

Investigations

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Triad: hyperglycaemia, acidosis and ketonaemia

Diagnostic criteria

Joint British Diabetes Societies Inpatient Care Group (2013)

Glucose > 11 mmol/L or

known DM

HCO3 < 15 mmol/Land/or

venous pH < 7.30

Ketonaemia (≥ 3 mmol/l) or

2+ ketonuria

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Management

Treatment Further information

IV fluid SBP < 90 mmHg• 1 litre 0.9% NaCl over 15 mins• Call for senior help as required

SBP > 90 mmHg: typical regimen• 1 litre 0.9% NaCl over 1 hour• 1 litre 0.9% NaCl with KCl over next 2 hours• 1 litre 0.9% NaCl with KCl over next 2 hours• 1 litre 0.9% NaCl with KCl over next 4 hours• 1 litre 0.9% NaCl with KCl over next 4 hours• 1 litre 0.9% NaCl with KCl over next 6 hours

Insulin Fixed-rate insulin infusion:• Commence at 0.1 U/kg/h• Add in 10% glucose once glucose levels drop below 14.0 mmol/L• Do not stop long-acting insulin

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Management

Serum potassium concentration (mmol/L) Potassium replacement

> 5.5 None

3.5-5.5 40 mmol/L

< 3.5 Consider HDU/ITU for replacement via central line

• Potassium replacement• Total body potassium is low and correction of acidosis causes further reduction in

potassium

• Anticoagulation: patients are at increased risk of VTE

• Glucose, pH, bicarbonate, ketone levels, and electrolytes should be closely monitored throughout, 1-2 hourly

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Complications

Hypokalaemia and hyperkalaemia• Potentially life-threatening• Hyperkalaemia: extracellular shift of K+ due to acidosis• Hypokalaemia: due to correction of acidosis

Hypoglycaemia• Due to rapid correction of ketoacidosis• May result in rebound ketosis

Cerebral oedema• More common in children (70-80% of diabetes-related deaths)• Likely to be iatrogenic

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Top decile question

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References

1. Anoel8 / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0)