ESTRUCTURA CONCEPTUAL

Despite the level of presenting glycaemia, management of the diabetes often does not involve insulin and some patients manage on diet only. The patient needs to be given dietary advice and specific diabetes education on issues such as monitoring and foot care. This would usually involve the specialist diabetes nurse and a dietitian. Other aspects of cardiovascular risk need to be assessed and, in this case, blood pressure medication may be changed from a high-dose thiazide to an ACE inhibitor.

CASE 1.14 –  A 32-year-old woman with abdominal pain and vomiting and a plasma glucose of 22 mmol/L and urinary ketones.

A1: What is the likely diagnosis?

The likely diagnosis is diabetic ketoacidosis. This is an emergency complication of type 1 diabetes and can be the presenting feature, as in this scenario. Precipitating causes include intercurrent illness (e.g.

UTI) and withholding insulin (in an established case of type 1 diabetes). Abdominal pain and vomiting are common and can lead to the erroneous diagnosis of an acute abdomen.

A2: What investigations would be performed?

 Venous blood for plasma glucose (to confirm the finger-prick test), U&Es, osmolality, bicarbonate, amylase and FBC.

 Plasma ketones may become a more widely used test with the arrival of near-patient analyses.

 ABGs (will be performed less frequently as plasma ketone testing becomes available).

Box 1.1 Hyperosmolar non-ketotic coma (HONK) Insulin management of HONK

 Insulin 3 units/h via intravenous (IV) pump.

 Monitor glucose every hour using meter and laboratory testing.

 Aim for fall in glucose level of 3–6 mmol/h.

 At plasma glucose < 12 mmol/L, reduce to 1.5 units/h.

 Continue insulin infusion for at least 2 h.

Fluid management of HONK guided by central venous pressure line

 IV 0.9% saline if Na⁺ < 160 mmol/L:

 Change to 5% dextrose when plasma glucose < 12 mmol/L.

Electrolyte (K⁺) management of HONK

 No K⁺ in litre 1, pending laboratory reading:

 usually K⁺ 3.5–5.5 mmol/L: add 20 mmol/L

 recheck every 2 h and then every 4 h

 if K⁺ > 5.5 mmol/L: no K⁺ and then recheck in 1 h

 if K⁺ < 3.5 mmol/L: add 40 mmol/L and then recheck in 1 h.

 If Na⁺ > 160 mmol/L, use half 0.9% saline.

Diabetes emergencies 39

 Culture of urine and venous blood.

 Chest radiograph.

 ECG.

A3: How would the diagnosis be confirmed?

Confirmation of hyperglycaemia with ketonuria and acidosis (pH < 7.2, H⁺ > 63 mmol/L). Note that the hyperglycaemia is often not pronounced.

A4: What would be the initial management?

A4: The patient should be admitted to hospital. Intravenous access should be established for blood tests and infusion, and a cardiac monitor attached. Treatment should then be given with intravenous insulin and intravenous fluids while monitoring electrolytes (Box 1.2).

A5: What are the potential complications?

The prognosis for DKA should be good, given that it affects young people who rarely have other significant comorbidities. Cerebral oedema may occur during treatment, although the cause of this complication is unknown. Aspiration of gastric contents may occur in the setting of reduced consciousness.

A6: What issues need to be addressed when the patient has fully recovered?

The diagnosis of DKA implies that the patient has type 1 diabetes and will require life-long insulin.

She will therefore need to be educated about the condition, and taught to inject insulin and how to

Box 1.2 Diabetic ketoacidosis (DKA) Insulin management of DKA

 Insulin: 6 units/h via intravenous (IV) pump.

 Monitor glucose every hour using meter and laboratory testing.

 Aim for fall in glucose level of 3–6 mmol/h.

 At plasma glucose < 12 mmol/L, reduce to 2–3 units/h.

 Continue insulin infusion for at least 24 h and no urinary ketones.

Fluid management of DKA

 Change to 5% dextrose when plasma glucose <12 mmol/L.

Electrolyte (K⁺) management of DKA

 No K⁺in litre 1, pending laboratory reading:

 if K⁺ > 5.5 mmol/L: no K⁺ and recheck in 1 h

 if K⁺ < 3.5 mmol/L: add 40 mmol/L and recheck in 1 h

 if K⁺ 3.5–5.5 mmol/L: add 20 mmol/L and recheck every 2 and then every 4 h.

self-monitor using finger-prick testing. She will need to be given information about the immediate complications of her condition (hypoglycaemia, DKA) and advised to avoid pregnancy until good glycaemic control is achieved. Ultimately she will need to understand the long-term risks of small and large vessel disease. These issues are best addressed by a diabetes nurse specialist and a formal education programme.

CASE 1.15 –  A 18-year-old man, known to have type 1 diabetes, who is unconscious.

A1: What is the likely diagnosis?

The likely diagnosis is hypoglycaemia. As a general rule, an unconscious person with diabetes is hypoglycaemic until proved otherwise. This diagnosis is very likely in an otherwise fit young person who takes insulin. Precipitating factors in this case may be the exercise earlier in the day (the effects of exercise can last for many hours) and tight glycaemic control, which may provoke hypoglycaemia unawareness.

A2: What investigations would be performed?

See the answer to A3.

A3: How would the diagnosis be confirmed?

Treatment can be initiated without any investigation and before the hypoglycaemia has been confirmed (indeed, a satisfactory response to treatment will itself confirm the diagnosis). Finger-prick blood glucose testing will confirm a low blood glucose level.

A4: What would be the initial management?

In an unconscious patient the two main options are administration of glucagon or intravenous dextrose.

Glucagon may be available because patients with type 1 diabetes are encouraged to keep a supply for this type of emergency. It comes as a powder that must be dissolved in water (a vial of sterile water is part of the kit). One vial = 1 mg = 1 unit, which is the standard injection, usually into muscle (but it can be subcutaneous or intravenous).

Intravenous dextrose is given by diluting 50% dextrose to half-strength and injecting 50 mL via a cannula. An infusion of 5% dextrose is then set up to reduce the risk of phlebitis.

A5: What are the potential complications?

Patients can suffer injury if they have lost their warnings of hypoglycaemia. In older patients,

hypoglycaemia may present with neurological signs typical of stroke. Death is thought to be uncommon in this setting, although hypoglycaemia has been implicated in the higher incidence of the ‘dead-in-bed’

syndrome seen in type 1 diabetes. There is increasing evidence to implicate frequent hypoglycaemia as a risk factor for cardiovascular disease. With regard to the treatments, intravenous dextrose can cause phlebitis and glucagon is associated with nausea and vomiting.

A6: What issues need to be addressed when the patient has fully recovered?

You need to find out the cause of the event (too much insulin, too much exercise or too little food) and then provide education to prevent future recurrence. In this case, the active issues would be manipulation of the treatment regimen to be able to cope with exercise and possibly a relaxing of glycaemic control to reduce the risk of hypoglycaemia and decrease hypoglycaemia unawareness.

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OSCE counselling cases

OSCE COUNSELLING CASE 1.9 –  ‘What should I do with my insulin if I develop a vomiting illness that stops me eating?’

The issue here is what most people with diabetes refer to as ‘sick day rules’. Patients will understandably be concerned that they may become hypoglycaemic by taking insulin without food. Any intercurrent illness can cause blood glucose levels to rise, however, probably by increasing insulin resistance – hence the advice that ‘You should never stop insulin!’.

The patient should perform more frequent finger-prick testing, at least every 4 hours. This will allow detection of hypoglycaemia; if, as is likely, glucose levels rise, additional insulin (rapid acting) may then be needed.

For patients with type 1 diabetes, vomiting should raise the possibility of DKA and urine ketones should be checked at least twice a day. If these are positive to +++ or more, medical advice, and probably admission to hospital, must be sought. Near-patient plasma ketone testing is now more frequently performed by patients with type 1 diabetes, and they should be educated on the levels that may need medical intervention. In young people with type 1 diabetes, dehydration can develop very quickly and a low threshold for seeking medical advice should be promoted.

Patients should be aware of the actions to take during illness and how to access appropriate advice (probably not NHS Direct). This will mean telephone numbers of the diabetes specialist nurse team and agreed guidelines for out-of-hours management of diabetes emergencies

OSCE COUNSELLING CASE 1.10 –  ‘What advice do I give to my partner if they witness me having a “hypo”

reaction?’

Symptoms of hypoglycaemia include lack of concentration, bad temper, change in behaviour, confusion and pallor, all of which are easily (perhaps more easily) recognized by a third party. It is vital that the partner of a person with diabetes is aware of the symptoms and signs of hypoglycaemia and is able to take appropriate action.

If the person’s partner suspects hypoglycaemia, ideally he or she should encourage the patient to check a finger-prick glucose level. There is little to be lost by instituting treatment without confirmation of the diagnosis, however. Assuming the patient is alert, this involves taking food by mouth, usually in the form of glucose tablets: 10 g glucose is equivalent to three sugar lumps or one Dextrosol tablet.

Patients with diabetes should always carry some form of glucose replacement; Dextrosol tablets are recommended because they are less palatable than sweets (and so less likely to be consumed as treats).

Alternatives include 200 mL milk or 100 mL Coca-Cola (not Diet Coke). A longer-acting carbohydrate such as bread or biscuits should then be consumed.

If the patient is semiconscious, a glucose gel can be administered via the buccal membrane.

Glucostop is a glucose gel supplied in a plastic bottle with a nozzle. The gel can be squeezed into the mouth between the teeth and cheek and is absorbed into the circulation without the need for swallowing.

If the patient is unconscious, he or she should be placed into the recovery position. If the person’s partner has been trained, glucagon can be administered (see above), otherwise medical aid should be summoned.

Perhaps the most important advice to the partner is not to panic and to be reassured that the normal outcome of a ‘hypo’ is that blood glucose levels rise in response to the body’s natural adrenergic response.

 Diagnostic guidelines for diabetes are revised every 10 years or so and are based on consensus opinion rather than absolute cut-offs for symptoms or complications. These typically apply to type 2 diabetes. The diagnosis of type 1 diabetes, if suspected, should never be delayed by requesting investigations such as a glucose tolerance test or HbA1c, which may take days to be reported.

 A diagnosis of diabetes should never be casually applied to a patient, since it is likely that this can never be erased from their medical record and will have a major impact on their insurance premiums (e.g. life assurance, travel insurance). This shows the importance of laboratory testing rather than near-patient testing in type 2 diabetes.

 Diabetes has major implications for driving, the authorities being particularly interested in hypoglycaemia and the presence of complications such as retinopathy and peripheral neuropathy.

The regulations are constantly changing, and readers should refer to the relevant website for the latest situation for their country.

 Targets for glycaemic control, typically measured by HbA1c, should be tailored according to the circumstances of the individual, bearing in mind the downsides of treatment (hypoglycaemia, weight gain).

 There are several therapeutic options that may be used to lower blood glucose (currently seven classes). The choice will be guided by considerations of cost, safety, efficacy and patient preference.

Cost pressures have had a major impact on national guidelines, such as those of NICE.

 Small vessel, diabetes-specific complications affect the eyes, feet and kidneys. Screening for these complications forms part of the diabetes review, with prevention being far more effective than

‘cure’.

 Large vessel complications, affecting the coronary, cerebral and peripheral arteries, are more common in people with diabetes, and hence there are aggressive blood pressure and lipid targets.

The impact of tight glycaemic control, especially in people with established large vessel disease, is a controversial topic.

 An unconscious person with diabetes should always be suspected of being hypoglycaemic. In a person with diabetes who has abdominal pain and vomiting, diabetic ketoacidosis should be excluded.