Type 1 diabetes mellitus

T1DM is characterised by complete, or near-complete, deficiency of insulin production from the pancreatic beta cells due to auto-immune destruction of pancreatic islets. Diagnosis is usually clinical but is supported by finding high titres of anti-islet cell, or anti-glutamic acid decarboxylase antibodies, and low levels of C-peptide in the face of hyperglycaemia. Treatment is mandatory insulin therapy.

General examination

This is essential as part of assessing whether the patient is systemically unwell and requires admission, or is well enough to be managed as an out patient.

Specifically, in the acutely unwell case with DKA, assess whether the patient is dehydrated. 

 Blood pressure

In the newly diagnosed patient, assess whether they are dehydrated, hypotensive or have a postural drop in blood pressure on standing.

At routine follow up, assess for hypertension as this is a potent nephropathy, retinopathy and cardiovascualr disease risk factor.

 Foetor

Assess whether the patient has a ketotic foetor.

 CNS

In the acutely unwell with DKA, assess whether the patient is obtunded or confused, these are markers of disease severity and should prompt consideration of nursing in a level 3 environment (HDU or ITU).

In the newly diagnosed patient with suspected T1DM, look for hearing aids or a hearing deficit - these can be pointers to the differential diagnosis of mitochondrial diabetes.

 Abdo

It is important to carefully assess the abdomen in patients with diabetic ketoacidosis complaining of abdominal pain. Abdominal pain is a common feature of the presentation and indeed the serum amylase is often elevated as well.

While the majority of such cases remit with rehydration and metabolic correction, a minority of cases will have a true intra-abdominal pathology such as acute appendicitis and it is therefore mandatory to periodically re-assess the patient clinically and arrange further investigations of the abdominal pain if it is not settling.

Does the patient have retinopathy?

Retinal examination should be a routine part of the examination of all patients with newly presenting diabetes. This is both to establish the baseline and to detect any pre-existing retinopathy.

Ideally this is performed by digital retinal photographic screening as part of an accredited retinal screening service. At the very least it should be performed using an ophthalmoscope with the pupils fully dilated with a mydriatic agent such as tropicamide 1%.

Does the patient have any neuro-vascular deficit in the feet?

The feet of all patients presenting with newly diagnosed diabetes should be carefully assessed for vascular and neurological deficit. The dorsalis pedis and posterior tibial pulses should be palpated.

Sensation should be assessed by testing two modalities - usually 10 g monofilament sensation and vibration perception on each foot. While the latter is traditionally undertaken with a 128 Hz tuning fork, a neurothesiometer is preferable as it allows objective quantification of any deficit.

In addition the general condition of the feet, especially whether there are any architectural changes, should be recorded.

Diabetesbible is for health professionals