History and exam

Key diagnostic factors

common

acute cognitive impairment

Record the patient’s Glasgow Coma Scale (GCS) score or AVPU (Alert, Voice, Pain, Unresponsive) scale score. [ Glasgow Coma Scale Opens in new window ]

  • Involve senior or critical care support if GCS is <12 or AVPU is abnormal.

  • Cognitive impairment is common and can range from disorientation and lethargy to coma.[11] This may be due to cerebral oedema in severe cases, significant electrolyte disturbances, changes in osmolality, dehydration, infection and sepsis, hypoglycaemia during treatment, or renal failure.[6]

presence of risk factors

Infection

  • The most common causes are pneumonia and urinary tract infection.[3][9][17]​​​​

  • Always consider diabetic foot infection.[2]​[47]

    • Always remove the patient's shoes, socks, bandages and dressings before examining their feet thoroughly.

Inadequate insulin or oral antidiabetic therapy

  • In practice, look out for patients with worsening glycaemic control.

Risk factors for hyperglycaemia (e.g., corticosteroids or antipsychotic drugs)[9][24]​​[32][33]​​​​

  • In practice, HHS secondary to corticosteroids is commonly seen in patients who develop HHS during admission to hospital.

Acute illness

  • Common causes include myocardial infarction, sepsis, and stroke.[9]​​

    • Be aware that patients with stroke are at increased risk of dehydration (and subsequent HHS) due to difficulty drinking because of limb weakness or dysphagia.

Other diagnostic factors

common

polyuria

There may be gradual onset (over days to weeks) of polyuria.[46]

polydipsia

There may be gradual onset (over days to weeks) of polydipsia.[46]

weight loss

May be present in a patient with HHS.

nausea and vomiting

May be present in a patient with HHS.

weakness

There may be gradual onset (over days to weeks) of weakness.[6][46]

dry mucous membranes

A sign of hypovolaemia.

poor skin turgor

A sign of hypovolaemia.

tachycardia

A sign of hypovolaemia.

hypotension

Systolic blood pressure <90 mmHg; a sign of hypovolaemia.

uncommon

hypothermia

Measure the patient’s temperature.

  • Patients may be normothermic or hypothermic primarily because of peripheral vasodilation, even if there is concurrent infection.[11]

  • Severe hypothermia is associated with a poor prognosis.[11]

  • Involve senior or critical care support if the patient is hypothermic.[6]

oliguria

The patient may present with oliguria if they are very dehydrated.

abdominal pain

Abdominal pain may be due to HHS or to an acute intra-abdominal precipitating cause (e.g., pancreatitis). Abdominal pain is uncommon in HHS, however; suspect diabetic ketoacidosis if there is no obvious cause for the pain.[1]

focal neurological signs

Assess for focal neurological signs such as hemianopia and hemiparesis.[11]

seizures

These may be generalised, focal, myoclonic jerking, or movement induced.[3]

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