Diagnosis
Criteria
According to the American Diabetes Association, diagnostic features include:
Plasma glucose level >30 mmol/L (>600 mg/dL)
Serum osmolality >320 mOsm/kg
Profound dehydration, up to an average of 9L (and therefore substantial thirst (polydipsia))
Serum pH >7.30
Bicarbonate >15 mEq/L
Small ketonuria (~+ on dipstick) and absent-to-low ketonemia (<3 mmol/L)
Some alteration in consciousness
BUN > 30 mg/dL (increased)
Creatinine > 1.5 mg/dL (increased)

Imaging
Cranial imaging is not used for diagnosis of this condition. However, if MRI is performed, it may show cortical restricted diffusion with unusual characteristics of reversible T2 hypointensity in the subcortical white matter. Differential diagnosis
The major differential diagnosis is diabetic ketoacidosis (DKA). In contrast to DKA, serum glucose levels in HHS are extremely high, usually greater than 40-50 mmol/L (600 mg/dL). Metabolic acidosis is absent or mild. A temporary state of confusion (delirium) is also more common in HHS than DKA. HHS also tends to affect older people more. DKA may have fruity breath, and rapid and deep breathing.DKA often has serum glucose level greater than 300 mg/dL (HHS is >600 mg/dL). DKA usually occurs in type 1 diabetics whereas HHS is more common in type 2 diabetics. DKA is characterized by a rapid onset, and HHS occurs gradually over a few days. DKA also is characterized by ketosis due to the breakdown of fat for energy.Both DKA and HHS may show symptoms of dehydration, increased thirst, increased urination, increased hunger, weight loss, nausea, vomiting, abdominal pain, blurred vision, headaches, weakness, and low blood pressure with standing. Management
Intravenous fluids
Treatment of HHS begins with reestablishing tissue perfusion using intravenous fluids.
Aspiration pneumonia is a type of lung infection that is due to a relatively large amount of material from the stomach or mouth entering the lungs. Signs and symptoms often include fever and cough of relatively rapid onset. Complications may include lung abscess, Acute respiratory distress syndrome, empyema, and parapneumonic effusion. Some include chemical induced inflammation of the lungs as a subtype, which occurs from acidic but non-infectious stomach contents entering the lungs.Infection can be due to a variety of bacteria. Risk factors include decreased level of consciousness, problems with swallowing, alcoholism, tube feeding, and poor oral health. Diagnosis is typically based on the presenting history, symptoms, chest X-ray, and sputum culture. Differentiating from other types of pneumonia may be difficult.Treatment is typically with antibiotics such as clindamycin, meropenem, ampicillin/sulbactam, or moxifloxacin. For those with only chemical pneumonitis, antibiotics are not typically required. Among people hospitalized with pneumonia, about 10% are due to aspiration. It occurs more often in older people, especially those in nursing homes. Both sexes are equally affected. Signs and symptoms
The person may have an insidious course with increased respiratory rate, foul-smelling sputum, hemoptysis, and fever. Complications may occur, such as exudative pleural effusion, empyema, and lung abscesses. If left untreated, aspiration pneumonia can progress to form a lung abscess. Another possible complication is an empyema, in which pus collects inside the lungs. If continual aspiration occurs, the chronic inflammation can cause compensatory thickening of the insides of the lungs, resulting in bronchiectasis.