HYPERGLYCEMIC HYPEROSMOLAR NONKETOTIC SYNDROME (Pathophysiology (HHS is…
HYPERGLYCEMIC HYPEROSMOLAR NONKETOTIC SYNDROME
• There is lack of effective insulin (i.e., insulin resistance).
• When hyperglycaemia is persistent, it causes osmotic diuresis, resulting in losses of water and electrolytes.
• In this case, ketosis is minimal or absent
• Water shifts from the intracellular ﬂuid space to the extracellular ﬂuid space, to maintain osmotic equilibrium
• A very serious condition whereby hyperosmolarity and hyperglycaemia predominate, with sensorium (sense of awareness) being altered.
• Hypernatremia and increased osmolarity occur in presence of glucosuria and dehydration. (Quinn, 2001c).
• high risk for renal failure secondary to severe dehydration.
• Nursing care must be directed by nurse to the condition that may have precipitated the onset of HHNS.
• Close monitoring of vital signs, ﬂuid status, and laboratory values.
• HHNS tends to occur in older patients, the physiologic changes that occur with aging make careful assessment of cardiovascular, pulmonary, and renal function important throughout the acute and recovery phases of HHNS (Quinn, 2001c).
• insulin administration.
• close monitoring of volume and electrolyte status is important for prevention of ﬂuid overload, heart failure, and cardiac dysrhythmias.
• correction of electrolyte imbalances.
• Fluid treatment is started with 0.9% or 0.45% NS, depending on the patient’s sodium level and the severity of volume depletion. (ADA, Hyperglycaemic Crises in Patients With Diabetes Mellitus, 2003).
• ﬂuid replacement.
Assessment and Diagnostic Findings
• Electrolyte and BUN levels are consistent with the clinical picture of severe dehydration.
• Mental status changes, focal neurologic deﬁcits, and hallucinations are common secondary to the cerebral dehydration that results from extreme hyperosmolality.
• The blood glucose level is usually 600 to 1,200 mg/dL, and the osmolality exceeds 350 mOsm/kg.
Postural hypotension accompanies the dehydration (ADA, Hyperglycaemic Crises in Patients with Diabetes Mellitus, 2003).
• A range of laboratory tests must include blood glucose, electrolytes, BUN, complete blood count, serum osmolality, and arterial blood gas analysis.
• Profound dehydration (dry mucous membranes, poor skin turgor),
• Variable neurologic signs (e.g., alteration of sensorium, seizures, hemiparesis).
Nursing Care Plans
Decreased intake of fluids due to diminished thirst sensation or functional inability to drink fluids.
Excessive gastric losses due to nausea and vomiting.
Hyperglycemia-induced osmotic diuresis.
HHS is characterized by extreme elevations in serum glucose concentrations and hyperosmolality without significant ketosis
These metabolic derangements result from synergistic factors including insulin deficiency and increased levels of counterregulatory hormones
Hyperglycemia develops because of an increased gluconeogenesis
accelerated conversion of glycogen to glucose (glycogenolysis)
by inadequate use of glucose by peripheral tissues, primarily muscle.
(The American Diabetes Association,2014)
As the glucose concentration and osmolality of extracellular fluid increase, an osmolar gradient is created that draws water out of the cells
Glomerular filtration is initially increased, which leads to glucosuria and osmotic diuresis
The initial glucosuria prevents the development of severe hyperglycemia as long as the glomerular filtration rate is normal
However, with continued osmotic diuresis, hypovolemia eventually occurs, which leads to a progressive decline in glomerular filtration rate and worsening hyperglycemia.