Flashcards in Non-vascular complications of DM Deck (30):
What is DKA?
- an acute metabolic complication of diabetes
- an absolute insulin deficiency
- potentially fatal if not tx properly
- characterized by biochemical triad of hyperglycemia, ketonemia, and anion gap metabolic acidosis
- usually evolves rapidly, over a 24 hr period
Pathophys of DKA?
- reduction in net effective concentration of circulating insulin
- elevation of counter regulatory hormones: glucagon (stimulates free FAs into ketones), cortisol, GH
- hyperglycemia: osmotic diuresis (water and electrolyte loss) and dehydration
process of DKA?
- beta cell dysfunction in pancreas seen in type 1 DM leads to insulin deficiency which results in:
- resultant elevation in glucagon - free fatty acid conversion to ketones - ketonuria
- inability to drive glucose into cells which leads to cell starvation and breakdown of fats for energy - leads to free fatty acid conversion to ketones - to ketonuria
Precipitating factors of DKA?
- most common events associated with DKA:
inadequate insulin therapy, infection (pneumonia, and UTI)
- other factors include: severe dehydration, acute major illnesses (MI, CVA, pancreatitis)
- new onset type 1 diabetes
- drugs that affect carbohydrate metabolism
Clinical presentation of DKA?
- thirst, polydipsia
- abdomincal pain
- orthostatic hypotension
- poor skin turgor
- dry skin and mucous membranes
- Kussmaul's respirations (acidotic response)
- fruity breath (ketones)
- altered mental status or coma
Lab findings in DKA?
- blood glucose: 250-800
- serum osmolality normal to high
- serum Na+ normal to low (130-145) pulling Na into vasculature and urinating it out
- serum K+ high (greater than 5, glucose is going to pull K+ out of cells)
- serum bicarb low, less than 20
- serum anion gap is greater than 12 meq/L
- pH is less than 7.3, acidotic
- ketones + positive
What is a hyperosmolar hyperglycemic state (HHS)?
- occurs almost exclusively in type 2
- elderly and physically impaired
- limited access to free water
How is HHS distinguished from DKA?
- severe hyperglycemia (greater than 600)
- hyperosmolality (induced hepatic outpt of glucose -kidneys can't get rid of glucose fast enough)
- develops more insidiously with polyuria, polydipsia, and wt loss, often persisting for several days before hospital admission
- greater degree of dehydration: relative absence of acidosis and ketones, mortality rates 5-20%
Causes of HHS?
- catabolic stress
Clinical presentation of HHS?
- wt loss
- mental status changes
- slower progression
- severe dehydration: dry skin and mucous membranes, and extreme thirst
- Neuro signs (not in DKA):
lethargy, sensory impairment, seizures, hyperthermia
HHS lab findings?
- blood glucose greater than 600 (higher than in DKA)
- serum osmolality: greater than 320
- serum Na+ normal to high (135-145)
- serum K+ normal (4-5)
- serum bicarb: greater than 20 (high)
- pH greater than 7.3
- ketones are negative
- can be complicated by thromboembolic events arising because of high serum osmolality
- prognosis less favorable than DKA
Tx for DKA and HHS?
- medical emergencies that require prompt recognition and management
- initial assessment: ABC status, mental status, volume status
- IV fluid and electrolyte replacement: slower rate and greater volume needed for HHS, insulin replacement starts after rehydration is in progress
- insulin therapy (want to make sure K is higher than 3.3 before insulin, if not insulin will push K back into cell and pt becomes hypokalemic).
Differences in HHS and DKA?
- DKA and HHS differ clinically according to presence of ketoacidosis and usually degree of hyperglycemia
- significant overlap b/t DKA and HHS has been reported in more than 1/3 of pts
- in HHS: amino acids are being broken down and used in gluconeogenesis, and glycogenesis is occuring this leads to hyperglycemia and osmotic diuresis (dehydration)
- in DKA: adipose tissue releases free fatty acids and liver breaks them down into keton bodies and this leads to hyperketonemia - decreased alkaline buffer - acidosis
Where is hypoglycemia seen the most?
- in type 1 diabetics, especially in pts receiving intensive therapy
- plasma glucose concentrations may be less than 50 to 60 mg/dL as much as 10% of the time
- type 1's suffer an average of 2 episodes of symptomatic hypoglycemia per week, one episode of severe hypoglycemia per year
- hypoglycemia is less frequent in type 2
- overall event rate for severe hypoglycemia (requiring assistance of another individual) in insulin tx type 2 is approx 30% of that in type 1
Classification of hypoglycemia?
- functional: fasting and postprandial (reactive)
Causes of hypoglycemia?
- insulin injections
- oral hypoglycemic agents
- hepatic and renal dysfunction
- cahnging of injection site
hypoglycemia not in diabetics: alcohol, insulinoma, wt loss and infection
Clinical presentation of hypoglycemia?
- rapid onset and progression
- neurogenic sxs: catecholamine-mediated/adrenergic: tremor, palpitations, and anxiety/arousal
acetylcholine-mediated/cholinergic: sweating, hunger and paresthesias
- neuroglycopenic sxs: cognitive impairment, behavioral changes, psychomotor abnormalities, and at very low plasma glucose, seizure and coma
Signs of hypoglycemia?
- elevated blood pressure
What is hypoglycemia unawareness in diabetes?
- absent sxs of hypoglycemia, which is thought to be the result of reduced of sympathoadrenal, predominantly sympathetic neural, responses to a given degree of hypoglycemia caused by:
- loss of autonomic warning: recent antecedent hypoglycemia, prior exercise, or sleep
- autonomic neuropathy: epi response diminished or lost
- meds: beta blockers
Management of hypoglycemia?
outside hospital: oral, SQ/IM
hospital: IV, 1 amp of D50 (20-50 ml)
What is non-diabetic hypoglycemia? and what is it based upon?
- based upon presence of whipple's triad
- sxs and signs consistent with hypoglycemia, a low plasma glucose at time of sxs, and resolution of those signs and sxs after raising the plasma glucose
- in individuals w/o diabetes hypoglycemia is most often due to a drug, less common causes include critical illness, endocrine deficiency, or a nonislet cell tumor
- endogenous hyperinsulinism or accidental, surreptitious or malicious hypoglycemia are more likely in well appearing pt
What is surreptitiously induced hypoglycemia?
factitious hypoglycemia occurs secondary to surreptitious use of insulin or insulin secretagogues. The term factitious hypoglycemia has been used in medical palance to imply covert human activity
- insulin and C peptide are secreted in an equimolar fashion, as a result, the plasma concentrations of these 2 peptides parallel each other in pts with endogenous hyperinsulinemia
- in contrast, the plasms concentrations of 2 peptides are inversely related in pts with exogenous insulin factitious hypoglycemia: plasma insulin will be high while C peptide is low
- this observation applies to both nondiabetic pts and to those with type 2 DM
- pts with type 1 diabetes are characteristically severely insulin deficient and have low or undetectable plasma concentrations of C peptide
What is hypoglycemia coma?
- recovery from hypoglycemia may be delayed, because of cerebral edema
- unconsciousness lasting more than 30 minutes after plasma glucose is corrected is called post-hypoglycemic coma
Tx for hypglycemic coma?
- IV mannitol for cerebral edema
- glucocorticoids (dexamethasone)
- or both can be used along with maintenance of normal plasma glucose levels
What is the dawn phenomenon?
high morning blood glucose
- between 5 and 9 am: counter-regulatory hormones are released
- don't have hypoglycemia at all, just hyperglycemia in the morning
What is the somogyi effect?
- hypoglycemia begets hyperglycemia
- rebound hyperglycemia: iatrogenic, too much insulin because in middle of night will have low sugars and in morning sugars will rebound and will be high, the body is overcompensating for low blood sugars and hormones cause an increase in blood sugar
How do you tell the difference between somogyi and dawn phenomenon?
- to sort out whether an early morning hifh blood sugar level is caused by dawn phenomenon or somogyi effect, check blood sugar levels around 2 to 3 am for several nights
- if blood sugar level is low at 2 to 3 suspect somogyi effect
- if blood sugar level is normal or high at 2 to 3 its likely the dawn phenomenon
Triad of DKA?
- anion gap metabolic acidosis
Most common precipitating event ID in pts with DKA or HHS?
- infection or inadequate insulin therapy