43651 - Diabetic Ketoacidosis Abdelaziz Elamin Professor of...

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Unformatted text preview: Diabetic Ketoacidosis Abdelaziz Elamin Professor of Pediatric Endocrinology University of Khartoum, Sudan Introduction DKA is a serious acute complications of Diabetes Mellitus. It carries significant risk of death and/or morbidity especially with delayed treatment. The prognosis of DKA is worse in the extremes of age, with a mortality rates of 510%. With the new advances of therapy, DKA mortality decreases to > 2%. Before discovery and use of Insulin (1922) the mortality was 100%. Epidemiology DKA is reported in 25% of known type 1 diabetic patients in industrialized countries, while it occurs in 3540% of such patients in Africa. DKA at the time of first diagnosis of diabetes mellitus is reported in only 23% in western Europe, but is seen in 95% of diabetic children in Sudan. Similar results were reported from other African countries . Consequences The latter observation is annoying because it implies the following: The late diagnosis of type 1 diabetes in many developing countries particularly in Africa. The late presentation of DKA, which is associated with risk of morbidity & mortality Death of young children with DKA undiagnosed or wrongly diagnosed as malaria or meningitis. Pathophysiology Secondary to insulin deficiency, and the action of counterregulatory hormones, blood glucose increases leading to hyperglycemia and glucosuria. Glucosuria causes an osmotic diuresis, leading to water & Na loss. In the absence of insulin activity the body fails to utilize glucose as fuel and uses fats instead. This leads to ketosis. Pathophysiology/2 The excess of ketone bodies will cause metabolic acidosis, the later is also aggravated by Lactic acidosis caused by dehydration & poor tissue perfusion. Vomiting due to an ileus, plus increased insensible water losses due to tachypnea will worsen the state of dehydration. Electrolyte abnormalities are 2ry to their loss in urine & transmembrane alterations following acidosis & osmotic diuresis. Pathophysiology/3 Because of acidosis, K ions enter the circulation leading to hyperkalemia, this is aggravated by dehydration and renal failure. So, depending on the duration of DKA, serum K at diagnosis may be high, normal or low, but the intracellular K stores are always depleted. Phosphate depletion will also take place due to metabolic acidosis. Na loss occurs secondary to the hyperosmotic state & the osmotic diuresis. Pathophysiology/4 The dehydration can lead to decreased kidney perfusion and acute renal failure. Accumulation of ketone bodies contributes to the abdominal pain and vomiting. The increasing acidosis leads to acidotic breathing and acetone smell in the breath and eventually causes impaired consciousness and coma. Precipitating Factors New onset of type 1 DM: 25% Infections (the most common cause): 40% Drugs: e.g. Steroids, Thiazides, Dobutamine & Turbutaline. Omission of Insulin: 20%. This is due to: Nonavailability (poor countries) fear of hypoglycemia rebellion of authority fear of weight gain stress of chronic disease DIAGNOSIS You should suspect DKA if a diabetic patient presents with: Dehydration. Acidotic (Kussmaul's) breathing, with a fruity smell (acetone). Abdominal pain &\or distension. Vomiting. An altered mental status ranging from disorientation to coma. DIAGNOSIS/2 To diagnose DKA, the following criteria must be fulfilled : 1. Hyperglycemia: of > 300 mg/dl & glucosuria 2. Ketonemia and ketonuria 3. Metabolic acidosis: pH < 7.25, serum bicarbonate < 15 mmol/l. Anion gap >10. Anion gap= [Na]+[K] [Cl]+[HCO3]. This is usually accompanied with severe dehydration and electrolyte imbalance. Management The management steps of DKA includes: Assessment of causes & sequele of DKA by taking a short history & performing a scan examination. Quick diagnosis of DKA at the ER. Baseline investigations. Treatment, Monitoring & avoiding complications. Transition to outpatient management. Assessment History: Symptoms of hyperglycemia, precipitating factors , diet and insulin dose. Examination: Look for signs of dehydration, acidosis, and electrolytes imbalance, including shock, hypotension, acidotic breathing, CNS status...etc. Look for signs of hidden infections (Fever strongly suggests infection) and If possible, obtain accurate weight before starting treatment. Quick Diagnosis Known diabetic children confirm D hyperglycemia, K ketonuria & A acidosis. Newly diagnosed diabetic children be careful not to miss because it may mimic serious infections like meningitis. Both Hyperglycemia (using glucometer) glycosuria, & ketonuria (with strips) must be done in the ER and treatment started, without waiting for Lab results which may be delayed. Baseline Investigations The initial Lab evaluation includes: Plasma & urine levels of glucose & ketones. ABG, U&E (including Na, K, Ca, Mg, Cl, PO4, HCO3), & arterial pH (with calculated anion gap). Venous pH is as accurate as arterial (an error of 0.025 less than arterial pH) Complete Blood Count with differential. Further tests e.g., cultures, Xrays...etc , are done when needed. Pitfalls in DKA High WCC: may be seen in the absence of infections. BUN: may be elevated with prerenal azotemia secondary to dehydration. Creatinine: some assays may crossreact with ketone bodies, so it may not reflect true renal function. Serum Amylase: is often raised, & when there is abdominal pain, a diagnosis of pancreatitis may mistakenly be made. Treatment Principles of Treatment: Careful replacement of fluid deficits. Correction of acidosis & hyperglycemia via Insulin administration. Correction of electrolytes imbalance. Treatment of underlying cause. Monitoring for complications of treatment. Manage DKA in the PICU. If not available it can be managed in the special care room of the pediatric inpatient ward. Fluids replacement Determine hydration status: A. administer 0.9% saline, Ringer's lactate or a plasma expander as a bolus dose of 2030 ml/kg. This can be repeated if the state of shock persists. Once the patient is out of shock, you go to the 2nd step of management. Hypovolemic shock: Fluids replacement/2 B Dehydration without shock: 1. 2. Administer 0.9% Saline 10 ml/kg/hour for an initial hour, to restore blood volume and renal perfusion. The remaining deficit should be added to the maintenance, & the total being replaced over 36 48 hours. To avoid rapid shifts in serum osmolality 0.9% Saline can be used for the initial 46 hours, followed by 0.45% saline. Fluids replacement/3 When serum glucose reaches 250mg/dl change fluid to 5% dextrose with 0.45 saline, at a rate that allow complete restoration in 48 hours, & to maintain glucose at 150250mg/dl. Pediatric saline 0.18% Na Cl should not be used even in young children. Insulin Therapy start infusing regular insulin at a rate of 0.1U/kg/hour using a syringe pump. Optimally, serum glucose should decrease in a rate no faster than 100mg/dl/hour. If serum glucose falls < 200 prior to correction of acidosis, change IV fluid from D5 to D10, but don't decrease the rate of insulin infusion. The use of initial bolus of insulin (IV/IM) is controversial. Insulin Therapy/2 Continue the Insulin infusion until acidosis is cleared: pH > 7.3. Bicarbonate > 15 mmol/l Normal anion gap 1012. Correction of Acidosis Insulin therapy stops lipolysis and promotes the metabolism of ketone bodies. This together with correction of dehydration normalize the blood PH. Bicarbonate therapy should not be used unless severe acidosis (pH<7.0) results in hemodynamic instability. If it must be given, it must infused slowly over several hours. As acidosis is corrected, urine KB appear to rise. Urine KB are not of prognostic value in DKA. Insulin Therapy/3 If no adequate settings (i.e. no infusion or syringe pumps & no ICU care which is the usual situation in many developing countries) Give regular Insulin 0.1 U/kg/hour IM till acidosis disappears and blood glucose drops to <250 mg/dl, then us SC insulin in a dose of 0.25 U/kg every 4 hours. When patient is out of DKA return to the previous insulin dose. Correction of Electrolyte Imbalance Regardless of K conc. at presentation, total body K is low. So, as soon as the urine output is restored, potassium supplementation must be added to IV fluid at a conc. of 2040 mmol/l, where added to IV fluid at a conc. 50% of it given as KCl, & the rest as potassium phosphate, this will provide phosphate for replacement, & avoids excess phosphate (may precipitate hypocalcaemia) & excess Cl (may precipitate cerebral edema or adds to acidosis). Potassium If K conc. < 2.5, administer 1mmol/kg of KCl in IV saline over 1 hour. Withhold Insulin until K conc. becomes> 2.5 and monitor K conc. hourly. If serum potassium is 6 or more, do not give potassium till you check renal function and patients passes adequate urine. Monitoring A flow chart must be used to monitor fluid balance & Lab measures. serum glucose must be measured hourly. electrolytes also 23 hourly. Ca, Mg, & phosphate must be measured initially & at least once during therapy. Neurological & mental state must examined frequently, & any complaints of headache or deterioration of mental status should prompt rapid evaluation for possible cerebral edema. Complications Cerebral Edema Intracranial thrombosis or infarction. Acute tubular necrosis. peripheral edema. Cerebral Edema Clinically apparent Cerebral edema occurs in 1 2% of children with DKA. It is a serious complication with a mortality of > 70%. Only 15% recover without permanent damage. Typically it takes place 610 hours after initiation of treatment, often following a period of clinical improvement. Causes of Cerebral Edema The mechanism of CE is not fully understood, but many factors have been implicated: rapid and/or sharp decline in serum osmolality with treatment. high initial corrected serum Na concentration. high initial serum glucose concentration. longer duration of symptoms prior to initiation of treatment. younger age. failure of serum Na to raise as serum glucose falls during treatment. Presentations of C. Edema Cerebral Edema Presentations include: deterioration of level of consciousness. lethargy & decrease in arousal. headache & pupillary changes. seizures & incontinence. bradycardia. & respiratory arrest when brain stem herniation takes place. Treatment of C. Edema Reduce IV fluids Raise foot of Bed IV Mannitol Elective Ventilation Dialysis if associated with fluid overload or renal failure. Use of IV dexamethasone is not recommended. The End ...
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This note was uploaded on 03/08/2012 for the course PHARM 300 taught by Professor Staff during the Fall '11 term at Rutgers.

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