Endocrinology Flashcards
(38 cards)
Life threatening causes of polydispsia? (List 3)
DI (central and nephrogenic), DM, primary polydipsia
DDx of polydipsia?
o Diabetes mellitus
o Diabetes insipidus (ADH deficiency - CNS causes vs. nephrogenic)
o Sickle cell
o Less common: electrolyte imbalance, catecholamine excess, cystinosis, medications (lithium, methylxanthines, diuretics, other nephrotoxins)
o Primary polydipsia: ingestion of water in excess of that needed to maintain water balance
o Bartter syndrome
o Catecholamine excess – pheochromocytoma, neuroblastoma, ganglioneuroma
Clinical features of DKA
polyuria, polydipsia, dehydration, nausea/vomiting, abdo pain, tachypnea - Kussmaul breathing, fruity acetone breath, altered mental status
Definition of DKA?
- Random BG > 11.1
- pH < 7.3 or bicarb < 15
- urine/serum ketones
Fluid management in DKA?
o Initial fluid resuscitation: 10ml/kg NS bolus over 30 minutes, can repeat if ongoing hypoperfusion or tachycardia
If not in shock - 5-7 mm/kg over 1 hour
o Ongoing fluids: 4-6ml/kg/hr (max 250ml/hr), initial NS, D10 if glucose <15 or <25 and dropping by 5. Add 40mmol/L KCl if K <5/5.5 and pt voided.
o Insulin 0.1U/kg/hour after first hour
Risk factors for cerebral edema (list 4)?
Elevated BUN Low PCO2 (initial acidosis) Treatment with bicarb Failure of measured Na to rise with treatment Age < 3 years New-onset diabetes
Hypoglycemia WITHOUT ketones is consistent with?
hyperinsulinism or FAO (ex. MCAD)
Components of critical sample?
blood glucose, gas, lactate, ammonia, electrolytes, insulin, growth hormone, free fatty acids, cortisol, acyl carnitine, amino acids beta-hydroxybutyrate, urine ketones, urine organic acid, C- peptide
Definition of hypoglycemia?
Blood glucose < 3.3 WITH symptoms (altered LOC, confusion, seizures)
or blood glucose < 2.7 WITHOUT symptoms
Symptoms of hypoglycemia?
- Adrenergic: palpitation, anxiety, tremors, hunger, sweating
- Neuroglycopenic: irritability, headache, confusion, fatigue, seizure, LOC
Management of hypoglycemia?
- Initial step: Rule of 50’s: IV/IO 0.5 g/kg = 5 ml/kg D10, 2 ml/kg D25, 1 ml/kg D50; no access can give glucagon 0.03 mg/kg (max 1mg) IM/SC
- Then D10 NS infusion 1.5 maintenance (GIR 6-8 mg/kg/min)
Which toxins cause hypoglycemia?
ethanol, beta-blockers, oral hypoglycemics (sulfonylureas)
How does growth hormone (GH) deficiency present in infants?
hypoglycemia and micropenis (< 2 cm stretched penile length)
Lab findings in adrenal insufficiency?
hyponatremia, hypoglycemia, hyperkalemia, metabolic acidosis, possible hypercalcemia; low cortisol (can also do ACTH stim test)
Treatment of adrenal insufficiency?
o Hydrocortisone 50-100 mg/m2 IV (if no BSA give 1-2 mg/kg); continue high dose steroids 48 hours
o IV fluids – NS boluses, then D10W NS with no K
o treat hyperkalemia if cardiac ECG changes (peaked T waves, prolonged QRS, Vfib)
o hypoglycemia - dextrose and steroids
o treat infection or precipitating factor
3 common presentations of CAH?
ambiguous genitalia
acute salt wasting crisis (infants)
precocious puberty (virilization)
Salt wasting occurs after 2 weeks of life (usually 2-5 weeks old)
Most common cause of CAH?
21-hydroxylase deficiency
Stress dose steroids in CAH?
If unwell - 50 mg/m2 hydrocortisone IM/IV
If well appearing (but fever)– give usual dose PO but given TID (3X daily dose), or HC 50 mg/m2 div TID (given PO)
Clinical presentation of pheochromocytoma?
episodic headache, palpitations, sweating, flushing, tachycardia, HTN (paroxysmal, occurs when symptomatic)
How to treat HTN in pheochromocytoma?
alpha-blocker (ie. Prazosin, sodium nitroprusside IV).
*Unopposed beta-blockade should be avoided as it can cause severe hypertension.
Lab workup of suspected pheochromocytoma?
elevated urine catecholamines and plasma metanephrines – then find the mass with CT or MRI
Clinical presentation of diabetes insipidus?
Polyuria, enuresis, polydipsia, signs of dehydration with “normal” urine output
Lab findings of diabetes insipidus?
High serum Osm (> 300) and sodium (> 145) in presence of dilute urine (Osm < 600 mOsm/L)
Blood glucose normal; Cr normal.
Causes of diabetes insipidus?
- Central = AHD deficiency: head injury, meningitis, idiopathic, suprasellar tumors and treatment by surgery and/or radiotherapy (craniopharyngioma/optic nerve glioma), midline cleft palate, septic optic dysplasia, Wolfram syndrome, histiocyostis X
- Nephrogenic DI: sex linked recessive, renal disease, PCKD, chronic pyelonephritis, lithium, SCD, idiopatic
