acetazolamide

During case presentations, student presented that a patient was taking acetazolamide for hydrocephalus until she could get in for surgery, I was unaware of this use for it so needed to look into it more:

hydrocephalus: disorder of excessive amount of cerebrospinal fluid which accumulates in the ventricles and subarachnoid space

• CSF is produced by the choroid plexus -- epithelium and connective tissue in cerebral ventricles
• epithelial cells produce CSF using active transport which is dependent upon carbonic anhydrase
• CSF production is generally constant unless intracranial pressure is increased (absorption matches the production)
• production rate ~20mL/hour, complete turnover 3-4 time a day
• hydrocephalus results from imbalance between inflow and outflow
• obstruction of circulation
• inadequate absorption
• overproduction
• leads to increased intracranial pressure and ventricular dilation
• etiology: congenital, neural tube defects, CNS malformations, intrauterine infections, choroid plexus carcinoma, infections, tumors, post-hemorrhagic
• symptoms: headache, N/V, personality/behavior changes, lethargy
• bradycardia, hypertension, altered respiratory rate
• macrocephaly
• compression of cranial nerves
• Progressive (need to manage or will get worse)
• most effective treatment: surgical drainage using a ventriculostomy shunt (prevents excess accumulation of CSF, shunts CSF to either systemic circulation or peritoneum)
• Medical therapy:
• diuretics: furosemide and acetazolamide decrease CSF production
• used for short periods in slowly progressive hydrocephalus that is too unstable for surgery or until surgery can be done
• diuretics generally not effective for infants
• acetazolamide can be used for: acute mountain sickness, edema, glaucoma, retinal edema,
• need to dose adjust for renal impairment, caution in liver disease (can induce coma
• Mechanism of action: inhibits carbonic anhydrase from catalyzing the reversible hydration of carbon dioxide and dehydration of carbonic acid
• delays abnormal paroxysmal excessive discharge from CNS neurons and affects promotion of diuresis and urinary alkalinization
• adverse effects: metabolic acidosis, stevens Johnson syndrome, hepatic necrosis, agranulocytosis, thrombocytopenia, angle-closure glaucoma
• monitoring: CBC and electrolytes