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increased intracranial pressure (ICP)

Etiology: 1) obstruction to CSF flow a) intracranial hemorrhage b) ischemic stroke c) head trauma d) CNS infections, encephalopathy e) brain tumor - brain metastases most common malignancy-related cause [3] - lung cancer - cutaneous melanoma - also associated with intracranial hemorrhage - primary brain tumor less common malignancy-related cause - glioma - CNS lymphoma f) other mass lesion (abscess, hematoma) g) hydrocephalus h) vasculitis 1) pseudotumor cerebri (idiopathic intracranial hypertension) 2) obstruction to venous flow a) venous sinus thrombosis b) superior vena cava syndrome c) right heart failure d) dural arteriovenous malformation with shunt 3) pharmaceuticals a) hypervitaminosis A b) isotretinoin c) anabolic steroids d) growth hormone e) glucocorticoid withdrawal f) tetracyclines, doxycycline, minocycline 4) endocrine disease a) Addison's disease b) hypoparathyroidism c) polycystic ovary disease d) obesity e) pregnancy 5) idiopathic (pseudotumor cerebri) Pathology: - any increase in intracranial pressure is not tolerated because of the fixed intracranial volume imposed by a rigid skull - exacerbated by supine position, increased pCO2, decreased resorption of CSF [5] Clinical manifestations: 1) headache a) generally 1st presenting symptom b) worse in morning [2,5] c) exacerbated by Valsalva maneuver 2) nausea/vomiting 3) altered mental status - confusion 4) papilledema 5) focal neurologic deficits - cranial nerve 6 palsy is a false localizing sign associated with intracranial hypertension [3] 6) visual changes 7) dizziness 8) ataxia 9) Cushing's triad a) systolic hypertension b) bradycardia c) irregular respiration or widening pulse pressure 10) loss of consciousness 11) obesity common with idiopathic intracranial hypertension Special laboratory: - ophthalmoscopy for papilledema - lumbar puncture may indicated after mass lesion is excluded by neuroimaging Radiology: - neuroimaging - head CT to evaluate for mass lesions (neoplasm, intracranial bleed) midline shift or cistern effacement suggestive of increased intraranial pressure - 10-15% of patients may be without these findings - magnetic resonance imaging (MRI) - better image quality - patient in less monitored setting - not as fast as CT - optic nerve ultrasonography may detect intracranial hypertension at the bedside [7] Management: 1) avoid obstruction to jugular venous drainage a) elevate head of bed to 30 degrees b) maintain neck & alignment 2) glucocorticoid (dexamethasone) - useful for vasogenic edema from tumors & abscesses - immediate administration indicated [3] 3) ventriculostomy to measure & maintain ICP < 20 mm Hg a) sedation (midazolam, propofol) b) mannitol 1] initially: 0.5-1.0 mg/kg 2] maintenance: 0.25-0.5 g/kg every 3-5 hours 3] may be used in conjunction with diuretics c) hyperventilate to pCO2 of 30-35 torr a) induces respiratory alkalosis b) cerebral vasoconstriction c) may reduce intracranial pressure by 25-30% d) short term measure: may decrease cerebral blood flow 4) maintain cerebral perfusion pressure (CPP) > 70 mm Hg a) control ICP b) maintain euvolemia c) vasopressors 5) ventricular drainage for patients with hydrocephalus 6) avoid hypotonic solutions (D5W, 1/2 NS) 7) acetazolamide for idiopathic intracranial hypertension (pseudotumor cerebri) 8) anticonvulsants: - phenytoin 100 mg IV/NG every 8 hours for 7 days - levetiracetam may be better 9) high dose barbiturate therapy (phenobarbital)

Related

cerebral perfusion pressure (CPP) criteria for removal of intracranial pressure (ICP) monitor Cushing's triad intracranial pressure (ICP)

Specific

pseudotumor cerebri; idiopathic intracranial hypertension

General

sign/symptom disease/disorder primarily affecting brain

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 1019
  2. CHS Patient Care Protocol 11/98, protocol 244-6140
  3. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2012, 2015, 2018.
  4. Eisenberg HM et al, Initial CT findings in 753 patients with severe head injury. A report from the NIH Traumatic Coma Data Bank, J Neurosurg 1990, 73:688 PMID: 2213158
  5. Dunn LT. Raised intracranial pressure. J Neurol Neurosurg Psychiatry. 2002 Sep;73 Suppl 1:i23-7. PMID: 12185258
  6. Hoffmann J, Goadsby PJ Update on intracranial hypertension and hypotension. Curr Opin Neurol. 2013 Jun;26(3):240-7 PMID: 23594732
  7. Koziarz A, Sne N, Kegel F et al Bedside Optic Nerve Ultrasonography for Diagnosing Increased Intracranial Pressure: A Systematic Review and Meta-analysis. Ann Intern Med. 2019. Nov 19. PMID: 31739316 https://annals.org/aim/article-abstract/2755727/bedside-optic-nerve-ultrasonography-diagnosing-increased-intracranial-pressure-systematic-review