extra case 1. 22 year old female pc: 2/52 headache hpc: daily throbbing headache involving entire...
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PRESENTATION 22 year old female PC: 2/52 headache HPC: daily throbbing headache involving entire head Worse upon waking, get better as day goes on Has nausea, vomiting and intermittent diplopia (2/7) Some alleviation by paracetamol and ibuprofen PMHx: asthma Meds: COCP Allergies: sulphurs FHx: An aunt died of a brain tumour in her 50s SHx: Receptionist, shares a flat with friend
EXAMINATION
O/E: Afebrile, BP 110/70, PR 80 reg Neck supple, no meningismus CVS/ RESP/ABDO: normal Neuro: alert, uncomfortable from pain Cranial nerves: pupils reactive, bilateral
papilloedema, right sixth nerve palsy. Motor Examination: normal strength Reflexes: Normal, plantar response down
going bilaterally. Normal co-ordination and gait.
WHAT IS PAPILLOEDEMA? WHAT ARE THE COMMON CAUSES OF PAPILLOEDEMA?
= swelling of the optic disc due to raised intracranial pressure
Intracranial mass lesions (eg. tumour, hematoma) Cerebral oedema (eg. Due to acute hypoxic ischemic
encephalopathy, large cerebral infarction, severe traumatic brain injury)
Increased CSF production (eg. choroid plexus papilloma) Decreased CSF absorption (eg. arachnoid granulation
adhesions after bacterial meningitis) Obstructive hydrocephalus Obstruction of venous outflow (eg. venous sinus
thrombosis, jugular vein compression, neck surgery) Idiopathic intracranial hypertension (pseudotumor
cerebri)
WHAT IS THE DIFFERENTIAL DIAGNOSIS? Idiopathic (benign) intracranial hypertension Migraine; tension-type headache; medication overuse
headache but these would not have papilloedema Malignant hypertension optic neuropathy can be
mistaken for papilloedema Secondary intracranial hypertension
Metastatic tumour, hematoma intracranial mass lesion Acute hypoxic ischemic encephalopathy, large cerebral
infarction, severe traumatic brain injury cerebral oedema Choroid plexus papilloma inc CSF production Arachnoid granulation adhesions after bacterial meningitis
dec CSF absorption Obstructive hydrocephalus Venous sinus thrombosis, jugular vein compression, neck
surgery obstruction of venous outflow
WHAT TEST(S) WOULD YOU PERFORM? Neuroimaging then lumbar puncture (to rule out other Dx and
determine opening pressure) MRI > CT if IIH, MRI may show
Flattening of the posterior sclera (80%) Distension of perioptic subarachnoid space (50%) Enhancement (with gadolinium) of the prelaminar optic nerve (45%) Empty sella (70%) Intraocular protrusion of the prelaminar optic nerve (30%) Vertical tortuosity of the orbital optic nerve (40%)
MRV is more sensitive than MRI for finding cerebral venous thromboses
LP: measure opening pressure; analyse CSF for cell count, glucose and protein may indicate need for culture for microbial agents; CSF cytology or; antigen testing (eg, CSF VDRL)
Also need to check visual fields (assess severity and monitor response) either Goldmann kinetic perimetry or computer-assisted static perimetry May find: enlarged blind spot; generalized constriction; inferonasal vision
loss
WHAT IS THE PROBLEM WITH THE PATIENT’S VISION?
Intermittent diplopia believed to be due to fluctuations in perfusion of the nerve head
Papilloedema: inc ICP transmitted to the optic nerve sheath mechanical disruption of axoplasmic flow swelling of the axons and leakage of water/protein/other cellular contents into the extracellular space of the optic disc optic disc oedema
CNVI palsy due to inc ICP; CNVI has long intracranial course before exiting the skull
INVESTIGATIONS Contrast-enhanced MRI of the brain
normal LP 30mL CSF drained Lumbar puncture:
Headache improves considerably Nausea and vomiting resolve over 1-2/7 Diplopia resolves over 1/52
TECHNIQUE
Lateral recumbent position (or sitting upright) for accurate measurement of opening pressure
Level of entry for spinal needle: use highest points of iliac crests as guide for L4 vertebral body palpate spinous processes and interspaces of L3, L4 and L5 insert needle into subarachnoid space at L3/4 or L4/5 interspace below the termination of the spinal cord
Pt must be in foetal position neck, back and limbs in flexion; lower lumbar spine flexed determines success of obtaining CSF
Clean and disinfect skin local anaesthetic for lumbar intervertebral space insert 20 or 22 gauge spinal needle with a stylet advance needle slowly, angling slightly towards head (aim for umbilicus) transiently remove stylet at subarachnoid space to confirm CSF flow
pt should slowly straighten legs (allow CSF flow) measure opening pressure with manometer collect fluid (usually 8-15mL, but can be up to 40mL for culture) replace stylet remove spinal needle
Queckenstedt manoeuvre: measure CSF pressure then manually compress both jugular veins and note change in pressure old method to show flow from ventricles to lumbar space
http://www.youtube.com/watch?v=R2_0gOI8uV0
INDICATIONS AND CONTRAINDICATIONS Indications: diagnosis of CNS infections and sometime to help
diagnose subarachnoid haemorrhage, CNS malignancies, demyelinating diseaes and Guillain-Barre syndrome
Urgent LP for suspected CNS infection (except for brain abscess or a parameningeal process) and suspected subarachnoid haemorrhage with a negative CT scan
Nonurgent LP is indicated for diagnosis of: IIH, carcinomatous meningitis, tuberculous meningitis, normal pressure hydrocephalus, CNS syphilis, CNS vasculitis
LP in therapy: spinal anaesthesia; intrathecal chemotherapy/antibiotic administration; injection of contrast media for myelography/cisternography
Contraindications: no absolute contraindications, but take care with
Possible raised intracranial pressure Thrombocytopenia or other bleeding diathesis (including
anticoagulant therapy) Suspected spinal epidural abscess
SIDE EFFECTS AND COMPLICATIONS Complications: post-LP headache; infection; bleeding;
cerebral herniation; minor neurologic symptoms (radicular pain, numbness); late onset of epidermoid tumours of the thecal sac; back pain
Post-LP headache: due to leakage of CSF from dura and traction on pain-sensitive structures
Infection: either meningitis or other (discitis or vertebral osteomyelitis) but uncommon
Back pain and/or neurologic symptoms: can suggest haematoma take care if bleeding disorder
Cerebral herniation: take care if suspected inc ICP Epidermoid tumour: rare, may only be evident years after
procedure is performed can be due to epidermoid tissue being transplanted into the spinal canal when not using a stylet or if the stylet is poorly fitting
CNVI palsy: results from intracranial hypotension, generally accompanied by other features of post-LP headache
WHAT IS THE NORMAL CONSTITUENTS AND OPENING PRESSURE OF CSF?
Opening pressure: 50–200 mm H2O CSF Colour: colourless Turbidity: crystal clear Mononuclear cells: <5 per mm3
Polymorphonuclear leukocytes: 0 Mean total protein: 22–38 mg/dl
Range: 9–58 mg/dl (mean ± 2.0 SD) Glucose: 60–80% of blood glucose
HOW DO THESE TESTS AND FINDINGS HELP IN THE DIAGNOSIS? Opening pressure – pressures over 180 are considered
abnormal Can compare opening and closing pressure to estimate the
volume of CSF reservoir. Clarity - pleocytosis (inc cell count) is the usual reason for
cloudy fluid. >200 white cells per cubic millimeter can be present without
altering the clarity >500 white cells per cubic millimeter usually produces cloudiness. Red cell concentrations between 500 and 6000 per mm3 can cause
the fluid to appear cloudy; concentrations of over 6000 give a grossly bloody appearance.
A markedly elevated protein can also alter the clarity of the CSF. But little clinical use as a large number of cells can be present
without affecting the clarity. Colour - Xanthochromia commonly indicates spontaneous
subarachnoid hemorrhage. A variety of conditions, however, can also produce xanthochromia: a traumatic tap; bilirubin due to jaundice; protein; etc.
Cells – CNS infections produce 3 basic CSF types which suggest diagnoses
WHICH CONDITIONS ARE ASSOCIATED WITH BIH? Affects the brain, appears to be (but is not) a tumour; often reversible. Clinical criteria: include headache, papilloedema, vision loss, elevated
ICP with normal cerebrospinal fluid composition, and no other cause of intracranial hypertension evident on neuroimaging or other evaluations.
Despite its prior name (BIH), it is not a benign disorder. Many patients suffer from intractable, disabling headaches, and there is a risk of severe, permanent vision loss.
Pathogenesis is unknown. Associated conditions:
Medication – may just be anecdotal Systemic illnesses — In addition to obesity, systemic illnesses reportedly
associated with IIH include: Addison disease Hypoparathyroidism Anaemia, usually severe Sleep apnoea Systemic lupus erythematosus (SLE) Behcet's syndrome Polycystic ovary syndrome Coagulation disorders Uremia
DISCUSS TREATMENT OF THIS CONDITION The treatment of IIH has two major goals: the alleviation
of symptoms (usually headache) and the preservation of vision.
Weight loss – low sodium wt reduction program Medications - carbonic anhydrase inhibitors, loop
diuretics, and corticosteroids Carbonic anhydrase inhibitors – believed to reduce rate of CSF
production Cautious with corticosteroids because of weight gain, steroid
withdrawal may cause severe rebound intracranial hypertension Headache prophylaxis Serial lumbar punctures – not recommended as CSF
reforms within 6 hours, therefore short term treatment, uncomfortable, complications
Surgery – CSF shunting, optic nerve sheath fenestration
ARE THERE ANY LONG-TERM COMPLICATIONS OF THIS CONDITION?
Permanent vision loss is the major morbidity associated with IIH.
A recurrence of symptoms may occur in 8 to 38 percent of patients after recovery from an episode of IIH or after a prolonged period of stability. Weight gain is a common but not universal antecedent to recurrent IIH