IDIOPATHIC INTRACRANIAL HYPERTENSION

IDIOPATHIC INTRACRANIAL HYPERTENSION

What is Idiopathic intracranial hypertension (IIH)?

IIH is a condition characterized by raised intracranial pressure (ICP) of unknown etiology. It is also known as benign intracranial hypertension or pseudotumor cerebri.

What are the common symptoms of IIH?

The commonest symptom of IIH is headache. In some cases, visual blurring or double vision may occur.

What is the dreaded complication in patients with IIH?

If IIH is left untreated, there is a threat to vision. Partial or complete loss of vision may occur. In many of these cases, vision may not revert to normal even after treatment.

How is the diagnosis of IIH confirmed?

The diagnostic criteria for IIH, including those of the Dandy criteria as described by Dandy in 1937 and later modified, are as follows (source: Medscape)

·       There are symptoms and signs of increased intracranial pressure

·       There are no localizing neurologic signs (with the exception of a unilateral or bilateral sixth nerve paresis)

·       Cerebrospinal fluid (CSF) may show increased pressure, but there are no cytologic or chemical abnormalities

·       Neuroimaging reveals no structural cause or hydrocephalus

·       No other causes of increased intracranial pressure found through workup

Subsequent additions to these criteria include the following

·       The diagnostic lumbar puncture should be performed with the patient in the lateral decubitus position

·       Magnetic resonance venography should be included to rule out intracranial venous sinus thromboses

What are the common abnormalities of IIH on MRI/MR Venogram brain?

Brain MRI with gadolinium contrast venogram is the imaging modality of choice, as it can effectively rule out meningitis/meningeal infiltrates, hydrocephalus, mass lesions, cerebral venous sinus thrombosis, etc. In addition, there are certain abnormalities, which are typically seen in patients with IIH:

·      Partial empty sella

·      Flattening of posterior globe

·      Distension of perioptic subarachnoid space

·      Vertical tortuosity of orbital optic nerve

What is the role of lumbar puncture in the diagnosis of IIH?

Lumbar puncture should be done in left lateral decubitus. It confirms the elevated ICP, opening pressure >200 mm water. Lumbar puncture also helps in excluding meningitis.

What is the mainstay of treatment?

Medical treatment with diamox (acetazolamide) is the primary treatment to be started in patients with IIH. Starting dose should be 500-1000 mg per day and a maximum dose of 4 grams per day can be used. Common side effects include paresthesia and tingling.

Diamox to lower intracranial pressure is indicated when there is 

1) visual field loss on automated perimetry, 

2) transient visual obscurations, 

3) binocular diplopia, or 

4) pulsatile tinnitus.

Does weight loss help in patients with IIH?

Yes, a weight loss of 5-10% can lead to substantial reduction in reducing symptoms of IIH and papilledema.

Do patients with IIH need surgery?

There are a group of patients that need surgery. Patients with severe papilledema with impending threat to visual loss or those presenting with loss of vision require an early surgery. Another group of patients who may need surgery are those that continue to worsen despite being on adequate doses of acetazolamide.

What are the surgical options in IIH?

1.     Optic nerve sheath fenestration

2.     CSF diversion procedures such as theco-peritoneal or ventriculo-peritoneal shunt surgery.

Dr Sudhir Kumar MD DM

Consultant Neurologist

Apollo Hospitals, Hyderabad

drsudhirkumar@yahoo.com

DEEP BRAIN STIMULATION (DBS) IN PARKINSON’S DISEASE

DEEP BRAIN STIMULATION (DBS) IN PARKINSON’S DISEASE

Major Symptoms of Parkinson’s disease

Parkinson’s disease (PD) is a progressive neurological disease, characterised by tremors, rigidity, slowness of movements and postural imbalance. Though it is more common after the age of 40, people younger than 40 can also get affected (when it is known as young onset PD).

Other symptoms of PD include low volume speech (sometimes totally incomprehensible), expressionless face, reduced blink rate, reduced arm swing while walking, stooped posture, small handwriting (called micrographia), short-shuffling steps, tendency to fall forwards. Many people also have pain and aches in the affected limbs. Sleep disturbance and restless leg syndrome are common comorbid illnesses in people with PD. Severe memory impairment is NOT a feature of PD, however, in advance PD, mild memory impairment may occur in about 10% of patients. Similarly, loss of bladder control or erectile dysfunction is not a feature of PD. When these features are present, one should suspect multiple system atrophy (MSA).

Diagnosis of PD

The diagnosis of PD is still best made on the basis of clinical examination by an experienced neurologist (preferably trained in movement disorders, though not a must). PET and DaT scans are available to help in the diagnosis of PD, but they are not superior to a good clinical examination by an experienced neurologist.

Treatment of PD

Treatment of PD is still primarily medical and DBS is not the first option.

The most effective medicine is levodopa-carbidopa combination. If a patient does not respond to levodopa treatment, we should doubt the diagnosis (it may not be PD). Even though levodopa is the most effective medication, we should delay starting it by 2-3 years, to avoid side effects and lack of efficacy later on. Other medications in use are pramipexole, ropinirole, trihexiphenydyl, selegiline, rasagiline, amantadine, entacapone, safinamide, etc.

Role of Deep Brain Stimulation (DBS) surgery in PD

DBS was approved for PD in 2002. In the past 15 years, about 1,35,000 patients worldwide have undergone DBS for PD.

What does DBS surgery involve?

A neurosurgeon places the leads (thin wires) that carry electrical signals to specific areas of the brain. Then, the surgeon places a battery-run neurostimulator (like a pacemaker) under the skin of the chest.

The surgeon may use a programming device to adjust the settings. You may have a device, similar to a remote control, which allows you to turn the system on and off and check the battery. You may also be able to adjust the stimulation within options programmed by your doctor.

A neurologist initially evaluates a patient to determine whether he or she is the right candidate for DBS surgery. Then, further evaluations include brain imaging (MRI, CT, PET, etc), neuropsychological testing, UPDRS scoring, etc. Once the patient is found to be suitable for DBS, he is referred to the neurosurgeon.

Which patients are likely to benefit from DBS surgery?

1.     The diagnosis of PD should be definite.

2.     Patient has had PD for five years or more.

3.     Patient continues to respond to levodopa, even though the response may or may not be good.

4.     There are motor fluctuations, such as on-off phenomena, with or without dyskinesia.

5.     Various medical treatments have not had desired benefit.

6.     PD symptoms are severe enough to interfere with activities of daily living.

Which patients are NOT likely to benefit from DBS surgery?

1.     Patients with atypical Parkinsonian symptoms,

2.     Patients with multiple system atrophy (where bladder and sexual dysfunction are prominent symptoms),

3.     Patients with progressive supranuclear palsy,

4.     Patients with dementia or severe cognitive impairment,

5.     Patients with unstable psychiatric illnesses,

6.     Patients with advanced PD, who are confined to bed/wheelchair; despite being on medications,

7.     Patients with NO response to levodopa therapy,

Who are the best candidates for DBS surgery in PD?

1.     Excellent response to levodopa therapy,

2.     Younger age,

3.     Mild or no cognitive impairment,

4.     Few or no axial (affecting neck or trunk) motor symptoms,

5.     Absence of or well controlled psychiatric disease.

Are there any complications of DBS surgery?

DBS surgery is generally safe if performed by a trained group of specialists. However, complications may occur in upto 3% of patients, which include:

1.     Bleeding (hemorrhage) in the brain,

2.     Infection,

3.     Stroke,

4.     Speech impairment

5.     Erosion, migration or fracture of the lead,

6.     Death

What to expect after DBS surgery?

Most patients report a reduction in severity of symptoms after surgery. Tremors, dyskinesia, slowness all respond to the surgery.

PD medications, however, can not be stopped even after DBS. Most patients still need to take medications, however, at much lower doses.

The benefits are seen at five years after surgery, however, the effect tends to wane in later years.

DBS does not alter the disease progerssion, and disease continues to get worse even after DBS.

Is MRI safe after DBS?

Yes, MRI can be safely done after DBS surgery.

What is the cost of DBS surgery ?

The cost of surgery is approximately INR 9,00,000 to 10,00,000.

Dr Sudhir Kumar MD (Med) DM (Neuro)

Senior Consultant Neurologist

Apollo hospitals, Hyderabad

http://www.facebook.com/bestneurologist/

drsudhirkumar@yahoo.com

04023607777/60601066