Antihyperglycemic agents. The term "biguanidine" often refers specifically to a class of drugs that function as oral antihyperglycemic drugs used for diabetes mellitus or prediabetes treatment. Examples include: Metformin - widely used in treatment of diabetes mellitus type 2.
2. 1- neuroimaging:
Now days the most useful imaging modalities are
harmless to patients.
In most situations the only modalities to be consider is
( MRI ) and in patients whom MRI cannot be performed
( CT ) is usually satisfactory.
CT scan is the first choice to exclude surgical
emergencies.
Plain x-rays of the skull is obsolete, but a limited role
for plain x-rays of the spine.
3. Plain x-rays:
-A- skull fractures either pathological or non-pathological.
-B- spine:
1-trauma.
2- instability in non-traumatic conditions. e.g RA, down
syndrome.
3- spondylotic spinal stenosis.
4- spinal metastasis and other tumors which destroy or
erode bone need to remove 50-70 % of bone mass
before it become apparent on plain x-rays.
5- osteomylitis with root or spinal cord compression.
6- chest x-rays used to excluding many systemic
diseases which may present neurologically.
4. CT scanning:
CT scan account for 13% of the radiological
examinations and 30% of the overall
radiation exposure attributable to
examinations.
Although (MRI) has better sensitivity than (CT)
for detecting intra-axail and extra-axial brain
and spine lesions.
CT still remains the quickest and most efficient
means of screening the patient with certain
condition such as head trauma, calcification,
SAH, fracture of orbit, temporal bone, and
skull.
5. Indications:
1- acute head trauma.
2- SAH.
3- fractures of orbit, temporal bones, face and
skull.
4- detection of calcification.
5- subtle bony irregularities.
6- bony spinal lesions.
7- disease of the temporal bone.
8- sinusitis.
9- when MRI is contraindicated.
6. Intracranial calcifications:
1- physiological.
1- pineal gland ( 20%).
2- choroid plexus ( usually bilateral )
3- dura matter and falx cerebri.
2- non-physiological.
1- neoplasm.
2-inflammatory.
3- infections like TB.
4- vascular malformation and chronic subdural
hematoma.
7. MRI scanning:
T1 weighted images ( T1W) are most useful for
analyzing anatomical details and are
employed in conjunction with gadolinium
contrast because enhancing lesions appear
bright on it.
T2 W are very sensitive to the presence of
increase water and can visualize
edema.
9. Contraindications:
1- cardiac pacemaker.
2- cochlear prostheses.
3- intracranial aneurysm clips.
4- ocular implants.
5- magnetic dental implants.
6- magnetic sphincters.
7- deep brain stimulators.
8- foreign bodies in the eyes.
9- severe claustrophobia.
10- swan- ganz catheter.
10. Angiography:
- it is invasive test.
The indication for diagnostic angiography have greatly
diminished since the advent of CT.
-
Four vessels technique performed, two carotid and two
vertebral arteries.
Indications:
1- aneurysms greater than 4mm in diameter are reliably
shown.
2- AVM.
3- arteritis.
4- carotid stenosis is controversial
5- dural sinus thrombosis.
6- preliminary to endovascular treatment.
11. Complications:
1- hematoma or infection in 5% at the arterial
puncture.
2- arterial vasospasm.
3- stroke in 1-2%.
4- death in 1-2%.
12. :
CSF :
samples of CSf may be obtained with
relative ease at the bedside by lumbar
puncture.
The best positioned on the side, flexed and
with the spine horizontal.
The needle is usually introduced at the L3/L4
interspace which is indicated by a line drawn
joining the tips of the iliac crests.
13. Indications for brain imaging
prior to LP:
S & S of raised ICP ( headache, vomiting,
papelledemia).
Focal neurological deficit.
Fixed dilated or poorly reactive pupil.
Coma or a rapidly deteriorating concious level.
Signs of posterior fossa lesion ( dysarthria,
ataxia ).
Immunocompromized patients ( malignancy,
transplants )
14. Normal CSF:
Clear colourless fluid.
Pressure 40-180 mm H2o.
Cells 0-5 lymphocytes.
Sugar 2.5-4.4 mmol/l ( 2/3 of blood
glucose )
Protien o.2 o.5 g/L
16. Low CSF protien:
1- CSF leaks.
2- removal of a large csf volume.
3-pseudotumor cerebri in 1/3 of
patient.
4- acute water intoxication.
5- aged between 6 months – 2 years.
6- hyperthyroidism.
7- leukemias.
17. Elevated CSF protein with a cellular
response:
1- G.B.S ( AIDP)
2- chronic inflammatory demylinating
polyneuropathy.
3- schwannoma.
4- spinal cord compression.
19. Special CSF tests:
-A- oligoclonal bands:
use of variety of supporting media including agarose
gels and polyacrylamide gels, for the electrophoretic
separation provides a visual separation of
homogeneous immunoglobulins as bands when stain
appropriately.
Three patterns of bands can be observed in the gamma
region monoclonal, polyclonal, and oligoclonal ( 2-5
bands).
-
A single oligoclonal band is commonly seen in
otherwise normal CSF of normal subjects.
-
Two or more is abnormal.
-
20. Causes of oligoclonal bands:
1- multiple sclerosis 83-94% of definite ms.
2- subacute scleroting panencephaliktis (
SSPE). In 100% of patients .
3- CNS infection in 50% of bacterial, viral
and fungal infections.
4- CNS inflammatory disorders.
vasculitis
neurosarcoidosis.
CNS lupus
G.B.S
behcet disease.
21. -B- myelin basic protein:
it is a product of oligodendroglia, it is antigen
represent when there is damage to CNS appear in
the CSF, blood and urine.
its concentration in normal CSF is very low less
than 0.4mg/dl.
Common causes of elevated MBP:
1- multiple sclerosis.
2- sroke.
3- trauma.
4- tumors.
5- CNS infections
6- polyneuropathy.
7- dementia.
8- leukodystrophy.
