Category: SCIENCE BLOG

Anatomy of the eye.
The eye is the organ of sight. It is situated in the orbital cavity and is supplied by the optic nerve . It is almost spherical in shape and about 2.5 cm in diameter. The space between the eye and orbital cavity is occupied by adipose tissue . The bony walls of the orbit and the fat protects the eye from injury.
STRUCTURE- There are three layer of tissue in the walls of the eye:-
• The outer fibrous layer :sclera and cornea
• The middle vascular layer or uveal tract:consisting of the choroid,ciliary body and iris
• The inner nervous tissue layer :the retina
SCLERA AND CORNEA:- The sclera ,or white of the eye ,forms the outermost layer of the posterior and lateral aspects of the eyeball and is continous anteriorly with the cornea.
CHOROID:- The choroid lines the posterior five-sixth of the inner surface of the sclera and it is rich in blood vessels and it absorbs light which enters in the eye through the pupil.
Ciliary body:The ciliary body is the anterior continuation of the choroid consisting of the ciliary muscle and secretory epithelial cells.
Iris: The iris is the visible coloured ring at the front of the eye and extends anteriorly from the ciliary body,lying behind the cornea and in front of the lens.
Lens: The lens is a highly elastic circular biconvex body,lying immediately behind the pupil .
RETINA:- The retina is the innermost lining of the eye. It is extremely delicate structure and well adapted for stimulation by light rays.
BLOOD SUPPLY TO THE EYE:- The eye is supplied with arterial blood by the ciliary arteries and the central retinal artery. These are branches of ophthalmic artery.
Venous drainage is by a number of veins ,including the central retinal vein.
NERVE SUPPLY TO THE EYE:- The eye is supplied by the optic nerve ,which is the second cranial nerve.

Meningitis is an inflammation of the linings around the brain and spinal cord caused by bacteria .
Causative agents:- Streptococcus pyogenes , niesseria meningitides and haemophilus influenza.
Risk factors:- -winter and early spring season.
-Viral upper respiratory infection.
-Otitis media.
-Immune system deficiency.
PATHOPHYSIOLOGY:- Once the causative agent enters the bloodstream,it crosses the blood brain barrier and proliferates in the cerebro spinal fluid. The host immune response stimulates the release of cell wall fragments and lipopolysaccharides ,facilitating of the subarachnoid and pia mater.
Because the cranial vault contains little room for expansion ,the inflammation may cause increased intracranial pressure. Crebro spinal fluid circulates through the subarachnoid space ,where inflammatory cellular materials from the affected meningeal tissue enter and accumulate,as a result clinical manifestation occurs.
CLINICAL MANIFESTATION:- Initial symptoms are headache and fever.
. Neck immobility.
. Positive kerning sign.
.Positive brudzinskis sign.
.Photophobia.
.Disorientation and memory impairement.
.Lethargy, unresponsiveness and coma.
.Seizures and increased intra cranial pressure.
.Brain stem herniation.
.Septicemia.
.Shock.
.Disseminated intravascular coagulation .
DIAGNOSTIC EVALUATION:- . Positive clinical manifestation.
. CT scan and MRI.
.Bacterial culture and gram staining .
.Glassgow coma scale.
MEDICAL MANAGEMENT:- . Vancomycin hydrochloride in combination with one of the cephalosporins is administered intravenously.
. Dexamethasone is administered 15 to 20 minutes before the first dose of antibiotic and every 6 hours for the next 4 days.
.Fluid volume expanders is given.
. Phenitoin is given to control the seizures.
NURSING MANAGEMENT:-
1. Neurological status and vital signs are assessed regularly.
2. Protecting the patient from injury secondary to seizures activity.
3. Preventing complications associated with immobility , such as pressure ulcers and pneumonia.
4. Instituting infection control precautions until 24 hours after initiation of antibiotic therapy.
5. Blood pressure is assessed for incipient shock ,which precedes cardiac or respiratory failure.
6. Insertion of a cuffed endotrachial tube and mechanical ventilation may be necessary to maintain adequate tissue ventilation.
7. Monitoring daily body weight ,serum electrolytes and urine volume ,specific gravity and osmolality ,especially if the syndrome of inappropriate anti diuretic hormone is suspected.