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MeningitisPROBLEM BASED LEARNING (PBL)

PREPARED BY: MUHAMMAD ARIFF B. MAHDZUB

BACHELOR MEDICINE AND SURGERY (MBBS)

UNIVERSITY COLLEGE SHAHPUTRA, KUANTAN

Infection&

Tumors

Infectious agents reach the Nervous System through

• Hematogenous spread: through arterial blood supply.

• Direct implantation of microorganisms.

• Local extension with infections of the skull.

• Peripheral nerves: entry of pathogens such as rabies.

INFECTIONS

• Meningitis.

• Parenchymal infections.

• Prion diseases.

Meningitis

• Acute Pyogenic Meningitis (Bacterial Meningitis)

• Aseptic Meningitis (Viral Meningitis).

• Chronic Meningitis.

Acute Pyogenic Meningitis (Bacterial Meningitis)

• The organisms vary with patient age.• Neonates: Escherichia coli and group B streptococci.• Adolescents and young adults: Neisseria meningitidis.• Older individual: Streptococcus pneumoniae and Listeria

monocytogenes.• Signs: meningeal irritation and neurologic impairment

(headache, photophobia, neck stiffness).• Lumbar puncture: increase

pressure, CSF show abundant neutrophils, elevated protein and reduced glucose.

Aseptic Meningitis (Viral Meningitis).

• Patient: meningeal irritation, fever and alterations in consciousness (acute onset).

• Lumbar tap: CSF show lymphocytosis, moderate protein level, normal glucose level.

Chronic Meningitis.

• Tuberculous Meningitis.- Mycobacteria.- S&S: headache, malaise, mental confusion &

vomiting.

• Spirochetal Infections.- Neurosyphilis (tertiary stage of syphilis):

untreated Treponema pallidum infection.- S&S: progressive loss of mental and physical

functions, mood alterations and severe dementia.

Parenchymal infections.

• Brain Abscesses.

- Nearly always caused by bacterial infections.

- Arise by direct implantation of organisms, hematogenous spread.

- Patient: progressive focal deficits, general signs related to increased intracranial pressure.

• Viral Encephalitis

- Parenchymal infection of the brain that associated with meningeal inflammation.

- eg: rabies virus, poliovirus.

Prion diseases.• Agents: abnormal form of a cellular protein.

• Eg; Creutzfeldt-Jakob disease(CJD).

- A rapidly progressive dementing illness, changes in memory and behavior (death in 7 month).

TUMORS

• Gliomas – astrocytomas, oligodendrogliomas, ependymomas.

• neuronal tumors.

• Embyronal (Primitive) Neoplasms –medulloblastoma.

• Meningiomas.

• Metastatic tumors.

Epidemiology

• Primary brain tumors in adults – 70% occur above the tentorium cerebelli.

• Primary brain tumors in children – 70% occur below the tentorium cerebelli (second most common cancer in children).

• Risk factors – Turcot syndrome, neurofibromastosis, cigarette smoking.

• General clinical findings – headache, seizures.

Astrocytoma

• Accounts for about 70% of all neuroglialtumors.

• In adults – tumor usually involves frontal lobe.

• In children – tumor usually involves cerebellum.

• Low-grade cancer : Grades I and II.

• High-grade cancers: Grades III and IV.

• Rarely metastasize outside the CNS.

Oligodendroglioma

• Benign tumour derived from oligodendrocytes.

• Primarily occur in adults.

• Site of calcifies – usually frontal lobes.

Ependymoma

• Benign tumor derived from ependymal cells.

• In adults – arise in cauda equina.

• In children – arise in the fourth ventricle, can produce noncommunicating hydrocephalus.

Medulloblastoma

• Malignant small cell tumour – primarily occurs in children.

• Arises from the external granular cell layer of cerebellum.

• Often invades the fourth ventricles.

Meningiomas

• Most common benign brain tumour in adults.

• Derived from meningothelial cell within the arachnoid membrane.

• Firm tumours

- Not invade the surface of brain.

- Often infiltrate the overlying bone – caused increased bone density.

Metastatic tumors

• Most common brain malignancy.

• Common cancer : lung, breast, skin (melanoma), kidney, gastrointestinal tract (in order of decreasing frequency).

• Prostate cancer can metastasize to brain and dura (but rarely to the brain).