Meningitis Exam Questions

Question 1

53. List four (4) examples of information that is carried by the spinothalamic tract. (2 marks)

Answer 1

pain, temperature, gross touch, pressure.

Question 2

54. When a space occupying lesion is causing the cerebral hemispheres to enlarge, a consequence may be that the hindbrain is forced caudally (herniates). Name this condition, and briefly describe the herniation. (2 marks)

Answer 2

Coning of the medulla – tonsils of cerebellum herniate through foramen magnum, compressing the brain stem (2)

Question 3

55. List three (3) functional consequences of herniation and indicate in each case the specific brain area involved. (6 marks)

Answer 3

Decreased level of consciousness – distortion of the reticular formation (2)
Decreased pupillary light reflexes & dilation of pupils – impairment of 3rd Nerve function, due to compression (2)
Decreased vital function involving both respiratory and cardiac function - compression of the medulla (2)

Question 4

Is it advisable under the circumstances of brain herniation to do a lumbar puncture in order to draw a sample of CSF? (½ mark)

b) Give one (1) reason for your answer. (1 mark)

Answer 4

a) No, a lumbar puncture should not be performed.

b) Removing CSF would reduce the CSF pressure below the foramen magnum and therefore the condition would be aggravated due to increased coning of the medulla.
There would also be progressive loss of consciousness and further impairment of breathing, which may ultimately be fatal.

Question 5

57. List three (3) different types of brain herniation. (1½ marks)

Answer 5

Subfalcine (cingulate), transtentorial (uncinate, mesial temporal), tonsillar herniation

Question 6

58. Outline the main mechanism of death in cerebral herniation. (1½ marks)

Answer 6

Compression of cardiac and respiratory centres in the medulla oblongata

Question 7

59. Define “hydrocephalus ex vacuo”. (1½ marks)

Answer 7

Dilatation of ventricular system

Increase in CSF volume due to loss of brain parenchyma

Question 8

60. Use the following table to create a list of differential diagnoses for an acquired cerebral space occupying lesion. (5½ marks)

Inflammatory Infective Two examples:

Inflammatory Non-infective One example:

Neoplastic primary Two examples:

Neoplastic secondary Two examples:

Traumatic Two examples:

Vascular Two examples:

Answer 8

Inflammatory Infective Two examples:
Abscess, Tuberculosis, Toxoplasmosis, Hydatid disease

Inflammatory Non-infective One example:
Demyelinating pseudotumour

Neoplastic primary Two examples:
Meningioma, glial and neuronal neoplasms, poorly-
differentiated CNS neoplasms e.g. Medulloblastoma,
primary CNS lymphoma, germ cell tumours

Neoplastic secondary Two examples:
Carcinoma, melanoma, lymphoma, sarcoma

Traumatic Two examples:
Extradural, subdural haematoma

Vascular Two examples:
Intracerebral haemorrhage, aneurysm

Question 9

61. When a lesion in the nervous system occurs and nerve connections are disrupted, the injured neurons show certain distinct histological features. List these features. (2 marks)
62. Name the process. (1 mark)

Answer 9

Chromatolysis, swelling of cell body, degradation of axon and myelin sheath

62. Wallerian degeneration

Question 10

64. Outline the role of the following cell types after an injury to the nervous system:

 Schwann cells (2 marks)
 Oligodendrocytes (2 marks)
 Astrocytes (2 marks)
 Microglia (2 marks)

Answer 10

schwann cells - (Phagocytosis of debris, expression of axon growth-promoting cell adhesion molecules, support of neuron survival and axon re-growth by neurotrophin secretion)

oligodendrocytes- (Inhibition of axon regeneration through up-regulation of several growth inhibitory proteins)

Astrocytes - (Hypertrophy and formation of glial scar: mechanical barrier to axon re-growth, as well as up-regulation of inhibitory proteoglycans)

Microglia- (Phagocytosis of cell debris, degradation of extracellular matrix, but also promotion of inflammation and cytotoxic effects on neurones)

Question 11

66. Briefly describe the typical signs you may expect to find on any patient with raised intracranial pressure in the following areas of examination:

 Fundoscopy: (½ mark)
 Cardiovascular: (1 mark)
 Neurological: (1½ marks)

Answer 11

fundoscopy - Papilloedema

cardiovascular - High BP, slow pulse

Neurological - Confused or decreased level of consciousness, possible cranial nerve pathology

Question 12

68. Give the medical definition of coma. (1½ marks)

Answer 12

Coma = Medical definition, “a state much like sleep in which patients are unarousable and are unresponsive to external stimulation and their own inner needs”.

Question 13

69. State the purpose of the Glasgow coma scale. (1 mark)

Answer 13

To assess the depth and changes in the level of consciousness. If the level of consciousness dropped this would alert medical staff to take action.

Question 14

70. List the components of this scale and indicate the criteria for the definition of coma. (3 marks +2 marks = 5 marks)

Answer 14

Best verbal response, motor response and eye response.
The scale is out of 15 with any score below 9 being a coma if physical limitations have been discounted, such as paralysis, eye injuries etc

Question 15

71. State the recommended test for pain response. (1 mark)

Answer 15

Sternum rub

Question 16

72. If you wish to examine the burden of disease in the province due to brain cancer, a number of different measures , such as Years of Life Lost (YLL)’ and Disability Adjusted LifeYears (DALYs) can be used to characterise the burden of disease. Define the terms Years of Life Lost (YLL) (1 mark) and Disability Adjusted LifeYears (DALYs) (2 marks)

Answer 16

Years of Life Lost, YLLs A measure of premature loss of life due to a particular disease (It takes into account death due to a particular disease. Some methods take into account age weighting and discounting).

DALYs combines both mortality and morbidity associated with a disease into one index/measure. It takes account of years lived with a disease by converting it using a disability index into a value that can be added to the complete disability caused by death. In this way, you can sum the effect of morbidity and mortality, and you can compare different diseases that have different impacts

Question 17

. Name two causes of meningitis for which there are effective vaccines. (2 marks)

Answer 17

Haemophilus influenzae grp B
TB meningitis
Mumps meningitis
Pneumococcus 
Meningococcus

Question 18

74. If the initial CSF laboratory results indicate a possible bacterial meningitis, state the empiric antibiotic therapy that would be appropriate while waiting for the bacterial culture and antibiotic sensitivity results. Motivate why this is the antibiotic of choice. (2½ marks)

Answer 18

Ceftriaxone/ cefotaxime or “3rd generation cephalosporin” (½)
Covers the 3 common bacteria causing meningitis (1) + (1) for extra information e.g. names of organisms or something about pen resistant pneumococci.

Question 19

75. List the names of the encephalopathic diseases that can be caused by measles through these different pathophysiologic mechanisms. Outline how each is brought about, indicating for each whether or not virus can be cultured from the brain. (3 marks x 2 = 6 marks)

Answer 19

Measles meningo/encephalo/myelitis [virus +ve]
Acute perivenous demyelination [virus –ve]
SSPE [subacute sclerosing panencepahlitis] [virus +ve]

Question 20

76. In a patient with a raised total CSF protein, state the significance of an increased IgG/albumin ratio in CSF, particularly if this ratio in plasma is normal. (2 marks)

Answer 20

Local IgG production due to an infective or autoimmune process within the CNS, rather than a non-specific increase in blood-brain barrier permeability.

Question 21

77. Describe the psychosocial effects of deafness/hearing impairment on:

 patient (6 marks)

 His family (4 marks)

Answer 21

Effects on the individual (6)
• Inclusion –isolation
o Difficulty with acceptance amongst groups of people due to stigmatisation
– Obstacles to developing relationships with self, family, peers, community, society - Socialising more difficult

• Has to adapt
o New communication skills
o Has to manage frustrations in a social system which is not adaptive

• Access to social resources – barriers to access
– Access to schools- learning and education, skills development
– Accessing equipment to assist functioning in living environment (accommodation telephones/teldems, door lightbells, security, driving, etc, etc)

Effects on the family (4)
• Have to learn how to communicate with Bart differently
• Changes within family relationships including between parents
• Economic adversity – new expense, lost earnings through medical appointments, mother stopping work, cost of care
a) Increased stress – Maternal Mental Health, Problems understanding deafness (audiological, social, cultural), Concerns about the child’s progress and future options

Question 22

78. Define a teratogen. ` (1 mark)

Answer 22

[any environmental agent that can produce a permanent abnormality in structure or function, restriction of growth, & /or death of embryo or foetus]

Question 23

79. List three (3) known teratogens. (1½ marks)

Answer 23

[Alcohol, thalidomide, androgens, diethylstilboestrol, rubella virus, iodine, hyperthermia, tetracycline, warfarin etc]

Question 24

80. List three (3) facial features of foetal alcohol syndrome. (1½ marks)

Answer 24

[telecanthus, absent philtrum, thin vermilion border of upper lip, short up-turned nose]

Question 25

81. List three (3) additional (non-facial) physical features in a 6-year old child that could indicate foetal alcohol syndrome. (1½ marks)

Answer 25

[small head circumference, short stature, strabismus, ptosis, attention deficit, hockeystick palmar crease,]

Question 26

82. a) Name the part of the nervous system that, if damaged, would give rise to impairment of fine motor skills with poor hand eye coordination. (1 mark)
    b) Name one other possible consequence of damage to this structure. (1 mark)

Answer 26

a) Intermediate hemisphere of the cerebellum

b) Impaired planning of movement, impaired learning of motor skills, difficulty maintaining balance.

Question 27

83. Hyperactivity may result from a disturbance in the dopamine neurotransmitter system in the brain. Explain how dopamine acts to initiate movement. (5 marks)

Answer 27

Dopamine acts on D1 receptors in the striatum to stimulate the direct pathway, i.e. glutamate neurons projecting from cortex to striatum to inferior globus pallidus, or substantia nigra pars reticulate, to thalamus and back to cortex, to provide positive feedback to the cortex. At the same time dopamine acts on D2 receptors to inhibit the indirect pathway, cortex - striatum - external GP-STN - internal GP/SNr – thalamus – cortex, which is inhibitory thereby disinhibiting neurons in the thalamus to give positive feedback to the cortex to select and initiate appropriate movement.)

Question 28

84. State the specific nucleus and its location in the brain to which visual information is transmitted from the retina and where it is processed before being transmitted to the visual cortex. (1 mark)

Answer 28

Lateral geniculate nucleus of the thalamus

Question 29

85. Outline the physiological mechanism which inhibits transmission of somatosensory information to the somatosensory cortex while the child is asleep. (2 marks)

Answer 29

Activation of the reticular nucleus which releases GABA and inhibits activity of other thalamic nuclei

Question 30

Outline the production, flow and reabsorption of cerebrospinal fluid. (You may make
use of a diagram). (7 marks)

Answer 30

Choroid plexus in ventricles I, II, III, IV – production.
Flow – interventricular foramina – III to aqueduct in mesencephalon – IV – central canal of spinal cord; 1 median and 2 lateral apertures in posterior medullary velum – subarachnoid space – reabsorption by arachnoid villi into superior saggital sinus.

Question 31

2. Differentiate between what is meant by communicating and non-communicating
   hydrocephalus.

Answer 31

Whether CSF can enter subarachnoid space from ventricle IV (mainly).

Question 32

Outline how the canal of the cranial end of the developing neural tube in the embryo is
transformed into the various compartments of the ventricular system of the brain. (4 marks)

Answer 32

Telencephalon – lateral ventricles (I & II)
Diencephalon – ventricle III
Mesencephalon – aqueduct of midbrain
Rhombencephalon – ventricle IV

Question 33

With the aid of a labelled diagram, describe the histological structure of the cranial
meninges. (4 marks)

Answer 33

Endosteal dura, meningeal dura, dural border cells, arachnoid barrier cells, subarachnoid space with arachnoid trabecular cells and blood vessels, pia (0.5 marks each feature)

Question 34

6. The constituents of normal cerebrospinal fluid (CSF) are comparable to extracellular
   fluid (ECF).

i) With reference to ECF, indicate whether the concentrations of glucose and of protein
are higher or lower compared with CSF. (1 mark)

ii) Is [Cl-] in normal CSF the same as in plasma? Explain your answer. (1.5 marks)

Answer 34

(i) [Glucose] <
[Protein] « (1 Mark)

Cl- is higher (0.5) to maintain electrical neutrality because the protein is very much
lower (1)

Question 35

List four functions of cerebrospinal fluid. (4 marks)

Answer 35

Possible Answers:
• constant external environment for neurons and glia
• specific drainage route of CSF assists removal of harmful metabolites
• mechanical cushioning
• provides buoyancy – reduces effective weight
• adjusts to changes in intracranial pressure due to alterations in cerebral blood flow
• all the functions performed by lymph

Question 36

Describe the macroscopic appearance of normal CSF. (0.5 mark)

Answer 36

Crystal clear (like water)

Question 37

. Name two biochemical tests commonly performed on CSF when meningitis is
suspected and state how the results change in bacterial meningitis. (2 marks)

Answer 37

Glucose (goes down, often to zero)

Protein (increases many fold)

Question 38

Define ‘xanthochromia’ of CSF. Give two causes of xanthochromia. (1.5 marks)

Answer 38

Yellow discoloration of CSF

Old bleed OR high protein – eg TBM, spinal block (Froin’s Syndrome

Question 39

11. Give the full names of the three organisms likely to cause meningitis in this age
    group.

Answer 39

Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae

Question 40

Explain why ceftriaxone is the antibiotic chosen for the empiric treatment of
meningitis in South Africa. (3 marks)

Answer 40

Covers the common organisms (1)
Is still active against penicillin-resistant S. pneumoniae. (1)
Therapeutic levels are achieved in the CSF/Crosses the BBB. (1)

Question 41

In a large labelled plan diagram, indicate the histological layers of the
cerebellum. (3 marks)

Answer 41

Diagram, molecular layer, Purkinje cell layer, granule cell layer, white matter, deep
nuclei (0.5 marks each)

Question 42

In the diagram above, draw and label the different neuronal structures forming
the neuronal circuitry and indicate the flow of information into and out of the
cerebellar cortex. (7.5 marks)

Answer 42

Afferent (0.5) mossy fibres (0.5) synapse onto granule cell (0.5) dendrites, axons of granule cells form parallel fibres (0.5) that synapse on Purkinje cell dendrites (0.5). Afferent (0.5) climbing fibres (0.5) synapse directly on Purkinje cells. The axons (0.5) of Purkinje cells (efferent, 0.5) connect to the deep nuclei (0.5) of the cerebellum) (2.5 for diagram)

Question 43

Explain why damage to the cerebellum causes past-pointing. (1 mark)

Answer 43

Damage to the intermediate hemisphere causes past-pointing due to poor control of antagonist muscles at end of movement (1 mark)

Question 44

Use a diagram (2 marks) to illustrate the different parts of the cerebellum and the
nuclei that are involved in planning complex movements (1 mark), control axial muscles (1 mark), control distal muscles of the limbs. (1 mark)

Answer 44

Diagram showing four main subdivisions (1 mark)
The cerebrocerebellum & dentate nuclei - planning complex movements (1 mark)
The vermis & fastigial nucleus control axial muscles (1 mark)
Intermediate hemisphere & interposed nuclei control the distal muscles of
limbs (1 mark)

Question 45

Give a brief explaination of the mechanism of the coagulation cascade. (5 marks)

Answer 45

The coagulation cascade consists of a series of enzyme reactions (1), which require cofactors, Ca++ and phospholipid (1.5). E ach step amplifies the previous one (1), and the end result is the formation of large amounts of fibrin to form a stable clot (1.5)

Question 46

Outline the mechanism of the anti-thrombotic action of aspirin. (3½ marks)

Answer 46

Aspirin irreversibly inhibits (1/2) the enzyme cyclooxygenase (1/2) in platelets (½ ).
This prevents the formation of Thromboxane A2 from arachidonic acid (1) Thromboxane A2 is a vasoconstrictor and platelet aggregator (1)

Question 47

Give an overview of the course of the Facial nerve (Cranial nerve VII) in the region of the face. Include the groups of muscles that are innovated by this nerve, as well as their actions. You may use a fully labelled diagram, if you wish. (10 marks)

Answer 47

N. VII leaves the skull through the stylomastoid foramen. Travels through the parotid salivary gland. Branches (above) arise from the edges of the gland and supply the groups of muscles of facial expression.
The clinicly relevant groups of muscles that students were required to learn are:
1) orbicularis oculi – blinking, screwing up of eyelids
2) orbicularis oris – sphincter of mouth/lips
3) platysma – tensing skin of neck
4) occipitofrontalis – moving scalp
5) buccinator - blowing
6) small groups for moving ears, flaring nostrils, wrinkling forehead, changing shape of mouth, and so forth.

Question 48

10. List five clinical signs of unilateral lower motor neuron Facial nerve palsy.
    (5 marks)

Answer 48

LMN damage = flaccid paralysis – hypotonia or atonia, hyporeflexia.
Relate to the functions listed above.
For the signs of deficit, students should know to ask the patient to smile, show the teeth, close eyes, close lips, blow, suck, whistle, tense neck skin for shaving, wrinkle forehead, raise eyebrows, and so forth. Ptosis of lower eyelid only.
Loss of nasolabial folds; drooling, dribbling, drooping of angle of mouth, lack of expression/movement in hemi-face (entire half cf UMN lower quadrant only)

Question 49

11. Briefly describe the arterial supply to the occipital lobe of the brain. You may use a diagram, if you wish. (5 marks)

Answer 49

Brief description of the arterial cerebral circle – L & R posterior cerebral arteries arising from the posterior half of the circle. These run caudally to supply the occipital lobe medially, inferiorly, caudally, superiorly, and a small portion laterally.

Question 50

12. Give two examples of functional losses if the arterial supply to the caudal region of one of the occipital lobes becomes obstructed. (2 marks)

Answer 50

Visual cortex at caudal pole of occipital lobe – all special sensation (vision) from the opposite field of vision is lost.
Visual association area surrounds visual cortex – interpreting what is seen – loss.

Question 51

(2 marks X 3 = 6 marks)

(i) resting membrane potential (2 marks)
(ii) depolarisation (2 marks )
iii) Voltage gated (Na+) channels (2 marks)

Answer 51

(i) resting membrane potential (2 marks)

At rest, membrane potential (Vm) is negatively charged inside wrt to outside of cell in the range -65 to – 85mV. At rest Vm is close to EK ( approx -80 mV) thus as this ion dominates at equilibrium it is manly responsible for maintaining Vm at this level

(ii) depolarisation (2 marks )

This a change in the charge distribution across the membrane from RMP in a more positive direction ( i.e Vm becomes less negative) .
This is due to increased gNa+ ( sodium conductance ) in the inward direction ( i.e inward current carried by Na+ )
[May also give a diagram of the action potential with arrow indicating phase – but need to explain what is happening during this phase ]

(iii) Voltage gated (Na+) channels (2 marks)

These are special channels with two gates ( inactivation and activation gates ) that are opened/ closed ( at different rates) by a depolarizing current ( hence a change in voltage) They are specific for Na+ ions and are located both at the axon hillock and nodes of Ranvier.

Question 52

Outline the role of myelin in the conduction of an action potential in a myelinated axon. (2 marks)

Answer 52

Myelin has insulating properties. Due to its high resistance to electric current flow myelin prevents leakage of current out of the axons. Since it is interrupted at the Nodes of Ranvier it causes current to flow rapidly form node to node – hence “saltatory “ conduction. Hence in myelinated axons there is more rapid transmission of the action potential than in a non -myelinated axon .

Question 53

Briefly describe the changes that occur in a peripheral neuron if its axon is cut (axotomy). (5 marks)

Answer 53

Distal to the cut, the axon degenerates – it undergoes Wallerian degeneration. Myelin becomes fragmented, Schwann cells die and distal stump atrophies. Area invaded by macrophages
Proximal to cut nerve cell bodies become swollen (oedematous) granular material in cytoplasm becomes dispersed toward the periphery ( rough endoplasmic reticulum disintegrates). The nucleus moves to an eccentric position.(process called Chromatolytic reaction)
After a variable period there may be sprouting of the axon of the proximal stump. These form growth cones which induce Schwann cells ( mitogenic response) to start laying down myelin around the endoneural tube ( if aligned ) and a new axon is formed by the extending growth cone.

Question 54

Define the term “receptive field” giving an example in the somatosensory system.
(4 marks)

Answer 54

This is the area on the surface of the body (receptive surface) from where a particular receptor type or cell in the sensory relay pathway en route to the Somatosensory area of the cortex receives its input (i.e. stimulus).
RF’s of specialized receptors vary in size depending on location in epidermis eg Merkel Disks, Meissner’s corpuscles ( both are superficial) have small receptive filed while Ruffini endings and Pacinian corpuslces (lie deeper)have large receptive fields

Question 55

17. Describe 3 main functions of cerebrospinal fluid. (3 marks)

Answer 55

Provides bouyancy – brain weighs less in CSF
Provides a cushioning effect against impact
Helps maintain a stable external microenvironment around the brain (i.e homeostasis)
Acts as a lymphatic system for removal of waste products draining into the venous system

Question 56

Draw and fully label a cross section through the developing neural tube in the thoracic region of the embryo, giving a short explanation of the functional implications for each of the structures that you have labelled. (10 marks)

Answer 56

Neural tube is divided into:
• ventricular zone – giving rise to ependymal layer, lining the central canal
• mantle layer – giving rise to grey matter (neurones)
• marginal layer – giving rise to white matter (tracts)
Mantle layer is divided by the level of the sulcus limitans into alar plate dorsally and basal plate ventrally –» alar plate = sensory / afferent = dorsal horn, & basal plate = motor / efferent = ventral horn.
Asking for the thoracic region will, hopefully, trigger recall of the lateral horn – autonomic (sympathetic) outflow, and the resulting lateral horn (visceral), versus the dorsal and ventral horns (somatic).

Question 57

2. Give a short description of a meningomyelocoele. (2 marks)

Answer 57

Bulging fluid-filled “sac” on surface of the body – contents could be meninges, cerebrospinal fluid, neural elements (caudal end of spinal cord).

Question 58

briefly explain the process of development of a meningomyelocoele. (5 marks)

Answer 58

Explain how the overlying ectoderm and mesoderm need to seal off the neural tube from the surface by growing over the top of the neural tube. Ectoderm forms epidermis; mesoderm forms dermis, hypodermis, connective tissue, bone (vertebrae) and skeletal muscles. Failure of this process will result in elements bulging onto the surface of the body – in this case meninges and neural elements.[ Possible tethering of the neural tube, leading to hydrocephalus later.]

Question 59

6. List two (2) unrelated investigations whereby a meningomyelocoele can be suspected in utero.
   (2 marks)

Answer 59

[ultrasound examination(1) and maternal serum and/or amniotic fluid alpha foetoprotein levels(1)]

Question 60

7. How can the risk of a meningimyelocoele be reduced? (1 mark)

Answer 60

[planned pregnancy with folate (1) for 3 months prior to conception (1)]

Question 61

9. The aetiology of neural tube defect is multifactorial. List three (3) independent factors which may play a role in its aetiology and give an example of each. (3 marks)

Answer 61

[genetic e.g. monogenic mutations, chromosomal trisomy 18; environmental including specific geographic areas, maternal diet – folic acid deficiency, iatrogenic - drugs taken by mother (valproate), metabolic - maternal diabetes]

Question 62

11. List two (2) signs that are commonly associated with spina bifida occulta which you would find over the sacrum in the neonate. (1 mark)

Answer 62

Sacral depression / dimple, tuft of hair, soft fatty deposits, port wine naevus

Question 63

12. Even though a patient with spina bifida occulta may initially have no symptoms or signs, problems can develop later. As the Family Practitioner you should be on the alert for signs and symptoms of neurological dysfunction. List three (3) common symptoms arising from spinal cord tethering. (1 ½ mark)

Answer 63

foot weakness, bowel and bladder dysfunction, headache

Question 64

13. Hydrocephalus is a common complication of neural tube defects. List four (4) signs that would make you concerned that an infant is suffering from raised intracranial pressure. (2 marks)

Answer 64

Any four of bulging fontanelles/ splayed sutures, vomiting, increased head circumference, decreased level of consciousness, irritability, sunset eyes

Question 65

14. At present, routine screening specifically for Neural Tube Defects is not offered, although severe defects would be seen in routine scanning. Do you think that routine screening should be offered to every pregnant woman? Yes / No? Justify your answer. (4 marks)

Answer 65

Should know something about the criteria for screening? Eg. Condition must be common, important, diagnosable by acceptable methods, screening must be simple and cheap, intervention must be available, screening needs to be sensitive, specific, safe, acceptable to pt, easy to interpret, high positive predictive value. Ethics of allocation of health resources

Question 66

For each of the following subheadings, explain the prognosis of NTD’s. In your explanation, mention at least one member of the multidisciplinary team who would have a prominent role. (6 marks)

a) Mobility (2 marks)
b) School performance / cognitive ability (2 marks)
c) Continence (2 marks)

Answer 66

a) Mobility is likely to be impaired to some degree. However, with the aid of physios and orthopaedic surgeons, 70% of children with NTD will eventually walk independently.
b) Cognitive performance is nearly always affected, although the degree of severity will only become apparent with time. Some children may be able to attend mainstream schools, others will need special schools. Social workers, physios, child psychologists, and the paediatrician will be involved in determining the level of support needed.
c) Both urinary and bowel continence are common issues. The bowel can be managed with a high fibre diet and the use of bowel aperients. The urinary side may require regular intermittent catheterisation. Nurses play a big role in educating the parents how to manage the continence while the Family Physician and / or Paediatrician need to be on the alert for complications such as UTIs. Management of water intake.

Question 67

16. Describe the CSF findings for cells, glucose and protein that would make you consider a diagnosis of acute bacterial meningitis. (2 marks)

Answer 67

Increased polymorphs (½), decreased glucose (½) (relative to blood glucose) (½) raised protein (½)

Question 68

17. The finding of organisms on the Gram stain would confirm bacterial meningitis. Given that Ayesha is 5 years old, list the three (3) most likely Gram stain results and give the full name of the organism you would expect for each result. (4 ½ marks)

Answer 68

gram-negative (intracellular) diplococci (½) Neisseria (½) meningitidis (½)
gram-positive diplococci (½) Streptococcus (½) pneumoniae (½)
gram-negative coccobacilli (½) Haemophilus (½) influenzae (½)

Question 69

18. Name the drug of choice for empiric treatment of meningitis in a child of this age. (1 mark)

Answer 69

Third generation (½) cephalosporin (½)

Question 70

20. Explain the difference between leptomeningitis and pachymeningitis. (2 marks)

Answer 70

Leptomeningitis – inflammation arachnoid / subarachnoid space
Pachymeningitis – inflammation of dura

Question 71

21. Describe the route of flow of CSF from its production through to its reabsorption. (10 marks)

Answer 71

Choroid plexus [arteries] in ventricles 1, 2 and 3; separate choroid plexus in ventricle 4. (2)
Ventricle I to 3 via interventricular foramen. (1)
Ventricle 2 to 3 via interventricular foramen. (1)
Ventricle 3 to 4 via aqueduct of midbrain. (1)
Ventricle 4 to central canal of spinal cord. (1)
Through 3 foraminae in roof of ventricle 4 to subarachnoid space. (2)
Reabsorption of CSF via arachnoid granulations into superior sagittal [venous] sinus. (2)

Question 72

22. Give the total volume of CSF present in the CNS at any given time. (½ mark)

Answer 72

150ml

Question 73

23. Give the volume of the total daily production of CSF. (½ mark)

Answer 73

500ml /day

Question 74

24. Explain how the CSF compartment prevents intracranial pressure changes when blood flow to the brain is increased. (4 marks)

Answer 74

• Increased amounts of CSF are squeezed from the ventricles (1)
• Displaced CSF flows into the subarachnoid space around spinal cord (1)
• Dura mater lining spinal column is more elastic (1)
• Dura stretches to compensate for the increased volume (1)

Question 75

25. In a patient with a high total CSF protein, describe how you would distinguish increased protein permeability of the blood/brain barrier from antibody production within the CNS (such as may occur in neurosyphilis or multiple sclerosis). (2 marks)

Answer 75

By examining the ratio of CSF IgG to albumin, or ideally, by dividing the CSF IgG/albumin ratio by the serum IgG/albumin ratio. The value for increased permeability is <0.7, while for local IgG production it is >0.7.

Question 76

26. a) State the most common endocrine disorder complicating meningococcal meningitis. (1 marks)
    b) Describe how you would suspect this disorder (Q.26) clinically, and how you would confirm it biochemically. (2 ½ marks)

Answer 76

Adrenal failure (Waterhouse-Friederichson syndrome) (1)

b) Profound shock / circulatory collapse (1)

Hypoglycaemia, hyperkalaemia, hyponatraemia, acidosis (1 ½) (also accept low cortisol, low aldosterone, high renin)

Question 77

indicate the structures that contribute to the blood-brain barrier. (4 marks)

Answer 77

(astrocyte endfeet, non-fenestrated endothelium, endothelial tight junctions, thick basement membrane: 2 marks for diagram, 0.5 marks for each structure)