Cases Flashcards
A 72-year-old man with a history of coronary artery disease, diabetes, and hypertension is brought to the primary care physician by his wife. She reports a stepwise decline in her husband’s function over the past year, beginning with lapses in memory, then subtle personality changes, and now difficulty talking. MRI scan of the head is shown in Figure 10-44.- what is the diagnosis ?
Multi-infarct dementia, also known as vascular dementia.
ascular dementia is the second most common cause of dementia after Alzheimer disease.
The stepwise decline in these patients can be subtle and may lack major defining events.
It is characterized by a stepwise decline in cognitive, executive, and motor or language function
IMPORTANT– risk factors include hypertension, diabetes mellitus, hyperlipidemia, and advanced age
A 27-year-old man presents to the emergency department after being stabbed and knocked to the ground in an assault.
The patient describes 8/10 pain in his right hand. On examination, there is a small, open fracture on the anterior aspect of his right arm. His capillary refill time in the digits distal to the trauma is 2 seconds, but the patient is unable to extend his right hand. The doctor orders a CT scan, which reveals an undisplaced transverse fracture of the right distal radius and neurotmesis of the right radial nerve.
Which feature of this man’s presentation most strongly indicates a poor functional prognosis?
a) Capillary refill time
b) Neurotmesis
c) Open wound
d) Pain score
e) Radius fracture
Nerve lacerations cause a neurotmesis and even with surgical nerve repair there is poor recovery
Penetrating trauma can cause a complete nerve laceration, leading to neurotmesis. This injury carries a poor prognosis even with surgical repair.
A 27-year-old male is involved in a car during which he suffers a spinal cord injury. Following the accident, he loses the ability to relax his internal sphincter to pass urine, but his urinary continence reflex is intact.
The nerves that are damaged originate from which region of the spinal cord?
a) Thoracic and lumbar spinal cord
b) Lumbar and sacral spinal cord
c) Thoracic, lumbar, and sacral spinal cord
d) Sacral spinal cord only
e) Cauda equina only
A 27-year-old male is involved in a car during which he suffers a spinal cord injury. Following the accident, he loses the ability to relax his internal sphincter to pass urine, but his urinary continence reflex is intact.
The nerves that are damaged originate from which region of the spinal cord?
Thoracic and lumbar spinal cord 15% Lumbar and sacral spinal cord 29% Thoracic, lumbar, and sacral spinal cord 3% Sacral spinal cord only 42% Cauda equina only 11%
The parasympathetic nervous system arises from cranial nerves 3,7,9 and 10 and the sacral spinal nerves (S2,3,4)
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Described is a condition in which sympathetic innervation of the detrusor muscle and internal sphincter (for continence) is intact, but the parasympathetic innervation (for micturition) is not. The parasympathetic nerves that arise from the spinal cord arise only from the sacral spinal region (S2, 3, 4), through the pelvic splanchnic nerves.
Following this event, neurogenic detrusor activity may be seen with a damaged micturition reflex, leading to detrusor-sphincter dyssynergia, a state in which urine is passed inefficiently due to reflex contraction of the internal sphincter during detrusor muscle contraction.
Sympathetic innervation of the bladder arises from the thoracic and lumbar spinal cord.
Parasympathetic innervation of the bladder arises from the sacral spinal cord.
The cauda equina does not describe the origin of sympathetic or parasympathetic nerves.
Autonomic nervous system
The autonomic nervous system is the part of our nervous system which regulates involuntary functions, such as heart rate, temperature, respiratory rate, pupillary response, urination, sexual arousal and digestion. It is comprised of two main components; the sympathetic and parasympathetic nervous system. Some also include the enteric nervous system as another component.
Anatomy
The autonomic nervous system is comprised of preganglionic neurons which arise from the CNS, usually synapsing onto a postganglionic neuron which then innervates a target organ.
The sympathetic division arises from the lateral horns of grey matter from T1-L2/3 and preganglionic neurons synapse onto postganglionic neurons at paravertebral or prevertebral ganglia. They directly synapse onto chromaffin cells of the adrenal medulla.
The parasympathetic division arises from cranial nerves 3,7,9 and 10 and the sacral spinal cord (S2,3,4) and synapse with postganglionic neurons at parasympathetic ganglia of the head or near the wall of an organ supplied by vagus or sacral nerves. The vagus nerve contains about 75% of all parasympathetic fibres.
There is also a sensory division within the autonomic nervous system which is found in the geniculate, petrosal and nodose ganglia and is transmitted via glossopharyngeal and vagus nerve to the brain stem. These include baroreceptors and chemoreceptors, and monitor blood levels of oxygen, carbon dioxide (carotid body- petrosal ganglion) and glucose. They also monitor arterial pressure and the contents of the stomach and intestines. The sensory neurons synapse in the medulla oblongata forming the solitary tract nucleus which combines all visceral information. This sensory information unconsciously attunes autonomic sympathetic and parasympathetic motor activity.
The neurons in the autonomic nervous system release several neurotransmitters. These include; noradrenaline and co-transmitters at end organs, mostly released by sympathetic neurons (e.g. to blood vessels and the heart), acetylcholine at ganglia and by all parasympathetic and some sympathetic postganglionic neurons (e.g. to sweat glands).
Function:
The sympathetic and parasympathetic systems act in opposing ways, but work together to achieve necessary functions and regulate homeostasis.
The sympathetic nervous system is thought of as causing ‘fight or flight’ type responses and typically:
Increases heart rate and contractility and vasodilates coronary arteries. Constricts vessels to the skin and intestines
Causes bronchodilation and increases blood flow to the lungs
Vasodilates to the skeletal muscles and relaxes the ciliary muscle to the lens
Inhibits gut peristalsis and constricts intestinal and urinary sphincters
Dilates the pupils
Controls ejaculation
The parasympathetic nervous system is thought of causing ‘rest and digest’ type responses and typically
Vasodilates to the gut and stimulates gut motility and secretions
Slows the heart rate and lowers the blood pressure
Constricts the pupil and contracts the ciliary muscles to allow closer focus
Stimulates sexual arousal.
Autonomic dysfunction:
Autonomic dysfunction refers to the abnormal functioning of any part of the autonomic nervous system. It can present in many forms depending on the cause, as either over or under-activity, as localised or generalised symptoms and can affect any of the many autonomic systems. For example, sympathetic adrenergic failure (causing postural hypotension and failure of male ejaculation) will present differently to sympathetic cholinergic failure (causing an inability to sweat) and so on. Some disorders may have a combination of under-activity in one system and overactivity in another. Hence the symptoms and signs can be very complex.
Assessing a patient for autonomic dysfunction:
If you suspect autonomic dysfunction, a detailed history should be taken and the patient examined to look for signs of skin dryness, sweatiness, cold hands. Pupillary reflexes should be examined and a full neurological examination completed. Lying and standing blood pressure and pulse rate should be measured. General examination should be performed to assess for underlying causes such as diabetes. If then necessary, the patient will undergo further complex physiological, biochemical and pharmacological testing at an autonomic laboratory.
A 38-year-old female presents to the GP with a facial droop. Sher is diagnosed with a facial nerve palsy. The GP knows that this nerve has a motor, sensory and autonomic function and thus examines her for any loss of these. To which glands does this nerve provide autonomic stimulation?
Parotid Lacrimal, submandibular and sublingual Parotid, lacrimal and submandibular Submandibular and sublingual Parotid and lacrimal
The facial nerve passes out of the cranial cavity via the internal acoustic meatus. It then travels through the stylomastoid foramen to pass through the parotid gland. In this gland, the nerve divides into branches and supplies motor to the muscles of facial expression and sensory to the anterior 2/3rds of the tongue. It also supplies autonomic stimulation to the lacrimal, submandibular and sublingual glands.
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Cranial nerves
The table below lists the major characteristics of the 12 cranial nerves:
Nerve Functions Clinical Pathway/foramen
I (Olfactory) Smell Cribriform plate
II (Optic) Sight Optic canal
III (Oculomotor). Eye movement (MR, IO, SR, IR) Palsy results in Superior orbital fissure (SOF)
Pupil constriction • ptosis
Accomodation • ‘down and out’ eye
Eyelid opening • dilated, fixed pupil
IV (Trochlear) Eye movement (SO) Palsy results in defective downward gaze → vertical diplopia SOF
V (Trigeminal) Facial sensation Lesions may cause:
V1: SOF, V2: Foramen rotundum,
Mastication • trigeminal neuralgia V3: Foramen ovale
• loss of corneal reflex (afferent)
• loss of facial sensation
• paralysis of mastication muscles
• deviation of jaw to weak side
VI (Abducens) Eye movement (LR) Palsy results in defective abduction → horizontal diplopia SOF
VII (Facial) Facial movement Lesions may result in: Internal auditory meatus
Taste (anterior 2/3rds of tongue) • flaccid paralysis of upper + lower face
Lacrimation • loss of corneal reflex (efferent)
Salivation • loss of taste
• hyperacusis
VIII (Vestibulocochlear) Hearing, balance Hearing loss Internal auditory meatus
Vertigo, nystagmus
Acoustic neuromas are Schwann cell tumours of the cochlear nerve
IX (Glossopharyngeal) Taste (posterior 1/3rd of tongue) Lesions may result in; Jugular foramen
Salivation • hypersensitive carotid sinus reflex
Swallowing • loss of gag reflex (afferent)
Mediates input from carotid body & sinus
X (Vagus) Phonation Lesions may result in; Jugular foramen
Swallowing • uvula deviates away from site of lesion
Innervates viscera • loss of gag reflex (efferent)
XI (Accessory) Head and shoulder movement Lesions may result in; Jugular foramen
• weakness turning head to contralateral side
XII (Hypoglossal) Tongue movement Tongue deviates towards side of lesion Hypoglossal canal
Some cranial nerves are motor, some sensory and some are both. The most useful mnemonic is given below.
CN I ———————————————————————-→XII
Some Say Marry Money But My Brother Says Big Brains Matter Most
S = Sensory, M = Motor, B = Both
View from the inferior surface of the brain showing the emergence of the cranial nerves
Diagram showing the nuclei of the cranial nerves in the brainstem
Cranial nerve reflexes
Reflex Afferent limb. Efferent limb
Corneal Ophthalmic nerve (V1) Facial nerve (VII)
Jaw jerk Mandibular nerve (V3) Mandibular nerve (V3)
Gag Glossopharyngeal nerve (IX) Vagal nerve (X)
Carotid sinus Glossopharyngeal nerve (IX) Vagal nerve (X)
Pupillary light Optic nerve (II) Oculomotor nerve (III)
Lacrimation Ophthalmic nerve (V1) Facial nerve (VII)
A 25-year-old man is rushed to the emergency department by the paramedics after being shot in a gunfight. He is alert but in extreme pain and is unable to answer any questions.
On initial assessment, his airway is patent, is breathing normally, with no signs of cardiovascular compromise.
On examination of his lower limbs, he is found to have a bullet wound 2cm below his popliteal fossa. The emergency doctor suspects traumatic injury to the tibial nerve, which runs just below the popliteal fossa.
Which of the following examination findings are most likely to be found in this patient?
Loss of plantar flexion, weakened inversion and normal toe flexion Loss of plantar flexion, loss of toe flexion and normal inversion Loss of plantar flexion and inversion Loss of plantar flexion, loss of flexion of toes and weakened inversion Loss of flexion of toes, weakened inversion and normal plantar flexion
Damage to tibial nerve results in loss of plantar flexion, loss of flexion of toes and weakened inversion
Damage to the tibial nerve is rare and is often a result of direct trauma, entrapment through narrow space or compression for long period of time. Damage results in loss of plantar flexion, loss of flexion of toes and weakened inversion; tibialis anterior can still invert the foot, therefore foot inversion is weakened and not completely absent. The rest of the options do not correctly identify the clinical signs of tibial nerve injury and therefore are wrong.
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Tibial nerve Begins at the upper border of the popliteal fossa and is a branch of the sciatic nerve.
w Root values: L4, L5, S1, S2, S3
Muscles innervated
Popliteus
Gastrocnemius
Soleus
Plantaris
Tibialis posterior
Flexor hallucis longus
F lexor digitorum brevis
Terminates by dividing into the medial and lateral plantar nerves.
TIPPED = tibial nerve versus peroneal nerve TIP = Tibial nerve Inverts and Plantarflexes the foot → cannot walk on TIPtoes when injured. And flexes the toes (inversion is weekend not lost cuase inversion is also done by the tibilais antieorr muscle
PED = Peroneal nerve Everts and Dorsiflexes the foot → foot drop when injured
A 30-year-old male comes to the emergency department due to a seizure. He has had a severe headache for the last few hours and has been feeling nauseous. An urgent MRI reveals oedema in the temporal lobe. He is promptly started on antivirals. Which of the following cells are phagocytes of the central nervous system?
Astrocytes Schwann cells Oligodendrocytes Microglia Ependymal cells
Microglia are specialised phagocytes of the central nervous system
The brain contains relatively few immune cells. Microglia are specialised phagocytes that ‘scavenge’ extracellular debris. Moreover, they can help form the immune response to bacterial or viral infections in the central nervous system. In the scenario, the patient most likely suffered from herpes simplex virus encephalitis - oedema of the temporal lobe is a classic sign.
Oligodendrocytes myelinate axons in the central nervous system. Schwann cells myelinate axons in the peripheral nervous system. Astrocytes provide structural support and remove excess potassium ions from extracellular space. Ependymal cells line the ventricles of the brain. Cells of the nervous system Cell type Notes Oligodendroglia Produce myelin in the CNS Affected in multiple sclerosis Schwann cells Produce myelin in the PNS Affected in Guillain-Barre syndrome Cell type of acoustic neuromas Astrocytes Provides physical support Removes excess potassium ions Help form the blood-brain barrier Physical repair Microglia Specialised CNS phagocytes Ependymal cells Provide the inner lining of the ventricles
A 44-year-old lady is recovering following a transphenoidal hypophysectomy. Unfortunately there is a post operative haemorrhage. Which one of the following features is most likely to occur initially?
Cavernous sinus thrombosis Abducens nerve palsy Bi-temporal hemianopia Inferior homonymous hemianopia Central retinal vein occlusion
he pituitary is covered by a sheath of dura and an expanding haematoma at this site may compress the optic chiasm in the same manner as an expanding pituitary tumour.
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Pituitary gland
The pituitary gland is located within the sella turcica within the sphenoid bone in the middle cranial fossa. It is covered by a dural fold and weighs around 0.5g. It is attached to the hypothalamus by the infundibulum. The anterior pituitary receives hormonal stimuli from the hypothalamus by way of the hypothalamo-pituitary portal system. It develops from a depression in the wall of the pharynx (Rathkes pouch).
Anterior pituitary Posterior pituitary Derivation Oral ectoderm Neuroectoderm Hormones secreted ACTH ADH TSH Oxytocin FSH LH Both are made in the hypothalamus before being transported by the hypothalamo-hypophyseal portal system GH Prolactin GH and prolactin are secreted by acidophilic cells ACTH, TSH, FSH & LH are secreted by basophilic cells
A 47-year-old male presents to the emergency department with severe back pain. He rates this pain as 7/10. His past medical history includes asthma, for which he takes salbutamol inhalers, and constipation. Although he usually takes laxatives, these were stopped following a few recent episodes of bloody diarrhoea. A significant family history exists for cardiovascular disease, and he neither smokes nor drinks alcohol. On examination, there is symmetrical, ascending weakness in the lower limbs. No further abnormalities were identified on examination.
What is the organism most likely associated with his current condition?
Campylobacter jejuni Clostridium difficile EHEC (Entero HaemorrhagicEscherichia coli) Entamoeba histolytica Vibrio cholerae
A 47-year-old male presents to the emergency department with severe back pain. He rates this pain as 7/10. His past medical history includes asthma, for which he takes salbutamol inhalers, and constipation. Although he usually takes laxatives, these were stopped following a few recent episodes of bloody diarrhoea. A significant family history exists for cardiovascular disease, and he neither smokes nor drinks alcohol. On examination, there is symmetrical, ascending weakness in the lower limbs. No further abnormalities were identified on examination.
What is the organism most likely associated with his current condition?
Campylobacter jejuni 45% Clostridium difficile 18% EHEC (Entero Haemorrhagic Escherichia coli ) 27% Entamoeba histolytica 7% Vibrio cholerae 3%
Guillain-Barre syndrome is classically triggered by Campylobacter jejuni infection
Important for meLess important
The correct answer is Campylobacter jejuni, as this is most associated with Guillain-Barre syndrome. Guillain-Barre syndrome must be suspected due to back pain, preceding gastrointestinal infection and the symmetrical, ascending weakness found on examination. Campylobacter jejuni is also associated with reactive arthritis.
Three of the other options cause bloody diarrhoea but are not classically associated with Guillain-Barre syndrome:
Clostridium difficile: Associated with antibiotic use (cephalosporins, ciprofloxacin)
EHEC (Entero Haemorrhagic Escherichia coli): Associated with undercooked meat (e.g. burgers), as well as haemolytic uraemic syndrome
Entamoeba histolytica: Associated with recent travel abroad
Vibrio cholerae typically causes rice-water stools and can be spread through contaminated water.
Guillain-Barre syndrome
Guillain-Barre syndrome describes an immune-mediated demyelination of the peripheral nervous system often triggered by an infection (classically Campylobacter jejuni)
Pathogenesis
cross-reaction of antibodies with gangliosides in the peripheral nervous system
correlation between anti-ganglioside antibody (e.g. anti-GM1) and clinical features has been demonstrated
anti-GM1 antibodies in 25% of patients
Miller Fisher syndrome
variant of Guillain-Barre syndrome
associated with ophthalmoplegia, areflexia and ataxia. The eye muscles are typically affected first
usually presents as a descending paralysis rather than ascending as seen in other forms of Guillain-Barre syndrome
anti-GQ1b antibodies are present in 90% of cases
