Nissl body is a neuron-specific cellular structure. It is composed of rough endoplasmic reticulum and fine granules. The rough endoplasmic reticulum contains free ribosomes, and are the hub of protein synthesis. When these substances are exposed to a cresyl violet solution, they show selective-staining by turning purple-blue. In pathologic processes, they may undergo chromatolysis.

Epilepsy is a common paediatric neurologic disorder characterized by seizures of varying frequency and intensity. There are many childhood or infantile epilepsy syndromes that can be categorized as benign epilepsy syndromes as the child suffering from these usually outgrows them after reaching a certain age, and they do not lead to significant cognitive or physical impairment. Some of these may not need any treatment. Such benign epilepsy syndromes include benign rolandic epilepsy, Panayiotopoulos syndrome, Gastaut type-idiopathic childhood occipital epilepsy, and idiopathic photosensitive occipital lobe epilepsy. West syndrome, also called infantile spasms, is a serious infantile epileptic encephalopathy, characterized by multiple clusters of myoclonic spasms, and regression of the previous normally attained milestones. It is associated with severe cognitive and physical impairment, often leading to life long disability.

The CSF picture in bacterial meningitis has the following characteristics: several polymorphs, cells, protein that is maximum 5g/l, a few lymphocytes and glucose that accounts for the two thirds of the blood level.

The patient’s clinical presentation is highly suggestive of Charcot–Marie–Tooth syndrome.It is a hereditary sensory and motor neuropathy. It is also the commonest cause of inherited peripheral neuropathy. The lower motor neuron signs are usually mild in childhood, the age of onset is very variable, and the distal weakness can take years to progress. It is not fatal and does not affect the normal life expectancy.

The clinical presentation and way the boy ‘climbs up’ his legs to get up from a supine position (Gowers’ sign) suggests proximal muscle weakness secondary to dermatomyositis.Dermatomyositis is an inflammatory myopathy that typically presents between the ages of five years and ten years. The onset is insidious, and the proximal muscle weakness and raised creatine kinase might be mistaken for muscular dystrophy. However, the systemic illness and rash are characteristic features of the condition.

Autism is a neurodevelopmental disorder characterized by difficulties with social interaction, language delays, and some repetitive behaviours. Autism may be associated with some dysmorphic facial features, including macrocephaly, which denotes an abnormally large head. Macrocephaly is usually most observable during early childhood. The other features mentioned are not found to be associated with autism.

Neuroanatomically, the frontal lobe is the largest lobe of the brain lying in front of the central sulcus. It is divided into 3 major areas defined by their anatomy and function. They are the primary motor cortex, the supplemental and premotor cortex, and the prefrontal cortex. Damage to the primary motor, supplemental motor, and premotor areas lead to weakness and impaired execution of motor tasks of the contralateral side. The inferolateral areas of the dominant hemisphere are the expressive language area (Broca area, Brodmann areas 44 and 45), to which damage will result in a non-fluent expressive type of aphasia.

The most important test recommended among the given options is the measurement of creatine kinase levels.The child presents with a gross motor developmental delay, and multiple investigations can be undertaken to confirm the diagnosis. However, the clinching point in the given clinical scenario is the presence of a positive Gower’s sign.Gower’s sign is an excellent screening test for muscle weakness, which is typically observed as an early clinical feature of Duchenne muscular dystrophy (DMD).Creatinine kinase measurement is an easy and rapid test to aid in the diagnosis. Early diagnosis has significant implications not only for the child but for the family, particularly for genetic counselling. DMD is an X-linked recessive disorder, with an abnormal gene at the X chromosome at the Xp21 locus. It is a progressive degenerative muscular condition where muscle fibres are replaced by fat and fibrosis (i.e., become dystrophic).

The most probable diagnosis in this patient would be febrile seizure plus syndrome.Rationale:All of the answers are possible epileptic conditions that this 8-year-old may have. However, the background history of febrile seizure together with a family history of febrile seizures, in a boy who is growing well, with no developmental delay, make febrile seizures plus the most appropriate differential diagnosis for this patient.Other options:- Epilepsy with myoclonic absences are often challenging to treat and may continue into adulthood. There is a male predominance (70%). At presentation, approximately half of cases have a learning disability. An absence seizure is common in this diagnosis and usually occurs daily.- Juvenile absence epilepsy may present with initial generalised tonic-clonic epilepsy followed by absences after that. They are also seen with a background of febrile seizure, and the peak age of presentation is usually at eight years old. Given the current history and lack of absences, this diagnosis is least likely.- Juvenile myoclonic epilepsy usually presents with a myoclonic seizure, although the presentation maybe with a generalised tonic-clonic seizure. It occurs more frequently. Background history of febrile fit may be present in 5-10% of the cases.- Temporal lobe epilepsy is usually associated with aura, and that is not seen in this patient.

The most probable cause for the patient’s presenting symptoms is encephalitis secondary to measles infection.Encephalitis:Encephalitis occurs in 1 per 1000 measles cases. It usually presents within 1–14 days of the rash, usually day 5. It may present with fever, headache, vomiting, stiff neck, meningeal irritation, drowsiness, seizures, reduced consciousness| 15% will have neurological sequelae| 10% mortality.Other options:- Acute disseminated encephalomyelitis occurs in 1 per 1000 measles cases. It is thought to be a postinfectious immune response. Clinical manifestations include fever, headache, neck stiffness, seizures and mental status changes. It could fit this presentation although it tends to present in the recovery phase of measles infection, typically two weeks after the exanthem. In contrast, encephalitis tends to occur within a few days of the rash.- The history is not that of a typical febrile seizure as it lasted >15 minutes. He has also not recovered consciousness at 4 hours. The diazepam should have been eliminated within 4 hours and so should no longer be contributing to his reduced level of consciousness. Also, the history states the recent diagnosis of measles, and so complications of measles should be considered.- Intracranial bleed secondary to thrombocytopenia: Measles is not known to cause thrombocytopenia.- Subacute sclerosing panencephalitis (also known as Dawson’s encephalitis): This is an extremely rare complication of measles. It is a progressive degenerative disease of the central nervous system that occurs 7–10 years after a measles infection. The treatment for SSPE is mainly intraventricular interferon therapy through an Ommaya reservoir. The prognosis is poor, and it is usually fatal.

The most likely cause of microcephaly in an asymptomatic 3-year-old child is congenital rubella syndrome.Microcephaly is defined as head circumference > two standard deviations below the mean.The causes of microcephaly include:- Genetic disorders: Down syndrome, Edward syndrome, Patau syndrome, Williams syndrome, Angelman syndrome, and Rett syndrome.- Infective: Meningitis, toxoplasmosis, CMV, rubella, varicella, HIVand Zika.- Acquired causes: Severe brain malformations, neurodegenerative diseases, hypoxic-ischemic injury, infarction, antenatal exposure to drugs, alcohol, and other toxins. Severe malnutrition and uncontrolled phenylketonuria in the mother are other causes of microcephaly in children.- Craniosynostosis- Neurometabolic disorders- Early non-accidental trauma- Fanconi anaemia- Other causes include: Familial and nonfamilial nonsyndromic microcephalyMost children with microcephaly have one or several associated symptoms:- Developmental delay- Seizures- Visual abnormalities- Short stature

The vignette describes an infant with a sustained post-delivery brachial plexus injury that does not improve with time. MRI is the most appropriate intervention to assess the injury and evaluate the treatment options.

The central nervous system comprises of two types of cells| neurons and neuroglial cells. Glial cells are the support cells that serve a number of important functions. Three types of neuroglia comprise the mature nervous system, which are ependymal cells, microglia, and macroglia. The macroglia are of two types oligodendrocytes and astrocytes. Microglia are the neuroglial cells that serve the function of phagocytosis since they are derived from the hematopoietic stem cells and share properties with tissue macrophages. They remove the cellular debris from the site of injury or normal cellular turnover by performing scavenger function.

The sympathetic chain lies posterior to the parietal pleura. During a thorascopic sympathectomy, this structure will have to be divided. The intercostal vessels lie posteriorly. They may be damaged with troublesome bleeding but otherwise are best left alone as the deliberate division will not improve surgical access.The sympathetic nervous system:The cell bodies of the preganglionic efferent neurones lie in the lateral horn of the grey matter of the spinal cord in the thoracolumbar regions.The preganglionic efferents leave the spinal cord at levels T1-L2. These pass to the sympathetic chain.Lateral branches of the sympathetic chain connect it to every spinal nerve. These postganglionic nerves will pass to structures that receive sympathetic innervation at the periphery.Sympathetic chains:These lie on the vertebral column and run from the base of the skull to the coccyx.Clinical correlation:Interruption of the head and neck supply of the sympathetic nerves will result in an ipsilateral Horner’s syndrome.For the treatment of hyperhidrosis, the sympathetic denervation can be achieved by removing the second and third thoracic ganglia with their rami. Removal of T1 will cause a Horner’s syndrome and is therefore not performed.In patients with vascular disease of the lower limbs, lumbar sympathectomy may be performed, either radiologically or (more rarely now) surgically. The ganglia of L2 and below are disrupted. Care should be taken to preserve the L1 ganglion. If it is removed in male patients, ejaculation may be compromised.

Lamotrigine does not significantly increase risk of birth defects during pregnancy.

The most probable diagnosis for the above clinical scenario, of a child presenting with motor and vocal tics for more than a year is highly suggestive of a diagnosis of Tourette syndrome. The symptoms often wax and wane, and although several different drugs are available, none are entirely useful, and side-effects are relatively common. With these considerations in mind, it is essential to try and avoid treatment initially as the tics can spontaneously improve with time. Informing the teacher and class about the nature of the condition and allowing the child ‘time out’ to tic might help to avoid the need for medication.

The spinal cord ends at L3 in the new-bornmigrates cephalad during childhood to end at L1 – L2 and reaches adult size by the age of 10.

CSF is produced mainly by a structure called the choroid plexus in the lateral, third and fourth ventricles. CSF flows from the lateral ventricle to the third ventricle through the interventricular foramen (also called the foramen of Monro). The third ventricle and fourth ventricle are connected to each other by the cerebral aqueduct (also called the Aqueduct of Sylvius). CSF then flows into the subarachnoid space through the foramina of Luschka (there are two of these) and the foramen of Magendie (only one of these).Absorption of the CSF into the blood stream takes place in the superior sagittal sinus through structures called arachnoid villi . When the CSF pressure is greater than the venous pressure, CSF will flow into the blood stream.

Acoustic neuroma/vestibular schwannoma is a benign slow-growing tumour. The clinical picture of the child suggests neurofibromatosis type 1 (NF1), with cafe-au-lait spots and axillary and inguinal freckling.

NICE guidelines suggest that at the premonitory stage (pre-hospital) the patient should receive Diazepam 10−20 mg given rectally, or midazolam 10 mg given buccally. If seizures continue, the patient should receive lorazepam IV.

In people with juvenile myoclonic epilepsy, symptoms can be brought on by: -Sleep deprivation-Psychological stress-Alcohol and drug use-Noncompliance of medication-Flickering lights such as strobe lights -Menses-Time of day – usually mornings

Clinical diagnosis of neurofibromatosis type 1 requires the presence of at least 2 of 7 criteria to confirm the presence of neurofibromatosis, type 1. Many of these signs do not appear until later childhood or adolescence, and thus confirming the diagnosis often is delayed despite a suspicion of NF1. The 7 clinical criteria used to diagnose NF1 are as follows:- Six or more café-au-lait spots or hyperpigmented macules greater than 5 mm in diameter in prepubertal children and greater than 15 mm postpubertal- Axillary or inguinal freckles (>2) – Two or more typical neurofibromas or one plexiform neurofibroma- Optic nerve glioma- Two or more iris hamartomas (Lisch nodules), often identified only through slit-lamp examination by an ophthalmologist- Sphenoid dysplasia or typical long-bone abnormalities such as pseudarthrosis- A first-degree relative (e.g., mother, father, sister, brother) with NF1

The nerve supply to the tensor tympani is the mandibular nerve.The mandibular nerve is the only division of the trigeminal nerve that carries motor fibres.Tensor tympani is a muscle that lies in a bony canal just superior to the pharyngotympanic tube. It originates from the cartilaginous portion of the pharyngotympanic tube, the bony canal in which it sits, and the greater wing of the sphenoid bone. It inserts into the upper part of the handle of the malleus. When contracted, it pulls the handle of the malleus medially. This action increases the tension across the tympanic membrane, reducing the magnitude of vibrations transmitted into the middle ear. This dampens loud noises or noises produced by chewing. Tensor tympani is innervated through the nerve to tensor tympani, which arises from the mandibular nerve.Other options:- The vestibulocochlear nerve is the eighth cranial nerve. This nerve has two components, a vestibular division that carries balance information, and a cochlear division that carries hearing information.- The glossopharyngeal nerve is the ninth cranial nerve. It has a wide range of functions. It carries taste and sensation from the posterior third of the tongue, as well as sensation from the pharyngeal wall and tonsils, the middle ear, external auditory canal and auricle. It carries parasympathetic fibres that supply the parotid gland. It also supplies the baroreceptors and chemoreceptors of the carotid sinus and supplies the secretomotor fibres to the parotid gland.- The maxillary nerve carries only sensory fibres.- The facial nerve is the seventh cranial nerve. It supplies the muscles of facial expression, as well as stylohyoid, the posterior belly of digastric, and stapedius (the only other muscle associated with the middle ear). It carries taste from the anterior two-thirds of the tongue and sensation from part of the external acoustic meatus, parts of the auricle and the retro-auricular area. It provides secretomotor fibres which supply to the submandibular gland, sublingual gland (via chorda tympani nerve), nasal glands and lacrimal glands.

Broca’s area is usually supplied by branches from the middle cerebral artery and thus will be spared when the anterior cerebral artery is occluded.Note:The two internal carotid arteries and two vertebral arteries form an anastomosis known as the Circle of Willis on the inferior surface of the brain. Each half of the circle is formed by:1. Anterior communicating artery2. Anterior cerebral artery3. Internal carotid artery4. Posterior communicating artery5. Posterior cerebral arteries and the termination of the basilar arteryThe circle and its branches supply the corpus striatum, internal capsule, diencephalon and midbrain.

Absence epilepsy is the most common type of generalized childhood epilepsies. It is mainly idiopathic, but 10-40% of the cases have a positive family history. It is characterized by frequent absence seizures and periods of unconsciousness. The hallmark of absence epilepsy on EEG is the bilaterally synchronous 2–4 Hz spike and wave discharges (SWDs). The average age of onset is around 4-8 years, being more prevalent among girls. Treatment resistance is not common.

The most appropriate next step would be to request for an EEG (electroencephalogram).The two primary differential diagnoses for the clinical scenario presented would be night terrors (hypnopompic hallucinations) due to underlying narcolepsy or frontal lobe epilepsy.Though occult airway obstruction and obstructive sleep apnoea can cause sleep disturbances, the clinical scenario presented is more suggestive of neurological disorders.The hyper-motor activity, along with arm posturing (often dystonic in appearance) and multiple occurrences per night would favour epilepsy. The daytime somnolence could be secondary to the nocturnal seizures.

Injuries to the peroneal nerve can cause numbness, tingling, pain, weakness and foot drop. The branches of the common peroneal nerve innervate and control the muscles in the legs that lift the ankle and toes upward (dorsi flexion).

Common neurological symptoms of Wilson disease that may appear and progress with time include tremor, involuntary movements, difficulty swallowing (dysphagia), difficulty speaking and poor articulation (dysarthria), lack of coordination, spasticity, dystonic postures, and muscle rigidity.

While the cause for Bell’s palsy is still under debate, it is observed that Bell’s palsy is often preceded by a viral infection. Bell’s Palsy:Bell’s palsy (idiopathic facial palsy) is an acute unilateral lower motor neurone palsy. It typically occurs two weeks after viral infection such as Epstein–Barr, herpes simplex, herpes zoster or mumps. A careful assessment may suggest an alternative aetiology for the acute onset of weakness, e.g. acute otitis media, Lyme disease, hypertension. Causes:In childhood, Bell’s palsy is probably a post-infectious (i.e. immune-mediated) phenomenon, while in adults, there is increasing evidence that the majority of cases follow reactivation of previous HSV infection. Management:The prognosis is generally good in childhood with full recovery in the majority. However, permanent weakness is observed in around 5%. Steroids and acyclovir may have some benefit in adults with recent onset of weakness, but the evidence of the treatment benefit is much less convincing in childhood. Exposure keratitis is an important complication and children should be managed with eye drops and taping of the eyelid at night until recovery is complete.

A vasovagal episode or vasovagal syncope is the most common form of reflex syncope. Reflex syncope is a general term used to describe types of syncope resulting from a failure in autoregulation of blood pressure, and ultimately, in cerebral perfusion pressure resulting in transient loss of consciousness. The mechanisms responsible for this are complex and involve both depression of cardiac output as well as a decrease in vascular tone. Other types of reflex syncope include carotid sinus syncope and situational syncope, for instance, cough or micturition syncope. Vasovagal syncope may be triggered by pain or emotional upset, although frequently a specific trigger cannot be identified.