Tag Archives: Infectious

Neonatal Myasthenia

Diagnosis: Myasthenia in a new born to a mother with myasthenia gravis AChR antibodies: positive Clinical features: Weakness, hypotonia, dysphagia, weak cry and suck, Edraphonium/Tensilon test positive Mother with myasthenia gravis Treatment: Neostigmine Rarely plasma exchange Related articles: Approach to weakness, neuromuscular disease patterns, neuromuscular junction disorders,


Diagnosis: A combination of clinical features and CSF analysis Clinical features: Prodrome: upper respiratory tract infection Followed by: Mild meningismus +headache Myalgial, paraesthesia, paralysis and respiratory weakness After recovery LMN features and flaccid weakness. Autonomic features (swollen, clammy, cold, purple) in Lower limbs. Findings in Investigations: CSF: Pleocytosis Serology NCS/EMG: Asymmetrical involvement. Motor evoked potential … Continue reading Poliomyelitis

Isolated Facial palsy, CN VII

Upper motor neuron lesion: Diagnosis: This is a clinical diagnosis. The underlying cause is determined by investigations and clinical correlation. Clinical features: Sparing of the forehead muscles Asymmetry of face at rest or on movement: smile, puffing the cheeks and on wincing The palpebral fissure may be widened on the affected side Investigations to consider: … Continue reading Isolated Facial palsy, CN VII

Superior Orbital Fissure Syndrome

Synonyms: Anterior cavernous sinus syndrome, Rochon-Duvigneaud’s syndrome Diagnosis: This is a clinical diagnosis. Underlying causes are identified by investigations and clinical assessment. Dysfunction of cranial nerves oculomotor (III), trochlear (IV), abducens (VI) and first division of the trigeminal nerve (V1). Also sympathetic fibers may be involved causing a Horner syndrome (this becomes cavernous sinus syndrome). … Continue reading Superior Orbital Fissure Syndrome

Klüver-Bucy syndrome

Diagnosis: This is a clinical diagnosis Clinical features: Hypersexuality, hyperorality, visual agnosia, and placidity (diminished emotional reactions). Investigations to consider: MRI: Lesions in bilateral medial temporal lobes, e.g. Traumatic brain injury, herpes, other infections Consider tests for dementias (FTLD, Alzheimer’s) & infections Related articles: Traumatic brain injury, encephalitis, frontotemporal dementia, Alzheimer disease,


Diagnosis: Neuropsychological/Psychometric testing Or Clinical features The underlying etiology is determined by a combination of clinical features, neuropsychological testing, imaging and laboratory testing   Clinical features: This is an acquired persistent disorder where there is an impairment of the content of consciousness (intellectual function) with compromise in at least 2, e.g.: Memory Language i.e. aphasia … Continue reading Dementia

Cerebral Edema

This is an abnormality that can occur due to multiple potential causes. It is treated based on the underlying cause and severity. Diagnosis: CT: Hypodensity Local effacement of sulci and ventricles and cisterns Blurring of the grey-white interface MRI: DWI: Allows differentiation between vasogenic (no abnormal diffusion restriction) vs. cytotoxic (abnormal diffusion restriction) types of … Continue reading Cerebral Edema

JC virus Granule Cell Neuronopathy (JCV GCN)

Diagnosis: Clinical features plus MRI and evidence of JC virus infection Clinical features: ataxia Findings on Investigations: MRI: Cerebellar atrophy with or without features of PML CSF: JC virus positive Pathology, biopsy: Cerebellum: focal Internal granule cell layer loss, some enlarged granule cell neurons Special studies: Immunohistochemistry for polyomavirus: positive In situ hybridization ISH for … Continue reading JC virus Granule Cell Neuronopathy (JCV GCN)

Progressive Multifocal Leukoencephalopathy (PML)

Diagnosis: Clinical and imaging features plus laboratory findings Clinical features: Gradual onset & progressive. Seizures & aphasia may occur Occurs in the setting of immunosupression: e.g. HIV infection/AIDS, immunosupressant medications, Findings on Investigations: JC virus in CSF: by PCR MRI: White matter lesions, usually asymmetric but bilateral, periventricular and subcortical involvement of U fibres, spares … Continue reading Progressive Multifocal Leukoencephalopathy (PML)

Variant Creudtzfedt-Jakob Disease (vCJD)

Synonyms: New variant CJD, Diagnosis: Clinical +/-EEG +/-MRI +/-CSF findings +/-brain biopsy Clinical features: Abnormal movements (myoclonus, dystonia, chorea), ataxia, slurred speech, tremor, dementia, akinetic mutism Non-specific sensory symptoms Psychiatric symptoms: withdrawal, delusions, depression Findings on Investigations: MRI: Thalamic hyperintensities: bilateral pulvinar (posterior thalamus) a.k.a. ‘Pulvinar sign’. In some there is also bilateral dorsomedial nucleus … Continue reading Variant Creudtzfedt-Jakob Disease (vCJD)

Fungal Intracranial Abscess

Candida abscess: Diagnosis: Biopsy or blood culture isolation of organisms Treatment: Fluconazole, amphotericin B   Cryptococcosis (Cryptococcus neoformans): See under Cryptococcosis (Cryptococcus neoformans), Cryptococcal meningitis & related   Aspergillosis a.k.a. Aspergillus fumigatus or flavus: Diagnosis: Suggested by MRI, but confirmed by biopsy Pathology: Biopsy: Within distribution of anterior or middle cerebral artery. Multiple. Necrosis, hemorrhage. … Continue reading Fungal Intracranial Abscess

Spinal Cord Abscess

Diagnosis: A combination of clinical features, MRI, and biopsy Clinical features: Features of myelopathy Findings on investigations: MRI: intramedullary ring enhancing lesion, Spinal cord biopsy & culture: confirmatory of organisms Treatment: Antibiotics Consider surgical drainage Related articles: Approach to weakness, Bacterial Meningitis, intracranial empyema, brain abscess, epidural abscess (brain or spinal),

Epidural Abscess (intracranial or spinal)

Diagnosis: Imaging (MRI with and without contrast) plus biopsy for confirmation Pathology: Biopsy: Necrosis with inflammation (neutrophils & later macrophages & lymphocytes), rim of fibrosis (if absent this is cerebritis) Surrounding gliosis Clinical features: Intracranial: focal neurological deficit Spinal: transverse myelopathy and a flexed posture resisting extension, back pain with fever. Investigations to consider: FBC, … Continue reading Epidural Abscess (intracranial or spinal)

Brain Abscess

Synonyms: Intracranial abscess a.k.a. intracerebral abscess: Diagnosis: Suggested by imaigng. Confirmed by biopsy and culture Clinical features: Presents with focal neurological deficits: weakness, aphasia, neglect May present with headache or seizure Meningismus in <30% Pathology: Biopsy: Necrosis with inflammation (neutrophils & later macrophages & lymphocytes), rim of fibrosis (if absent this is cerebritis) Surrounding gliosis … Continue reading Brain Abscess

Intracranial Empyema

Diagnosis: A combination of clinical features, imaging and Growth on cultures from the collection Clinical features: seizures, cognitive dysfunction, hemispheric symptoms (aphasia, apraxia, hemiparesis) Findings on Investigations: CT: cavity +low density +gas MRI: resectricted diffusion in an axtra-axial collection Growth on cultures from the collection Related articles: Approach to cognitive dysfunction, Approach to weakness, Epilepsy,

Subacute Sclerosing Panencephalitis (SSPE)

Diagnosis: Clinical features, plus EEG Clinical features: Previous measles infection. Children or young adults. Subacute onset of progressive cognitive deficits, behavioural problems, spasticity, rigidity, Myoclonus, generalised seizures Findings on Investigations: EEG: flat with episodic bursts Anti-measles antibodies CSF: raised IgG index Pathology: Gross: hard brain (gliosis), Microscopic: intracellular (type A) and intracytoplasmic neuronal and glial … Continue reading Subacute Sclerosing Panencephalitis (SSPE)

HIV Associated Neurocognitive Disorders (HAND)

Synonyms: HIV associated dementia HAD, formerly Subacute or Chronic HIV encephalitis a.k.a. AIDS dementia complex formerly AIDS encephalopathy/AIDS encephalitis Diagnosis: Acquired impairment in at least 2 cognitive domains: Learning, information processing speed, attention/concentration +Marked impairment of ADLS +No delirium +No other cause for dementia Other features & tests: Limb incoordination, gait ataxia, abnormal smooth pursuit … Continue reading HIV Associated Neurocognitive Disorders (HAND)

Schistosomal Myeloradiculopathy

Schistosomal myelopathy and radiculopathy Diagnosis: A combination of Schistosoma tests plus MRI and clinical features Clinical features: Features of myelopathy & radiculopathy & current or past Schistosomal infection Findings on Investigations: MRI: lower thoracic & cona medularis or cauda equina, enlargement, T2 hyperintensity, T1 gadolinium enhancement (linear or micronodular) Tests for: S. mansoni or S. … Continue reading Schistosomal Myeloradiculopathy

HTLV-1 Myelitis

Synonyms: a.k.a. tropical spastic paraparesis Diagnosis: Clinical features: features of myelopathy MRI: may show T2 hyperintense lesions Viral studies: HTLV-1 viral load= mean of 83 copies/100 cells in TSP vs. a mean of 1.9 copies/100 cells in HTLV-1 infected, nonTSP patients. Related articles: Approach to weakness,

Viral Myelitis

Diagnosis: Clinical +MRI +laboratory studies +evidence of viral infection Types: Herpes viruses: CMV myelitis HSV myelitis VZV myelitis: VZV PCR or antibodies against VZV EBV myelitis HHV6 HIV myelitis HTLV-1 myelitis: serology Enteroviruses, Echovirus, coxsackie virus, hepatitis A, hepatitis B, rubella, measles, mumps, lymphocytic choriomeningitis LCM Poliomyelitis, West nile virus: +/- LMN signs Treatment: Treat … Continue reading Viral Myelitis


Synonyms: Taenia solium (pork tapeworm) Diagnosis: Imaging plus clinical features Clinical features: Seizures, Meningitis may occur Findings on Investigations: MRI: T1 +contrast: multiple ring enhancing lesions with edema T1, punctuate signal void FLAIR: hyperintensity (gliosis) surrounds the lesions CT: Multiple calcified lesions +/-surrounding edema Migrating intraventricular cyst +positive serology for neurocysticercosis Treatment: Albendazole 800mg P.O. … Continue reading Neurocysticercosis

Varicella Zoster Virus VZV vasculopathy

Diagnosis: Clinical: large artery or small vessel ischemic stroke, recurrent, protracted course. Rash may be absent or occur months before MRI, CT: large artery or small vessel ischemic stroke, typically at grey-white junction. Imaging is sensitive but not specific Anti-VZV IgG & VZV PCR: IgG is more sensitive for VZV vasculopathy, also reduced serum/CSF ratio … Continue reading Varicella Zoster Virus VZV vasculopathy

Listeria Rhombencephalitis

Synonyms: Listeria brainstem encephalitis, neurolisteriosis, Listeria meningitis if without parenchymal involvement Diagnosis: Positive CSF gram stain & culture: gram positive bacillus, Listeria monocytogenes Or Positive blood culture: growing Listeria monocytogenes Listeria meningitis if without parenchymal involvement Clinical features: Fever +headache, then brainstem signs, then coma & respiratory failure Findings on Investigations: MRI: lesion in brainstem … Continue reading Listeria Rhombencephalitis

Viral Encephalitis

Viral encephalitis is the commonest cause of encephalitis. The general features and causes of encephalitis are described in a separate section. Here we discuss the various viral encephalitides.   HSV Encephalitis: Diagnosis: Clinical findings combined with MRI features and isolation of virus by PCR or pathology Findings on investigations: CT: Low density in: Insular regions, … Continue reading Viral Encephalitis


Encephalitis is the term used to describe an inflammatory process of the substance of the brain. This distinguishes it from meningitis which is an inflammatory process of the coverings of the brain. There are patients who have inflammation of both areas and this is described as meningo-encephalitis. Patients with encephalitis and those with meningitis present … Continue reading Encephalitis

Fungal Meningitis

There are various fungi that may cause meningitis. The manifestations vary by causative organism and host immune status. Some organisms are more common in certain geographical locations. Patients may present acutely with headache and encephalopathy or may have a much more indolent course.     Cryptococcal meningitis: Synonyms: Cryptococcosis (Cryptococcus neoformans) Diagnosis: Clinical findings plus … Continue reading Fungal Meningitis

Tuberculous Meningitis

Synonyms: Mycobacterium tuberculosis meningitis, TB meningitis, tuberculoma, tuberculous meningovasculitis Diagnosis: Clinical features plus confirmatory CSF analysis or TB studies Findings in Investigations: Findings remain after 10 days treatment White cell count: moderately high, Usually <500/microL, (100-300/mm3) Mainly lymphocytes Protein: High, >0.8g/L Glucose: Low ,<2.2 mmol/l Or atypically: Neutrophilia if early, normal protein, normal glucose Eosinophilia … Continue reading Tuberculous Meningitis

Bacterial Meningitis

Diagnosis: Clinical features plus confirmation by CSF analysis Findings in Bacterial meningitis: High opening pressure >180 mmH2O, turbid/purulent appearance White cell count: high, 10-10,000/microL Mainly neutrophils (usually >100), but monocytes are suggestive of Listeria monocytogenes Protein: High, >0.45 g/L (>45 mg/dL) Glucose: low, <0.4 of serum (roughly <1/2 serum), or <2.2 mmol/L (<40 mg/dL) Borrelia … Continue reading Bacterial Meningitis


Clinical features: Patients present with headache and necks stiffness. They typically have a fever, unless they are immunosupressed, and may have a rash. The classic triad in bacterial meningitis is headache, fever and rash. It is a serious life-threatening medical emergency that often results in significant disability. However, the commonest cause of meningits overall is … Continue reading Meningitis

Tick Paralysis

Tick paralysis also known as Tick bite paralysis is a neuromuscular condition that causes ascending symmetric flaccid paralysis. Clinical features: Prodrome phase followed by weakness Then acute generalised weakness (ascending symmetric flaccid paralysis), involves cranial nerves, usually occurs in children, usually spring or summer. No sensory symptoms +Tick bite or tick attached to skin In … Continue reading Tick Paralysis

Diphtheria Polyneuritis

Diphtheria polyneuritis is a neuromuscular condition that is caused by the bacteria Corynebacterium diphtheriae. It classically causes pharyngitis followed by descending weakness that starts with bulbar weakness and progresses to involve the limbs. Clinical features: Corynebacterium diphtheriae infection: this causes pseudomembrane of the pharynx/tonsils, URI, sore throat Then at 1-2 weeks pharyngeal & laryngeal paralysis, … Continue reading Diphtheria Polyneuritis