Exploring Nelson with Vasu : CNS 3

It is a series of blog-post, for asynchronous learning written by Dr Vasu Burli which are actually his handpicked notes he derived from Nelson Textbook of Pediatrics. The notes are divided system-wise. The third in this series is ready to go online!

Series 1: CNS Questions
1. Stroke
2. Viral meningoencephalitis
        About Dr Vasu Burli
Budding intensivist, currently persuing Pediatric critical care fellowship from Apollo Chennai, did his DNB in Pediatrics from renowned institute Kanchi Kama -Koti CHILD’S trust Hospital, Chennai. His area of interest are pediatric Intensive care and Emergency medicine.


1. Stroke
Stroke has emerged as an important cause of acquired brain injury in newborns and children.

Types

Ischemic: arterial ischemic stroke (AIS) cerebral sinovenous thrombosis (CSVT)
Hemorrhagic: hemorrhagic stroke and cerebrovascular disease.

Causes for arterial ischemic stroke:

Arterio-pathic

Focal cerebral arteriopathy

Transient cerebral arteriopathy

Moyamoya

Arterial infection

migrane

Cardiac


Complex cyanotic heart disease

Cardiac procedures

Arrhythmias

Endocarditis

cardiomyopathy
Genetic


Hereditary dyslipoproteinemia

Heritable disorders of connective tissue

Organic acidemias

Mitochondrial encepahalomyoapthies

Haematological


Sickle cell anemia
Iron deficiency anemia

Inherited prothrombotic
(factor V Leiden,
prothrombin gene mutation)

Acquired prothrombotic
(e.g., protein C/S deficiency, antithrombin III deficiency, lipoprotein [a],
antiphospholipid antibodies,
oral contraceptives,
pregnancy)

Causes of hemorrhagic stroke  

Vascular disorders

Arteriovenous malforma
tions
Cavernous malformations (cavernomas)
Venous angiomas
Hereditary hemorrhagic telangiectasia
Intracranial aneurysm
Choroid plexus angiomas
Drugs/ toxins
Blood disorder

Idiopathic thrombocytopenic purpura

Hemolytic uremic syndrome

Hepatic disease/failure

coagulopathy
Vitamin K deficiency
(hemorrhagic disease of the newborn)

Disseminated intravascular coagulation
Trauma

Middle meningeal
artery injury
Bridging vein
injury (subdural hematoma)
Subarachnoid
hemorrhage
Hemorrhagic
contusions (coup and contrecoup)
Non accidental trauma
Iatrogenic
(neurosurgical
procedures,
angiography)

 Clinical Featers

Clinical features:

Arterial ischemic stroke (AIS)


The acute onset of a focal neurologic deficit in a child is stroke until proven otherwise.

The most common focal presentation is hemiparesis but acute visual, speech, sensory, or balance deficits also occur.

Children with these presentations require urgent neuroimaging and consultation with a child neurologist as emergency interventions may be indicated.
Hemorrhagic stroke (HS)


Clinical presentations vary according to location, cause, and rate of bleeding.

Acute hemorrhages may feature instantaneous or thunderclap headache, loss of consciousness, and nuchal rigidity focal neurologic deficits and seizures.

HS can be rapidly fatal.

In bleeds associated with vascular malformations, pulsatile tinnitus, cranial bruit and high-output heart failure may be present.
Investigations



CT imaging can demonstrate larger mature AIS and exclude hemorrhage.
MRI identifies early and small infarcts and is therefore required to exclude ischemic stroke.
Diffusion weighted MRI (DWI) can demonstrate AIS within minutes of onset.
MR angiography can confirm vascular occlusion


lumbar puncture may be required to exclude subarachnoid hemorrhage.
CT is highly sensitive to acute HS.
MRI is highly sensitive to even small amounts of acute hemorrhage.
Angiography by CT, MR, or conventional means is often required to exclude underlying vascular abnormalities.
Treatment
1.antithrombotic statergies- heparin, aspirin

2. neuroprotective statergies
 Control of seizures, blood glucose and temperature.

3. disease specific
Transfusion in sickle cell and iron def  anemia
Immunosupression – vasculitis
Surgery in moyamoya

4. Sec stroke prevention

5. Rehabilitation

The same principles of neuroprotection as in AIS.


Reversal of anticoagulant therapy may be required (e.g., vitamin K, fresh frozen plasma) but the role of factor VII are unstudied.


Emergent neurosurgical intervention for large or rapidly expanding lesions.

Neuroimaging findings:

      CT: hyperdense region surrounded by edema, intraventicular hemorrhages

      CT Venography: filling defects

      MRI: Focal increased diffusion, multifocal and restricted diffusion. Demyelination. Follow up MRI may show atrophy/ gliosis.

      MR Angiogram: occlusion, stenosis, decreased flow, puffed smoke appearance
 (moya moya), aneurysms, vascular malformations

      MR Spectroscopy: increased lactate in MELAS

      Gradient ECHO: can show presence of blood products

Differential diagnosis of stroke like disorders in children

DISORDER
CLINICAL DISTINCTION FROM STROKE
IMAGING DISTINCTION FROM STROKE
Migraine
Evolving or “marching” symptoms, short duration, complete resolution, headache, personal or family history of migraine
Typically normal
Migrainous infarction is rare
Seizure
Positive symptoms, Todd paralysis is postseizure and limited
Normal or may identify source of seizures (e.g., malformation, old injury)
Infection
Fever, encephalopathy, gradual onset, meningismus
Normal or signs of encephalitis/cerebritis, which are typically diffuse and bilateral

Demyelination
Gradual onset, multifocal symptoms, encephalopathy Accompanying optic neuritis
Multifocal lesions, typical appearance (e.g., patchy in ADEM, ovoid in MS),
Hypoglycemia
Risk factor (e.g., insulin therapy), related to meals, additional systemic symptoms
Bilateral, symmetric
Posterior dominant pattern
Watershed infarction due to global HIE
Risk factor (e.g., hypotension, sepsis, heart disease), bilateral deficits
Bilateral, symmetric restricted diffusion in border zones between major arteries (watersheds)
Hypertensive encephalopathy (PRES)
Documented hypertension, bilateral visual symptoms, encephalopathy
Posterior dominant, bilateral, patchy lesions involving gray and white matter
Inborn errors of metabolism
Pre-existing delays/regression, multisystem disease, abnormal biochemical profiles
MR spectroscopy changes (e.g., high lactate in MELAS)
Vestibulopathy
Symptoms limited to vertigo, imbalance (i.e., no weakness) Gradual onset
Normal
Acute cerebellar ataxia
Sudden onset bilaterally symmetric ataxia postviral
Normal
Channelopathy
Syndromic cluster of symptoms not localizing to single lesion
Gradual onset, progressive evolution
Normal
Alternating hemiplegia
History contralateral events
Choreoathetosis/dystonia
Normal


ADEM, acute disseminated encephalomyelitis; HIE, hypoxic-ischemic encephalopathy; MELAS, mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes; MR, magnetic resonance; MS, multiple sclerosis; PRES, posterior reversible leukoencephalopathy syndrome.

MIS W HAD A/C  HIV (mis world had acute on chronic hiv) migrane, infections, seizure, watershed infarcts due to HIE, hypoglycemia, ataxia, demyelination, alternating hemiplegia, channelopathies, HTN, IEM, vestibulopathy.


2. Viral meningoencepahalitis

Viral meningoencephalitis is an acute inflammatory process involving the meninges and, to a variable degree, brain tissue.

Etiology:

Enteroviruses are the most common cause of viral meningoencephalitis.

Arboviruses are arthropod-borne agents, responsible for some cases of meningoencephalitis during summer months.

Several members of the herpes family of viruses can cause meningoencephalitis. (HSV-1) (HSV-2) (VZV) (CMV) (EBV) (HHV-6).

Other virusesmumps and occasionally by respiratory viruses (adenovirus, influenza virus, parainfluenza virus), rubeola, rubella, or rabies.

Pathogenesis and pathology:

Neurologic damage is caused by direct invasion and destruction of neural tissues by actively multiplying viruses or by a host reaction to viral antigens.

Temporal lobe - HSV
Entire brain – Arbovirus
Basal structures - Rabies

Clinical features:

Fever, nausea and vomiting, photophobia, and pain in the neck, back, and legs are common. The presenting manifestations in older children are headache and hyperesthesia, and in infants, irritability and lethargy. 

Headache is most often frontal or generalized; adolescents frequently complain of retrobulbar pain. As body temperature increases, there may be mental dullness, progressing to stupor in combination with bizarre movements and convulsions. Exanthems often precede or accompany the CNS signs.

Investigations: 
  
The diagnosis of viral encephalitis is usually made on the basis of the clinical presentation of nonspecific prodrome followed by progressive CNS symptoms. The diagnosis is supported by examination of the CSF, which usually shows a mild mononuclear predominance. EEG typically shows diffuse slow-wave activity, usually without focal changes. Neuroimaging studies (CT or MRI) may show swelling of the brain parenchyma. Isolation of the virus from the CSF. PCR for entero and HSV.

Treatment:    
  
With the exception of the use of acyclovir for HSV encephalitis, treatment of viral meningoencephalitis is supportive. Treatment of mild disease may require only symptomatic relief. More severe disease may require hospitalization and intensive care. If cerebral edema or seizures become evident, vigorous treatment should be instituted.

Prevention:

1. Widespread use of effective viral vaccines for polio, measles, mumps, rubella, and varicella.

2. The availability of domestic animal vaccine programs against rabies has reduced the frequency of rabies encephalitis.

3. Control of encephalitis due to arboviruses has been less successful because specific vaccines for the arboviral diseases are not available.

4. Control of insect vectors by suitable spraying methods and eradication of insect breeding sites.

5. Furthermore, minimizing mosquito bites through the application of DEET-containing insect repellents on exposed skin and wearing long-sleeved shirts, long pants, and socks when outdoors, especially at dawn and dusk, reduces the risk of arboviral infection.
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