48 Neurological Disorders

William Howlett 25/09/18

An overview of the big diseases in Neurology.

Obviously stroke is huge.

  • Infections (including Tetanus/Cerebral Malaria)
  • Neuropathies
  • Quadraparesis
  • Coma
  • Neurodegeneration
  • SOL
  • Movement Disorders

Don’t forget about Functional Disorders

Neurology breaks down into classes and sub-classes

48.1 The Big 5

  • Epilepsy
  • Infections
  • Paraplegia/Neuropathy
  • Neurogenerative
  • Stroke

Paraplegia is much more common in African setting than High Income Countries. As is infection.

Rates of neurodegenerative and MS are rarer than in High Income Countries. But rates of neurodegenerative are increasing.

The reason for these differences are mainly due to population distribution. Average age of adult survival is 60 years.

Environment and genetics also have an impact.

Neurology accounts for 20% of hospital admissions

48.1.1 Epilepsy

Global prevalence = 0.5%

SSA prevalence = 0.5->1.5%

But the majority of epilepsy is around the same the world over when you adjust for risk factors.

The big differences are due to congenital and pre/peri natal stuff.

But also increased rates of cysticercosis. You can see 10-40% developing seizures. Accounts for 30% of late onset epilepsy endemic areas.

48.1.1.1 Nodding Disease

Northern Uganda, Southern Sudan

It skews the prevalence of epilepsy in these areas.

It’s seen with a high frequency of onchocerchiasis.

Presents with generalized tonic-clonic seizures, nodding seizures, hallucinations, cognitive decline.

Also presents with ngalanga. Facial, chest, thoracic deformities, delayed secondary sex characteristics. Seen in 10% of cases

Very strange. Does go away when you eliminate onchocerciasis.

48.1.2 Infections

The main infections would be:

  • HIV Opportunistic Infections
  • Cerebral Malaria (Mortality 10-20%): This has decreased significantly over the last 30 years
  • Tetanus (Mortality 40-60%)
  • Rabies
  • Trypanasomiasis (majority seen in DRC and southern sudan. It is really falling in Tanzania)
  • Bacterial Meningitis (mainly children)

Other infections would be:

  • HTLV1 (causes spastic paraparesis)
  • Ebola/Marburg
  • Zika
  • Konzo
  • Tropical Ataxic Neuropathy

48.1.2.1 HIV

HIV is strongly strongly strongly associated with neurology presentations in high prevalance environments. You have to look for HIV in neurological presentations.

Why? Opportunistic infections in 20-25%. Also 70% from Direct Infections. Also ~1% inflammatory/autoimmune

CNS Opportunistic infections cause 20% of HIV deaths in SSA (TB Cause 40%. Pneumonia cause 20%. Malignancy cause 10%. Direct organ failure from HIV 10%)

What CNS infections are causing these deaths? In this order of importance:

  • Cryptococcal (case fatality ~60%. Pretty Unchanged by ART. CFR In HIC is around 20%)
  • TB (case fatality ~60%. Pretty Unchanged by ART. CFR In HIC is around 20%)
  • Bacterial (case fatality ~60%. Completely Unchanged by ART. CFR In HIC is around 10%)
  • Toxoplasma
  • PML
  • Lymphoma

Presentations are super non-specific for different causes of meningitis. Acute bactreial a bit faster, but else v difficult.

48.1.2.1.1 Direct HIV Infection
  • HIV Associated neurocognitive dysfunction (HAND) (40-50%)
  • Vacuolar Myelopathy (Virus in spinal cord, causing subclinical myelopathy) (20%)
  • Peripheral neuropathy (30%)

It’s a bystander effect that the neurones die. HIV doesn’t live in neurons, it lives in supporting cells.

ART doesn’t get rid of HAND. It reduces rate from around 40% to around 30%

You could identify primitive reflexes clinically:

  • Snout
  • Palmomental

Bells’ palsy and peripheral neuropathies should get an HIV test.

You get two types of inflmamatory neurological disorders: AIDP (guillain barre) and CIDP (chronic)

48.1.2.1.2 MND/ALS in HIV

ALS can get better with HIV suppression!

48.1.3 Blah

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