Neurology and Clinical Chemistry Flashcards
What are neurological causes of coma?
- Cerebral infarction, hemorrhage
- Space occupying lesion/tumour, abscess, hematoma
➔ trauma - Infections — meningitis, encephalitis
➔ epilepsy
What are the metabolic causes of coma?
- DM
- Hypoglycemia
- Renal failure
- Liver failure
What are the endocrine causes of coma?
- Hypopituitary coma
- Adrenal insufficiency
- Myxoedema coma
- Parathyroid abnormalities
What is CSF exam used for?
Blood in CSF suggests subarachnoid hemorrhage
- Look for xanthochromia due to:
1. oxyHb
2. methemoglobin
3. bilirbin last 2-3 weeks
A lot of intact RBCs in CSF exam suggest…
Traumatic tap — needle inadvertently entered an epidural vein during insertion
What is indicator of brain injury?
- CK-BB in CSF
- Serum S100B
What is the most common cause of acute bacterial meningitis? Symptoms?
Meningococcal meningitis
Symptoms
- Headache
- Stiff neck
- Fever
- Coma and death
What are the lab investigations for bacterial meningitis? What are the CSF findings in bacterial meningitis?
Culture & gram stain
CSF Findings
1. high PMN
2. low glucose — need for glucose as fuel by infiltrating immune cells in response to infection
3. high lactate — lactate produced by bacterial anaerobic metabolism
What are the two types of diabetic coma?
- DKA
- Glucose > 20 mmol/L
- high ketones
- low pH — metabolic acidosis - Hyperosmolar non-ketotic diabetic coma:
- glucose > 40 mmol/L
- normal ketones
- low pH — lactic acidosis, secondary to dehydration
low blood volume
- hypoglycaemic coma
What are the clinical symptoms of acute intermittent porphyria?
Abdominal pain
Vomiting
Weight loss
What confirms acute intermittent porphyria?
ALA & PBG in urine
What are the symptoms of Guillain Barre Syndrome and CIDP and how to test for it?
Symptoms
- Generalized paralysis due to Ab destruction of myelin sheath
- Ascending paralysis
Test ➔ rule out hypo/hyperkalemia
- elevated protein in CSF
- normal WBC
What are examples of chronic and acute inflammatory neuropathies?
Chronic
➔ IgG4 Nodal/Paranodal Abs
➔ MGUS — IgM anti-MAG
➔ Multifocal Motor Neuropathy (MMN) — IgM + GM1/GM2 gangliosides
Acute
➔ GBS — IgG GD1 alp/beta, GM1 alp/beta & GT1 alpha ganglioside
What are the toxins and drugs that may cause peripheral neuropathy?
- Arsenic
- Pb
- Organophosphates
- Tricyclic antidepressants
- Dilantin
What can metabolic neuropathy be caused by?
- Alcohol — Vit B1 deficiency
- Vit B12 deficiency
- Diabetic neuropathy
- Uremia
- Myeloma
What are 3 lab investigations for peripheral neuropathy?
- Hematological studies
- Serum
- Protein electrophoresis
How to classify intellectual disability (ID) or mental retardation?
IQ — 90-109 (50% of population)
➔ <90 (25% of population)
➔ <70 (1.8% of population) — mild ID
➔ <50 (0.4% of population) — severe ID
What are the leading causes intellectual disability? (In decreasing order)
- Indeterminate (genetic?)
- Perinatal disorders
- Chromosome abnormalities
What are some examples of congenital disorders? (decreasing order of frequency)
- Spina bifida
- Down’s
- Sex chromosomal disorder
What are examples of perinatal disorders of extracerebral origin?
- Hypoxia & ischemia
- Cerebral palsy
- Hypoglycemia
What are causes of intellectual disability in neonates and infants?
- Fetal alcohol syndrome
- Prematurity
- Heavy metal poisoning (Pb)
What are some causes and investigations of dementia?
- Alzheimer’s ➔ beta amyloid and tau protein
- Hypothyroidism ➔ thyroid function test
- Nutritional deficiency ➔ Vit B12
- Creutzfeldt Jacob disease ➔ proten 14-3-3 for prion disease
How much CSF is formed? How is it formed? How is it sampled?
- 500 mL formed/day
- Ultrafiltrate of plasma formed in choroid plexus
- Sampled by lumbar puncture
What is the difference between CSF and plasma?
- Lower total protein
➔ lower proportion of high MW proteins (lower IgG:albumin ratio)
➔ contains CSF specific transferrin also called tau protein, beta and gamma trace protein
➔ contains prominent prealbumin band - Lower glucose
- Low cell count
What is the clinical presentation for MS?
CP — Evidence of two separate attacks
1. Weakness
2. Numbness
3. Vision problems
4. Slurred speech
What are the diagnostic tests for MS?
- MRI
- CSF IgG & CSF IgG synthetic rate
- Oligoclonal banding — examine IgG band pattern in both serum and CSF, look for 2 or more unique clonal bands present in CSF but not in serum
- Myelin basic protein in CSF
- Aquaporin 4 Ab detected in serious variant of MS (transverse myelitis)
What is paraneoplastic neurologic syndrome?
Small portion of patients with occult or undetected malignancies may present many years before diagnosis of cancer with neurologic symptoms
➔ AutoAb generated in response to these cancers may be detected in the blood and may be responsible for the problem
