BODY FLUIDS. CEREBROSPINAL FLUID (CSF ) CSF is formed from the blood plasma, in the choroid plexuses...

BODY FLUIDS

CEREBROSPINAL FLUID(CSF )

CSF is formed from the blood plasma, in the choroid plexuses of the brain ventricles, partly by ultrafiltration and partly by active secretion Amount produced /day: 450 - 500 ml Normally, it contains 1-5 lymphocytes /HPF

Volume : 100-150 ml pH : 7.4

CSF Circulation

Method of CSF Sampling

Examination of CSF: CSF is normally colorless & clear, turbidity is usually

due to leucocytes, but it may be due to micro-organisms.

- Blood stained CSF may indicate :

- Recent subarachnoid hemorrhage

- Traumatic tap (damage to blood vessel during specimen collection

- Xanthochromia (yellow color) is the result of :

- CSF protein concentration is very high

- previous hemorrhage into the CSF (Lysis of RBCs and breakdown of hemoglobin).

- jaundiced patients.

Normal composition of CSFAppearance: Clear ,Colorless

Lymphocytes: 1 - 5/ H.P.F.

pH: 7.4

Total Volume: 100 - 150 ml

Daily Secretion: 450 - 500 µl

Specific Gravity: 1.006 - 1.007

Protein: 15 - 45 mg/dl

Glucose: 50 - 80 mg /dl

Chloride: 115 - 130 mmol /L

Calcium: 1.0 - 1.40 mmol/L

Phosphorus: 0.4 - 0.7 mmol/L

Magnesium: 1.2 - 1.5 mmol/L

Potassium: 2.6 - 3.0 mmol/L

Chemical composition of CSF : is similar to that of the blood plasma, only

differing in the concentrations of :

A - The non-Diffusible Substances

B - Some Diffusible Substances

A - The non-Diffusible Substances:

1- Proteins, mostly albumin are found in the CSF (15-45 mg/dl), the A/G ratio being 4/1

- 80% of CSF protein originates from plasma by ultrafiltration and the remainder is from intrathecal synthesis.

- CSF protein concentration due to:- permeability of blood brain barrier to

plasma proteins.- Brain tumors.

- Acute bacterial meningitis.

intrathecal synthesis of immunoglobulins particularly IgG result from proliferation of limited number of clones of plasma cells and is associated with oligoclonal bands that are present in CSF but not in serum.

- Examination of the oligoclonal bands by electrophoresis has a great importance in diagnosis of demyelinating diseases (Multiple sclerosis).

2 - Lipids and bilirubin :

They are almost all protein bound in the plasma So, they cannot cross the blood brain barrier and almost absent in CSF.

3- Calcium:

Being only partly bound to the plasma proteins, Free calcium radially crosses into the CSF So, calcium concentration in CSF is lower than that in the plasma.

B - Some Diffusible Substances :

1- Glucose:

- CSF glucose concentration is lower than that in the blood plasma (50 - 80 mg/dl).

- In hypoglycemia [CSF glucose] may be very low.

- In hyperglycemia, it is raised.

- CSF glucose conc. may be low or undetectable in patients with - Acute bacterial meningitis,

- Tuberculous meningitis - Carcinomatous meningitis

due to consumption of glucose by leucocytes or other rapidly metabolizing cells.

- In viral meningitis it is usually normal.

2 - Potassium and phosphates are present in lower concentration than in the blood plasma 3 - Chlorides and magnesium are present in

higher concentrations than in the blood plasma - The chloride concentration is explained on

the basis of the ( Donnan equilibrium). - Chlorides :

- markedly in acute bacterial meningitis

- slightly in viral meningitis & brain tumors.

ParameterCondition

Bacterial Meningitis

Tuberculous Meningitis

Viral Meningitis

Brain Tumor

Protein↑ ↑↑ ↑ Normal↑

Glucose↓ ↓ ↓ ↓

Normal or

slightly ↓

Chlorides↓ ↓↓ ↓ Normal or Normal or

Abnormal findings of CSF in some pathological conditions

URINE

Urine is a fluid obtained through renal glomeruli with considerable changes which occur in this filtrate before it is excreted as urine.

Normal urine contains about 1.5 liters of water per day.

Composition of urine

Urine contains organic and inorganic solids:

Chief organic solids:

Non protein nitrogen (NPN) compounds

Organic acids

Sugars

Traces of proteins, vitamins, hormones and pigments

Composition of urine… contd.

Chief inorganic solids:

Sodium

Potassium

Chlorides

Small amounts of Ca, Mg, S & phosphates

Traces of Fe, Cu, Zn and I2

Urine testing using Dipstick

Abnormal constituents of urine

A) Proteins : Normally less than 200 mg protein is excreted in

the urine daily; more than this level leads to a condition called “Proteinuria”.

Proteinuria is either Glomerular or Tubular .

Glomerular proteinuria is due to glomerular permeability filtration of high molecular weight proteins ( e.g. glomerulonephritis).

Tubular proteinuria occurs as a result of tubular reabsorption with normal glomerular permeability excretion of low molecular weight proteins (e.g. chronic nephritis)

Proteinuria is divided into Prerenal, Renal and Postrenal.

1 - Prerenal proteinuria:

Occurs in: Bence – Jones protein:

This abnormal gamma globulin ( light chains only) is synthesized by malignant plasma cells (Multiple myeloma).

It precipitates at 60OC, redissolves at 100OC and reprecipitates on cooling.

2 - Renal proteinuria: is due to - Severe muscular exercise - After prolonged standing (Orthostatic proteinuria)

- Heart failure - Nephrotic syndrome - Glomerulonephritis - Microalbuminuria:

- Presence of small amounts of albumin in the urine (20 – 200 mg/L) that cannot be detected by ordinary urine testing & needs special tests for detection.

- It is an early indicator of glomerular affection due to uncontrolled DM or hypertension.

3 - Postrenal proteinuria: is due to

- Lower urinary tract inflammation, tumors or stones

B) Glycosuria : (Presence of any sugar in urine)

1 - Glucosuria: (Presence of detectable amount of glucose in urine )

- Uncontrolled DM :The concentration of glucose in the plasma exceeds the renal threshold.

- Renal glucosuria : Normal plasma glucose concentration with proximal tubular malfunction renal threshold (Gestational Diabetes & Fanconi’s syndrome).

2 - Fructosuria: (Presence of fructose in urine) - Alimentary causes : fructose intake - Metabolic : fructokinase or aldolase B in the

liver.

3 – Galactosuria: (Presence of galactose in urine) - Alimentary : galactose intake - Metabolic : galactokinase or galactose -1- phosphate uridyl transferase in the liver.

C) Ketonuria : (Presence of ketones “ Acetone, Acetoacetic acid & Hydroxybutyric acid” in urine)

1 – Diabetic ketoacidosis

2 – Glycogen storage disease

3 – Starvation

4 – Prolonged vomiting

5 – Unbalanced diet: high fat & Low CHO diet

D) Nitrite : Positive nitrite test is significant of bacteria in urine

E) Choluria : ( Presence of bile in urine) 1 – Bilirubin / Bile salts : in cases of - Hepatocellular damage. - Obstruction of bile ducts either extrahepatic (stone) or intrahepatic (hepatic tumors)

2 - Urobilinogen: - Normally present in trace amounts in urine - Marked in :

- hemolytic anemia - hepatocellular damage

F) Blood :

I - Hematuria: (Presence of detectable amount of blood in urine )

a – Acute & chronic glomerulonephritis b – Local disorders of kidney & genito-urinary tract (Trauma , cystitis , renal calculi and tumors) c – Bleeding disorders (Hemophilia).

II - Hemoglobinuria: (Presence of hemolysed blood in urine) a – Hemoglobinopathies (Sickle cell anemia& Thal) b – Malaria (P. falciparum) c – Transfusion reaction (Bl. Incompatibility)

G) Chyluria :

(Presence of lymph / fat in urine)

- Due to abnormal connection between the intestinal lymphatic system and

urinary tract, which may be:

- Congenital

- Acquired (Filariasis)

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