Wednesday, October 20, 2010

Tonicity

Tonicity is a measure of the osmotic pressure (as defined by the water potential of the two solutions) of two solutions separated by a semipermeable membrane.



facilitated diffusion

facilitated diffusion The transport of molecules across the plasma membrane of a living cell by a process that involves a specific transmembrane carrier (see transport protein) located within the plasma membrane but does not require expenditure of energy by the cell.

Osmotic pressure

Osmotic pressure is the pressure applied by a solution to prevent the inward flow of water across a semipermeable membrane.[1]

diffusion

diffusion (passive transport) The random movement of particles (e.g. molecules or ions) from an area of high concentration to an area of low concentration until an even distribution of particles (i.e. uniform concentration) is obtained

osmosis

Osmosis:the movement of water across a selectively permeable membrane from an area of high water potential (low solute concentration) to an area of low water potential (high solute concentration).

Friday, October 15, 2010

euthyroid

 Figure 3. Sonograms showing longitudinal (left panel) and transverse (right panel) images of the left lobe containing a degenerated thyroid nodule. Note the thick wall and irregularity. N=nodule, H=hemorrhagic degenerated region.
 Figure 4. The left panel shows an anterior scintiscan of a euthyroid patient who had a tense nodule in the left thyroid lobe. The nodule is "cold". * * * =nodule. The right panel shows a sonogram of the neck in the longitudinal plane revealing that the nodule is a smooth-walled cystic structure without internal echoes. between the + + symbols. Note the dark dense echoes distal to the cyst. C=cyst, L=thyroid lobe.

Figure 5. Sonogram of the neck in the longitudinal plane showing a hypoechogenic nodule that was surrounded by an echo free rim, called a halo. Doppler examination demonstrated great vascularity in the halo, identified as bright spots. Small blood vessels are also seen elsewhere. N=nodule, L=heterogenous thyroid lobe, m=muscle.

Thyroid hormone synthesis

Figure 3
  Schematic diagram of a follicular cell, illustrating the steps involved in thyroid hormone synthesis. TSH receptor (TSHR) bound to TSH stimulates iodide transport into the thyroid gland by the sodium iodide symporter (NIS). Subsequently, iodide is oxidised by hydrogen peroxide, generated by the recently discovered NADPH oxidase system (ThOX) and bound to tyrosine residues in thyroglobulin (TG) to form iodotyrosine (iodide organification). Some of these hormonally inactive iodotyrosine residues (monoiodotyrosine and diiodotyrosine) couple to form the hormonally active iodothyronines, T4 and T3. Thyroid peroxidase (TPO) catalyses the oxidation, organification, and coupling reactions. The exact function of pendrin, a chloride-iodide transporter, in thyroid hormone synthesis is as yet unknown but it is thought to transport iodide into the colloid from the thyrocyte. Defects in any of these steps lead to dyshormonogenesis, which manifests clinically as congenital hypothyroidism with goitre.

Wednesday, October 13, 2010

epigastric pain

A 21-year-old white man presents to the emergency department with a 10-hour history of epigastric pain that is radiating to the chest.



http://cme.medscape.com/viewarticle/729522?src=emed_case_nl_0&uac=149212BX

A 19-year-old white woman presents to the clinic after a hospital visit for headaches.

A 19-year-old white woman presents to the clinic after a hospital visit for headaches. She has had headaches for approximately 5 years and they have been progressively increasing in frequency.



http://cme.medscape.com/viewarticle/730007?src=emed_case_nl_0&uac=149212BX

Mauriceau–Smellie–Viet maneuver





Lovset's Maneuver





Monday, October 11, 2010

Open book fracture

  • Most serious fracture
  • destroys at least two elements
  • high risk of arterial bleeding
  • unstable 
  • needs surgical repair

Sacral Fracture

  • High Impact anterior or posterior truama
  • fracture at or lateral to sacroiliac joints
  • usually part of complex pelvic fracture
  • causes open book  fracture when at least one other element is fracture
  • unstable fracture

Dashboard Fracture

  • Fracture of Posterior Ramus of Acetabulum by Femoral Head
  • Associate severe knee injure

Ishcial Tuberosity Avulsion

  • Ischial tuberosity Avulsion
  • Effect Function of Sartorius, Rectus Femmorus or Hamstring Muscles
  • Horizontal Trauma
  • Usually Heals with Deformity

Straddle Fracture

  • Fracture of bilateral inferior pubic rami
  • Direct Horizontal
  • Frequently Injures the Urethra

Aortic Disruption

  • Wide mediasternum
  • Apical Cap
  • Lt Mainstem Bronchus Depress
  • Rt Mainstem Bronchus Elevate
  • Deviation of trachea
  • Obliteration of Aortic knob(disappear of aortic arch)
  • Absence of Aorticopulmonary window
  • Widened Paratracheal stripe
  • Left Hemothorax

X-Ray


Structures seen on a posteroanterior (PA) chest x-ray. 1 = first rib; 2РІР‚“10 = posterior aspect of ribs 2РІР‚“10; AK = aortic knob; APW = aortopulmonary window, BS = breast shadow (labeled only on right); C = carina; CA = colonic air; CPA = costophrenic angle, DA = descending aorta; GA = gastric air; LHB = left heart border (Note: Most of the left heart border represents the left ventricle; the superior aspect of the left heart border represents the left atrial appendage.); LPA = left pulmonary artery; RC = right clavicle (left clavicle not labeled); RHB = right heart border (Note: The right heart border represents the right atrium.); RHD = right hemidiaphragm (left hemidiaphragm not labeled); RPA = right pulmonary artery; T = tracheal air column.




Structures seen on a lateral chest x-ray. A = aorta; CPA = posterior costophrenic angle; LHD = left hemidiaphragm; PHB = posterior heart border (Note: The posterior heart border represents the left atrium superiorly and left ventricle inferiorly; the anterior heart border is not clearly defined on this film but represents the right ventricle.); RA = retrosternal airspace; RHD = right hemidiaphragm; RMF = right major fissure (left major fissure and minor fissures not well visualized on these films but can occasionally be seen); S = scapula; T = tracheal air column.

Pneumothorax

British professional guidelines have traditionally stated that the measurement should be performed at the level of the hilum (where blood vessels and airways enter the lung),[4] while American guidelines state that the measurement should happen at the apex (tip) of the lung.[9] The latter method may overestimate the size of a pneumothorax if it is located mainly at the apex, which is a common occurrence.[4] The various methods correlate poorly, but are the best immediately available ways of estimating pneumothorax size.

Dens Fracture

 Radiologic evaluation is utilized to confirm the diagnosis and estimate the degree of spinal instability. Initial evaluation includes open-mouth, anterior-posterior, and flexion-extension lateral radiographs. Os odontoideum appears as a round or oval ossicle with a smooth, uniform cortex separated from the base of the axis by a wide gap. The ossicle border does not directly match up with the axis body. The gap separating the os and the axis proper should lie above the level of the superior articular facets. Orthotopic os odontoideum (see image below) may appear free and in a relatively anatomic position.30,31,32

Clay Shoveler's Fracture

  • oblique fracture
  • Lower cervical spine process, usually C7
  • caused by Hyperflexion (bending work)

Hangman's Fracture


- Bilateral posterior Pedicle Fracture of C2
-Associated with anterior dislocation of c2 vertebral body
-Caused by severe extension injury (face hitting windshield)

extension Tear Drop Fracture

  • Fracture of the cervical spine caused by the sudden pull of the anterior longitudinal ligament on the anterior, inferior aspect of the vertebral body following extreme hyperextension of the neck
  • Usually involves C2
    • Anterior longitudinal ligament inserts on anteroinferior aspect of C2
  • Fracture of C2 is stable in flexion and unstable in hyperextension

Apical Cap in aortic injury

 The lateral margins of the lateral masses (inferior
articular facets of C1) should align with the lateral
margins of the structures below it (superior articular
facets of C2).  The space between these two facets is
the atlanto-axial joint.  In  this radiograph, the lateral
masses of C1 are displaced outward, indicating a
"bursting" of the ring of C1 (the Jefferson Fracture).

jefferson fracture

 The lateral margins of the lateral masses (inferior
articular facets of C1) should align with the lateral
margins of the structures below it (superior articular
facets of C2).  The space between these two facets is
the atlanto-axial joint.  In  this radiograph, the lateral
masses of C1 are displaced outward, indicating a
"bursting" of the ring of C1 (the Jefferson Fracture).

Sunday, October 10, 2010

Different Between spinal and neurogenic shock?

neurogenic shock occure after spinal cord injury but spinal shock occure long time month or year after spinal cord injury

Subarachnoid Hemorrhage

Figure 3: Non-contrast CT scan of the brain demonstrating subarachnoid hemorrhage (SAH) in a patient with the sudden onset of a severe headache and stiff neck 1 hour prior to this scan.

Cerebral Contusion:

This is a scan of a patient who has sustained a severe head injury. There is extensive bruising of the right side of the brain, showing up as a large, diffuse grey area. You can also see that there are patches of white within the grey area. This represents bleeding. The grey area represents swelling (oedema). The area of the cortical contusion is outlined in purple. You will normally find a centimetre scale at the right hand side of a CT scan. This scan would be classified on the Early Outcome Form as "Cortical contusion - greater than 1cm in diameter.

Diffuse Axonal Injury:

One or more petechial haemorrhages within the brain
The presence of petechial haemorrhages is usually an indication of a very severe primary brain injury. Petechial haemorrhages tend to occur at the interface of grey and white matter. It can also occur in the dorsolateral quadrant of the midbrain at the middle orange arrow, as well as elsewhere within the brain substance. Note on this scan, that the lateral ventricles and the third ventricle are visible and there is no midline shift. It is often a characteristic of diffuse axonal injury, in which there are numerous petechial haemorrhages that there is no evidence of brain swelling, or midline shift. This scan would be classified as showing one, or more, petechial haemorrhages within the brain.

Acute Extradural Haematoma:

Intracranial haematoma - non-evacuated
This scan shows another intracranial haematoma, namely an extradural. You will note that this haematoma has a concave shape, a bit like the human lens and this is because it is occurring between the bone and the dura and is not actually lying on the surface of the brain itself. The points of attachment of the dura limit the extension of this haematoma anteriorly and posteriorly. You can see that there is shift of the midline. Look at the frontal horns in their relation to the falx cerebri (falx cerebri is outlined on the normal scan). This scan would be classified "Intracranial haematoma - non evacuated."

Acute Subdural Haematoma Demonstrating Midline Shift:

Midline shift >5mm
Intracranial haematoma - non evacuated
Cortical contusion >1cm in diameter

Obliteration of 3rd Ventricle (not seen - refer to normal CT scan)

This CT scan shows a right sided acute haematoma, as well as an associated cerebral contusion (bruising). The true midline has been outlined by yellow dots and you can see that the frontal horns of the lateral ventricles have been pushed over to the left. In addition, the third ventricle is now not visible and it is also extremely difficult to make out the basal cisterns. This scan demonstrates four of the features which are included on the Early Outcome Form, namely midline shift greater than 5mm, intracranial haematoma - non evacuated, cortical contusion greater than 1cm in diameter and obliteration of the third ventricle. This haematoma requires surgical evacuation, otherwise deterioration of the patient's condition is inevitable. 

Normal CT Scan:

It is worth spending a few minutes familiarising yourself with the appearances of a normal CT scan. It is much easier to detect abnormalities once you are accustomed to normal appearances. The scan below is a slice through the human brain and you should imagine that you are viewing it as if looking up from the patient's feet. Therefore, the patient's left is to the right of the screen. The shape of the ventricles is quite distinctive and they are shown outlined in green and orange. The presence of the third ventricle in the midline is one of the first things to look for. If the third ventricle is either not visible, or shows signs of shift away from the midline, this suggests that there is an abnormality. The basal cisterns is the fluid filled space around the back of the midbrain outlined here in purple. Blood clots, or swelling of the brain may cause this to become narrowed, or not visible altogether. Note in this scan, that the frontal horns of the lateral ventricles are symmetrical, with the septum between them in the midline.