Saturday, January 1, 2011

Anemias and it`s corresponding RBC`s shape

Erythrocytes may have abnormal shapes and sizes in certain diseases.In iron deficiency you would expect to see ?!
  • a.Microcytic, hypochromatic anemia with smaller mature erythrocytes
  • b.Macrocytic, hyperchromatic anemia with fewer, larger mature erythrocytes
  • c.Poikilocytosis and more fragile erythrocytes
  • d.Spherocytosis
  • e.No change in erythrocyte size or shape, but a substantial drop in the hematocrit

The answer is a.
Iron deficiency leads to anemia with the presence of smaller, pale-staining erythrocytes (microcytic, hypochromatic). Hyperchromatic, macrocytic anemia results from vitamin B 12 deficiency (answers b and e).

The presence of spherical rather than biconcave erythrocytes is known as spherocytosis (answer d). The RBC membrane undergoes deformation due to the inability of ankyrin to bind spectrin. The shape change results in trapping in the splenic sinusoids and excessive destruction of red blood cells in that organ. Poikilocytosis is the generic term for abnormally shaped erythrocytes (answer c).
Hereditary elliptocytosis and hereditary poikilo-cytosis are inherited diseases in which there is RBC membrane fragility and abnormal shape due to spectrin mutations. Mutations in Band 3 (anion exchanger 1) result in RBCs that are hyperchromatic with poikilocytosis.

Labels: ,

ABC of Spinal cord trauma

Spinal cord trauma is potentially the most devastating consequence of injury to the spine. This well-established, practical guide provides a detailed overview from the scene of the accident to rehabilitation and discharge from hospital care. This latest edition has been substantially rewritten to include the most recent developments in practical management of patients with potential spine injury and risk-minimisation techniques. There is also a new chapter on spinal cord injury in developing countries.

Labels: , ,

Contraindications to MRI procedure

The principal contraindications of the MRI procedure are mostly related to the presence of metallic implants in a patient. The risks of MRI scans increase with the used field strength. In general, implants are becoming increasingly MR safe and an individual evaluation is carried out for each case.

Absolute Contraindications for the MRI scan:
# Intracranial aneurysm clips (Unless the referring physician is certain that it is made of nonferromagnetic material such as titanium).

# Intra-orbital metal fragments

# Any electrically, magnetically or mechanically activated implants (including cardiac pacemakers, biostimulators, neurostimulators, cochlear implants, and hearing aids).

Relative Contraindications for the MRI scan:
-cochlear implants
-other pacemakers, e.g. for the carotid sinus
-insulin pumps and nerve stimulators
-lead wires or similar wires (MRI Safety risk)
-prosthetic heart valves (in high fields, if dehiscence is suspected)
-haemostatic clips (body)
-non-ferromagnetic stapedial implants