A schizophrenic presents with galactorrhea. The patient’s medication regimen includes haloperidol. Blockade of which neurotransmitters is responsible for this patient's clinical presentation?
Dopamine. Since it is a Prolactin Inhibitor - Inhibition of Dopamine causes hyperprolatctinemia.
Doubt: Level of dopamine also decreases in Parkinson's disease. So can hyperprolactinemia also be seen in Parkinson's disease?
In Parkinson's, there is loss of dopamine only in the substantia niagra.
There are 4 main dopaminergic pathways in the CNS:
1. Nigrostrial pathway which is involved in Parkinson's disease.
2. Mesolimbic pathway involved in Schizophrenia.
3. Paraventricular pathway involved in satiety.
4. Tuberoinfundibular pathway involved in prolactin secretion.
Drugs can affect all pathways, that's why, the side effects. But Parkinson's only hits the nigrostrial pathway.
What is dead space?
Physiologic or total dead space is the sum of anatomic dead space and alveolar dead space. Anatomic dead space is the volume of gas within the conducting zone (as opposed to the transitional and respiratory zones) and includes the trachea, bronchus, bronchioles, and terminal bronchioles; it is approximately 2 mL/kg in the upright position. Alveolar dead space is the volume of gas within unperfused alveoli (and thus not participating in gas exchange either); it is usually negligible in the healthy, awake patient.
Flexion of the head decreases dead space. Why?
Flexion of head decreases anatomical dead space. Therefore, physiological dead space will also be decreased.
Neck extension and jaw protrusion can increase the dead space twofold.
Supine position decreases dead space and the dead space increases in upright position. Why?
In upright position, there is decreased perfusion to the uppermost alveoli.
Intubation decreases dead space by 70 ml approx. Why?
The size of the ET tube is smaller than the trachea. Therefore, reduction in the dead space.
Administration of bronchodilator increases dead space. Why?
The conduction zone, from the nose to the respiratory bronchioles, is dead space. Bronchodilators dilate the brochus and bronchioles and not the alveoli, increasing dead space.
Certain anaesthetics, like halothane and sevoflurane, cause bronchodilation. Hence, an important concept and MCQ.
The cause of increased dead space in general anesthesia is multifactorial, including loss of skeletal muscle tone and loss of bronchoconstrictor tone.
That's all!
Pray that my goals are completed on a timely basis. I need your prayers.
-IkaN
Diabetes Mellitus (DM) is a heterogeneous group of disorders, characterised by hyperglycaemia and it's complications.
Hyperglycaemia according to American Diabetes Association is when
1. Fasting Blood Sugar level is more than or equal to 126mg/dL
2. Post prandial Blood sugar is more than or equal to 200mg/dL
The interesting part is here
DM Type 2 is either because of
i) increased glucose production by the liver ( when a person is sleeping) or
ii) impaired insulin secretion ( usually noticed after meals as insulin reserves are not sufficient or there is insulin resistance)
Let's talk of 2 scenarios,
In case i) Fasting blood glucose is high and
In case ii) Post Prandial blood glucose is high.
Now,
For case i), Metformin which is said to decrease the glucose production from liver is a better treatment option.
(Remember, Metformin also works against Insulin Resistance, so it also works in case ii !)
For case ii), since the problem is with insulin secretion or its resistance, Insulin Secretagogs work the best! Sulfonylurea increase the insulin secretion from ß cells in the pancreas, thereby tackling the problem.
Remember, Sulfonylureas are commonly used after Metformin!
If you want a super drug :P to tackle both these scenarios then Metformin and Thiazolidinediones are your best options. However, the side effect profile of the latter one is worrisome so used less often.
Here's one of my favourite quotes, Hardwork beats talent when talent doesn't work hard !
That's all!
- Rippie
