Question

Part 1

1) How is .9% NaCl is isotonic ?

part 2

Guy McKhann, M.D., a neurologist at the Johns Hopkins School of Medicine, describes a ward of Beijing Hospital that he visited on a trip to China in 1986. Dozens of paralyzed children—some attached to respirators to assist their breathing—filled the ward to overflowing. The Chinese doctors thought the children had Guillain-Barré syndrome (GBS), a rare paralytic condition, but Dr. McKhann wasn’t convinced. There were simply too many stricken children for the illness to be the rare Guillain-Barré syndrome. Was it polio—as some of the Beijing staff feared? Or was it another illness, perhaps one that had not yet been discovered? Dr. McKhann decided to perform nerve conduction tests on some of the paralyzed children in Beijing Hospital. He found that although the rate of conduction along the children’s nerves was normal, the strength of the summed action potentials traveling down the nerve was greatly diminished.

Dr. McKhann then asked to see autopsy reports on some of the children who had died of their paralysis at Beijing Hospital. In the reports, pathologists noted that the patients had normal myelin but damaged axons. In some cases, the axon had been completely destroyed, leaving only a hollow shell of myelin. Dr. McKhann named the disease acute motor axonal polyneuropathy (AMAN)—might be triggered by a bacterial infection. He also thought that the disease initiated its damage to axons at neuromuscular junctions.

1. Briefly describe GBS, Which division(s) of the nervous system may be involved in GBS?

2. How can one diagnose GBS?

3. Name other diseases involving altered transmission.

4. Briefly describe AMAN

Answer 1

Part 1

1.Anything higher than 295 mOsm/L is considered hypertonic, and anything below 275 hypotonic. There are of course some exceptions, take for instance Normal Saline, or 0.9% NaCl. Its osmolarity is generally around 308, but it is still considered isotonic because it contains the electrolyte combination NaCl as its solute.The fact is that it is isotonic with blood serum. This means they have the same osmotic pressure as each other which controls how they pass through the semi permeable membrane of blood vessels.

Part 2

1.Guillain-Barre syndrome is a rare but serious autoimmune disorder that affects the peripheral nervous system. The peripheral nervous system is the portion of the nervous system that is outside the brain and spinal cord. Autoimmune means the patient's immune system begins to attack healthy tissue, which in this case are nerve cells which communicate with muscles. Specifically, they attack the mylein sheaths surrounding the axons of nerve cells. In some cases they even attack the axons themselves.There are three types Acute inflammatory demyelinating polyradiculoneuropathy (AIDP),Miller Fisher syndrome (MFS),Acute motor axonal neuropathy (AMAN) and acute motor-sensory axonal neuropathy (AMSAN)

2. GBS can be diagnosed by :Physical Exam(as the peripheral nerves are damaged in Guillain-Barré, reflexes, such as the common knee-jerk reflex, are usually absent),Lumbar Puncture(In autoimmune disorders affecting the nervous system, the amount of protein in the body's cerebrospinal fluid (CSF) can be high),Electromyography and Nerve Conduction Studies (EMG/NCS),Blood Tests(In some cases, this can help find the antibody responsible. For example, the Miller-Fisher variant of Guillain-Barré is usually associated with an antibody called GQ1b.).

3.The other diseases involving altered transmission are Alzheimer disease,Autism spectrum disorders,Neuroleptic malignant syndrome,Parkinson disease,Myasthenia gravis,Amyotrophic lateral sclerosis and Schizophrenia.

4.Its a type of Guillain-Barré syndrome. In acute motor axonal neuropathy (AMAN) , only the axons of motor neurons are damaged causing primary axonal degeneration in the absence of prominent T cell inflammation.(AMAN) is a pure motor variant of GBS seen most commonly in China, Japan, and Mexico,