Skip to main content

sickle cell crisis | sickle cell anemia

Post a Comment

Myasthenia gravis

Myasthenia gravis


Introduction-
an autoimmune disorder of neuromuscular            junction. It is caused due to production of antibodies against the Nm receptors of NMJ that results in a decrease in the number of Nm receptors.

It is characterized by grave weakness of the          muscle due to the inability of neuromuscular       junction to transmit impulses from nerve to           the  muscle. It is a serious and sometimes a fatal disease.

Causes of myasthenia gravis


 The main cause is Development of antibodies (IgG) against the receptors of Ach (acetylcholine).
 Body develops antibodies against its own Ach receptors. IgG antibodies destroy the receptors.

Symptoms of myasthenia gravis


  Common symptoms

  Slow and weak muscular contraction because of the defective neuromuscular activity. Inability to maintain the prolonged contraction of the skeletal muscle. Difficulty in speech due to weakness of muscles of speech.(dysphonia)

  Difficulty in swallowing due to weakness of throat muscles.(dysphagia). Quick fatigability when the patient attempts repeated muscular contraction. Weakness and fatigability of arms and legs.

Double vision (diplopia) and droopy eyelids  (ptosis) due to the weakness of ocular muscle.

in severe conditions-
 paralysis of muscles occurs and patient dies mostly due to paralysis of respiratory muscles.

*Muscles which are more susceptible for myasthenia gravis-
 - Muscles of neck
 - Muscles of limbs
 - Muscles of eyeball
 - Muscles responsible for movement of eyelids
 - Muscles responsible for chewing
 - Muscles responsible for swallowing
 - Muscles responsible for speech
 - Muscles responsible for respiration

Diagnosis of myasthenia gravis

 Edrophonium test-
 Edrophonium(2-10mg) given slow i.v. shows dramatic improvement of symptoms in patients with myasthenia gravis but not in muscular dystrophy.

Treatment of myasthenia gravis


 treatment of myasthenia gravis is  administration of inhibitors of cholinesterase
(Anticholinesterase), Neostigmine and Pyridostigmine.

Additional knowledge

There is an increased incidence of  myasthenia gravis in patients with thymoma.
Thymoma is a tumor originating from the epithelial cells of the thymus gland.

Myasthenia gravis is a example of type 2 hypersensitivity reactions.
  

Labels:

Comments

Post a Comment

Popular posts from this blog

Tetanus | tetany | Hypoparathyroidism | Hypocalcemia | Disorder of parathyroid gland | hypercalcaemia | hyperparathyroidism

[Disorder of parathyroid gland]- There are two types of parathyroid disorder- 1. Hypoparathyroidism 2. Hyperparathyroidism 1. Hypoparathyroidism ( Hypocalcemia) • Hypo secretion of PTH(parathormone), leads to decrease in blood calcium level. Causes of hypoparathyroidism- a. Parathyroidectomy Surgical removal of parathyroid gland b. Thyroidectomy During Surgival removal of thyroid gland , removal of parathyroid gland c. Pseudo hypoparathyroidism •  There is deficiency of receptors for parathormone (PTH) in target cells, • in this the secretion of PTH is normal or may be increased but hormone can not act on the target cells. d. Autoimmune disease >Effect of Hypoparathyroidism- • due to decrease in resorption of calcium from bones hypoparathyroidism leads to Hypocalcemia. • it causes neuromuscular hyperexcitability , resulting in hypocalcemic tetany. * Normally tetany occurs when plasma calcium level decreases below 6mg/dl. # normal plasma calcium lev...
Post a Comment
Read more

Juxta glomerular apparatus (JGA)

JUXTA GLOMERULAR APPARATUS (JGA) •Defination It is a specialised organ situated near the glomerulus of each nephron. • Structure of JGA It is formed by three structures- 1. Macula densa 2. Juxta glomerular cells 3. Extra glomerular mesangial cells 1. Macula densa- - it is situated between afferent and efferent arterioles of the nephron. - it is very close to afferent arteriole. - it is formed by cuboidal epithelial cells. 2. Juxta glomerular cells- - also called granular cells  Because they contain secretary granules in their cytoplasm. - JG cells are smooth muscle cells. - JG cells situated in the wall of afferent arteriole just before it enters the bowman capsule. - JG cells are mostly present in tunica media and tunica adventitia of the wall of afferent arteriole. # Polar cushion / polkissen It is a thick cuff that is formed by JG cells around the afferent arteriole before it enters the bowman capsule. 3. Extra glomerular mesangial cells- Also called-...
Post a Comment
Read more

Addison disease | adrenal crisis | adrenal Insufficiency | addisonian crisis | skin pigmentation

ADDISON DISEASE - Chronic adrenal insufficiency • if adrenal cortex fails to secrete corticosteroids it is known as addison disease.   TYPES OF ADDISON DISEASE 3types 1. Primary addison disease 2. Secondary addison disease 3. Nursery addison disease 1. Primary addison disease It occurs due to adrenal cause. 2. Secondary addison disease It occurs due to failure of anterior pituitary to secrete ACTH. 3. Tertiary addison disease it occurs due to failure of hypothalamus to secrete corticotropin-releasing factor (CRF) CAUSES OF PRIMARY ADDISON DISEASE a. Destruction of the gland because of Tuberculosis. b. destruction of hormone secreting cells in adrenal cortex by malignant tissues. c. Congenital failure to secrete cortisol. d. Adrenalectomy ( surgical removal of adrenal gland) and failure to take hormone therapy. e. Atrophy of adrenal cortex due to autoimmune disease. SIGNS AND SYMPTOMS signs and symptoms develop in addison disease because of deficiency o...
1 comment
Read more