Blepharospasm

Botulinum neurotoxins are widely used as therapeutic agents to cause reduction or paralysis of skeletal muscle contraction. They are used to treat cervical dystonia, which causes regional involuntary muscle spasms often associated with pain. Moreover, they are used in strabism, blepharospasm, hemifacial spasm, and... 

Vesicants affect both exterior and interior parts of the body. Vesicants cause inflammation, blisters, and general destruction of tissues. These agents have a greater impact on moist areas of the body. Eyes are especially susceptible to vesicants and contact results in irritation, lacrimation, and involuntary blinking (blepharospasm). 

Etiology and classification. Dystonia may arise from a variety of disease processes, the majority of which involve the basal ganglia. Dystonia can be classified as a generalized or focal disorder. The most common forms of dystonia are focal in nature (e.g. spasmodic torticollis, blepharospasm, writer s cramp, etc.) and occur in adults, while many of the childhood dystonias are generalized. 

Eyes Severe damage. Instant pain, conjunctivitis and blepharospasm leading to closure of eyelids, followed by corneal scarring and iritis. Mild exposure produces reversible eye damage if decontaminated instantly. More permanent injury or blindness is possible within one minute of exposure. 

The eyes are observed for any immediate signs of discomfort after instilling the test substance. Blepharospasm and/or excessive tearing are indicative of irritating sensations caused by the test substance, and their duration should be noted. Blepharospasm does not necessarily indicate that the eye will show signs of ocular irritation. 

Botulinum toxin from Clostridium botulinum is the most potent poison known. The lethal dose in an adult is approx. 3x10 mg. The toxin blocks exo-cytosis of ACh in motor (and also parasympathetic) nerve endings. Death is caused by paralysis of respiratory muscles. Injected intramuscularly at minuscule dosage, botulinum toxin type A is used to treat blepharospasm, strabismus, achalasia of the lower esophageal sphincter, and spastic aphonia. 

Characteristic effects of CS exposure are instantaneous conjunctivitis, blepharospasm, burning, and pain. Prolonged exposure to high concentrations in enclosed spaces may cause pulmonary edema and severe bronchospasm. ... 

High concentrations of vapor cause conjunctival irritation and blepharospasm. Liquid chloroform splashed in the eye causes immediate burning pain and conjunctival irritation the corneal epithelium may be injured, but regeneration is prompt, and the eye returns to normal in 1-3 days. Applied to the skin, chloroform causes burning pain, erythema, and vesiculation. ... 

Exposure of workers to fumes from hot hexachloroethane resulted in blepharospasm, photophobia, lacrimation, and reddening of the conjunctiva but no corneal injury or permanent damage. No chronic effects have been reported from industrial exposure, although significant skin absorption is said to occur. ... 

Yellow phosphorus fume causes severe eye irritation with blepharospasm, photophobia, and lacrimation the solid in the eye produces severe injury. Phosphorus burns on the skin are deep and painful a firm eschar is produced and is surrounded by vesiculation. ... 

Arrhythmias palpitations tachycardia transient hypertension bradycardia headache lightheadedness dizziness drowsiness tremor insomnia nervousness restlessness giddiness psychological disturbances prolonged psychosis weakness nausea gastric irritation hypersensitivity reactions such as rash, urticaria, leukopenia, agranulocytosis, and thrombocytopenia orofacial dystonia sweating blepharospasm urinary retention may occur in patients with prostatic hypertrophy. 

Strabismus and blepharospasm associated with dystonia (Botox only) For the... 

Blepharospasm (Botox only) For blepharospasm, reconstituted botulinum toxin type A is injected using a sterile, 27- to 30-gauge needle without electromyographic guidance. The initial recommended dose is 1.25 to 2.5 units (0.05 to 0.1 mL volume at... 

Primary axillary hyperhidrosis Adverse events (in at least 3% of patients) included injection site pain and hemorrhage, nonaxillary sweating, infection, pharyngitis, flu syndrome, headache, fever, neck or back pain, pruritus, and anxiety. Blepharospasm The most frequently reported treatment-related adverse reactions were ptosis (20.8%), superficial punctate keratitis (6.3%), and eye dryness (6.3%). Strabismus Extraocular muscles adjacent to the injection site can be affected, causing ptosis, vertical deviation, spatial disorientation, double vision, or past-pointing, especially with higher doses of botulinum toxin type A. 

Botulinum toxin is used clinically in the treatment of blepharospasm, writer s cramp, spasticities of various origins, and rigidity due to extrapyramidal disorders. It is also used to treat gustatory sweating and cosmetically to decrease facial wrinkles. Botulinum toxin A Botox, Oculinum) injected intramuscularly produces functional denervation that lasts about 3 months. Clinical benefit is seen within 1 to 3 days. Adverse effects range from diplopia and irritation with blepharospasm to muscle weakness with dystonias. 

C. Hydroquinone inhibits the enzyme tyrosine kinase, which converts tyrosine to melanin. It also damages melanocytes. Becaplermin (A) is a recombinant human platelet-derived growth factor that is useful in enhancing wound healing. Etanercept (B) is a recombinant fusion protein approved for treatment of psoriatic arthritis and rheumatoid arthritis. Botulinum toxin (D) is a purified form of bofu-linum foxin fype A approved for fherapy of blepharospasm and sfrabismus. 

Abscess formation at injection site, blepharospasm, convulsions, thrombocytopenia, and transient neutropenia occur rarely. 

Other serious effects may include involuntary movements, impaired motor coordination, loss of balance, blepharospasm, facial grimaces, feeling of heaviness in the lower extremities, depression, nightmares, delusions, overstimulation, sleep disturbance, and anger. 

Morgenstern et al reported on over 200 workmen in an American chemical plant making H during World War II, focusing on 10 case histories that illustrated the immediate and delayed effects of daily exposure to small quantities of H vapor. Exposure for 3 wk. to 6 mo ed these men to the dispensary for treatment of respiratory distress. Typically, a man developed some or all of the following symptoms red eyes, photophobia, lacrimation, impaired vision, blepharospasm, loss of taste and smell, nosebleed, sore throat, chest pain, wheeting, and dyspnea. After several such occurrences, a worker was removed from further contact with H. 

Ballantyne and Swanston developed a laboratory procedure to measure the threshold concentrations of CS that produced sensation in the human eye and tongue, to compare various irritant agents. Threshold concentrations of CS were also measured in the rabbit and guinea pig with blepharospasm as the criterion of ocular response. 

Exposure to CN causes an immediate burning sensation or stinging in the eyes, nose, throat, and exposed skin. Lacrlmation, sail-vation, rhinorrhea, and dyspnea or a constricting sensation in the chest follow. The lacrlmatory action persists for about 20 min after exposure, but conjunctivitis and blepharospasm may last for 24 h. CN is more toxic than CS or CR. High concentrations of CN may result in chemical injury to the eye, with corneal and conjunctival edema, loss of corneal epithelium, and chemosis.2,20... 

The effects on the aerosol-exposure subjects were transient, generally resolving within minutes of removal of the agent. There also seemed to be tolerance In experienced subjects, often Increased by closing the eyes. Predominant effects of aerosol exposure were ocular lacrlmatlon, blepharospasm, conjunctivitis, and, rarely, palpebral edema. Respiratory effects of aerosol exposure were nasopharyngeal Irritation, rhlnorrhea, and, rarely, dyspnea. Skin Irritation was prominent on shaved areas. Other rare effects of aerosol exposure were headaches and dizziness. No laboratory analyses were recorded for aerosol exposure. 

Rengstorff et al.2 applied 0.025 ml of a SX solution of CR 5 d/wk for 4 wk. The animals were kept under observation for 60 d. Instillation of the dally doses was followed by a brief period of blepharospasm (about 15 min), after which the eyes appeared to be normal. During the test period, superficial and slit-lamp examination did not reveal any Injury to the eyes. At the end of the experimental period, the eyes were examined by light and electron microscopy. No abnormalities were found. 

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