Cyanide poisoning




Cyanide poisoning


Upper respiratory tract disorders

Choanal atresia


Allergic rhinitis

Nasal polyps

Upper respiratory tract infection



Retropharyngeal and peritonsillar abscesses

Bacterial epiglottitis

Nasopharyngeal carcinoma

Lower respiratory tract disorders

Tracheoesophageal fistula

Congenital pulmonary airway malformation

Pulmonary hypoplasia

Neonatal respiratory distress syndrome

Transient tachypnea of the newborn

Meconium aspiration syndrome

Apnea of prematurity

Sudden infant death syndrome

Acute respiratory distress syndrome

Pulmonary changes at high altitude and altitude sickness

Decompression sickness

Cyanide poisoning



Chronic bronchitis


Cystic fibrosis


Alpha 1-antitrypsin deficiency

Restrictive lung diseases


Idiopathic pulmonary fibrosis

Hypersensitivity pneumonitis



Bacterial tracheitis

Lung cancer

Pancoast tumor

Superior vena cava syndrome

Pleura and pleural space disorders


Pleural effusion


Pulmonary vascular disorders

Pulmonary embolism

Pulmonary edema

Pulmonary hypertension

Apnea and hypoventilation

Sleep apnea

Apnea of prematurity

Respiratory system pathology review

Respiratory distress syndrome: Pathology review

Cystic fibrosis: Pathology review

Pneumonia: Pathology review

Tuberculosis: Pathology review

Deep vein thrombosis and pulmonary embolism: Pathology review

Pleural effusion, pneumothorax, hemothorax and atelectasis: Pathology review

Obstructive lung diseases: Pathology review

Restrictive lung diseases: Pathology review

Apnea, hypoventilation and pulmonary hypertension: Pathology review

Lung cancer and mesothelioma: Pathology review


Cyanide poisoning


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USMLE® Step 1 questions

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High Yield Notes

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Cyanide poisoning

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USMLE® Step 1 style questions USMLE

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A 25-year-old woman is brought to the emergency department after being found unconscious near the doorway of a smoke-filled house. Temperature is 37.3°C (99.1°F), pulse is 120/minute, respirations are 20/min, and blood pressure is 110/65 mm Hg. Physical examination shows generalized flushing of the skin as well as black soot near the nares and mouth. There is no evidence of any burns or trauma. Capillary refill time is 5 seconds. Supplemental oxygen is administered. Laboratory results are shown below. Hydroxocobalamin is provided for medical management. Which of the following best describes the mechanism of action of this medication?  

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Cyanide poisoning is a type of chemical poisoning that occurs when cyanide ions are introduced into the body. Cyanide ions disrupt cellular respiration at the mitochondrial level, by inhibiting an enzyme called cytochrome C oxidase. This can lead to asphyxiation as the body is no longer able to use oxygen, and it can also cause damage to the heart, liver, and other organs. Symptoms of cyanide poisoning may include headache, seizures, confusion, nausea, cardiac arrest, and death.


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