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Cases
Hot Nose Sign
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Background
A 28-year-old man is brought to the emergency department by ambulance after he was found unresponsive after a rollover motor vehicle accident. He has a severe closed head injury and has been unconscious for an undetermined time. On arrival, the patient has shallow respirations and decorticate posturing, and his pupils are mildly reactive to light. He was electively intubated, but asystole soon develops. Resuscitative measures are continued for a prolonged period before a perfusing rhythm is achieved. He is then transferred to the surgical intensive care unit (SICU) for further therapeutic intervention.
On his arrival to the SICU, the patient's temperature is 35.7°C. His blood pressure is 110/76 mm Hg with vasopressors, his pulse is 82 beats per minute, and he is breathing at the set ventilatory rate. He was comatose but is now unresponsive to verbal or tactile stimuli. His pupils were fixed and dilated. His eyes did not move when his head was turned. He has no corneal, gag, or cough reflexes. Apnea testing yields failing results.
The patient has no signs of significant trauma other those involving his head. Findings on heart, lung, and abdominal examinations are normal. Head CT demonstrates intraparenchymal and subarachnoid blood, along with diffuse, severe brain edema. The next day, a nuclear brain flow study with technetium-992 pertechnetate is performed (see Image).
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***** HINT *****
What you don't see is important.
***** ANSWER *****
Brain death: In the United States, the diagnosis of brain death is based on clinical findings. The patient must be comatose and not hypothermic. Brainstem reflexes (papillary, corneal, oculocephalic, and oculovestibular) and spontaneous respirations (as assessed on apnea testing) must be absent. Although not required, confirmatory studies may be done to support the clinical findings. Common studies are EEG and nuclear brain flow studies. Less common studies are tests for brainstem-evoked responses, cerebral angiography, MRI, CT, and Doppler sonography.
The nuclear brain flow study shows the hot nose sign (see Image). This sign appears because of an absence of blood flow from the internal carotid and vertebral arteries to the brain. Blood flow through the external carotid arteries and the numerous blood vessels in and around the nose and sinuses are thereby accentuated. When combined with appropriate physical findings, results of this test are consistent with brain death and confirm brain death.
The physician in the SICU approached the patient's family regarding organ donation. In addition to transplantable organs such as the lungs, heart, kidneys, and liver, other harvestable tissue are the corneas, bone, skin, tendon, fascia, cartilages, and heart valves. Contraindications to harvesting are age older than 80 years and death from infectious disease, cancer, or toxic exposure. Patients with lethal exposure to cocaine, carbon monoxide, lead, or barbiturates have donated organs successfully, but a case-by-case analysis by the transplant team is necessary in these cases.
Studies show that healthcare professions approach only 43% of the families of potential organ donors despite the growing shortage of transplantable organs. The correct time to approach family members is after they have viewed the patient's body. The family should be given time for bereavement and to accept their loved one's death.
81%, positive predictive value [PPV] = 43%); for this purpose, RaVR was better than a QRS interval of 0.010 s (sensitivity = 82%, PPV = 35%).
For more information on brain death, see the eMedicine article Medicolegal
Neurology: Special Issues (within the Neurology specialty).
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References
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Baron M, Bransfield J: A 37-year-old man with severe head trauma, and a "hot nose" sign on brain flow study. Chest 1999; 116: 1468-70.
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Tien Rd, Lin DS, Kutka N. The "hot nose" sign in the cerebral radionuclide angiogram. Semin Nucl Med 1992; 22: 295-6.
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Takehara Y, Takahashi M, Isoda H, et al. Scintigraphic evaluation of brain death with 99mTc-d l-hexamethyl-propyleneamine oxime (HMPAO). Radioisotopes
Author:
Ryland P. Byrd, Jr, MD, Chief of Pulmonary Medicine, Medical Director of Respiratory Therapy, Quillen Mountain Home Veterans Affairs Medical Center; Professor, Department of Internal Medicine, Division of Pulmonary Diseases and Critical Care Medicine, James H. Quillen College of Medicine, East Tennessee State University
Thomas M. Roy, MD, Chief, Division of Pulmonary Diseases and Critical Care Medicine, Professor of Medicine, Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University
eMedicine Editor:
Rick Kulkarni, MD, Attending Physician, Department of Emergency Medicine, Olive View - UCLA Medical Center, Assistant Professor of Medicine, David Geffen School of Medicine at UCLA
Source
http://emedicine.com
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