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[MEDSCAPE]: 10种中毒或疾病的皮肤表现
2017年04月17日 临床话题, 模拟诊室 暂无评论

Poisoning Clues on the Skin: 10 Cases

Jessica Harmon, MD; Raffi Kapitanyan, MD  |  April 6, 2017

This image shows an individual suffering a severe allergic reaction 4 days after exposure to poison oak. Acute poisonings often manifest on the skin, with presentations that can provide vital diagnostic clues to the clinician. Sinister or dangerous etiologies may be responsible for cutaneous signs, and consultation with the local poison control center (USA: 1-800-222-1222) is often warranted. Can you correctly diagnose the underlying toxicity for the following critical cases?

Image courtesy of Wikimedia Commons | Abm6868.

A 45-year-old man presented to the emergency department (ED) in February complaining of vomiting, watery diarrhea, lightheadedness, and headache. He had arrived in town the previous night to present at a conference and was staying at a local hotel. His roommate experienced similar, but less severe, symptoms. The patient received intravenous (IV) fluids, ondansetron, and ketorolac, and he was discharged a few hours later after feeling much better. The next morning, the patient failed to show up for his conference presentation. He was found in bed without a pulse and could not be resuscitated. His skin appeared pink and blotchy in places (shown).

Which of the following tests could have made the diagnosis on his initial presentation to the ED?

  1. Carboxyhemoglobin (COHb)
  2. Hemoglobin (Hb)
  3. Serum bicarbonate
  4. Methemoglobin (metHb)
  5. White blood cell (WBC) count

Answer: A. Carboxyhemoglobin (COHb)

Two classic, but rare, dermatologic findings that are associated with CO poisoning are a cherry-red skin coloring (shown) and the development of cutaneous bullae; these occur only after excessive exposure.[1]

Carbon monoxide (CO), an odorless, colorless, poisonous gas, can cause sudden illness and is the leading cause of US poisoning deaths.[2,3] The patient in this case had a COHb level of 68% (normal range: 0-5%). The most common and earliest symptoms of CO poisoning are usually nonspecific (headache, confusion, dizziness, weakness, nausea/vomiting, chest pain),[2,3] and they are often diagnosed as a viral syndrome. Initial therapy consists of administering 100% oxygen via mask or endotracheal tube until the patient is symptom-free, and performing serial neurologic exams.[2,4,5]Hyperbaric oxygen therapy may be necessary in severe cases (eg, COHb level >25-30%, cardiac involvement, neurologic impairment).

Image courtesy of Dr. Abbas Koronfel.

This patient has patchy skin hyperpigmentation on his back (shown), chest, and neck. His pertinent medical history includes water ingestion from a well over a prolonged time period.

Which of the following contaminants should be suspected in the water?

  1. Strychnine
  2. Foxglove
  3. Arsenic
  4. Cyanide
  5. Belladonna

Image courtesy of the Centers for Disease Control and Prevention (CDC) | Arsenic Foundation.

Answer: C. Arsenic

The pigmented lesions in arsenic poisoning often present as bilateral, symmetrical, finely freckled or raindrop-like macules (shown).

Arsenic poisoning is often caused by industrial/workplace exposure;[6-8] ingestion of contaminated groundwater, food, or moonshine;[6-8] or malicious intent.[8] Arsenic affects nearly all organ systems,[8]but the skin is most sensitive to its effects.[7] Patchy hyperpigmentation,[6-8] a pathologic hallmark of chronic exposure, may be found anywhere on the body, but it occurs particularly on the eyelids, temples, neck, nipples, axillae, and groin. In severe cases, it extends broadly over the chest, back, and abdomen. Dark-brown patches with scattered pale spots are sometimes described as "raindrops on a dusty road." Other signs/symptoms include vomiting, abdominal pain, diarrhea, paresthesia of the extremities, muscle cramping, and cardiac, neurologic, pulmonary, hepatorenal, and hematologic dysfunction.[6-8] A garlic odor may be present in the breath and body tissues.[8]

Image courtesy of Dr. Ken Greer | Visuals Unlimited.

In addition to hyperpigmentation, the skin lesions that most often occur with chronic arsenic exposure are hyperkeratosis and several types of skin cancer[6-8] (eg, basal cell carcinoma, Bowen disease, Merkel cell carcinoma).[9] Liver, bladder, and lung cancer can also arise.[6] Arsenical keratoses (shown) are usually multiple lesions and typically occur at sites of friction and trauma, especially on the palms and the soles,[6-8] as well as on the dorsum of the hands and the arms and legs. The keratoses usually appear as small, nontender, horny, hard, yellowish, 0.2- to 1-cm papules; the lesions may coalesce into larger verrucous papules or plaques. Benign arsenical keratoses may progress to malignancy. Workup for arsenic poisoning includes urinary and serum arsenic levels, hematologic studies, arterial blood gases (ABGs), electrocardiography (ECG), and chest and abdominal radiographs.[8] In acute cases, aggressively monitor/support the patient's cardiopulmonary and hemodynamic functions, irrigate exposed areas, provide IV hydration, and, in symptomatic patients, administer chelation therapy.[10] For chronic cases, identify and, if possible, remove the toxic source.

Image courtesy of Medscape.

This patient presented with the skin discoloration shown. When taking his history, you should inquire about possible routes of exposure to which of the following metals?

  1. Silver
  2. Gold
  3. Mercury
  4. Nickel
  5. Zinc

Image courtesy of Rice University | Herbert L. Fred, MD, and Hendrik A. van Dijk.

Answer: A. Silver

The patient (right) had used silver-containing nose drops for many years. Skin biopsy showed silver dermal deposits, which confirmed argyria, a permanent bluish-gray skin discoloration that is the primary manifestation of chronic silver overexposure. Silver is a naturally occurring element that may be released into the air, food, and water.[10] Industrial activity and hobbies (jewelry-making, soldering, photography) are other sources of exposure. Argyria develops in stages, beginning with a gray-brown gingival staining, followed by a bluish gray discoloration in sun-exposed areas.[11,12] Eventually, the sclera, nail beds, and mucous membranes become hyperpigmented. Although the pigmentary changes are permanent, argyria has no known effect on health. However, high-level silver exposure in the air can cause respiratory and gastrointestinal (GI) irritation, and skin contact may result in mild allergic reactions.[10] Workup includes urinary and serologic silver levels[10] and skin biopsy.[11]Treatment may include use of 5% hydroquinone and Q-switched 1064-nm Nd:YAG laser.

Image courtesy of Rice University | Herbert L. Fred, MD, and Hendrik A. van Dijk.

A 25-year-old man who worked in a semiconductor manufacturing plant developed mild, persistent abdominal pain with intermittent severe pain and constipation. Three days after the initial painful episode, his hair started to fall out (shown); 2 days later, he was completely bald. One month later, he felt pain and tingling in his hands and feet and developed difficulty speaking, blurred vision, and trouble walking. He was hospitalized; 2 weeks later, he became comatose. Which of the following was responsible for his signs/symptoms?

  1. Selenium (Se)
  2. Acute intermittent porphyria
  3. Thallium (Tl)
  4. Arsenic
  5. Thiamine deficiency

Image courtesy of Medscape.

Answer: C. Thallium (Tl)

Mees lines, white lines that traverse the width of the nails (shown) (first described in arsenic poisoning), appear within 2-4 weeks after Tl exposure.[13]

Tl can be absorbed into the body by inhalation, ingestion, and skin contact.[14] Alopecia is the most common and classic manifestation of Tl toxicity; it occurs 7-12 days after the initial onset of symptoms, and complete hair loss often occurs by 1 month.[13] (Se and arsenic toxicity can also cause rapid-onset alopecia.) A painful ascending neuropathy and GI symptoms are also characteristic. In severe cases, death may occur 5-7 days after exposure.[14] Although many effects of Tl poisoning are nonspecific and occur over a variable time course, a clear toxic syndrome can be defined when the effects are combined. Workup includes urinary, blood, and quantitative atomic absorption levels of Tl; liver function tests (LFTs); complete blood count (CBC); ECG; plain abdominal radiography; and electromyography (EMG). Therapy includes cardiopulmonary support, activated charcoal, whole bowel irrigation with polyethylene glycol solution, Prussian blue (antidote), and hemodialysis/hemoperfusion.[13,14]

Image courtesy of Wikimedia Commons | Yannick Trottier.

A 74-year-old female with dermatitis herpetiformis presented to the ED with confusion, lightheadedness, weakness, and mild headache, as well as a grayish discoloration of the skin. She recently started dapsone, and her CBC was within normal limits. Despite treatment with 100% oxygen, the discoloration remained. What is the most likely diagnosis?

  1. Drug-induced dyspigmentation
  2. Methemoglobinemia
  3. Raynaud disease
  4. Metabolic acidosis
  5. Congestive heart failure

Image courtesy of Wikimedia Commons | James Heilman, MD.

Answer: B. Methemoglobinemia

In this image, the metHb fraction in tubes one and two is 70%, with the blood appearing brown. In tube three, the metHb fraction is 20%, while in tube four, it is normal.

Methemoglobinemia is a congenital or acquired condition in which red blood cells contain over 1% metHb[15] and hemoglobin (Hb) is unable to effectively release oxygen to body tissues.[16] Acquired causes include exposure to various chemicals (eg, organic and inorganic nitrites/nitrates, chlorates), foods, and drugs, including dapsone.[15,16] Symptoms are proportional to the metHb level; the most striking physical finding is discoloration of the skin (cyanosis or a grayish pigmentation) and blood (brown or chocolate).[15] At metHb levels of over 15%, neurologic and cardiac symptoms develop due to hypoxia; levels of over 70% are usually fatal. Suspect this condition when 100% oxygen fails to correct cyanosis. Workup includes routine blood tests (eg, CBC with reticulocyte count, electrolyte levels), liver and renal function tests, Hb electrophoresis and/or DNA sequencing, ABGs and/or pulse oximetry, potassium cyanide test, and head, chest, and cardiac imaging studies.[15] Therapy includes administration of supplemental oxygen, IV hydration, and IV methylene blue; identification and, if possible, removal of the underlying cause; exchange transfusions; and hyperbaric oxygen therapy.[15,16]

Image courtesy of Medscape.

While on vacation in the Caribbean, a couple had a local dinner of rice, cooked vegetables, mahi-mahi, and wine. An hour after eating, they both developed headaches and palpitations, and they started to feel a tingling sensation in their mouths. In addition, they noticed that their faces, necks, and chests had turned intensely red (the husband's eyes are shown). Because their skin also felt itchy, they took some diphenhydramine after returning to their hotel. A few hours later, their symptoms were almost gone. Which of the following types of poisoning was the couple likely exposed to?

  1. Paralytic shellfish
  2. Tetrodotoxin
  3. Ciguatera
  4. Scombroid
  5. Vibrio parahaemolyticus

Image courtesy of Wikimedia Commons | Grook Da Oger.

Answer: D. Scombroid poisoning

Cutaneous symptoms of scombroid poisoning include an intense, diffuse, blanching erythema of the face, neck, and upper torso (shown).

Scombroid poisoning results from eating cooked, smoked, canned, or raw fish from temperate or tropical waters that have a high concentration of histidine in their dark meat (eg, tuna, mackerel, mahi-mahi, sardine, anchovy, herring, bluefish, amberjack, marlin, albacore).[17,18] Certain bacteria commonly found on the surface of the fish contain a heat-stable histidine decarboxylase enzyme that acts on warm (not refrigerated), freshly killed fish, converting histidine to histamine. The onset of symptoms usually occurs 10-60 minutes after ingestion of the contaminated fish. Aside from cutaneous manifestations, symptoms include severe headache, palpitations, blurred vision, and GI features. Rarely, pruritus, urticaria, angioedema, and cardiopulmonary compromise may occur. Symptoms often resolve without treatment within 12 hours. Therapy includes supportive care (eg, IV fluids, antiemetics, cardiopulmonary support) and antihistamines.[17,18]

Image courtesy of Medscape | Amanda Oakley, MBChB, FRACP.

A politician became seriously ill in the midst of a bitter campaign for presidency. After a dinner meeting, he complained of a headache, severe abdominal pain, and severe backache. He was initially diagnosed with acute pancreatitis. Then, a few weeks later, his face became jaundiced, bloated, and pockmarked (shown). He claimed to have been poisoned at the dinner meeting by government agents.

Which of the following chemical agents should be the suspected toxin?

  1. Cyanide
  2. Dioxin
  3. Strychnine
  4. Lead
  5. Barbiturates

Image courtesy of Wikimedia Commons | Muumi.

Answer: B. Dioxin

On the basis of the distinctive facial cysts (chloracne) (shown), toxicologists suspected dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD]) poisoning. Testing confirmed blood dioxin levels that were 6000 times above the normal concentration.[19] Dioxins are a group of highly toxic, colorless organic compounds that are byproducts of some industrial processes and waste incineration; they are significant environmental pollutants.[20,21] Agent Orange is a dioxin that was used in the Vietnam War.[22] These agents can cause organ disease, increase the risk of cancer and heart attacks, suppress the immune system, interfere with hormones, and lead to diabetes, menstrual problems, increased hair growth, and weight loss.[20,21] Workup includes LFTs, CBC, coagulation studies, and electrophysiologic studies, as well as the use of gas chromatography and high-resolution mass spectrometry to measure levels of TCDD and its metabolites in blood serum, adipose tissue, skin, and other biologic samples (urine, feces, sweat).[23] Treatment primarily consists of supportive care and symptomatic management. Unfortunately, chloracne is resistant to methods that are used to treat acne vulgaris.[24]

Image courtesy of the National Institute for Occupational Safety and Health.

A patient presented with a lesion on his finger (shown). The lesion had a moist base.

Which causative agent should be suspected?

  1. Typhus
  2. Q fever
  3. Brucellosis
  4. Anthrax
  5. Tularemia

Image courtesy of Medscape | American Academy of Dermatology | Universidad Peruana Cayetano Heredia.

Answer: D. Anthrax

Cutaneous anthrax is typically caused when individuals handle infected animals or contaminated animal products (eg, wool, hides, hair), and Bacillus anthracis spores enter through microscopic or gross breaks in the skin;[25,26] the head/neck and forearms/hands are most often affected.[25] A pruritic papule develops at the infection site and enlarges within 24-48 hours (range, 1-7 days) to form a 1-cm vesicle; subsequently (≤7-10 days), a large, painless, necrotic ulcer with a black center (eschar) develops (shown).[25,26] Cutaneous anthrax often remains localized, but it can disseminate and result in bacteremia. Workup for cutaneous disease includes detection/isolation of B anthracis, culture identification/genotyping, and serology.[25] Therapy for local disease includes a 7- to 10-day course of an oral antibiotic (fluoroquinolones, doxycycline, or, if the organism is susceptible, penicillin/amoxicillin/penicillin VK) and/or an antitoxin (raxibacumab, anthrax immune globulin intravenous [AIGIV]).[27] Cutaneous anthrax is rarely fatal (<2% mortality) if treated.[26] Left untreated, however, about 20% of cutaneous cases progress to toxemia and death.[25,26]

Image courtesy of the Medscape | American Academy of Dermatology.

This patient presented with severe malaise, headache, shaking chills, and fever. Five days earlier, he had noted a swollen, ruptured inguinal lymph node. The patient is currently experiencing adenopathy in the affected regional lymph nodes. Which of the following gram-negative bacilli should be suspected?

  1. Coxiella burnetii
  2. Yersinia pestis
  3. Francisella tularensis
  4. Rickettsia prowazekii
  5. Brucella melitensis

Image courtesy of the CDC.

Answer: B. Yersinia pestis

This image shows the right hand of a patient with acral gangrene recovering from bubonic plague (a disease caused by Y pestis) that disseminated to the blood and lungs.

Y pestis causes three types of plague: bubonic, pneumonic, and septicemic.[28,29] Bubonic plague is transmitted from the bite of an infected rodent flea; signs/symptoms (incubation period, 2-5 days) include fever/chills, malaise, headache, and painful, enlarged (often inflamed, necrotic, hemorrhagic) regional lymph nodes called buboes (shown on the previous slide).[28,29] Y pestis can spread along the lymphatic channels and cause bacteremia and septicemia. Workup includes cultures and/or microscopic examination of blood samples and/or lymph node aspirates;[28,29] serology is another option.[28] First-line antibiotic therapy is intramuscular (IM) streptomycin or IM/IV gentamicin; alternative agents include IV doxycycline, ciprofloxacin, and chloramphenicol.[28] Left untreated, about 50% of patients with bubonic plague die.[29]

Image courtesy of the CDC | William Archibald.

This patient is shown 12 days after the onset of skin lesions on her face and extremities. The facial lesions are sparser and evolved more rapidly than the lesions on her extremities. What disease, considered to be a potential biologic weapon, is shown?

  1. Yellow fever
  2. Dengue
  3. Venezuelan equine encephalitis
  4. Ebola virus
  5. Smallpox

Image courtesy of the World Health Organization (WHO).

Answer: E. Smallpox

The images demonstrate smallpox rash at days 3, 5, and 7 of evolution, respectively.

Smallpox is a highly contagious, sometimes fatal disease that is spread through direct contact with infected bodily fluids or contaminated objects or via the air.[30,31] Owing to the efficacy of worldwide immunization, however, smallpox has been eradicated, with the last naturally acquired case reported in 1977 (although small quantities of the virus have been kept for research purposes).[30, 31]

Variola major is the more severe (30% fatality) form of smallpox; variola minor is a milder disease (≤1% fatality).[32] The characteristic and contagious smallpox rash first appears as small, red spots in the oropharynx that spread to the face and forearms and become small papules. The papules change into vesicles and pustules within 1-2 days and, in turn, form crusts and then scabs.[30] Patients are no longer contagious after all of the scabs fall off.[30,31] Workup includes coagulation studies, D-dimer and fibrinogen levels, WBC count with platelet count, and identification of variola DNA via polymerase chain reaction (PCR) assay or isolation of the variola virus, with PCR assay confirmation, in a CDC Laboratory Response Network facility.[33,34] No specific treatment exists; the only prevention is vaccination. Because of the ease of production and aerosolization of the smallpox virus, there is concern about its potential use as a bioterrorism agent.

Images courtesy of the WHO.


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