![]() When the diagnosis is uncertain, a brain MRI with contrast is obtained to evaluate for a retrocochlear lesion. Electronystagmography (ENG) may demonstrate a unilateral peripheral vestibular weakness on caloric testing. An FTA-ABS test may be obtained to rule out syphilis. Audiometry often demonstrates a low-frequency sensorineural hearing loss. Testing may be obtained to support the diagnosis and rule out other disorders. Meniere's disease is a clinical diagnosis mostly based on history. The histopathologic finding includes endolymphatic hydrops, which is thought to be caused by either overproduction or underresorption of endolymph in the inner ear. The cause is uncertain but is speculated to result from allergic, infectious, or autoimmune injury. Typical onset is in the fifth decade of life. Eating raw shellfish (C) can lead to gastrointestinal disorders and, on occasion, neurotoxic manifestations, but it is not associated with isolated lymphadenopathy.Ĭorrect Answer ( B ) Explanation: Meniere's disease is characterized by episodic severe vertigo lasting hours, with associated symptoms of unilateral tinnitus, fluctuating low-frequency hearing loss, and aural fullness. Symptomatic lead poisoning has a wide-ranging clinical presentation but is not associated with unilateral lymphadenopathy. Since the effects of detrimental lead levels are often clinically silent, emphasis is placed on periodic screening in preschool children. A small paint chip containing 50% lead can produce acute lead poisoning in a toddler. Most homes built before 1978 were painted with lead-based paint. Ingestion of lead-based paint (D) is the most common source of lead poisoning in children. Contact with domesticated birds (A) can result in Psittacosis, a respiratory infection with constitutional symptoms caused by the obligatory intracellular bacterium Chlamydia psittaci. Spontaneous resolution within 2-4 months is the norm. Single node involvement occurs in more than 50% of patients 65% involve axillary or cervical lymph nodes. The appearance of a papule at the inoculation site is the earliest symptom, followed by solitary or regional lymphadenopathy within 1-2 weeks. CSD is usually preceded by a scratch or bite from a cat (typically a kitten), which serves as the source of bacterial inoculation. CSD is one of the most common causes of chronic lymphadenopathy in children and adolescents. Patients can present with nausea, vomiting, abdominal pain, diarrhea that may be bloody, fevers, and myalgias.Ĭorrect Answer ( B ) Explanation: Cat scratch disease (CSD), also known as cat scratch fever or subacute regional lymphadenitis, develops postinoculation with Bartonella henselae, a gram-negative rod. Vibrio paraheamolyticus (E) infections are usually contracted by eating shellfish. Care is supportive, and prolonged intubation may be required. Death can occur from respiratory muscle paralysis. These may be followed by gastrointestinal disturbances and ultimately muscle weakness that progresses to an ascending paralysis. Symptoms can occur within minutes, including headache, parasthesias, and facial nerve palsies. Marine bacteria that accumulate in fish produce the toxin, which inhibits sodium channels. Tetrodoxin (D) is found in puffer fish and certain species of octopus. Histamine-mediated symptoms do not occur. Staphylococcus (C) food poisoning is due to ingestion of a preformed toxin that leads to the onset of gastrointestinal symptoms (nausea, vomiting, diarrhea, and abdominal cramping) within 6 hours. Distinct neurologic symptoms, including the sensation of loose or painful teeth, parasthesias of the face and tongue, metallic taste, and reversal of temperature discrimination may also be reported. ![]() Ciguatoxin increases neuronal sodium channel permeability leading to symptoms such as diaphoresis, headaches, abdominal pain, and cramps. Many species of fish can cause ciguatera poisoning (A), such as sea bass, grouper, and red snapper. The onset of symptoms is rapid, generally within the hour. Focal neurological findings are uncommon. When ingested, the histamine is absorbed and causes symptoms of flushing, headache, vomiting, abdominal pain, palpitations, and anxiety. Commonly implicated fish include the following: tuna, mackerel, and mahi-mahi. Bacteria on the surface of the fish decarboxylate histidine, a ubiquitous amino acid, forms a histamine. Histamine fish poisoning is a food-related illness that occurs because of consumption of improperly stored fish. Correct Answer ( B ) Explanation: This patient's presentation is most consistent with histamine fish poisoning.
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