Difference between revisions of "IPLab:Lab 9:RMSF"

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(Clinical Summary)
 
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This 9-year-old child was admitted with headache, fever, and a morbilliform rash on the arms and legs. There was a history of a tick being removed from her back. By the time a biopsy was performed, the rash had become petechial. Antibiotics were given and the child recovered within one week.
 
This 9-year-old child was admitted with headache, fever, and a morbilliform rash on the arms and legs. There was a history of a tick being removed from her back. By the time a biopsy was performed, the rash had become petechial. Antibiotics were given and the child recovered within one week.
  
== Biopsy Findings ==
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Examination of a skin biopsy of this patient's lesion was stained with hematoxylin and eosin. A different section was also stained with an immunoperoxidase technique using antibody against Rickettsia rickettsii. Organisms were demonstrated in the endothelial cells.
A skin biopsy of this patient's lesion was stained with hematoxylin and eosin. A different section was also stained with an immunoperoxidase technique using antibody against Rickettsia rickettsii. Organisms were demonstrated in the endothelial cells.  
 
  
 
== Images ==
 
== Images ==
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File:IPLab9RMSF8.jpg|This is a high-power photomicrograph of a thrombosed vessel in the dermis. Note that the endothelial cells are missing along part of the circumference of the vessel (arrows)--this is where the main part of the thrombus has attached. Also note the inflammation surrounding the vessel.  
 
File:IPLab9RMSF8.jpg|This is a high-power photomicrograph of a thrombosed vessel in the dermis. Note that the endothelial cells are missing along part of the circumference of the vessel (arrows)--this is where the main part of the thrombus has attached. Also note the inflammation surrounding the vessel.  
 
</gallery>
 
</gallery>
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== Virtual Microscopy ==
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<peir-vm>IPLab9RMSF</peir-vm>
  
 
== Study Questions ==
 
== Study Questions ==
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* <spoiler text="What is the usual clinical course of Rocky Mountain Spotted Fever?">An eschar develops at the site of the tick bite followed by a hemorrhagic rash that extends over the entire body, including the palms of the hands and soles of the feet. The vascular lesions that underlie the rash often lead to acute necrosis, fibrin extravasation, and thrombosis of the small blood vessels, including arterioles. In severe RMSF, foci of necrotic skin can form on the fingers, toes, elbows, ears, and scrotum.</spoiler>
 
* <spoiler text="What is the usual clinical course of Rocky Mountain Spotted Fever?">An eschar develops at the site of the tick bite followed by a hemorrhagic rash that extends over the entire body, including the palms of the hands and soles of the feet. The vascular lesions that underlie the rash often lead to acute necrosis, fibrin extravasation, and thrombosis of the small blood vessels, including arterioles. In severe RMSF, foci of necrotic skin can form on the fingers, toes, elbows, ears, and scrotum.</spoiler>
 
* <spoiler text="How does Rickettsia rickettsii produce the vasculitis?">Rickettsiae predominantly infect host endothelial and vascular smooth muscle cells causing a widespread vasculitis that may be complicated by thrombi and hemorrhages. Rickettsiae bind to cholesterol-containing receptors, are endocytosed into phagolysosomes, escape into the cytosol, and multiply until they burst the cells. Rickettsiae have an endotoxin but lack secreted toxins. In addition, R. rickettsii activate host kallikrein and kinins and cause local clotting.</spoiler>
 
* <spoiler text="How does Rickettsia rickettsii produce the vasculitis?">Rickettsiae predominantly infect host endothelial and vascular smooth muscle cells causing a widespread vasculitis that may be complicated by thrombi and hemorrhages. Rickettsiae bind to cholesterol-containing receptors, are endocytosed into phagolysosomes, escape into the cytosol, and multiply until they burst the cells. Rickettsiae have an endotoxin but lack secreted toxins. In addition, R. rickettsii activate host kallikrein and kinins and cause local clotting.</spoiler>
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== Additional Resources ==
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=== Reference ===
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* [http://emedicine.medscape.com/article/228042-overview eMedicine Medical Library: Rocky Mountain Spotted Fever]
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* [http://www.merckmanuals.com/professional/infectious_diseases/rickettsiae_and_related_organisms/rocky_mountain_spotted_fever_rmsf.html Merck Manual: Rocky Mountain Spotted Fever]
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* [http://www.merckmanuals.com/professional/infectious_diseases/rickettsiae_and_related_organisms/overview_of_rickettsial_infections.html Merck Manual: Overview of Rickettsial Infections]
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=== Journal Articles ===
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* Pantanowitz L, Telford SR, Cannon ME.  [http://www.ncbi.nlm.nih.gov/pubmed/11982962 Tick-borne diseases in transfusion medicine].  ''Transfus Med'' 2002 Apr;12(2):85-106.
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=== Images ===
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* [{{SERVER}}/library/index.php?/tags/2151-rmsf PEIR Digital Library: RMSF Images]
  
 
{{IPLab 9}}
 
{{IPLab 9}}
  
 
[[Category: IPLab:Lab 9]]
 
[[Category: IPLab:Lab 9]]

Latest revision as of 21:42, 9 July 2020

Clinical Summary[edit]

This 9-year-old child was admitted with headache, fever, and a morbilliform rash on the arms and legs. There was a history of a tick being removed from her back. By the time a biopsy was performed, the rash had become petechial. Antibiotics were given and the child recovered within one week.

Examination of a skin biopsy of this patient's lesion was stained with hematoxylin and eosin. A different section was also stained with an immunoperoxidase technique using antibody against Rickettsia rickettsii. Organisms were demonstrated in the endothelial cells.

Images[edit]

Virtual Microscopy[edit]

Study Questions[edit]


Additional Resources[edit]

Reference[edit]

Journal Articles[edit]

Images[edit]

Morbilliform means measles-like.

A thrombus is a solid mass resulting from the aggregation of blood constituents within the vascular system.