Rickettsial disease

Abstract

Rickettsioses are worldwide distributed infectious disease caused by intracellular small Gram-negative bacteria transmitted to humans by the bite of contaminated arthropods, such as ticks. Systemic disease typically consists of a triad of high fever, headache, and skin rash. It usually has a self-limited course, but severe, life-threatening complications can sometimes occur. It may be clinically difficult to differentiate rickettsial diseases from other febrile illnesses. Rickettsial infection has been largely underestimated as a cause of infectious uveitis for long decades in the past. Conversely, recent data show that ocular involvement is much more common than previously thought, with retinitis, retinal vasculitis, and neuroretinitis being the most typical and frequent findings. Early clinical diagnosis of rickettsial disease, while awaiting laboratory test results, is essential for prompt initiation of appropriate antibiotic treatment to prevent systemic and ocular morbidity. The prevention remains the mainstay of rickettsial infection control.

Case report: Infectious cerebral vasculitis due to rickettsiosis

“…Rickettsiae are able to invade and develop in a wide variety of host cells from different species and organs. In humans, the rickettsial pathogen is inoculated either by a tick or mite bite, or by scratching the skin after infected flea or louse excrement has been deposited on the skin [4] . They spread into the bloodstream, proliferating, and damaging the endothelium of small arteries, veins and capillaries and, in some cases, vascular smooth muscle cells, causing damage to the microcirculation of virtually every organ [3] .…”

“…Treatment of rickettsial vasculitis consists of 100 mg doxycycline every 12 hours for at least 7 days, and for at least 2 days after apyrexia. Doxycycline is the drug of choice for rickettsial infections, and treatment should be started as soon as the diagnosis is suspected; indeed, the mortality rate is significantly lower in patients treated within the first 5 days of illness than in those treated later [1] , [2] , [3] , [4] , [5] , [6] , [7] , [8] .…”

Post-fever Retinitis With a Positive Weil-Felix Test: A Study From a Tertiary Center in South India

“…Initially, the visual field examination did not detect the visual field defect, but six months later, there was a definite sickle-shaped inferior visual defect that corresponded with the nerve fiber bundle defect (Figure 4b ). A study reported retinal nerve fiber bundle defect and focal retinal thinning on OCT but did not report a corresponding visual field defect [ 18 ].…”

“…Visual recovery occurs over three to five months with a resolution of retinal lesions. Most studies and case reports reported good visual recovery in patients with PFR due to rickettsial disease [ 2 , 4 , 10 , 11 , 18 , 19 ].…”

Meningoencephalitis and retinal vasculitis due to rickettsial infection

“…Another particularity in the case of our patient were the ophthalmologic complications which occurred only secondarily. Ocular involvement with retinitis and retinal vasculitis are common findings in RMFS patients, however they usually occur with the initial symptoms and respond well to therapy [ 11 ]. Pathophysiologically, ocular damage may be due to two mechanisms: on the one hand, a direct invasion of the retinal vessels by the bacteria and, on the other hand, as a secondary immunological response to the bacterium [ 12 ].…”