| DISEASE AND CAUSES | PATHOPHYSIOLOGY | SIGNS AND SYMPTOMS |
| Rectal prolapse |
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- Protrusion of one or more layers of mucous membrane through the anus due to conditions that affect the pelvic floor or rectum
| Increased intra-abdominal pressure triggers the circumferential protrusion of one or more layers of the mucous membrane. | - Lower abdominal pain due to ulceration, bloody diarrhea, or tissue protruding from rectum during defecation or walking
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| Reiter's syndrome |
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- Cause unknown; mostly follows a period of diarrhea or sexual contact
- Genetic factor (HLA-B27) increases risk of acquiring disorder
| An infection (e.g., Chlamydia ) is thought to initiate an aberrant and hyperactive immune response that produces inflammation in involved target organs. | Urogenital tract:- Burning sensation with urination, penile discharge, and prostatitis in men
- Cervicitis, urethritis, and vulvovaginitis in women
Joint symptoms or arthritis:- Affects knees, ankles and feet
- Inflammation where tendon attaches to bone
Eye involvement:- Conjunctivitis and uveitis
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| Renal tubular acidosis |
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- Distal (type I): familial with another genetic disease or an isolated autosomal dominant disease
- Proximal (type II): accompanies several inherited diseases, multiple myeloma, vitamin D deficiency, chronic hypocalcemia, after renal transplantation, and following treatment with certain drugs
| In type I, the distal tubule is unable to secrete hydrogen ions across the tubular membrane, causing decreased excretion of titratable acids and ammonium and increased loss of potassium and bicarbonate. Prolonged acidosis leads to hypercalciuria and renal calculi. In type II, defective reabsorption of bicarbonate in proximal tubule causes bicarbonate to flood the distal tubule, leading to impaired formation of titratable acids and ammonium for excretion, resulting in metabolic acidosis. | In infants:- Vomiting, fever, constipation, anorexia, weakness, polyuria, growth retardation, nephrocalcinosis, and rickets
In children and adults:- Growth problems, urinary tract infections, and rickets
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| Retinal detachment |
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- Caused by trauma, after cataract surgery, severe uveitis, and primary or metastatic choroidal tumors
| The neural retina separates from the underlying retinal pigment epithelium. | - Floaters, flashing lights, scotoma in peripheral visual field (painless) and, eventually, a curtain or veil occurs in the field of vision
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| Retinitis pigmentosa |
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- Autosomal recessive disorder in 80% of affected children
- Less commonly transmitted as an X-linked trait
| Slow, degenerative changes in the rods cause the retina and pigment epithelium to atrophy. Irregular black deposits of clumped pigment are in equatorial region of retina and eventually in the macular and peripheral areas. | - Progressive night blindness, visual field constriction with ring scotoma, and loss of acuity progressing to blindness
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| Reye's syndrome |
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- Cause unknown
- Viral agents and drugs (especially salicylates) have been implicated
| Mitochondrial dysfunction and fatty vacuolization of the liver and renal tubules lead to hepatic injury and CNS damage. | - Vomiting
- Change in mental status progressing from lethargy to disorientation to coma
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| Rocky Mountain spotted fever |
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- Infection due to Rickettsia rickettsii carried by several tick species
| R. rickettsii multiplies within endothelial cells and spreads via the bloodstream. Focal areas of infiltration lead to thrombosis and leakage of RBCs into surrounding tissue. | - Fever, headache, mental confusion, and myalgia
- Rash develops as small macules progress to maculopapules and petechiae. Initially, rash starts on wrists and ankles and spreads to trunk. Especially diagnostic is rash noted on palms and soles.
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| Rosacea |
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| Small blood vessels of the face, usually the nose and cheeks, become flushed and dilated; also associated with papules and pustules. | - Pronounced flushing of nose and cheeks
- Papules, pustules, telangiectases can be superimposed
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