Pseudomonas aeruginosa Infections Clinical Presentation

Pseudomonal infections can involve any part of the body.

• Respiratory tract

  • Pneumonia is observed in patients with immunosuppression and chronic lung disease. It can be acquired nosocomially in the intensive care unit (ICU) setting and is associated with positive-pressure ventilation and endotracheal tubes. The pneumonia may be primary, following aspiration of the organism from the upper respiratory tract, especially in patients on mechanical ventilation. Alternatively, it may occur as a result of bacteremic spread to the lungs. This is observed commonly in patients following chemotherapy-induced neutropenia.
  • Bacteremic pneumonia occurs in patients with neutropenia following chemotherapy and in patients with AIDS.
  • Chronic infection of the lower respiratory tract with P aeruginosa is prevalent among patients with cystic fibrosis. These patients may present with chronic productive cough, anorexia, weight loss, wheezing, and tachypnea.^[3]
  • Symptoms of pneumonia include fever, chills, severe dyspnea, cyanosis, productive cough, confusion, and other signs of a systemic inflammatory response.
• Bacteremia

  • Bacteremia may be acquired via medical devices in hospitals and nursing homes, and the mortality rate remains greater than 10%.
  • Signs and symptoms depend on the primary site of infection.
• Endocarditis

  • P aeruginosa may infect native heart valves in individuals who abuse intravenous drugs and may infect prosthetic heart valves.
  • Right-sided and left-sided valve infections may occur.
  • Nonspecific symptoms include fever and malaise, with more specific symptoms depending on which cardiac valve is involved. Left-sided endocarditis typically presents with symptoms of congestive heart failure and those resulting from systemic spread of septic emboli.
• Central nervous system

  • P aeruginosa infection can cause meningitis and brain abscess.
  • Most infections follow an extension from a contiguous parameningeal structure, such as an ear, a mastoid, paranasal sinus surgery, or diagnostic procedures. In some patients, the involvement of the CNS is due to hematogenous spread of the organism from infective endocarditis, pneumonia, or UTI.
  • Patients present with fever, headache, and confusion. The onset may be fulminant or subacute, often depending on the immune status of the patient.
• Ear

  • In otitis externa (swimmer's ear), patients present with pain, pruritus, and ear discharge. The pain is worsened by traction on the pinna.
  • Pseudomonas infection is a common cause of chronic otitis media. Malignant otitis externa is a manifestation of invasive infection predominantly observed in patients with uncontrolled diabetes. It begins as ordinary otitis externa that fails to respond to antibiotic therapy. Presenting symptoms are persistent pain, edema, and tenderness of the soft tissues of the ear, with a purulent discharge. Fever is uncommon, and some patients present with a facial nerve palsy. Extension of the infection to the temporal bone can result in osteomyelitis, and further extension can create cranial nerve palsies and possibly a CNS infection.
• Eye

  • The cornea, aqueous humor, and vitreous humor comprise an immunocompromised environment, and Pseudomonas, when introduced, produces extracellular enzymes that cause a rapidly progressive and destructive lesion. P aeruginosa is a common cause of bacterial keratitis, scleral abscess, and endophthalmitis in adults and ophthalmia neonatorum in children.
  • Predisposing conditions for corneal involvement are trauma, contact lens use, predisposing ocular conditions, exposure to an ICU environment, and AIDS. Corneal lesions can progress to endophthalmitis and orbital cellulitis. Symptoms are pain, redness, swelling, and impaired vision.
• Bones and joints

  • The most common sites of involvement are the vertebral column, the pelvis, and the sternoclavicular joint.
  • Infection may be blood-borne, as in individuals who abuse intravenous drugs or in patients with pelvic infections or UTI. Alternatively, the infection may be contiguous, related to penetrating trauma, surgery, or overlying soft tissue infections. Patients at risk for pseudomonal bone and joint infections include those with puncture wounds to the foot, peripheral vascular disease, intravenous drug abuse, or diabetes mellitus.
  • Vertebral osteomyelitis may involve the cervical spine, and patients present with neck or back pain lasting weeks to months. Occasionally, patients with complicated UTI may develop lumbosacral vertebral osteomyelitis.
  • Patients with pyoarthrosis present with swelling and pain in the affected joint. Patients are persistently febrile.
• Gastrointestinal

  • Pseudomonal infections can affect every portion of the GI tract. The disease is often underestimated but usually affects very young children and adults with hematologic malignancies and chemotherapy-induced neutropenia. Additionally, colonization of the GI tract is an important portal of entry for pseudomonal bacteremia in patients who are neutropenic. The spectrum of disease can range from very mild symptoms to severe necrotizing enterocolitis with significant morbidity and mortality.
  • Epidemics of pseudomonal diarrhea can occur in nurseries. Young infants may present with irritability, vomiting, diarrhea, and dehydration.
  • The infection can cause enteritis, with patients presenting with prostration, headache, fever, and diarrhea (Shanghai fever).
  • Pseudomonas typhlitis typically presents in patients with neutropenia resulting from acute leukemia, with a sudden onset of fever, abdominal distension, and worsening abdominal pain.
• Urinary tract infections

  • Pseudomonal UTIs are usually hospital-acquired and are associated with catheterization, instrumentation, and surgery.
  • These infections can involve the urinary tract through an ascending infection or through bacteremic spread. In addition, these infections are a frequent source of bacteremia.
  • No specific characteristics distinguish this type of infection from other forms of UTI.
• Skin

  • Pseudomonas does not grow on dry skin, but it flourishes on moist skin.
  • Green nail syndrome is a paronychial infection that can develop in individuals whose hands are frequently submerged in water.
  • Secondary wound infections occur in patients with decubiti, eczema, and tinea pedis. These infections may have a characteristic blue-green exudate with a fruity odor.
  • Pseudomonas is a common cause of hot tub or swimming pool folliculitis. Patients present with pruritic follicular, maculopapular, vesicular, or pustular lesions on any part of the body that was immersed in water.
  • Pseudomonal bacteremia produces distinctive skin lesions known as ecthyma gangrenosum.
  • Pseudomonas also has emerged as an important source of burn wound sepsis. Invasive burn wound sepsis is defined as the bacterial proliferation of 100,000 organisms per gram of tissue, with subjacent involvement of subjacent unburned tissue.

• Endocarditis

  • Cardinal features of bacterial endocarditis include fever, murmur, and positive blood culture findings.
  • A new onset of cardiac murmur or a change in character of a preexisting murmur may develop, although these may be absent on presentation.
  • Peripheral stigmata of endocarditis include Roth spots, Janeway lesions, Osler nodes, splinter hemorrhages, and splenomegaly.
• Pneumonia

  • Patients have rales, rhonchi, fever, cyanosis, retractions, and hypoxia.
  • Shock may develop in patients with bacteremic pneumonia.
  • Patients with cystic fibrosis may develop clubbing, increased anteroposterior (AP) diameter, and malnutrition.
• Gastrointestinal tract

  • Young infants with diarrhea may have fever, signs of dehydration, abdominal distension, and signs of peritonitis.
  • Physical findings of Shanghai fever may include fever, splenomegaly, and rose spots. Depending on the severity of the illness, prostration, dehydration, and vascular collapse may be observed.
• Skin and soft tissue infections

  • Ecthyma gangrenosum lesions are hemorrhagic and necrotic, with surrounding erythema. These characteristic lesions are almost always caused by Pseudomonas infection and usually are found in the axilla, groin, or perianal area but may involve any part of body.
  • Subcutaneous nodules, deep abscesses, cellulitis, and fasciitis may also occur.
  • Pseudomonal burn wound infections appear black or as a violaceous discoloration or eschar. Systemic manifestations of burn wound sepsis may include fever or hypothermia, disorientation, hypotension, oliguria, ileus, and leukopenia.
• Skeletal infections

  • Vertebral osteomyelitis manifests as local tenderness and a decreased range of motion.
  • Osteomyelitis may complicate puncture wounds.
  • Neurological deficits, when present, suggest spinal cord involvement.
• With eye infections, the physical examination reveals lid edema, conjunctival erythema and chemosis, and severe mucopurulent discharge adherent to an underlying corneal ulcer.
• Malignant otitis externa

  • The external auditory canal is erythematous, swollen, and inflamed, and a discharge may be observed.
  • The tympanic membrane is hidden from view because of edema and may be ruptured.
  • Local lymphadenopathy may be present.
• Bacteremia

  • Patients have fever, tachypnea, and tachycardia.
  • Hypotension and shock may develop.
  • Jaundice may occur.
  • Skin shows characteristic skin lesions called ecthyma gangrenosum.

• Pseudomonal bacteremia occurs in association with malignancy, chemotherapy, AIDS, burn wound sepsis, and diabetes.
• Certain populations of patients are especially susceptible to pseudomonal infections. Predisposing conditions include placement of intravenous lines, severe burns, urinary tract catheterization, surgery, trauma, and premature birth (infants).
• Conditions predisposing to pseudomonal infections and major manifestations include the following:

  • Diabetes - Malignant otitis externa
  • Drug addiction - Endocarditis, osteomyelitis
  • Leukemia - Sepsis, typhlitis
  • Cancer - Pneumonia, sepsis
  • Burn wound - Cellulitis, sepsis
  • Cystic fibrosis - Pneumonia
  • Surgery involving CNS - Meningitis
  • Tracheostomy - Pneumonia
  • Neonatal period - Diarrhea
  • Corneal ulcer - Panophthalmitis
  • Vascular catheterization - Bacteremia, suppurative thrombophlebitis
  • Urinary catheterization - UTI