Nocardiosis is an infectious disease

Infectious disease

Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...

 affecting either the lung

Lung

The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s (pulmonary nocardiosis) or the whole body (systemic nocardiosis). It is due to infection by bacterium of the genus Nocardia

Nocardia

Nocardia is a genus of weakly staining Gram-positive, catalase-positive, rod-shaped bacteria. It forms partially acid-fast beaded branching filaments . It has a total of 85 species. Some species are non-pathogenic while others are responsible for nocardiosis. Nocardia are found worldwide in soil...

, most commonly Nocardia asteroides

Nocardia asteroides

Nocardia asteroides is a species of Nocardia.It can cause Nocardiosis, a severe pulmonary infection in immunocompromised hosts....

or Nocardia brasiliensis

Nocardia brasiliensis

Nocardia brasiliensis is a species of Nocardia.It can cause Nocardiosis....

.

It is most common in men, especially those with a compromised immune system. In patients with brain infection, mortality exceeds 80%; in other forms, mortality is 50%, even with appropriate therapy.

It is one of several conditions that has been called the great imitator

The great imitator

The Great Imitator is a phrase used for medical conditions that feature nonspecific symptoms and may be confused with a number of other diseases. Most great imitators are systemic in nature...

.

Cutaneous nocardiosis commonly occurs in immunocompetent hosts.

Causes

Normally found in soil, these organisms cause occasional sporadic disease in humans and animals throughout the world. Another well publicized find is that of Nocardia as an oral microflora. Nocardia spp. have been reported in the normal gingiva and periodontal pockets along with other species such as Actinomyces, Arthromyces and Streptomyces spp.

The usual mode of transmission is inhalation of organisms suspended in dust. Another very common method is that by traumatic introduction, especially in the jaw. This leads to the entrance of Nocardia into the blood stream and the propagation of its pathogenic effects. Transmission by direct inoculation through puncture wounds or abrasions is less common. Generally, nocardial infection requires some degree of immune suppression.

Symptoms

Pulmonary Infection

• Produces a virulent form of pneumonia (progressive)
• night sweat
  SWEAT
  SWEAT is an OLN/TSN show hosted by Julie Zwillich that aired in 2003-2004.Each of the 13 half-hour episodes of SWEAT features a different outdoor sport: kayaking, mountain biking, ice hockey, beach volleyball, soccer, windsurfing, rowing, Ultimate, triathlon, wakeboarding, snowboarding, telemark...
  
  s, fever
  Fever
  Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
  
  , cough
  Cough
  A cough is a sudden and often repetitively occurring reflex which helps to clear the large breathing passages from secretions, irritants, foreign particles and microbes...
  
  , chest pain
• Pulmonary nocardiosis is subacute in onset and refractory to standard antibiotherapy
• symptoms are more severe in immunocompromised individuals
• radiologic studies show multiple pulmonary infiltrates with tendency to central necrosis

Neurological Infection

• Headache, lethargy, confusion, seizures, sudden onset of neurological deficit
• CT scan shows cerebral abscess
• Nocardial meningitis is difficult to diagnose

Cardiac Conditions

• Nocardia has been highly linked to endocarditis as a main symptom
• In recorded cases, it has caused damage to heart valves whether natural or prosthetic

http://www.cdc.gov/ncidod/dbmd/diseaseinfo/nocardiosis_t.htm
Lymphocutaneous disease

• Nocardial cellulitis is akin to erysipela but is less acute
• Nodular lymphangeitis mimics sporotrichosis with multiple nodules alongside a lymphatic pathway
• Mycetoma
  Mycetoma
  Eumycetoma is a chronic, specific, granulomatous, fungal disease. It mainly affects the foot; and Mycetoma pedis is also known as Madura foot. This infection is endemic in Africa, India, and Central and South America.-Causes and presentation:...
  
   is a rare complication and osteitis may ensue

Ocular disease

• Very rarely nocardiae cause keratitis
  Keratitis
  Keratitis is a condition in which the eye's cornea, the front part of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves impaired eyesight.-Types:...
  
  
• Generally there is a history of ocular trauma

Disseminated nocardiosis

• Dissemination occurs through the spreading enzymes possessed by the bacteria
• Disseminated infection can occur in very immunocompromised patients
• It generally involves both lungs and brain
• Fever, moderate or very high can be seen
• Multiple cavitating pulmonary infiltrates develop
• Cerebral abscesses arise later
• Cutaneous lesions are very rarely seen
• If untreated, the prognosis is poor for this form of disease

Diagnosis

Diagnosis may be difficult.
Nocardiae are weakly acid-fast

Acid-fast

Acid-fastness is a physical property of certain bacteria, specifically their resistance to decolorization by acids during staining procedures.Acid-fast organisms are difficult to characterize using standard microbiological techniques Acid-fastness is a physical property of certain bacteria,...

 organisms and can be visualized by a modified Ziehl-Neelsen stain

Ziehl-Neelsen stain

The Ziehl–Neelsen stain, also known as the acid-fast stain, was first described by two German doctors; Franz Ziehl , a bacteriologist and Friedrich Neelsen , a pathologist. It is a special bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria...

 like Fite-Faraco method
In the clinical laboratory, routine cultures may be held for insufficient time to grow nocardiae, and referral to a reference laboratory may be needed for species identification.
Infiltration and pleural effusion

Pleural effusion

Pleural effusion is excess fluid that accumulates between the two pleural layers, the fluid-filled space that surrounds the lungs. Excessive amounts of such fluid can impair breathing by limiting the expansion of the lungs during ventilation.-Pathophysiology:...

 are usually seen via x-ray

X-ray

X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

.

Treatment

Nocardiosis requires at least 6 months of treatment, preferably with co-trimoxazole

Co-trimoxazole

Trimethoprim/sulfamethoxazole or co-trimoxazole is a sulfonamide antibiotic combination of trimethoprim and sulfamethoxazole, in the ratio of 1 to 5, used in the treatment of a variety of bacterial infections.The name co-trimoxazole is the British Approved Name, and has been marketed worldwide...

 or high doses of sulfonamide

Sulfonamide (medicine)

Sulfonamide or sulphonamide is the basis of several groups of drugs. The original antibacterial sulfonamides are synthetic antimicrobial agents that contain the sulfonamide group. Some sulfonamides are also devoid of antibacterial activity, e.g., the anticonvulsant sultiame...

s. In patients who don’t respond to sulfonamide treatment, other drugs, such as ampicillin

Ampicillin

Ampicillin is a beta-lactam antibiotic that has been used extensively to treat bacterial infections since 1961. Until the introduction of ampicillin by the British company Beecham, penicillin therapies had only been effective against Gram-positive organisms such as staphylococci and streptococci...

, erythromycin

Erythromycin

Erythromycin is a macrolide antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of penicillin, and is often used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma and...

, or minocycline

Minocycline

Minocycline is a broad-spectrum tetracycline antibiotic, and has a broader spectrum than the other members of the group. It is a bacteriostatic antibiotic, classified as a long-acting type...

, may be added.

Treatment also includes surgical drainage of abscesses and excision of necrotic tissue. The acute phase requires complete bed rest

Bed rest

Bed rest is a medical treatment involving a period of consistent recumbence in bed. It is used as a treatment for an illness or medical condition, especially when prescribed or chosen rather than resulting from severe prostration or imminent death...

; as the patient improves, activity can increase.

A new combination drug therapy (sulfonamide, ceftriaxone

Ceftriaxone

Ceftriaxone is a third-generation cephalosporin antibiotic. Like other third-generation cephalosporins, it has broad spectrum activity against Gram-positive and Gram-negative bacteria. In most cases, it is considered to be equivalent to cefotaxime in terms of safety and efficacy...

, and amikacin

Amikacin

Amikacin is an aminoglycoside antibiotic used to treat different types of bacterial infections. Amikacin works by binding to the bacterial 30S ribosomal subunit, causing misreading of mRNA and leaving the bacterium unable to synthesize proteins vital to its growth.-Administration:Amikacin may be...

) has also shown promise.