ICD-10-CM Diagnosis Code J18.9 - Pneumonia, unspecified organism (original) (raw)

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Pneumonia, unspecified organism

ICD-10-CM Code:

J18.9

ICD-10 Code for:

Pneumonia, unspecified organism

Is Billable?

Yes - Valid for Submission

Chronic Condition Indicator: [1]

Not chronic

Code Navigator:

J18.9 is a billable diagnosis code used to specify a medical diagnosis of pneumonia, unspecified organism. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2025 through September 30, 2026.

Unspecified diagnosis codes like J18.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

  1. Code Information
  2. Approximate Synonyms
  3. Clinical Classification
  4. Clinical Information
  5. Tabular List of Diseases and Injuries
  6. Index to Diseases and Injuries References
  8. Diagnostic Related Groups Mapping
  9. Convert to ICD-9 Code
  10. Patient Education
  11. Other Codes Used Similar Conditions
  12. Code History

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

CCSR Code: RSP002

Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.

Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

inflammation of the lung parenchyma that is associated with bronchitis, usually involving lobular areas from terminal bronchioles to the pulmonary alveoli. the affected areas become filled with exudate that forms consolidated patches.

pneumonia caused by infections with the genus chlamydia; and chlamydophila, usually with chlamydophila pneumoniae.

infection of the lungs in a patient who is not hospitalized or who has not resided in a long-term care facility for 14 days prior to the onset of symptoms. it is associated with some signs and symptoms of acute infection and is accompanied by the presence of an acute infiltrate on chest radiograph.(us pharm. 2007;32(10):44-5 https://www.uspharmacist.com/article/community-acquired-pneumonia)

an interstitial lung disease of unknown etiology, occurring between 21-80 years of age. it is characterized by a dramatic onset of a pneumonia-like illness with cough, fever, malaise, fatigue, and weight loss. pathological features include prominent interstitial inflammation without collagen fibrosis, diffuse fibroblastic foci, and no microscopic honeycomb change. there is excessive proliferation of granulation tissue within small airways and alveolar ducts.

acute idiopathic interstitial pneumonitis characterized by diffuse pulmonary alveoli damage with uniform edematous connective tissue proliferation. it is often associated with extensive fibroblastic distortion of the lung parenchyma and leads to adult respiratory distress syndrome in later stages.

infection of the lung often accompanied by inflammation that is acquired through an interaction within a healthcare institution often through a therapeutic experience (e.g., use of catheters or ventilators).

a group of interstitial lung diseases with no known etiology. there are several entities with varying patterns of inflammation and fibrosis. they are classified by their distinct clinical-radiological-pathological features and prognosis. they include idiopathic pulmonary fibrosis; cryptogenic organizing pneumonia; and others.

a diverse group of lung diseases that affect the lung parenchyma. they are characterized by an initial inflammation of pulmonary alveoli that extends to the interstitium and beyond leading to diffuse pulmonary fibrosis. interstitial lung diseases are classified by their etiology (known or unknown causes), and radiological-pathological features.

a species of the genus pneumovirus causing pneumonia in mice.

any obstructive lung disease characterized by consolidated formation of granulation tissue polyps within alveolar ducts and alveoli. it is classified as either primary (cryptogenic organizing pneumonia) or secondary organizing pneumonia. secondary organizing pneumonia after transplantation is called bronchiolitis obliterans syndrome.

infection of the lung often accompanied by inflammation.

chronic endemic respiratory disease of dairy calves and an important component of bovine respiratory disease complex. it primarily affects calves up to six months of age and the etiology is multifactorial. stress plus a primary viral infection is followed by a secondary bacterial infection. the latter is most commonly associated with pasteurella multocida producing a purulent bronchopneumonia. sometimes present are mannheimia haemolytica; haemophilus somnus and mycoplasma species.

a chronic, clinically mild, infectious pneumonia of pigs caused by mycoplasma hyopneumoniae. ninety percent of swine herds worldwide are infected with this economically costly disease that primarily affects animals aged two to six months old. the disease can be associated with porcine respiratory disease complex. pasteurella multocida is often found as a secondary infection.

a type of lung inflammation resulting from the aspiration of food, liquid, or gastric contents into the upper respiratory tract.

a cattle disease of uncertain cause, probably an allergic reaction.

inflammation of the lung parenchyma that is caused by bacterial infections.

pneumonia due to aspiration or inhalation of various oily or fatty substances or otherwise accumulation of endogenous lipid substances in the pulmonary alveoli.

interstitial pneumonia caused by extensive infection of the lungs (lung) and bronchi, particularly the lower lobes of the lungs, by mycoplasma pneumoniae in humans. in sheep, it is caused by mycoplasma ovipneumoniae. in cattle, it may be caused by mycoplasma dispar.

severe complication of pneumonia characterized by liquefaction of lung tissue.

a febrile disease caused by streptococcus pneumoniae.

a pulmonary disease in humans occurring in immunodeficient or malnourished patients or infants, characterized by dyspnea, tachypnea, and hypoxemia. pneumocystis pneumonia is a frequently seen opportunistic infection in aids. it is caused by the fungus pneumocystis jirovecii. the disease is also found in other mammals where it is caused by related species of pneumocystis.

chronic respiratory disease caused by the visna-maedi virus. it was formerly believed to be identical with jaagsiekte (pulmonary adenomatosis, ovine) but is now recognized as a separate entity.

pneumonia caused by infection with bacteria of the family rickettsiaceae.

pneumonia caused by infections with bacteria of the genus staphylococcus, usually with staphylococcus aureus.

serious inflammation of the lung in patients who required the use of pulmonary ventilator. it is usually caused by bacterial cross infection in hospitals.

inflammation of the lung parenchyma that is caused by a viral infection.

a condition characterized by infiltration of the lung with eosinophils due to inflammation or other disease processes. major eosinophilic lung diseases are the eosinophilic pneumonias caused by infections, allergens, or toxic agents.

inflammation of the lung due to harmful effects of ionizing or non-ionizing radiation.

a genus of the family paramyxoviridae (subfamily pneumovirinae) where the human and bovine virions have neither hemagglutinin nor neuraminidase activity. respiratory syncytial virus, human is the type species.

small polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.

a gram-positive organism found in the upper respiratory tract, inflammatory exudates, and various body fluids of normal and/or diseased humans and, rarely, domestic animals.

a family of gram-negative bacteria belonging to the order rickettsiales.

granular leukocytes with a nucleus that usually has two lobes connected by a slender thread of chromatin, and cytoplasm containing coarse, round granules that are uniform in size and stainable by eosin.

symptomatic; medical intervention indicated; limiting instrumental adl or mild/moderate impact on age-appropriate normal daily activity (pediatric)

severe symptoms; oxygen indicated; limiting self-care adl or severe impact on age-appropriate normal daily activity (pediatric)

gastritis that is characterized by erosion of the mucosal surface.

a rare, rapidly progressing interstitial lung disorder characterized by diffuse and bilateral alveolar damage. patients present with sudden onset of dyspnea and rapid development of respiratory failure. management is supportive and hospitalization and mechanical ventilation are usually required.

inflammation of the lungs due to the inhalation of solid or liquid material.

hypersensitivity granulomatous pneumonitis caused by the inhalation of avian antigens that are present in the dust of the droppings and feathers of many species of birds. in the acute phase it manifests as fever, chills, dyspnea, cough, and chest tightness. chronic exposure may lead to interstitial lung fibrosis.

inflammation of the lungs caused by the inhalation or aspiration of chemicals.

an inflammatory interstitial lung disease caused by hypersensitivity reaction to inhalation or ingestion of antigens. the antigens are usually related to the patient's occupation. it can present as an acute illness with flu-like symptoms, subacute with repeated episodes of pneumonia, or chronic with dyspnea and productive cough. the majority of patients recover following the cessation of the exposure to the antigen that causes the disease. chronic exposure may eventually progress to interstitial lung fibrosis.

interstitial lung fibrosis resulting from chronic hypersensitivity pneumonitis.

asymptomatic; clinical or diagnostic observations only; intervention not indicated

symptomatic; medical intervention indicated; limiting instrumental adl

severe symptoms; limiting self care adl; oxygen indicated

life-threatening respiratory compromise; urgent intervention indicated (e.g., tracheotomy or intubation)

death

evidence of hypersensitivity pneumonitis due to other organic dusts.

evidence of hypersensitivity pneumonitis due to unspecified organic dust.

non-infectious inflammation of the interstitial lung tissue of unknown etiology. this category includes desquamative interstitial pneumonia, usual interstitial pneumonia, lymphocytic interstitial pneumonia, acute interstitial pneumonia, and nonspecific interstitial pneumonia.

inflammation of interstitial lung tissue, usually associated with infection.

interstitial pneumonia characterized by the presence of bibasilar pulmonary interstitial infiltrates composed of lymphocytes and plasma cells. it may be associated with autoimmune and lymphoproliferative disorders. signs and symptoms include fever, cough, and dyspnea. symptomatic patients may require immunosuppressive treatment.

an inflammatory process affecting the lung parenchyma. it is a milder form of lung inflammation compared to pneumonia.

a disorder characterized by inflammation focally or diffusely affecting the lung parenchyma.

pneumonitis that is associated with irradiation.

pneumonitis that does not respond to corticosteroid therapy.

disease caused by the chlamydophila psittaci bacteria, usually transmitted from birds to humans.

References found for this diagnosis code in the External Cause of Injuries Index:

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

ICD-9-CM: 486

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

Pneumonia

What is pneumonia?

Pneumonia is an infection in one or both of your lungs. It causes the air sacs of your lungs to fill up with fluid or pus. Pneumonia can range from mild to severe, depending on what caused it, your age, and your overall health.

What causes pneumonia?

Bacterial, viral, and fungal infections can cause pneumonia.

Bacteria are the most common cause. Bacterial pneumonia can occur on its own. It can also develop after you've had certain viral infections such as a cold or the flu. Several different types of bacteria can cause pneumonia, including:

Viruses that infect the respiratory tract may cause pneumonia. Viral pneumonia is often mild and goes away on its own within a few weeks. But sometimes it is serious enough that you need to get treatment in a hospital. If you have viral pneumonia, you are at risk of also getting bacterial pneumonia. The different viruses that can cause pneumonia include:

Fungal pneumonia is more common in people who have chronic health problems or weakened immune systems. Some of the types include:

Aspiration can also cause pneumonia. It can happen when you aspirate (accidentally breathe in) food or fluid into the lungs. If you are not able to cough out the food or fluid, it may cause an infection.

Who is more likely to develop pneumonia?

Anyone can develop pneumonia, but certain factors can increase your risk:

What are the symptoms of pneumonia?

The symptoms of pneumonia can range from mild to severe and include:

The symptoms can vary for different groups. Newborns and infants may not show any signs of the infection. Others may vomit and have a fever and cough. They might seem sick, with no energy, or be restless.

Older adults and people who have serious illnesses or weak immune systems may have fewer and milder symptoms. They may even have a lower-than-normal temperature. Older adults who have pneumonia sometimes may feel weak or suddenly get confused.

What other problems can pneumonia cause?

Sometimes pneumonia can cause serious complications such as:

How is pneumonia diagnosed?

Sometimes pneumonia can be hard to diagnose. This is because it can cause some of the same symptoms as a cold or the flu. It may take time for you to realize that you have a more serious condition.

To find out if you have pneumonia, your health care provider:

If you are in the hospital, have serious symptoms, are older, or have other health problems, you may also have more tests, such as:

What are the treatments for pneumonia?

Treatment for pneumonia depends on the type of pneumonia, which germ is causing it, and how severe it is:

You may need to be treated in a hospital if your symptoms are severe or if you are at risk for complications. While there, you may get additional treatments. For example, if your blood oxygen level is low, you may receive oxygen therapy.

It may take time to recover from pneumonia. Some people feel better within a week. For other people, it can take a month or more.

Can pneumonia be prevented?

Vaccines can help prevent pneumonia caused by pneumococcal bacteria or the flu virus. Washing your hands often, not smoking, and having a healthy lifestyle may also help prevent pneumonia.

NIH: National Heart, Lung, and Blood Institute

[Learn More in MedlinePlus]