Q fever

What it is

From: Orphanet

Q fever, caused by Coxiella burnetii, is a bacterial zoonosis with a wide clinical spectrum that can be life-threatening and, in some cases, can become chronic.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Granuloma · Very frequent (99-80%)

A compact, organized collection of mature mononuclear phagocytes, which may be but is not necessarily accompanied by accessory features such as necrosis.

Diarrhea · Frequent (79-30%)

Abnormally increased frequency (usually defined as three or more) loose or watery bowel movements a day.

Elevated circulating hepatic transaminase concentration · Frequent (79-30%)

Elevations of the levels of SGOT and SGPT in the serum. SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) are transaminases primarily found in the liver and heart and are released into the bloodstream as the result of liver or heart damage. SGOT and SGPT are used clinically mainly as markers of liver damage.

Elevated erythrocyte sedimentation rate · Frequent (79-30%)

An increased erythrocyte sedimentation rate (ESR). The ESR is a test that measures the distance that erythrocytes have fallen after one hour in a vertical column of anticoagulated blood under the influence of gravity. The ESR is a nonspecific finding. An elevation may indicate inflammation or may be caused by any condition that elevates fibrinogen.

Fatigue · Frequent (79-30%)

A subjective feeling of tiredness characterized by a lack of energy and motivation.

Fever · Frequent (79-30%)

Body temperature elevated above the normal range.

Headache · Frequent (79-30%)

Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve.

Muscle weakness · Frequent (79-30%)

Reduced strength of muscles.

Myalgia · Frequent (79-30%)

Pain in muscle.

Nausea and vomiting · Frequent (79-30%)

Nausea is a commonly encountered symptom that has been defined as an unpleasant painless subjective feeling that one will imminently vomit. Vomiting has been defined as the forceful expulsion of the contents of the stomach, duodenum, or jejunum through the oral cavity. While nausea and vomiting are often thought to exist on a temporal continuum, this is not always the case. There are situations when severe nausea may be present without emesis and less frequently, when emesis may be present without preceding nausea.

Photophobia · Frequent (79-30%)

Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light.

Skin rash · Frequent (79-30%)

A red eruption of the skin.

Splenomegaly · Frequent (79-30%)

Abnormal increased size of the spleen.

Abnormality of the cardiovascular system · Occasional (29-5%)

Any abnormality of the cardiovascular system.

Other findings in the same source

From: Orphanet

Additional reported features include Abnormality of the liver (Occasional (29-5%)); Anemia (Occasional (29-5%)); Anorexia (Occasional (29-5%)); Anticardiolipin IgG antibody positivity (Occasional (29-5%)); Antiphospholipid antibody positivity (Occasional (29-5%)); Arthralgia (Occasional (29-5%)); Cough (Occasional (29-5%)); Depression (Occasional (29-5%)); Elevated circulating C-reactive protein concentration (Occasional (29-5%)); Endocarditis (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

All ages

Inheritance in the source

From: Orphanet

Not applicable

Frequency and the population described

From: Orphanet

Annual incidence: <1 / 1 000 000; United States; Value and class. Annual incidence: 1-9 / 100 000; Australia; Value and class. Annual incidence: 1-9 / 1 000 000; Europe; Value and class. Annual incidence: <1 / 1 000 000; Belgium; Value and class.

Which doctor should you see?

The suggested department for discussing Q fever is Infectious Diseases, with a general physician / infectious disease specialist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which exposure or organism is suspected, and what evidence would confirm it?
• Are precautions, vaccination or advice for close contacts relevant to this infection?
• What should happen if symptoms worsen or do not improve as expected?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Q fever. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.