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What is Peritonsillar abscess and explain in detail?
Peritonsillar abscess (PTA), also known as quinsy, is an accumulation of pus due to an infection behind the tonsil. Symptoms include fever, throat pain, trouble opening the mouth, and a change to the voice. Pain is usually worse on one side. Complications may include blockage of the airway or aspiration pneumonitis.PTA is typically due to infection by a number of types of bacteria. Often it follows streptococcal pharyngitis. They do not typically occur in those who have had a tonsillectomy. Diagnosis is usually based on the symptoms. Medical imaging may be done to rule out complications.Treatment is by removing the pus, antibiotics, sufficient fluids, and pain medication. Steroids may also be useful. Admission to hospital is generally not needed. In the United States about 3 per 10,000 people per year are affected. Young adults are most commonly affected.

Signs and symptoms
Physical signs of a peritonsillar abscess include redness and swelling in the tonsillar area of the affected side and swelling of the jugulodigastric lymph nodes. The uvula may be displaced towards the unaffected side.Unlike tonsillitis, which is more common in children, PTA has a more even age spread, from children to adults. Symptoms start appearing two to eight days before the formation of an abscess. A progressively severe sore throat on one side and pain during swallowing (odynophagia) usually are the earliest symptoms. As the abscess develops, persistent pain in the peritonsillar area, fever, a general sense of feeling unwell, headache, and a distortion of vowels informally known as "hot potato voice" may appear. Neck pain associated with tender, swollen lymph nodes, referred ear pain and foul breath are also common. While these signs may be present in tonsillitis itself, a PTA should be specifically considered if there is limited ability to open the mouth (trismus).

Complications
While most people recover uneventfully, there is a wide range of possible complications. These may include:
Retropharyngeal abscess
Extension of abscess in other deep neck spaces leading to airway compromise (see Ludwigs angina)
Airway obstruction
Aspiration pneumonitis
Lung abscess (following rupture)
Sepsis
Life-threatening hemorrhage (following erosion or septic necrosis into the carotid sheath of the neck)
Glomerulonephritis and rheumatic fever (chronic complications of strep throat)Difficulty swallowing can lead to decreased oral intake and dehydration.

Causes
PTA usually arises as a complication of an untreated or partially treated episode of acute tonsillitis. The infection, in these cases, spreads to the peritonsillar area (peritonsillitis).  This region comprises loose connective tissue and is hence susceptible to formation of an abscess.  PTA can also occur de novo. Both aerobic and anaerobic bacteria can be causative. Commonly involved aerobic pathogens include Streptococcus, Staphylococcus and Haemophilus. The most common anaerobic species include Fusobacterium necrophorum,  Peptostreptococcus, Prevotella species, and Bacteroides.

Diagnosis
Diagnosis is usually based on the symptoms. Medical imaging may be done to rule out complications. Medical imaging may include CT scan, MRI, or ultrasound is also useful in diagnosis.

Treatment
Medical treatment with antibiotics, volume repletion with fluids, and pain medication is usually adequate, although in cases where airway obstruction or systemic sepsis occurs, surgical drainage may be necessary