Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in the circulation. IgG molecules are created and released by plasma B cells.

Cytotoxic T cells, once activated, approach the infected cell, insert perforins and release granzymes inducing apoptosis.

Patients with a Quinsy or peritonsillar abscess (PTA) typically present with a history of acute pharyngitis accompanied by tonsillitis and worsening unilateral pharyngeal discomfort. Patients also may experience malaise, fatigue, and headaches. They often present with a fever and asymmetric throat fullness. Associated halitosis, odynophagia, dysphagia, and a hot potato–sounding voice occurs.The presentation may range from acute tonsillitis with unilateral pharyngeal asymmetry to dehydration and sepsis. Most patients have severe pain. Examination of the oral cavity reveals marked erythema, asymmetry of the soft palate, tonsillar exudation, and contralateral displacement of the uvula.Indications for considering the diagnosis of a PTA include the following:Unilateral swelling of the peritonsillar areaUnilateral swelling of the soft palate, with anterior displacement of the ipsilateral tonsilNonresolution of acute tonsillitis, with persistent unilateral tonsillar enlargementA PTA ordinarily is unilateral and located at the superior pole of the affected tonsil, in the supratonsillar fossa. At the level of the supratonsillar fold, the mucosa may appear pale and even show a small pimple. Palpation of the soft palate often reveals an area of fluctuance. Flexible nasopharyngoscopy and laryngoscopy are recommended in patients experiencing airway distress. The laryngoscopy is key to ruling out epiglottitis and supraglottitis, as well as vocal cord pathology.

The preauricular sinus is a benign congenital malformation of the preauricular soft tissues. Mostly it is noted during routine ear, nose and throat examination, though can present as an infected and discharging sinus. Preauricular sinus is more often unilateral, only occasionally are bilateral forms inherited. The right side is more often involved and females more than males. Most sinuses are clinically silent, eventual, however not rare, appearance of symptoms is related to an infectious process. Erythema, swelling, pain and discharge are familiar signs and symptoms of infection. The most common pathogens causing infection are Staphylococcal species and, less frequently Proteus, Streptococcus and Peptococcus species.Courses of treatment typically include the following:- Draining the pus occasionally as it can build up a strong odour- Antibiotics when infection occurs.- Surgical excision is indicated with recurrent fistula infections, preferably after significant healing of the infection. In case of a persistent infection, infection drainage is performed during the excision operation. The operation is generally performed by an appropriately trained specialist surgeon e.g. a otolaryngologist or a specialist General Surgeon.The fistula can be excised as a cosmetic operation even though no infection appeared. The procedure is considered an elective operation in the absence of any associated complications.

Lymphoid organs consist of lymph nodes, the thymus, spleen and tonsils. The thymus is the primary lymphoid organ as it is the organ in which the T cells mature.

Approximately 400 red blood cell group antigens have been described. The ABO group antigens are unusual in that naturally occurring antibodies occur in the plasma of subjects who lack the corresponding antigen, even if they have not been exposed to that antigen previously. The most important of these natural antibodies are anti-A and anti-B, which are usually IgM. Anti-D antibodies don’t occur naturally, and are therefore immune antibodies that result from previous transfusions or pregnancy. Only IgG antibodies are capable of transplacental passage and the most important immune antibody is the Rh antibody, anti-D.

The submandibular glands provide the bulk of salivary secretions contributing close to 70%. The sublingual glands provide 5% and the remainder from the parotid.

This patient has aphonia due to bilateral damage to the recurrent laryngeal nerve. Bilateral recurrent laryngeal nerve (RLN) injury is rare for benign thyroid lesions (0.2%). After extubation-stridor, respiratory distress, aphonia occurs due to the closure of the glottic aperture necessitating immediate intervention and emergency intubation or tracheostomy. Intra-operative identification and preservation of the RLN minimizes the risk of injury. The recurrent laryngeal nerves control all intrinsic muscles of the larynx except for the cricothyroid muscle. These muscles act to open, close, and adjust the tension of the vocal cords, and include the posterior cricoarytenoid muscles, the only muscle to open the vocal cords. The nerves supply muscles on the same side of the body, with the exception of the interarytenoid muscle, which is innervated from both sides.The nerves also carry sensory information from the mucous membranes of the larynx below the lower surface of the vocal fold, as well as sensory, secretory and motor fibres to the cervical segments of the oesophagus and the trachea.

Branchial cleft cysts are congenital anomalies that usually arise from second cleft/pouch, with remnants of the third and fourth pouch are rare. Children are typically born with these congenital lesions; however, they may not be evident for weeks, months, or possibly years. The lesions present as fistulae, cyst, sinus tracts, or cartilaginous remnants due to incomplete obliteration during embryogenesis.They are often asymptomatic, but can often become tender, enlarged, or inflamed with possible abscess formation during episodes of upper respiratory tract infections. The patient can present with purulent drainage of the sinus to skin or pharynx from spontaneous rupture of branchial cleft cyst abscess. The most concerning symptoms include dysphagia, dyspnoea, and stridor due to cyst compression of the upper airway.The physical examination will differ depending on the location of the branchial cleft cyst:- A primary branchial cleft cyst is typically smooth, non-tender, fluctuant mass found between the external auditory canal and submandibular area. It is usually with the parotid gland and facial nerve. Two types of lesions exist. Type 1 is rare and characterized as duplication of the membranous external auditory canal. Type 2 lesions contain both ectoderm and mesoderm elements including cartilage. The patient usually presents with soft tissue mass or draining sinus located on the angle of the mandible or otorrhea, making an otologic exam critical in these cases.- A secondary branchial cleft cyst is located between the lower anterior border of the sternocleidomastoid and the tonsillar fossa of the pharynx. It can be in proximity to the glossopharyngeal and hypoglossal nerve as well as carotid vessels. Compared to the primary branchial cleft cysts, secondary cysts are tender if secondarily inflamed or infected. If it is associated with a sinus tract, a mucoid or purulent discharge may be present on the skin or into the pharynx.The treatment of a branchial cleft cyst is typically elective excision due to the risk of infection or present infection, further enlargement, or malignancy.- Carotid Body Tumour: Painless oropharyngeal or upper anterior triangle of the neck; pulsatile, compressible with a bruit or thrill, mobile from medial to lateral direction.- Bartonella henselae infection is Isolated, mobile, fluctuant, tender, warm, erythematous, > 2 cm near the site of inoculation.- Thyroglossal duct cyst: In the Midline, adjacent to the hyoid bone; rises with deglutition.

The characteristic morphological features of hyaline degeneration is ground-glass, pinking staining cytoplasm with an intact cell membrane. The accumulation of lipids, calcium salts, lipofuscin and an amorphous cytoplasm with an intact cell membrane are all characteristically found in different situations. Pyknotic nucleus and orphan Annie eye nucleus are not seen in hyaline degeneration.